# Do you really need 1000A?



## Tesseract (Sep 27, 2008)

Lately it seems the mantra here is people want a controller capable of 1000A at 156V+. This is, of course, entirely possible, but if you don't actually need that high current capability, then why pay for it?

If the answer is, "so I'll feel confident the controller will work reliably at 500A", then would you be satisfied with a controller that could deliver a true 500A continuously but with current limiting set for not much more than that (e.g. - 600A)?

I am asking not only because I am developing a motor controller for commercial sale and this is valuable to know ahead of time (why bother making a product no one wants, right?) but also because in researching the various dc motors out there I haven't come across a single one rated to take 1000A. Heck, even the TransWarp11, one of the most brutal motors you can connect to a controller, is only graphed out to 453A (and it delivers a very respectable 135 ft-lbs at that current).

A popular motor for EVs is the 144V ES-31B, and while I can't remember what it's maximum allowable short-term current rating is off the top of my head, I do know that it's "one hour rating" (more or less continuous in this application) is 275A. 

I also should mentioned that the much vaunted Zilla Z1k had a peak current rating of 1000A, but it's continuous current rating was a much more modest 300A.

FYI - my prototype craps out right now after 3 seconds at 1070A, so while I can hit the 1000A target, there isn't much "breathing" room - giving my controller design an honest 1000A current capability will add significantly to the cost (mainly for the inputcapacitors, oddly enough). Given that, I was planning on having the controller reduce the pulse width after 10 cycles at around 700A, which seemed to be more than enough for all non-racing applications (especially since the controller can handle a 240V nominal battery pack as it is).

Finally, it is only when the motor is starting from a stop or a very low RPM that you could even cram that much current down it, so am I correct in assuming that the only good reason to have so high a current limit is to get better acceleration from a stop?


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## Guest (Jan 1, 2009)

Well I actually want 2000 amp peak. Many here would like to have a vehicle that can get up and go when they want or need. If I need to get out of the way real fast my 550 amps won't cut it. Many also are thinking of making an EV that can go to the track and have some fun with the gassers. We may not use that ability often but when we want we have it. I have a vehicle that has way more power than is actually needed but it has come in handy in a few cases and kept me out of trouble. I would have had my vehicle munched if I had not had the power to move fast. Zilla had the controller to die for but most could not afford it. So a controller with a decent price and 1000 amps would be good. I'd settle for 1000 amp controller but I'd prefer 2000 because I want a controller I can take to the track as I plan on building an electric drag buggy. I don't think that the $5k price tag for a 2000 amp controller is really good but I'd pay up to 3K for a good 2000 amp controller. If I had sponsors I may think of a zilla but Oooops they are not being made any longer. OUCH! No one is stepping up to the plate to make one like it. 

Pete : )


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## Jason Lattimer (Dec 27, 2008)

Another question is if it is actually 1000 amps. I've seen a few people that get higher top speed and acceleration out of a 500 amp Curtis than a 1000 amp Kelly.


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## Number 6 (Feb 18, 2008)

Tesseract said:


> Lately it seems the mantra here is people want a controller capable of 1000A at 156V+. This is, of course, entirely possible, but if you don't actually need that high current capability, then why pay for it?
> 
> If the answer is, "so I'll feel confident the controller will work reliably at 500A", then would you be satisfied with a controller that could deliver a true 500A continuously but with current limiting set for not much more than that (e.g. - 600A)?
> 
> ...


I, for one, would love to buy a reliable controller (with a good warranty) with an honest continuous rating of 500 Amps at 144 volts. A peak or limiting current setting of 700-800 Amps would be nice for those occasional highway ramp merging needs, but I'm usually not a traffic-light jackrabbit. Price - about $1500-$1800 tops. Is that economically feasible from a manufacturer's POV, Tesseract?
#6


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## Bowser330 (Jun 15, 2008)

yes we need 700-1000A, and it is for all he reasons already mentioned...from safety margin, to the occassional freeway romp, to the once in awhile jack-rabbit 0-60, to the freeway merge assist, etc...

My advice is this... Make a quality controller (that you guarantee) period...and seeing as there is already a few reliable 144V 500A controllers out there e.g. curtis...you have to differentiate yourself and offer something better (more amps)...

156V x 700A = 109kw (146hp peak)
156V x 800A = 109kw (167hp peak)

156V x 1000A = 156kw (209hp peak)


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## JRP3 (Mar 7, 2008)

The big hole in the market seems to be a controller that can take advantage of the potential of a Warp11. I'd like to do a small pickup truck that can haul a load up a hill or pull a trailer and when unloaded can haul ass from a stop light. 135 ft.lbs at 453 amps isn't going to cut it. If it's a big price difference then 700-800amps peak is probably acceptable in a controller that won't be killed by a Warp11.


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## Jason Lattimer (Dec 27, 2008)

I just received an email from Belktronix. He is going to introduce a package with a 144 volt 800 amp peak controller in the near future.


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## DIYguy (Sep 18, 2008)

Tesseract said:


> Lately it seems the mantra here is people want a controller capable of 1000A at 156V+. This is, of course, entirely possible, but if you don't actually need that high current capability, then why pay for it?
> 
> If the answer is, "so I'll feel confident the controller will work reliably at 500A", then would you be satisfied with a controller that could deliver a true 500A continuously but with current limiting set for not much more than that (e.g. - 600A)?
> 
> ...


It's a really valid question... and perhaps there is no "one" answer. May I suggest some kind of a poll? With the right questions, you may be able to show a graph indicating people's wants/needs/desires. Pick the apex of the bell curve.

I struggled with this question (for a purchase ) for quite a while. The Electrocraft 500 amp unit has 680 amp IGBT capacity. It is suppose to be able to pass about 300 amps continuous and 500 for 30 seconds or so. This is probably adequate for me... however, after much deliberation, I decided that an 800 amp unit (1110 amp IGBT capacity) was what I wanted. 

The issue of "rating" vs "performance" is a big issue. Another is comfort level. Occasional need for higher performance is another. Everyone has their own mental picture of what is ideal.... many of us are trying to come to this conclusion purely based on assumptions and learned theoretical information, without the real world experience. Like many things, there will be evolution in this ideal of course. Again, my hope is that the controller will perform it's primary function very well and very reliably. 

Cheers.


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## Bowser330 (Jun 15, 2008)

Jason Lattimer said:


> I just received an email from Belktronix. He is going to introduce a package with a 144 volt 800 amp peak controller in the near future.


his website says its near ready...


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## Tesseract (Sep 27, 2008)

Bowser330 said:


> yes we need 700-1000A, and it is for all he reasons already mentioned...from safety margin, to the occassional freeway romp, to the once in awhile jack-rabbit 0-60, to the freeway merge assist, etc...


I'm quoting you because you hit all the points I wanted to make in one convenient message - not picking on you, specifically 

Okay... let's keep this very important characteristic of series dc motors in mind: back emf is proportional to rpm and bemf opposes the flow of current (torque) through the motor. In other words, torque (amps) goes down as rpm goes up. Unless the battery pack voltage is a lot higher than the motor voltage you will not be able to get anywhere near the same acceleration from the motor at freeway speeds that you can get from a dead stop (and why complain about this - ICE's behave very similarly).



Bowser330 said:


> My advice is this... Make a quality controller (that you guarantee) period...and seeing as there is already a few reliable 144V 500A controllers out there e.g. curtis...you have to differentiate yourself and offer something better (more amps)...


The impression I have gotten from reading this forum is that there actually _isn't_ a reliable and widely available controller out there capable of 144V/500A. The Curtis 1231C comes closest, but it seems to be choking on the Warp11 and Warp13 motors (i.e. - not reliable). Yes, there are a couple of new contenders out there but since there aren't any user experience reports nor are they widely available (yet?) we should withhold judgment on them for now.

At any rate, once the M.E. gets the motor/load test rig built (hopefully next week) I'll be able to do a more detailed analysis of just how much current one needs and for how long.

I can tell you this, gottdi, the first version won't be capable of 2000A, but it is in the pipeline. Don't hold your breath, though, as it will probably be 6-8 months from now.


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## Guest (Jan 2, 2009)

I can wait for the big controller. I am still doing some testing with my 72 volt controllers anyway. I will be keeping an eye on all new controllers coming to the market. 
Thanks
Pete : )




> I can tell you this, gottdi, the first version won't be capable of 2000A, but it is in the pipeline. Don't hold your breath, though, as it will probably be 6-8 months from now.


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## CPLTECH (Sep 14, 2007)

I agree there is a need for a more robust controller which translates into a higher ampacity unit, but sorry to interject another scenario… Can your batteries withstand such an amp draw and if so, for how long? I chose the 6V/250AH battery to withstand high current, but have not seen data or heard experiences in this regard. As it is, I haul 1400# of these bad boys around & that is like dragging around a half ton of concrete blocks in the bed of an ICE truck, which is no fun whatsoever. The only time the tires ever break traction is when it snows. So if called upon, can my battery supply 3-4 times its rating?

I vote for something in the 800A (400A continuous???) range for assured reliability and for times a daily driver needs to merge into traffic. More than that, I question whether the batteries or their wiring will hold up. Or the bolts holding the motor to the transmission. Just my immediate concerns. Comments welcomed.

PS. Now is the time to build while fuel prices are low. I got mine when prices were moderate & how glad I am.
*Procrastination*
*Procrastination is my sin*
*It brings me naught but sorrow.*
*In fact, I think I’ll try to stop it…*
*But I’ll start tomorrow.*​


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## Bowser330 (Jun 15, 2008)

all depends on the batteries you get...from what ive read the LA batteries can take a high amp draw...so can the AGMs but they lose out because of their lack of AHs..and increased cost...Then come the highpower lifepo4s which are being offered and if have the green then you can play...

From what i have read via the forums is that Curtis 144V 500A is reliable...countless EVs with it and not many problems except for the whining sounds...haha...

The raptor controllers were ok, so Ive read, but they arent being sold to hold 1000amps anymore at 144V.

so the market is here and now for a reliable, guaranteed, powerful controller...


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## dimitri (May 16, 2008)

_



yes we need 700-1000A, and it is for all he reasons already mentioned...from safety margin, to the occassional freeway romp, to the once in awhile jack-rabbit 0-60, to the freeway merge assist, etc...

Click to expand...

_+1 , I want something a little better than Curtis, perhaps 30% more Amps, a little more voltage, minus whine and IGBT instead of MOSFETs. Everything else would be a bonus, but not a must. Low cost is a must, no more than $1500, IMHO.


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## Bowser330 (Jun 15, 2008)

> ...an honest 1000A current capability will add significantly to the cost (mainly for the inputcapacitors, oddly enough). Given that, I was planning on having the controller reduce the pulse width after 10 cycles at around 700A, which seemed to be more than enough for all non-racing applications (especially since the controller can handle a 240V nominal battery pack as it is...


So how much are we talking here? 

Is making 1000A (with cushion) capable with a 1500$ pricetag??

If the controller can handle 240V (from the pack), then does this mean that this controller will be able to dish out higher amps at higher rpm (because it will increase the voltage to the controller as rpm increases)
Reduce the impact of the back-EMF???? as you mentioned before?

Also, would it be possible to make the controller operate at 156V (since the Warp motors are very usable at that voltage) how much would this increase cost?

156V x 700A = 109kw (146hp peak)

with a pack voltage of 240V, and if it could retard some of the back-emf...and you could maintain 700A at higher rpms, say 4000rpm....??

(146hp x 5252)/4000 = 191 ftlbs torque @ 4000rpm (4:1) 60mph...


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## Tesseract (Sep 27, 2008)

Bowser330 said:


> So how much are we talking here?
> 
> Is making 1000A (with cushion) capable with a 1500$ pricetag??


1000A continuously? That is, for more than a thermal-conduction limited time period? No. Or, at least, not and using IGBT modules, enough capacitors to actually meet the required ripple current rating, and providing adequate heat-sinking. I suppose if you cheated, like Curtis, Kelly, et al., and relied on the customer to supply the heat sink, and if you went with discrete IGBTs in parallel (which has its own set of problems as I have discussed elsewhere) and you employed both the temperature and frequency multipliers for the electrolytic capacitors (limiting their life to their max temp rating) you could keep the cost to $1500 and still make *some* profit. Not enough to compel me to make them, and not enough to offset the inevitable warranty aggravation, but you could do it. 

You could certainly homebrew your own 1000A continuous controller for less than $1500 in parts cost, maybe even as low as $400 with careful shopping on eBay, etc., but this is, of course, valuing one's time at $0/hr. 



Bowser330 said:


> If the controller can handle 240V (from the pack), then does this mean that this controller will be able to dish out higher amps at higher rpm (because it will increase the voltage to the controller as rpm increases)
> Reduce the impact of the back-EMF???? as you mentioned before?


Yes. The real reason the Zilla Z1K was such an awesome controller was not that it could dish out 1000A peak for a couple of seconds but that it could do so with a 300V+ battery pack. If you have a 240V battery pack and a 120V rated motor you need only limit the maximum pwm duty cycle to 50% to prevent the motor experiencing an average voltage higher than what it is rated for, but you still get the benefit of that 240V when forcing current through the motor's inductance. Incidentally, this trick is used with stepper motor controllers all the time. *[edit: there is some debate as to whether the peak voltage is important or the rms voltage]*

That said, I still don't think any daily driver EV needs a 1000A peak current rating. 135 ft-lbs of torque at 450A should accelerate most "lead sleds" quite briskly - much more briskly than someone with an eye towards conservation should probably be accelerating, but who am I to judge???

Still, it seems something I've said before bears repeating: *The only time you can use the peak amp output of the controller is when the motor is at 0 rpm - once the motor starts spinning its back emf starts opposing the applied voltage which reduces the maximum amps that can flow!*

I put that in bold not only to be obnoxious but to help hammer this repeatedly-ignored point home. If you want more acceleration on the highway you need more volts. There is, of course, a limit to how many volts you can apply to a motor over and above what it was designed for before the commutator goes up in a ball of plasma (input from Jim Husted would be most welcome now), but I would think that going anywhere from 12V to as much as 48V above a motors rated voltage, while limiting the PWM duty so the motor doesn't "see" more voltage than it is rated for, would give a noticeable boost to the torque available at higher rpms.



Bowser330 said:


> Also, would it be possible to make the controller operate at 156V (since the Warp motors are very usable at that voltage) how much would this increase cost?


It won't increase the cost of my controller design at all. The base version will use a bank of 200V electrolytic caps but 250V electrolytics and, possibly, a special 350V pulse-power-rated film cap will be options.




Bowser330 said:


> ...with a pack voltage of 240V, and if it could retard some of the back-emf...and you could maintain 700A at higher rpms, say 4000rpm....??
> 
> (146hp x 5252)/4000 = 191 ftlbs torque @ 4000rpm (4:1) 60mph...


We really need a motor guy again for this one, but as a rule of thumb you can double the RPM at a given torque by doubling the voltage. I don't of know any motor that can take 700A for more than a second or two but I will ask the technical people at Netgain and Advanced on Monday. FYI - according to the graph for the Transwarp11 it can deliver approx. 140 ft-lbs at 1400 rpm if supplied by 72V and 455A. I imagine, then, you could double the rpm to 2800 if you doubled the supply voltage to 144V. Once again, though, I have to ask why you think you need 140 ft-lbs of torque at highway speeds???

Answer: you have a Need For Speed. Ok, I can appreciate that, but EVs are no different from ICE vehicles in that the faster you want to go the more money it's gonna cost ya.


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## Bowser330 (Jun 15, 2008)

thanks for the reply...

you asking why I (or anyone) would need 140ftlbs at highway speeds is like asking why we have cars that can go over 100mph...hehe


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## enganear (Jun 16, 2008)

I am an ME, not an EE, but I have been involved in combat robotics for a long time. My advice is to google OSMC controller for the work that was done on an open source DC motor controller for robotics that is scaleable to a certain extent. This controller has succesfully powered many robots in a very rough environment. It may not be able to support the parallel switching elements required to support EV levels of current, but there may be some additional information to be learned.
Stephen Chapman


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## Guest (Jan 4, 2009)

The need for speed! No one needs for a daily driver to have 140 lb/ft of torque at hwy speeds but where we need that torque is getting on the freeway. Once at speed we can tone things down. I want speed to also get out of the way if needed. As it is now I have to be extra careful in traffic as I cant accelerate that fast. I really want it to scoot when I say scoot. Not all the time mind you because it becomes wasteful but on the road we need quickness not top speed. So a controller that can give us that 750 amps or 1000 amps or 1200 amps for those needed short bursts or a quick trip down the track if that is what your after is really needed. Any good driver will at some time or another need that quickness to dart out of danger. 

Please bring on the Zilla competition. Others has said that $1500 is what they are willing to pay but if a controller is pumping out that kind of juice and is reliable and able to handle Race track kind of abuse and can live a long time then up to $2500 is not unreasonable. If it can be done for less and I honestly think it can and still give the maker a profit then by all means do the EV community a favor and offer it at a fair market price. Not a bloated market price just because you can. I await a good high voltage controller like the zilla and a high amp rating to boot. And the ability to program different parameters for the needed driving requirement. Kelly said if I burn up a 120v high amp controller at the track they pay for the controller. That's pretty ballsy of them. I honestly think they would. They want a controller of theirs at the track too. I think it is a good thing. 

Pete : )


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## evcars (Mar 15, 2008)

gottdi said:


> Kelly said if I burn up a 120v high amp controller at the track they pay for the controller. That's pretty ballsy of them. I honestly think they would. They want a controller of theirs at the track too. I think it is a good thing.


Don't trust them on that. I seriously doubt they would cover it based on my experiance with them.


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## Bowser330 (Jun 15, 2008)

several threads are talking about how Kelly has dropped the ball...

This market is here for the taking, if someone can just produce a reliable (over-engineered) DC controller similar to the Zilla...


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## Tesseract (Sep 27, 2008)

CPLTECH said:


> I agree there is a need for a more robust controller which translates into a higher ampacity unit...



Weeelllll, sort of. I would argue that accurate and fast current limiting is a better way to make a controller more robust rather than throwing more silicon at it.




CPLTECH said:


> So if called upon, can my battery supply 3-4 times its rating?


Yes - the types of batteries for EV use can typically deliver 5C of current, but you pay for this dearly in greatly reduced run time as a result of the Peukert Effect. Putting it another way, draining your battery pack for a total of 30 seconds at 5C might translate into 5 minutes of run time at the 1C rate.



CPLTECH said:


> I vote for something in the 800A (400A continuous???) range for assured reliability and for times a daily driver needs to merge into traffic...


Well, I will probably set the hard, or immediate, current limit to around 1000A, the "2 second" limit to 750A and the time-averaged, or continuous, limit to 500A with liquid cooling or 250A with air cooling (the heat sink will accomodate both methods). With a 192V battery pack this is more than enough current to deliver sporty performance in a daily driver. It won't win any races at the track (unless the competitor's controllers blow up) but we would actually like to make some money before blowing more on R&D for a product with even more limited commercial appeal.

This is to say, simple economics demands we make a "daily driver" controller first and, quite frankly, argues strongly against wasting any time or money on a racing controller at all since the market for such is *tiny*. I bet Cafe Electric didn't sell more than 10 of their flagship Z2Ks in a year, and, believe me, it took much more than twice as much effort to get that doubled current rating! No, the only reason to make such a controller is for *bragging rights*... We'll go for it, for sure, but we'd like to not go broke first!


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## JRP3 (Mar 7, 2008)

It sounds as if you are on the right track with your design and price target. If you can beat the performance of Curtis by a decent margin and beat the reliability of everyone else you should own the market. Prove your design by hooking it up to something with a Warp11 and not having it blow up in a week or two  Don't let your customers be your beta testers, unless they specifically agree to that. You also don't need as many features as the Zilla which should keep prices down. All those Hairball options may be nice but how much of it is necessary? Keep it simple and strong: KISAS


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## reggiewatson (Jan 4, 2009)

I'm converting my 1974 VW Super Beetle to eletric and have purchased a D&D 31B motor for it. I have been unable to decide on a controller yet because I'm wanting to have smoke the tires ability and dependability. What I need is not the same as what I want. Will 120V 500 amps do it or should I go for the 120V 800-1000 amps? I live in Mountain Home Arkansas and as far as I know there are not a lot of EVs ruuning around here, so I want to educate folks on Evs and I don't want one thats a wimp.


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## JRP3 (Mar 7, 2008)

reggiewatson said:


> I'm converting my 1974 VW Super Beetle to eletric and have purchased a D&D 31B motor for it. I have been unable to decide on a controller yet because I'm wanting to have smoke the tires ability and dependability.


I think that motor may be too small to give tire smoking performance


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## david85 (Nov 12, 2007)

Something that should be mentioned here is that there are a few smaller out fits that I know of that are already planning some sort of controller to fill the void left by kelly and the out dated/overpriced curtis products.

Frankly, there are probably hundreds of different small electronic shops all over the continent that could deliver what we need. The question is who will be the first.

What is encouraging about this is the fact that it seems to be smaller and smaller shops that could end up playing an increasing roll here. I think the future does look bright for us because I predict Tesseract and his employer will have competition.


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## Bowser330 (Jun 15, 2008)

What we also need is to offer selection to customers, and where most will be happy with a "honda" powered electric motor, some of us, many of us, are looking for a "muscle" powered electric motor...

..sort of like this one...

This is what happens when you take the DC motor made for a forklift, open it up, and re-wind it purposefuly for EV use...

Series-wound DC, 4-pole, w/interpole windings
12” diameter, 230 lbs.
400 peak horsepower
8000 rpm maximum
400 volts DC maximum
2000 amps DC maximum
775 ft.-lbs. peak torque

http://www.evconsultinginc.com/34ford.html​


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## Tesseract (Sep 27, 2008)

Muscle cars, racing cars, drag cars - these all fall under what I would call "want" applications. The economics of making a controller for DIY EV conversion dictate that it work in the widest range of applications AND be highly reliable AND be as inexpensive as possible.

Yeah, yeah, I know you speed freaks out there will "need" a bigger, badder controller - I'm one of those speed freaks myself - but for a good performing daily driver _I suspect even 500A would be more than enough but I don't know for sure!_ That's the whole point of this thread - trying to determine if people have actually pumped 500A through the motor in their current EV setup and found it wanting. When I look at the motor performance curves and plug the relevant numbers into the calculations I usually don't exceed 400A, but given the wide range of motors, transmissions, etc., I realize I might be missing something here.

It is very expensive to develop a motor controller because you have to keep blowing them up to find out the true limits of the design and components, burning up hundreds of dollars each time! This is assuming, of course, that you are doing the testing yourself, and not "in the field" (i.e. - relying on your customers  ). Furthermore, you need to test the controller with a range of motors unless you want to find out the hard way that your design chokes on the newest motor from NetGain (e.g. - like the Curtis 1231C when used with a Warp11 or Warp13). Needless to say, at anywhere from $800 to $4000 a pop, buying motors to test out a controller gets pretty expensive pretty quickly, too.

So, to reiterate, I really am trying to determine if people *need* 1000A for a peppy daily driver vehicle or if all this talk about 1000A is more or less a *want*. Ideally, a bunch of you with EVs out there can post what your motor amps are when accelerating from a stop to this thread along with other relevant specs like (estimated) total vehicle weight, motor, overall gear ratio if known, etc... It is knowing this information that will enable controller manufacturers to produce a better-suited product right from the beginning without relying on lots of nasty feedback/crappy reviews from customers, and isn't that what we all want here?


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## dimitri (May 16, 2008)

3800 Lb lead sled including driver and passenger, driven by ADC 9" and Curtis 144V setup. My 400 Amp meter is on motor side. From dead stop if I floor it, ammeter needle jumps to the opposite side and hits the stopper pin such that I can hear it  , my guess it there are 550-600 Amps for a split second. Within 2-3 seconds of acceleration, it falls back to 350-400 Amps even if I keep the "pedal to the metal". Within 5-7 seconds from dead stop I can't push more than 350 Amps even with WOT because RPMs are already high enough. When I shift to next gear and floor it again, it gets to 400-500 for a seconds or two and back to 350 with WOT.

Based on this I would like my next controller to handle 600-800 Amp peak and 400 Amp cont. I don't plan to use motor larger than 9" in my next EV. I don't race, just drive 

Hope this helps.


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## JRP3 (Mar 7, 2008)

Here's an example of changing from a 600 amp Raptor controller to a Zilla 1k in a Jeep Cherokee:
http://driveev.com/jeepev/convpgs/mcontrol2.php#des


> The very first thing that I noticed was that with the Zilla installed, the Zilla and the electric motor *sound* very different than before. From a stop, the motor and Raptor controller used to make sort of a light groaning/whining sound as the motor came up to speed. Not the Zilla. The Zilla and the motor now make this low sort of hissing/blowing air sound from a stop. I've been told that this sound is the result of the Zilla rapidly modulating the PWM switching frequency at low motor speeds, whereas the Raptor controllers have a fixed frequency that doesn't change. But regardless of that, it is really cool to put on the throttle and hear this responsive pssshhhshshhssh sound as you crank up the amps and take off into the night (or whatever ;-). The next things I noticed during my first drive with the Zilla is that my Jeep has a *lot* more power and "punch" now, and that accelerating from a stop is much smoother than it was with the Raptor controller.


Now I don't know what was limiting his performance with the Raptor and he doesn't post any numbers but I doubt he was hitting the 600 amp limit, yet he had a noticeable improvement with the Zilla even though this is not a racer.


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## Georgia Tech (Dec 5, 2008)

Bowser330 said:


> many of us, are looking for a "muscle" powered electric motor...
> http://www.evconsultinginc.com/34ford.html​


 
AMEN!!!!! to this!!!
I think this type of hot rodding is important in advancing this technology and also generating more intrest in EVs in general....


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## Bowser330 (Jun 15, 2008)

the jeep cherokee is an excellent point...

to advance the appeal of the technology we need 1000A, why because thats whats needed to make a 4x4 a respectable EV...and we all know how much people love their trucks and SUVs

plus it helps the smaller cars scoot faster...so it appeals to both customer groups..

The community needs a zilla replacement plain and simple..the company that can provide that power with the best reliability at a decent price will take this growing market...

Look how many DIYers there were 2 years ago compared to now? this industry/market is growing quick...

If Mr. Zilla created the controller to handle 1000A then there must have been good reason? Why question what the market needs/wants/etc when there already was an excellent product with excellent sales on the market to model from????

Additionally, say you feel 1000A is too much...and you feel the market needs less...ok...well how long until the market demands more than what you can offer? This is where I think Otmar got it right...yes, ok, maybe not everyone uses the 1000A, but as soon as they can,(battery technology) they will...

just my 2 cents...no offense meant...just rambling...


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## dogstar74 (Dec 6, 2008)

Isn't it better to have and not need than need and not have? I know it's a waste of power 90% of the time, but that 10% can really get you into trouble. Truthfully, this is why I'd fork out the extra money for the 1000A controller.


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## Jason Lattimer (Dec 27, 2008)

I think 1000 amps or 2000 amps would be fine for a street car. I own a 4000 lbs. Mercury Grand Marquis. 1990 version, boxy, heavy and very big. Last of the big rear drivers. I would love to someday convert this car over to electric so as to last a few generations. My family has owned this car from day one and I plan to own it for a very long time. Unfortunately for a car of this size I will need at least a 1000 amps or more. It is an automatic and would almost have to be direct drive or something.


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## Qer (May 7, 2008)

Tesseract said:


> Well, I will probably set the hard, or immediate, current limit to around 1000A, the "2 second" limit to 750A and the time-averaged, or continuous, limit to 500A with liquid cooling or 250A with air cooling (the heat sink will accomodate both methods).


Hm? You gonna rescale the feedback signal then? 750 Amps gonna be totally out of scale otherwise. And, uh, liquid cooling...?


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## frodus (Apr 12, 2008)

Jason Lattimer said:


> Unfortunately for a car of this size I will need at least a 1000 amps or more. It is an automatic and would almost have to be direct drive or something.


Can I see your calculations? How'd you come up with 1000A for that car?


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## Jason Lattimer (Dec 27, 2008)

I didn't exactly do the math, but the car is huge and weighs 3985 pounds with the 302 it has now. I just assumed that it would pull at least 1000 amps for it to move a car of that size. As I said, It has an auto and the car wasn't exactly designed to be a stick shift.


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## Tesseract (Sep 27, 2008)

dimitri said:


> 3800 Lb lead sled including driver and passenger, driven by ADC 9" and Curtis 144V setup. My 400 Amp meter is on motor side. From dead stop if I floor it, ammeter needle jumps to the opposite side and hits the stopper pin such that I can hear it  , my guess it there are 550-600 Amps for a split second. Within 2-3 seconds of acceleration, it falls back to 350-400 Amps even if I keep the "pedal to the metal". Within 5-7 seconds from dead stop I can't push more than 350 Amps even with WOT because RPMs are already high enough. When I shift to next gear and floor it again, it gets to 400-500 for a seconds or two and back to 350 with WOT.
> 
> Based on this I would like my next controller to handle 600-800 Amp peak and 400 Amp cont. I don't plan to use motor larger than 9" in my next EV. I don't race, just drive
> 
> Hope this helps.



Excellent data, Dimitri. This is exactly the sort of data needed to make informed decisions rather than guessing and "specsmanship" that reminds me a lot of the power claims made by audio amplifier manufacturers.


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## frodus (Apr 12, 2008)

Jason Lattimer said:


> I didn't exactly do the math, but the car is huge and weighs 3985 pounds with the 302 it has now. I just assumed that it would pull at least 1000 amps for it to move a car of that size. As I said, It has an auto and the car wasn't exactly designed to be a stick shift.


So, 1000A just "sounds" about right, but its still only a guess.....just like most of the other opinions on this thread.... 

dimitri's data sounds a LOT more realistic.


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## Jason Lattimer (Dec 27, 2008)

frodus said:


> So, 1000A just "sounds" about right, but its still only a guess.....just like most of the other opinions on this thread....
> 
> dimitri's data sounds a LOT more realistic.


You are comparing a 3800 pound 5 speed car to a 4000 pound automatic, which will tip the scales at 4200 pounds after the conversion. He said he needed 600-800 max for his stick, so 1000 for a direct drive car weighing 400 pounds more is about right.


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## Tesseract (Sep 27, 2008)

Bowser330 said:


> Additionally, say you feel 1000A is too much...and you feel the market needs less...ok...well how long until the market demands more than what you can offer? This is where I think Otmar got it right...yes, ok, maybe not everyone uses the 1000A, but as soon as they can,(battery technology) they will...
> 
> just my 2 cents...no offense meant...just rambling...


No offense taken...

I don't _think_ 1000A is too much, I _suspect_ it is too much. I'm asking for data from people who routinely hit the amp limit AND feel the acceleration is still lacking. So far, I'm not seeing any such data.

Also, please keep in mind the Zilla Z1K could only deliver 1000A for a brief (but unknown?) period of time and only 300A continuously. Maybe a higher peak to average ratio is better, but unless it can deliver the peak rating for seconds I don't see how it could possibly matter.

Finally, can your battery pack handle the abuse? If you are discharging lead-acid batteries at 5C or higher a rate there is a dramatic reduction in capacity. Once again, this is fine for the drag strip but how many drag strip controllers could we sell in one year? Five? Ten? Sorry, but that is not a compelling market to start with.

We need to hear from more Curtis 1231C owners as that controller seems to both work and deliver its rated current...


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## frodus (Apr 12, 2008)

Jason Lattimer said:


> You are comparing a 3800 pound 5 speed car to a 4000 pound automatic, which will tip the scales at 4200 pounds after the conversion. He said he needed 600-800 max for his stick, so 1000 for a direct drive car weighing 400 pounds more is about right.


I'm not actually comparing anything... I'm pointing out you haven't done the torque calculations of what you need to accelerate a 4000lbs lead sled.... Also, you state yours is a 4000lb automatic, then you say its direct drive.... which is it?

I only said his "calculations" were more realistic... whereas yours are all estimated and based on opinion... while they might not be far off in the end, you haven't done the calcs.... 

What motor are you using? It DOES matter .... 300A on one motor may give 75ftlbs, while on another might only give half that. The larger the motor and the larger the surface area on the armature, the more torque you can get out of it (more lbs of copper = more torque, and roughly, lbs of motor = lbs of torque). So if you calculate what torque you'd need to accelerate a 4000lb lead sled to 60mph in xxx seconds, then you could back calculate through the wheel to the gearbox/transmission (you will need gear reduction)... and what you're left with is what torque is required of the motor.... then you can take that, look at several motor choices, and see what amperage the motor actually needs to move that vehicle....and that information is on the torque curve for the motor.

Sounds like you haven't done any of that.... its still just a guess.

And I say this from experience..... 1000A is a LOT of amps... its all about continuous....you might see peak for only a second or two... so is it better to have a 1000A controller that can't dissipate heat and has a 200A continuous rating? or is it better to have 600-700A peak and a 400A continuous rating? If that 1000A is only good for under 2 seconds, and you're accelerating for 10, the other 8 seconds gets current limited, or the controller goes into thermal.... Its not the peak that really matters, its the continuous rating that should be of concern.


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## frodus (Apr 12, 2008)

Tesseract said:


> Also, please keep in mind the Zilla Z1K could only deliver 1000A for a brief (but unknown?) period of time and only 300A continuously.


From the Cafeelectric website....
Maximum motor current at 50°C heatsink temperature: 2000 Amps for Z2K, 1000 Amps for Z1K 
Continuous motor current @ 50°C coolant temp & 100% Duty Cycle: over 600 Amps for Z2K, 300 Amps for Z1K 

sounds like 50 degrees C... so it depends on how well you can keep it cool..... I suspect that the rate of cooling vs rate of heat generation at higher amps would be too low at higher currents... I've heard several seconds for a 1kA controller. If you can't get rid of the heat faster than its generated, that 50degree C heatsink temperature will be fairly quick.


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## Jason Lattimer (Dec 27, 2008)

O.k. I see your point now. Right now I don't plan to convert it. It'd cost too much. But when I do I assume it would have to be direct drive, because at the moment it is still an auto.

Also; is the thermal shutdown why I see so many people saying their 400 amp Curtis will out perform their 800 amp Kelly. If that is true, finding a good controller will be extremely hard not knowing when it will go into thermal overload.


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## frodus (Apr 12, 2008)

Jason Lattimer said:


> O.k. I see your point now. Right now I don't plan to convert it. It'd cost too much. But when I do I assume it would have to be direct drive, because at the moment it is still an auto.
> 
> Also; is the thermal shutdown why I see so many people saying their 400 amp Curtis will out perform their 800 amp Kelly. If that is true, finding a good controller will be extremely hard not knowing when it will go into thermal overload.


You could go direct drive, or get a manual tranny for it... it all depends on the car and how much you're willing to work on converting it. You can use an auto, but sacrifice efficiency.

As far as thermal, it sounds like they rate their controller absolute max part amperage, but cannot dissipate the heat, or there are some sort of limits through the controller. Its unclear what the reasons are.


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## Camaro (Jul 29, 2008)

Tesseract said:


> Well, I will probably set the hard, or immediate, current limit to around 1000A, the "2 second" limit to 750A and the time-averaged, or continuous, limit to 500A with liquid cooling or 250A with air cooling (the heat sink will accomodate both methods). With a 192V battery pack this is more than enough current to deliver sporty performance in a daily driver. It won't win any races at the track (unless the competitor's controllers blow up) but we would actually like to make some money before blowing more on R&D for a product with even more limited commercial appeal.


 
I think your on the right track Tesseract. Do you have a good idea of when your controller might be ready, and maybe a price range? I'm converting/rebuilding a 94 Camaro with a Warp 9, and I'll be ready to buy a controller in a few months. I wouldn't mind beta testing a controller.  I'm not a power engineer but I am an EE. 
 One big factor that was touched on earlier was an ideal controller needs to be programmable. I have an Altrax 400amp programmable controller that I love! If Altrax made a 144v 500amp controller I'd buy it in a heart beat, but they don't. The reason I love it so much is that I made a little interface unit that can talk to it with out a laptop. It was cheap to make and now I can monitor voltage, current, temperature, and program it on the fly. Thus eliminating the need to buy separate voltage, and current meters. Will your controller have a usb or RS232 interface?


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## Qer (May 7, 2008)

Camaro said:


> One big factor that was touched on earlier was an ideal controller needs to be programmable. I have an Altrax 400amp programmable controller that I love! If Altrax made a 144v 500amp controller I'd buy it in a heart beat, but they don't.




I'll steal Tesseracts feedback thread here. What would be the programmable features you want?




Camaro said:


> Will your controller have a usb or RS232 interface?




RS232. What speed is still to be determined but "as fast as possible" is the goal.


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## Camaro (Jul 29, 2008)

Qer said:


> I'll steal Tesseracts feedback thread here. What would be the programmable features you want?


I like the ability to change the max current output, and the throttle response, but what I really like is the ability to monitor the battery voltage, current, controller temperature, and error flags (over voltage, under voltage, max current output, high pedal). Another cool feature of the Altrax controller is the logging ability, but that's not that important to me. 
Are you working on this new controller Qer?


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## Bowser330 (Jun 15, 2008)

dimitri said:


> 3800 Lb lead sled including driver and passenger, driven by ADC 9" and Curtis 144V setup. My 400 Amp meter is on motor side. From dead stop if I floor it, ammeter needle jumps to the opposite side and hits the stopper pin such that I can hear it  , my guess it there are 550-600 Amps for a split second. Within 2-3 seconds of acceleration, it falls back to 350-400 Amps even if I keep the "pedal to the metal". Within 5-7 seconds from dead stop I can't push more than 350 Amps even with WOT because RPMs are already high enough. When I shift to next gear and floor it again, it gets to 400-500 for a seconds or two and back to 350 with WOT.
> 
> Based on this I would like my next controller to handle 600-800 Amp peak and 400 Amp cont. I don't plan to use motor larger than 9" in my next EV. I don't race, just drive
> 
> Hope this helps.


Its a huge help to this discussion.

So tell me something Dimitri....say you changed gears before the amp draw was reduced to 400...say you changed gears while the amps were still nearly max...then you could experience maximum acceleration...right?

I am still learning, and surely the different power profile of the electric motor affects the driving/shifting style...so shifting earlier to experience the max torque is the fastest way to drive a DC EV..no?

Please correct me If i am wrong.


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## Bowser330 (Jun 15, 2008)

Tesseract said:


> No offense taken...
> 
> Finally, can your battery pack handle the abuse? If you are discharging lead-acid batteries at 5C or higher a rate there is a dramatic reduction in capacity. Once again, this is fine for the drag strip but how many drag strip controllers could we sell in one year? Five? Ten? Sorry, but that is not a compelling market to start with.
> 
> We need to hear from more Curtis 1231C owners as that controller seems to both work and deliver its rated current...


We do need to hear from more experienced DIYers about their WOT statistics...

About the max amp draw and the detriment to the batteries...Texoma (in the battery sub forum) is working on a capacitor buffer pack....it cost him a whopping 85$ and hes working on doubling the size to see the further affect on his batteries...This could end up being a really nice hybrid-battery setup where most of the brunt force is absorbed by the hydrostatic caps and the true long range application is from the cool and non-abused battery pack...

Additionally, you make a good point about drawing at 5C all the time and it reducing your battery packs cycle life, however, many people who are talking about the power here in this trhead are not pro-dragsters, they wont, I wont, be drawing 5C on every single acceleration. We just would like the availability too drag off the line, every once in awhile... haha...

In another thread electrocraft is quoting people 1500$ USD for 144V 800A (max) controller, dont know what the continuous is though....so....we look forward to seeing your 1000Amp max for second, 700A, 400 continuous model soon.


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## Qer (May 7, 2008)

Camaro said:


> I like the ability to change the max current output, and the throttle response, but what I really like is the ability to monitor the battery voltage, current, controller temperature, and error flags (over voltage, under voltage, max current output, high pedal). Another cool feature of the Altrax controller is the logging ability, but that's not that important to me.




Duly noted. Can't promise anything since everything has a cost, construction wise, but I'll added it to my list of features, right after built in coffee brewer.



Camaro said:


> Are you working on this new controller Qer?


I'm the sidekick/groupie. 



Bowser330 said:


> So tell me something Dimitri....say you changed gears before the amp draw was reduced to 400...say you changed gears while the amps were still nearly max...then you could experience maximum acceleration...right


Not that simple, I'm afraid (even though my name is not Dimitri). Current through the motor gives torque, voltage over the motor gives RPM and current times voltage gives power. By changing gears your current will surely go up but as the RPM goes down so does the voltage, so the big question is what will the resulting power be?


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## dimitri (May 16, 2008)

> So tell me something Dimitri....say you changed gears before the amp draw was reduced to 400...say you changed gears while the amps were still nearly max...then you could experience maximum acceleration...right?
> 
> I am still learning, and surely the different power profile of the electric motor affects the driving/shifting style...so shifting earlier to experience the max torque is the fastest way to drive a DC EV..no?
> 
> Please correct me If i am wrong.


Like Qer said, when you shift gears RPM drops, so total power drops too if current cannot rise anymore. That is why Curtis is not good for racing EVs. In my list of priorities range goes before acceleration and battery life goes before burning rubber. I design EV to meet my priorities, so I don't actually want a controller that can kill my battery, I'd rather have it limited at 3C-5C to match my battery. Plus, with clutchless coupler I can't shift fast enough to test your theory 

I think the best for controller company is to offer 2-3 models, using same basic boards to minimize production cost, just swap power modules and adjust firmware to produce higher power models at higher cost, everyone wins.


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## garygi (Jan 6, 2009)

My first post but very interested in this thread. Any idea of a timeline for testing one of your new controllers. I'm beginning plans for conversion of my '96 VW Jetta diesel. Getting tired of making veggie diesel for it and my home has solar electric back up so would be cool to charge up car this way. My wife and I already enjoy electric-assist bicycles.


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## CPLTECH (Sep 14, 2007)

garygi said:


> I'm beginning plans for conversion of my '96 VW Jetta diesel. Getting tired of making veggie diesel for it and my home has solar electric back up so would be cool to charge up car this way. My wife and I already enjoy electric-assist bicycles.


Some build an EV for various reasons: Reduce oil dependency, reduce emissions, and reduce vehicle expenses, etc. I see that your Jetta does 2 of these. Are you sure you want to sacrifice a diesel? They are hard to come by these days. Consider another donor vehicle. I speak with fondness since I was a former owner of a Rabbit diesel.


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## Guest (Jan 10, 2009)

If the diesel is dead then by all means do a conversion but if it is still going strong then I'd agree that you should find a donor that has a dead engine. I too own a VW TDI and would never convert this one to electric. I love my diesel and for long drives it is the vehicle of choice. Find a Jetta without a running engine. You should be able to find one for a decent price too. Youre wife would be upset if you needed or wanted to use that diesel again and not have it available. Vegie diesel is a good alternative. I am sure it is quite the job to keep up a decent supply of vegi diesel but I commend your work. Keep it up. 

Pete : )




CPLTECH said:


> Some build an EV for various reasons: Reduce oil dependency, reduce emissions, and reduce vehicle expenses, etc. I see that your Jetta does 2 of these. Are you sure you want to sacrifice a diesel? They are hard to come by these days. Consider another donor vehicle. I speak with fondness since I was a former owner of a Rabbit diesel.


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## Double A (Jan 10, 2009)

I’m new to EV’s; I have my conversion planed already. All I’m waiting for before I start is a reliable controller like zilla. When I was ready to buy, zilla closed shop L 

I think most EV potential users and current EV users want is a car that will get from point A to point B for your daily commute. Keep in mind most car guys & gals that will take the time and energy to build such a vehicle also want the ability to have fun and be safe in the car as well. But if the EV is gutless (can’t get out of the way fast enough in case of an emergency) or get up to speed on the freeway i.e. those short on-ramps. No one will really feel safe in it, there for not many people will build one or buy one. 

If you build a controller that is made of good quality materials and has the bells and whistles like: reliable, programmable, warranted, 1000A (max) 700A, 450-500A continues, 156V (or +), liquid cooled, etc…like most people have posted already, and you have a winner. People like me will buy it. 

I think most people on this forum will understand that the cost is very high creating such equipment, and over time the price of these will go down. I would be willing to spend an extra $500-800 on a controller that is more reliable and better then Curtis, Kelly and all the rest out there. 

Field of Dreams quote-remix
“If you build it, they will buy it”

Just my $.02, I can’t wait to see what you come up with
Double A

I also agree with dimitri:
“I think the best for controller company is to offer 2-3 models, using same basic boards to minimize production cost, just swap power modules and adjust firmware to produce higher power models at higher cost, everyone wins.”


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## garygi (Jan 6, 2009)

I love my diesel and for long drives it is the vehicle of choice. Find a Jetta without a running engine. You should be able to find one for a decent price too. Youre wife would be upset if you needed or wanted to use that diesel again and not have it available. Vegie diesel is a good alternative. I am sure it is quite the job to keep up a decent supply of vegi diesel but I commend your work. Keep it up. 

Pete : )[/QUOTE]

Thank you for the feedback you guys. I would prefer to convert my wife's 2001 Saab 9.5 wagon but she won't let me have it since she loves it for her long drives. I can't see owning 3 cars as 2 is already one too many. But this has got me thinking that maybe one should try and find the most efficient car to convert ie lightest and aerodynamically correct. Ever heard of the eVaro by Fuel Vapor Technologies built near here (White Rock, BC). They claim 135 mpg so far with a range of 250 w/ onboard generator.

To get back to this thread, I agree with DoubleA in waiting for a good controller. Does anyone have even a ball park time frame for one?

Aloha, Gary G


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## Tesseract (Sep 27, 2008)

garygi said:


> ...Ever heard of the eVaro by Fuel Vapor Technologies built near here (White Rock, BC). They claim 135 mpg so far with a range of 250 w/ onboard generator.


They remind me a lot of those "300mpg carburetors" that used to be advertised in the back of Popular Science...

Let's just say, very sketchy sounding.




garygi said:


> Does anyone have even a ball park time frame for one?


That depends on the programmer... ahem...

(First rule of engineering: blame a programmer for budget overruns and schedule slips whenever possible).

I did short-circuit testing of the power section with a block of graphite last week - very cool to see graphite start smoking  . This week I''ll be working on a near-production version of the main power board with current limiting, etc. The programmer and I are still hashing out a few things for the control board but that won't take nearly as long to make as the power board. The ME has a good idea of the heat sink required and should be making some prototypes this week on the CNC (production version will use an extrusion drilled out for liquid cooling). What does all of this mean as far as a time frame? A big fat "dunno", unfortunately. Better to take a little longer than use you guys as our beta testers, though, eh?


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## Qer (May 7, 2008)

Tesseract said:


> (First rule of engineering: blame a programmer for budget overruns and schedule slips whenever possible).


Yeah, I get that a lot at my day time job as well. First you get an outrageous deadline, insane feature demands spiced with absurdly optimistic time-estimations, then, when the shit hits the fan, you're called into a meeting where the Big Guys ask why you didn't meet the deadline that everyone (but me) had agreed upon. And we don't even have a deadline (or Tesseract hasn't bothered to tell me).

*takes a zip of his Vodka and tonic*

Seriously though, I plan to drive a car based on this controller, and is there one thing I've realised as the beard accumulates grey strains is that I'm outta coins and I've been quite unsuccessful in gaining an extra life, so I'm planning on playing with this life as long as I can.

That said, what Tessseract said is that the *hardware* will limit the current to 1000 Amps, but that's the last defense line (he doesn't quite trust software, he's a hardware guy...) before dropping the contactor and nicely ask the driver to hitch-hike home. One of the primary tasks for the software is to make sure the current never stays even close to 1000 Amps for more than maybe a millisecond or so (and only if something extremely unexpected happens), because more than that would be cutting the safety margins a bit too short.

So this controller won't pitch out 1000 Amps. Ever. Sorry, but it's better to kill that misunderstanding before it turns into a well-known fact.


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## Tesseract (Sep 27, 2008)

Double A said:


> If you build a controller that is made of good quality materials and has the bells and whistles like: reliable, programmable, warranted, 1000A (max) 700A, 450-500A continues, 156V (or +), liquid cooled, etc…like most people have posted already, and you have a winner. People like me will buy it...


Just to be clear, the 1000A level will last for a few dozen milliseconds at the most and as far as the controller is concerned it will be in desat at that point and going into shutdown soon after. 750A is the targeted peak *usable* current. That is, you can demand 750A from the controller for approx 2-4 seconds (how long will be determined during thermal testing) as long as the rolling time-weighted average current does not exceed 500A over, say, the last 30 seconds to 2 minutes, depending on the heat sink temperature (which will depend greatly on whether liquid cooling or forced air convection is used).

In other words, the amp rating for a controller is a complex relationship between time, temperature and, yes, current. The hard limit of 1000A that I mentioned in a previous post is not "usable" current because that is the level where the hardware desat detection circuit kicks in, terminating the ON time early and sending a fault flag to the microcontroller. This circuit automatically resets at the next ON time and if the "short" persists it will fault again. If the microcontroller sees enough desat faults in a row it stops the PWM and blinks the idiot light (for now) the gist of which means, "there's something seriously wrong here - cycle power to reset". Since the controller is fast enough to regulate the current as long as there is some motor-like inductance present (once again, something which needs to be tested) the only time the current should exceed the max of 750A is if there is a hard short on the output (ie - a block of graphite simulates that fairly well - a block of copper simulates that perfectly  )

Just wanted to clear that up so there's no misconceptions. That said, my plan from the beginning has been to make the controller "modular and upgradeable". Not "field upgradeable", mind you - that's just asking for trouble..


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## JRP3 (Mar 7, 2008)

The biggest problem I see is that "1000 amp controller" just sounds cooler


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## Qer (May 7, 2008)

JRP3 said:


> The biggest problem I see is that "1000 amp controller" just sounds cooler


Can't argue with that, but my mom told me I shouldn't lie...


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## garygi (Jan 6, 2009)

Tesseract said:


> They remind me a lot of those "300mpg carburetors" that used to be advertised in the back of Popular Science...
> 
> Let's just say, very sketchy sounding.
> 
> ...


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## Qer (May 7, 2008)

garygi said:


> They are developing their own controller as well and plan on a range of 100 to 125 miles on electric with the onboard generator extending that range to 250 miles. I'm hoping to learn more about their new controllers soon and will update this thread.


For the record, what follows is my personal opinions and should not be considered some kind of official statement as a representant yada yada etc etc. You know the drill. 

My personal belief is that there will be a market both for hybrid cars and EV's and that ordinary ICE's will dwindle away in the future. I doubt that EV's will ever be able to replace todays ICE-cars on their own since they will always have the range problem. Even if it's technically possible to get a decent range (even beyond what Tesla claims they have today) and there's battery chemistry that can handle brutally quick charges within minutes or it's possible to construct battery packs that can be replaced on battery stations, I simply don't think it will work for various reasons (primarily infra structure) and there will always be situations when an EV simply won't be up for the task.

But hybrids and EV's will be two different kinds of beasts. Hybrids will have the range and there's not much the EV can do about that, but the hybrids will also have the regulare maintance we know from todays cars and they will also have a shorter range on a charge since the generator will "steal" battery space. For example, these guys claim up to 125 miles on one charge while Tesla Motors claim up to 244 miles on one charge, but after those 244 miles the Roadster is dead while this car can keep going "forever", like an ICE.

I wouldn't be surprised if there will even be different kinds of EV's as well, for example low power short range EV's for city commuting and high power long range EV's for commuting between for example a suburban and a city. After all, we do have different needs and that takes different solutions. Of course, even if hybrids and various kinds of EV's might not compete directly with eachother they will, of course, affect eachother anyway. For example, if Lithium batteries drops in price it might erode the market for low power, low range EV's until they're not profitable to produce anymore.

You could see it as that the ICE is very hard to replace, but personally I see it as that the ICE is a "fit none"-solution that just happens to be enough versatile without being inefficient enough for people to bother. I mean, it IS awfully expensive to run with all it's need for gas, maintance, repairs, decreasing value etc.

For my personal need I would love to have two cars, one high speed, medium range EV for daily use and one hybrid for dog transports and longer road trips (like vacation). We have the same setup today, but with two ICE's. Both ICE's are tailored for their respective task so replacing the commuting car with an EV would be just brilliant, as Gav usually put it.


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## JRP3 (Mar 7, 2008)

One word: *EESTOR  
*But seriously, batteries already exist that can handle fast recharges, Altairnano, A123, maybe others, and there is no technical barrier to high powered recharge stations. Remember, there was a time when there were no gas stations. It's reasonable to assume that battery tech will continue to improve and that a 300-400 mile range is achievable in the next 5-10 years, and a fast charging infrastructure is expanded. I can also see a genset trailer rental business springing up, so that way individuals don't have to deal with ICE maintenance. In the meantime there will be plenty of ICE's and hybrids on the road to take up the slack.


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## garygi (Jan 6, 2009)

Great discussion! And I agree with most of what you all. My current issue (beyond availability of 1000A) in researching the option of converting my Jetta is the time and cost of this conversion whether in this car or a donor versus what is now quickly, and/or possibly, coming out of the pipeline via this $10,000,000 prize in the X-Prize competition. I spent all day yesterday reading various website and watching videos on ways people are "pushing the envelope" to reach the race threshold of a minimum of 100 mpg equival. For instance, check out Aptera.com (EV w/ no drag), mdi.lu (compressed air engines), zeropollutionmotors.us, (US rep. for air cars) and fuelvaporcar.com (electric hybrid w/ super efficient onboard genset). The X-Prize Competition website has many more links (and more to come). I see the potential for exponential growth in various forms of motility when all these new technologies cross pollinate. There is even an inventor in Australia who has spent the past 30 years perfecting his rotary/circular piston engine that runs on compressed air and has virtually no internal friction as a result of the cushion of air. The current version in use in forklift weighs only 35 lbs and he is working on a model that will only weigh 15!
Thanks again for the feedback folks.
Gary in rainy White Rock BC


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## Qer (May 7, 2008)

JRP3 said:


> But seriously, batteries already exist that can handle fast recharges, Altairnano, A123, maybe others, and there is no technical barrier to high powered recharge stations.


The biggest problem I see is that if you have a battery pack on, say, 200 Ah and 150 Volt and you want to charge the car in 10 minutes you'll need to push in 30 kWh in 10 minutes, which means 180 kW or, at 240 Volt, 750 Amps. Oh, and then there's losses added on top of that, let's say there's 10% losses on that (probably very optimistic) then you have 18 kW heat that you have to vent off. Multiply with the amount of "pumps" the station has and it's an awful lot of Amps (and heat) going on.

I don't think it's impossible, but it's damn more complicated than pumping some litres of liquid fuel. Sweden is also a very sparsely populated country with many gas stations out in nowhere so I see a problem with building up an infra structure that can support long range EV's.

But I'm no Oracle, maybe that will be the future. Personally I don't think so, but I've been wrong before.


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## JRP3 (Mar 7, 2008)

We're dragging this thread way off topic here but real quick:


garygi said:


> For instance, check out Aptera.com (EV w/ no drag),


Not true, it's low drag but not "no" drag. Also 3 wheeled and won't sell well.


> mdi.lu (compressed air engines), zeropollutionmotors.us, (US rep. for air cars)


 Inefficient use of electricity and they have never demonstrated anything close to their claimed range. Don't believe all the hype.


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## JRP3 (Mar 7, 2008)

Qer said:


> The biggest problem I see is that if you have a battery pack on, say, 200 Ah and 150 Volt and you want to charge the car in 10 minutes you'll need to push in 30 kWh in 10 minutes, which means 180 kW or, at 240 Volt, 750 Amps.


 I'd imagine fast charge stations with 480 volt service.


> Sweden is also a very sparsely populated country with many gas stations out in nowhere so I see a problem with building up an infra structure that can support long range EV's.


See range extender trailers, or RET's, in my earlier post  But ok, in some cases hybrids may be best. Once the rest of us are tooling around in our BEV's there will be plenty of fuel for you.


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## dogstar74 (Dec 6, 2008)

Another problem that cannot/should not be ignored, is that a future like that would include a transferance of PM10 in the atmosphere to Lead and acid electrolytes in landfills on a massive scale. We may just poison our planet faster trying to save it. I really think that high capacity capacitors will end up being the answer. That's just my vision. 

As for the topic of 1000A necessary. Well probably not. But I prefer a vehicle whose speed is limited by the foot on the pedal, not limited by the hardware and mechanics. That's what will sell people. For some reason, everyone drives little sedans but "needs" a corvette with 600 hp. I guess we've grown accustomed to the compromise with ICEs but refuse to compromise with EVs. I know, it doesn't make sense but that's the truth of it.

Aaron


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## JRP3 (Mar 7, 2008)

dogstar74 said:


> Another problem that cannot/should not be ignored, is that a future like that would include a transferance of PM10 in the atmosphere to Lead and acid electrolytes in landfills on a massive scale. We may just poison our planet faster trying to save it.


I can't believe this is still being brought up. Lead acid batteries are one of the most recycled products in the world because even dead batteries have value. Lithium is non toxic and also has value. Batteries as pollution is a non issue.


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## david85 (Nov 12, 2007)

JRP3 said:


> I can't believe this is still being brought up. Lead acid batteries are one of the most recycled products in the world because even dead batteries have value. Lithium is non toxic and also has value. Batteries as pollution is a non issue.


 
+1 on that.....


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## Bowser330 (Jun 15, 2008)

JRP3 said:


> I can't believe this is still being brought up. Lead acid batteries are one of the most recycled products in the world because even dead batteries have value. Lithium is non toxic and also has value. Batteries as pollution is a non issue.


+1

oil company lobbyist work at its best...


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## Tesseract (Sep 27, 2008)

garygi said:


> I hope you guys are keeping up with developments in the X-Prize competition. (scam,scam, more scam) *I'm hoping to learn more about their new controllers soon and will update this thread. *
> 
> Gary G


No, please don't update this thread, start a new one!

That said, no, we are not keeping up with x-prize. Call us dull and unadventurous but we are only trying to make a quality controller at a reasonable price and are more than happy to let others spend millions on developing an x-prize winner on the slim chance of winning it back.


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## Tesseract (Sep 27, 2008)

dogstar74 said:


> As for the topic of 1000A necessary. Well probably not. But I prefer a vehicle whose speed is limited by the foot on the pedal, not limited by the hardware and mechanics. That's what will sell people. For some reason, everyone drives little sedans but "needs" a corvette with 600 hp. *I guess we've grown accustomed to the compromise with ICEs but refuse to compromise with EVs. I know, it doesn't make sense but that's the truth of it.*
> 
> Aaron


We need a "face buried in his hands" smiley...


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## Qer (May 7, 2008)

Tesseract said:


> We need a "face buried in his hands" smiley...


Or maybe this:


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## yarross (Jan 7, 2009)

Tesseract said:


> If you have a 240V battery pack and a 120V rated motor you need only limit the maximum pwm duty cycle to 50% to prevent the motor experiencing an average voltage higher than what it is rated for, but you still get the benefit of that 240V when forcing current through the motor's inductance. Incidentally, this trick is used with stepper motor controllers all the time.


Using a 240VDC DC bus will expose part of your motor winding to full voltage regardless of PWM duty (except of course 0% duty cycle) unless you add a dU/dt filter (voltage averaging filter) between controller and motor (classic choke and capacitor as in any regular step down converter will do well, but will be bulky and rather expensive). If motor magnet wire insulation is not rated for higher voltage, it will deteriorate soon.


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## frodus (Apr 12, 2008)

it will also really hurt efficiency levels too...


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## Tesseract (Sep 27, 2008)

yarross said:


> Using a 240VDC DC bus will expose part of your motor winding to full voltage regardless of PWM duty (except of course 0% duty cycle) unless you add a dU/dt filter (voltage averaging filter) between controller and motor (classic choke and capacitor as in any regular step down converter will do well, but will be bulky and rather expensive). If motor magnet wire insulation is not rated for higher voltage, it will deteriorate soon.


That is correct. I will edit the original post so as to not perpetuate this mistake. I was under the impression that the commutator was the weak link here and that as long as the average or rms voltage was less than the maximum the peak could be much higher. Of course, the dielectric strength of the insulation comes into play at some point but it is arc-over between the brushes that seems to be the true killer.

_[edit: actually, yaross, you might _not_ be correct - I will ask Warfield motors for some clarification on whether the limit is the result of the insulation or the commutator]_


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## JRP3 (Mar 7, 2008)

So since limiting the PWM still exposes the motor to full pack voltage momentarily, how did the Zilla allow higher voltage packs without damaging the motor?


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## frodus (Apr 12, 2008)

the motors were advanced 10-15 degrees

and they were built for the higher voltage.


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## JRP3 (Mar 7, 2008)

Not sure about that. Any DC motor running more than 48 volts is probably advanced that much, and I think these were motors rated much lower than what they were running. I'll try to find examples, but my impression was you could take a Zilla HV and hook it up to a regular ADC or Warp with a much higher voltage pack but run the motor at a lower setting. Maybe I'm completely wrong, but here's an ADC9 running 240 volts with a Zilla
http://evalbum.com/1638


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## frodus (Apr 12, 2008)

those ADC 9's are built for more than 48V, but are typically run in 48V forklifts. Go to the manufacturer, they have curves for 48, 60, 72, 96V for the same motor. I have a K91-4003 motor and its not advanced, but it runs just fine on 72V but its a 48V motor. If I want to go much past 2x the "voltage" I'd need to potentially advance the brushes to keep from arcing.


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## JRP3 (Mar 7, 2008)

Right but 240 volts? I mean Warps come advanced to around 12 degrees I think but they are rated for 192 volts max. Does an ADC9 only need advancing to handle 240 volts? Seems like we're missing something


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## rmay635703 (Oct 23, 2008)

Tesseract, I guess it appears many folks seem to want a simple bypass contactor.

Far as I know the only way to push anything beyond 1k amps is with a contactor and your motor turning slowly.

I would worry about brushes burning over time but if they need speed I would think a bypass contactor makes more sense and definately would have less resistance than silicon. Also in 1st gear stalled clipping the bypass contactor probably could spin tires if someone really wanted the side effects that go with it.

Also Before anyone says but that would be uncontrolled and might burn the motor, the same is true of anything past 500amps anyway.

Why so many overlook this simple device is beyond me, many gasser cars have a passing gear setup when you press the pedal against the floor, same could be done with a bypass contactor, press to the floor and you will have whatever number of amps your batteries and cabling will allow, which many times is less than 1000amps if the motor is turning.

Ah well, I would just like a controller that has a VERY WIDE operating voltage range without issues AKA 24v-240v would be nice with NO INTERNAL MODIFICATIONS. I like experimenting with different battery configurations and the artificial low and high ranges for controllers irritates me. I would like one that is very flexable and expandable so I don't have to worry about hitting a low or high wall in the voltages accepted. Also if the controller could have a module to allow for PWM charging using the controllers circuitry from right off the wall current that interests me. (why duplicate hardware for charging?)

Also 400amps would be more than enough for me but then again I have the old fogie car and a small micro van neither of which would ever need anything past 500amps ever.

I have a feeling controllers that can accept a very wide range of voltages will become much more usefull if the so called supercaps ever come to fruitition as the discharge curve is linear and transforming power is a pain.


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## Qer (May 7, 2008)

rmay635703 said:


> I would worry about brushes burning over time but if they need speed I would think a bypass contactor makes more sense and definately would have less resistance than silicon. Also in 1st gear stalled clipping the bypass contactor probably could spin tires if someone really wanted the side effects that go with it.


Let me put it this way:

*No way in hell!*

Period.

Tesseract and I are really racking our brains to make a safe and reliable controller where the software and hardware is extremely carefully designed to make sure the IGBT, motor, battery pack and whatsnot is never stressed beyond the safety limits. The main goal has always been to produce a safe and reliable controller aimed for the average driver and his, or hers, commuting needs, nothing else. There's NO WAY we're going to put a bullet in the revolver, spin the cylinder and asking the driver "Do you feel lucky, punk?".

If you add a bypass contactor on your own it's your problem, but there's no way we're going to game with others lifes to add the ability to create some tire smoke just for kicks.


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## Tesseract (Sep 27, 2008)

JRP3 said:


> Right but 240 volts? I mean Warps come advanced to around 12 degrees I think but they are rated for 192 volts max. Does an ADC9 only need advancing to handle 240 volts? Seems like we're missing something


I can sympathize with you, JRP3. I'm supposed to know what I am talking about and even I'm a bit confused at this point. There are at least two factors at work here (maybe a third):

1. commutator arcing - as each commutator segment goes past the brush the interruption in current causes an arc; advancing the brushes reduces this (why is explained elsewhere)

2. wire insulation - frankly, I don't see this being much of an issue since most Class H insulation coatings are good for several kV.

I'm shooting an e-mail off to Warfield/NetGain to try to get the straight dope, so to speak, on this issue.

My "assumption" was that the inductance of the motor would cause the voltage to collapse each switch turn on as the current builds up, and so you could get away with a lot higher supply (ie - pack) voltage than the motor is rated for as long as the switching frequency was high enough relative to the inductance.

I suppose I could always go look at the armature voltage waveform with a scope to get the answer myself... what a concept! Just have to build another controller prototype.


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## customcircuits (Dec 21, 2008)

Along these same lines, why then does the Zilla provide both battery and motor voltage over limits? Shouldn't the motor voltage just be the battery voltage minus the sag. At 240V no amount of sag is going to keep the motor in its recommended operating range.


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## Tesseract (Sep 27, 2008)

rmay635703 said:


> Tesseract, I guess it appears many folks seem to want a simple bypass contactor.
> ...
> Why so many overlook this simple device is beyond me, many gasser cars have a passing gear setup when you press the pedal against the floor, same could be done with a bypass contactor, press to the floor and you will have whatever number of amps your batteries and cabling will allow, which many times is less than 1000amps if the motor is turning.


So you think that totally losing all control over the motor current is a good trade-off for saving a volt or two of conduction loss, huh? And that the rest of us, by implication, are morons for not considering this?

That aside, Peukert effect and the internal resistance of the batteries will rob the motor of a *lot* more voltage than the controller will. A voltage sag of 20V or more is typical when demanding 5C+ from a lead-acid pack.




rmay635703 said:


> Ah well, I would just like a controller that has a VERY WIDE operating voltage range without issues AKA 24v-240v would be nice with NO INTERNAL MODIFICATIONS.


As it so happens, the power and control sides in my controller are totally separate, so you can run it at 5V if you want to. That said, this thread isn't for feature requests.




rmay635703 said:


> Also if the controller could have a module to allow for PWM charging using the controllers circuitry from right off the wall current that interests me. (why duplicate hardware for charging?)


Possible, but it requires access to only the field winding, requires the controller be matched to a specific motor (the charger circuit has to be designed with a specific inductance in mind) and will require several contactors to manage switching all of the high current pathways.

I already have concluded it is actually not much more expensive, but a helluva lot more versatile, to use a separate charger. There actually is not a lot of overlap between a dc motor controller and a switchmode ("PFC") charger. There is with an ac motor controller, but not a dc.


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## Tesseract (Sep 27, 2008)

customcircuits said:


> Along these same lines, why then does the Zilla provide both battery and motor voltage over limits? Shouldn't the motor voltage just be the battery voltage minus the sag. At 240V no amount of sag is going to keep the motor in its recommended operating range.


You ought to be asking Otmar, the Zilla's designer, that question.

Perhaps he has the same (mis)understanding as me? Dunno.


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## yarross (Jan 7, 2009)

Tesseract said:


> You ought to be asking Otmar, the Zilla's designer, that question.


Maybe the answer is that DC motor windings ARE rated for high voltage, much higher than motor rated voltage. Anyway, wire insulation must withstand voltage spikes that are inherent to brush operation. Maybe using switched mode power supply doesn't make things much worse.


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## JRP3 (Mar 7, 2008)

yarross said:


> Maybe the answer is that DC motor windings ARE rated for high voltage, much higher than motor rated voltage. Anyway, wire insulation must withstand voltage spikes that are inherent to brush operation. Maybe using switched mode power supply doesn't make things much worse.


I think that must be the answer. I asked the question on the EVDL:
http://www.nabble.com/How-does-a-Zilla-HV-control-high-pack-voltage-to-the-motor--td21435183.html


> Q. So the Zilla is restricting the PWM which sends an average voltage to the
> motor, doesn't the motor still see full voltage for a microsecond?
> Basically a controller sends full voltage then shuts it off. The averaged
> PWM voltage "looks" like the proper voltage to the motor components and even
> ...


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## JRP3 (Mar 7, 2008)

More debate from the EVDL:


> The motor does not actually see the maximum. The inductance ensures
> that voltage does not rise instantly to the max available but rises
> slowly and the nature of the circuit means the average is really what it
> sees. Besides that the motors insulation is good for 1000's of volts
> ...





> The switch (typically a FET or IGBT) repeatedly
> connects the motor directly to the battery pack, so
> the motor *does* see the full battery pack voltage,
> all controllers do this and only by using a series
> ...





> This is not quite correct. The commutator does NOT see the full pack
> voltage due to the series inductance of the field coils, it sees the
> average. The motor (series inductance plus armature) does see full
> pack voltage every time the switch turns on.


The debate continues, but I guess the bottom line is PWM of higher than motor rated pack voltage works because averaging the voltage is enough to prevent problems. That seemed like the obvious answer but I wanted to be sure how it worked.


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## rmay635703 (Oct 23, 2008)

Qer said:


> Let me put it this way:
> 
> *No way in hell!*
> 
> ...


I agree

I think you missed my sarcasm. My post was intended to dissuad the previous posts saying they would like a 1000-2000amp controller and want to burn rubber. I like you find that to be a foolish goal because you can only safely use 1000amp plus for under a second normally (depending on the motor) and most here seem to be posting like that would be a rescue solution, what can you do in 1 second in regards to accelleration?

Anyway back to the points I actually wanted to discuss at length. Have you considered having a wide voltage range controller available? I didn't explain well in the 1st post but many who are in the process of building an electric vehicle (who seem to be more than those completed) end up with a dillema as to when to buy a set of batteries that will sulphate. The issue is usually there is nothing like hooking up the batteries once everything is doubled checked and doing a basic move around test to see if the guages and everything mechanical functions, but this point usually seems to occur well before the conversion is really road ready or finished in the true sense. Having the abilty to buy just a few batteries and test the car would reduce the cost of initial ownership until that individual gets over the growing pains and finishes the conversion. This is something that the market does lack.

Also in my case I would love to have a wide range controller for testing and for upgradability. The main thing I don't like about my controller is not that it is only 400amp, its that it has a very narrow voltage range and I cannot even install an extra battery or two for a small voltage jump. I also cannot consider moving up to a 144v motor easily because of the controller again.

Sorry if I burnt your feathers, I was just not enjoying the I want to burn rubber statements, I just posted what I figured would be the logical solution for those individuals not for your controller.


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## Tesseract (Sep 27, 2008)

JRP3 said:


> More debate from the EVDL:
> The debate continues, but I guess the bottom line is PWM of higher than motor rated pack voltage works because averaging the voltage is enough to prevent problems. That seemed like the obvious answer but I wanted to be sure how it worked.


I wouldn't close the book on this just yet. Series wound dc motors have inductance, yes, but they are not simple inductors. I'm working on rev. 4 of the power control prototype right now and as soon as I finish it I am going to actually measure the armature voltage on an ES-31B while I ram a couple hundred amps through it...


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## JRP3 (Mar 7, 2008)

I'm still watching the debate, Otmar's chimed in if you haven't been following it.


> On Thu, 1/15/09, Otmar wrote:
> 
> > Don't run with these low current numbers. I
> > plan on much lower
> ...


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## engineer_Bill (Jun 24, 2008)

Just to throw my .02, I personally would like to see a controller on the order of a Zilla 1K. I am currently running a 72V 600Amp controller and would like a little more power. 144V at 800-1000amps sounds perfect to me. I can afford $1500.00 +- $200.00 for an upgrade. I don't need a lot of features, I want a plug and play. being able to easily alter any configurable settings, I.E. throttle response is a plus. I don't mind dip switches if well documented, or a serial port. I thought the Zilla hairball was a little over engineered. I expect this controller would meet most peoples needs whether they know it or not. Like mentioned before in most applications you would draw max 1000amps for only a few seconds, but that few seconds will get you up the ramp and out of trouble. With forced cooling, (liquid removes the heat the fastest), Everything should be cool again before the next light changes. I'm still testing my EV (2000lbs), So I will give hard numbers when I am finished right now it looks like 200amps continous with occasional bursts of 2-3times that will be typical. If I double the voltage I expect these numbers to also double. A second all out controller for the racers would be great, but I don't plan on buying one anytime soon.


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## Technologic (Jul 20, 2008)

engineer_Bill said:


> Just to throw my .02, I personally would like to see a controller on the order of a Zilla 1K. I am currently running a 72V 600Amp controller and would like a little more power. 144V at 800-1000amps sounds perfect to me. I can afford $1500.00 +- $200.00 for an upgrade.


you need a 144,000 watt controller? what on earth for? Even the most inefficient 9000 lb pick up won't need that much continuous capacity. If you decide to do a full on EV semi truck hauling 30,000 lb trailers... maybe.


> I don't need a lot of features, I want a plug and play. being able to easily alter any configurable settings, I.E. throttle response is a plus. I don't mind dip switches if well documented, or a serial port. I thought the Zilla hairball was a little over engineered. I expect this controller would meet most peoples needs whether they know it or not. Like mentioned before in most applications you would draw max 1000amps for only a few seconds, but that few seconds will get you up the ramp and out of trouble. With forced cooling, (liquid removes the heat the fastest), Everything should be cool again before the next light changes.


Unless I'm mistaken most IGBTs and quite a lot of mosfets could handle that amperage (in parallel) briefly.


> I'm still testing my EV (2000lbs), So I will give hard numbers when I am finished right now it looks like 200amps continous with occasional bursts of 2-3times that will be typical. If I double the voltage I expect these numbers to also double. A second all out controller for the racers would be great, but I don't plan on buying one anytime soon.


You expect if you double the voltage your amperage will also double? so you're quadrupling your wattage capacity?

The reason you see high voltage controllers with high amperage is they generally go hand and hand in circuit components, not necessarily in a car.

your amperage draw can be changed by a LARGE amount of variables. Coefficient of drag, gearing of transmission, weight of car, hills, your acceleration habits.

If you were using a CVT transmission I could see your 2000 lb car at most pulling 100amps no matter how hard you pressed on the gas pedal. 1000amps just isn't necessary and is almost a complete waste in my eyes. The marketability of such a large amperage DC motor controller is sooooooo small. I could see a proper engineering design pulling a semi trailer with less amperage draw.

Engineer the car then worry about the electronics I say. Electronics need to be fitting the best design possible, throwing money at a huge amperage controller won't fix the inherent dangers to all electrical components throwing thousands of amps around. Regearing your transmission would be a better use of the money IMO, and you'd see better fuel economy.

A 2 speed manual with a very high gearing and a "cruising gear" could cut down on a large amt of your amperage draw... as well as save battery life from constantly pulling it's max discharge rating


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## Technologic (Jul 20, 2008)

yarross said:


> Anyway, wire insulation must withstand voltage spikes that are inherent to brush operation. Maybe using switched mode power supply doesn't make things much worse.


Even the crappiest kinds of wire insultion for coil building is made for decently high temps and high voltages.

The enamals used (even the very crappy class H types) are rated for 180C temps before shorting is possible. I assume most GOOD motors use some of the higher classes since the wires are generally a whole 1 cent/lb more expensive with class S insulation than class H.
Some motors, at least if I was designing a motor for this kind of religiously small market duty, have nomex layers between the coil winds (upwards of 400C temp insulation).

Even 10 microns of nomex offers a huge electrical resistivity and thermal stability.

*shrugs*


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## Tesseract (Sep 27, 2008)

JRP3 said:


> I'm still watching the debate, Otmar's chimed in if you haven't been following it.


Nah, listservers drive me batty. They are so cumbersome and there's really no excuse to use them anymore. It's about as goofy as running a dial-up BBS these days.




> You got that right, Otmar. Behaves something like a saturable reactor. Inductance is current dependent. Inductance measurements I made years ago were done with high current pulses and calculated from dI/dt. Something you don't see using an inductance meter. _-Jeff M._


Yep - that is precisely what I would expect. As the field and/or armature saturates the inductance will drop off rapidly. This probably also interacts with the vector sum of the induced back EMF from the armature windings energized at that given moment in time...

At this point, it's far easier to just build a damn circuit and test it with a motor


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## Tesseract (Sep 27, 2008)

Technologic said:


> Some motors, at least if I was designing a motor for this kind of religiously small market duty, have nomex layers between the coil winds (upwards of 400C temp insulation).
> 
> Even 10 microns of nomex offers a huge electrical resistivity and thermal stability.
> 
> *shrugs*


There is a downside to thicker insulation: increased leakage inductance, which opposes the flow of current without contributing to the production of torque.

One plus, though, is reduced proximity effect... This mainly comes into play well above 20kHz and/or with multiple winding layers, though, so not much of a concern here.


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## Technologic (Jul 20, 2008)

Tesseract said:


> There is a downside to thicker insulation: increased leakage inductance, which opposes the flow of current without contributing to the production of torque.
> 
> One plus, though, is reduced proximity effect... This mainly comes into play well above 20kHz and/or with multiple winding layers, though, so not much of a concern here.


of course it will have a higher inductance for larger wind spacing (from insulation or otherwise) from my experience though, nomex is basically the same. Class S insulation is about 15-20 microns thick if I recall correctly so a single 40 micron (1.5 mil) sheet of nomex would be identical in spacing. 
Ideally you'd want ot use 3-4 microns of diamond between coil layers ... buuuuuuuuuuuuuuuuuuuuuuuuut


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## JRP3 (Mar 7, 2008)

Tesseract said:


> Nah, listservers drive me batty. They are so cumbersome and there's really no excuse to use them anymore. It's about as goofy as running a dial-up BBS these days.


I agree, but the link I posted http://www.nabble.com/How-does-a-Zilla-HV-control-high-pack-voltage-to-the-motor--to21435183.html
takes you to a forum interface to read the messages and you might want to check it out since it's more up your alley might give you some ideas. You can also post to the list through the forum interface, which is what I do on the few occasions I need to. There are still a lot of people there who have been doing this stuff for a long time. I've tried to convince people a number of times to switch to a full forum, or just migrate over here, but the old timers don't want to do it. One reason I'm so glad this place came about


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## JRP3 (Mar 7, 2008)

Technologic said:


> Even the crappiest kinds of wire insultion for coil building is made for decently high temps and high voltages.
> 
> The enamals used (even the very crappy class H types) are rated for 180C temps before shorting is possible. I assume most GOOD motors use some of the higher classes since the wires are generally a whole 1 cent/lb more expensive with class S insulation than class H.


I think most of the motors we use are class H, other than the specialty builds from Jim Husted and maybe some others.


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## Technologic (Jul 20, 2008)

JRP3 said:


> I think most of the motors we use are class H, other than the specialty builds from Jim Husted and maybe some others.


That seems silly to me, but Class H should still withstand a few thousand volts (at least still resisting arcing from skin effects)... obviously amperage at such a low temp would be more important.

You can "probably" put more than rated voltage if the amperage stays fairly low. I'd just worry about back EMF. Also higher the voltage higher the RF interference... might interfere with other things. Not sure how well motors are shielded.

I need to dig one open one day and see if I can think of a way to make it superconducting


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## JRP3 (Mar 7, 2008)

These motors were intended for 36/48 volt operation, so class H is way more than enough. From what I've read the problems come when higher voltages are put through motors with less than perfect assembly. Small problems that don't show up at 48 volts can be major problems at 144 volts and higher. A little piece of insulation slightly out of place at higher voltage can allow arcing. Net Gain supposedly addresses these issues with their Warps but Jim still found some issues, at least with earlier ones. He notified Net Gain so presumably they are paying more attention to detail.


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## major (Apr 4, 2008)

JRP3 said:


> These motors were intended for 36/48 volt operation, so class H is way more than enough.


Hey JRP3,

Class H insulation refers to the temperature rating. Nothing about the dielectric strength. You'd most likely find that in the UL spec.

Regards,

major


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## Tesseract (Sep 27, 2008)

engineer_Bill said:


> ...Like mentioned before in most applications you would draw max 1000amps for only a few seconds, but that few seconds will get you up the ramp and out of trouble...


The White Zombie in its early years used a 1200A Zilla prototype and smoked the pants off of most of the other ICE muscle cars on the track. And you feel that the average daily driver needs 1000A, huh?




engineer_Bill said:


> I'm still testing my EV (2000lbs), So I will give hard numbers when I am finished right now it looks like 200amps continous with occasional bursts of 2-3times that will be typical. If I double the voltage I expect these numbers to also double....


*sigh* I feel like a broken record... 

You can only extract maximum torque from a series dc motor when it is at 0 to very low RPM. Once the motor is spinning at "cruising speed", typically 2000-3000 RPM, the BEMF severely curtails the maximum current that can flow through it. Doubling the voltage will allow you to double the current, yes, but in the case of the Warp9, for example, you might go from a maximum of 250A at 2500 RPM to 500A. You just won't be able to cram 1000A through that motor if it is spinning at faster than hundred RPM or so unless you apply a voltage to it that significantly exceeds its commutator rating.

Furthermore, by extrapolating from the amps vs. torque curve for the Warp9 it looks like it can deliver around 130 ft-lbs at 750A, which is the current it can safely handle for 2 seconds when accelerating from a stop*. This amount of torque, at 0 rpm, will deliver way better acceleration performance than the original ICE could even dream about. 



* - according to George at NetGain


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## JRP3 (Mar 7, 2008)

major said:


> Hey JRP3,
> 
> Class H insulation refers to the temperature rating. Nothing about the dielectric strength. You'd most likely find that in the UL spec.
> 
> ...


Good point. I made an incorrect assumption they'd go hand in hand but obviously there is no reason for that to be the case.


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## major (Apr 4, 2008)

Tesseract said:


> You just won't be able to cram 1000A through that motor if it is spinning at faster than hundred RPM or so unless you apply a voltage to it that significantly exceeds its commutator rating.


Take a look at post 27, the first link. Mike is able get 1900 amps at 1000 RPM and 1000 amps at 3000 RPM. And I don't think he has smoked his comms yet.

http://www.diyelectriccar.com/forums/showthread.php/electric-crazyhorse-pinto-16474p3.html


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## Tesseract (Sep 27, 2008)

major said:


> Take a look at post 27, the first link. Mike is able get 1900 amps at 1000 RPM and 1000 amps at 3000 RPM. And I don't think he has smoked his comms yet.
> 
> http://www.diyelectriccar.com/forums/showthread.php/electric-crazyhorse-pinto-16474p3.html


Looks like he is using a siamese Warp9/TransWarp9 setup, too, so maybe this isn't the best illustration of the point you were trying to make?


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## major (Apr 4, 2008)

Tesseract said:


> Looks like he is using a siamese Warp9/TransWarp9 setup, too, so maybe this isn't the best illustration of the point you were trying to make?


Hi Tesseract,

When you say 


> Doubling the voltage will allow you to double the current, yes, but in the case of the Warp9, for example, you might go from a maximum of 250A at 2500 RPM to 500A.


you are incorrect. The maximum increase in current at a given RPM is much greater than a direct proportion of increased voltage.

Regards,

major


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## gerd1022 (Jun 9, 2008)

> When you say
> 
> 
> > Doubling the voltage will allow you to double the current, yes, but in the case of the Warp9, for example, you might go from a maximum of 250A at 2500 RPM to 500A.
> ...


Exactly. For a permanent magnet motor, doubling the voltage will allow double the amps at a given RPM, like Tesseract said, but for a field wound motor, this relationship does not hold true.

Major, does increasing the voltage shift the torque speed curve for series wound motors the same way it does for perm magnet motors? In one of my design classes, we studied perm magnet motors in depth, but only touched on field wound motors.


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## engineer_Bill (Jun 24, 2008)

Technologic said:


> Even the crappiest kinds of wire insultion for coil building is made for decently high temps and high voltages.
> 
> The enamals used (even the very crappy class H types) are rated for 180C temps before shorting is possible. I assume most GOOD motors use some of the higher classes since the wires are generally a whole 1 cent/lb more expensive with class S insulation than class H.
> Some motors, at least if I was designing a motor for this kind of religiously small market duty, have nomex layers between the coil winds (upwards of 400C temp insulation).
> ...


Lets drop the wire insulation topic. the way the coils are wound each layer only "see's" a small percentage of the total applied voltage. Adjacent turns will at most have a few tenths of a volt different potential between them. The varnish used in most coil windings has a breakdown in the thousands of volts, unless overheated. I have seen personally even motors with "burnt" windings still operate, (though they ran hot and at reduced power). as even though the insulation was obviously leaking the few ohms of resistance per layer was still an order of magnitude more than the few tenths of an ohm per loop of wire,


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## major (Apr 4, 2008)

gerd1022 said:


> For a permanent magnet motor, doubling the voltage will allow double the amps at a given RPM,


Hi gerd,

This isn't necessarily true. For the DC motor, PM, series or sepex, I = (V-Eg)/R. One has to be careful when dealing with a series motor because Eg is current dependent, but if we're talking about reasonable loads, then Eg won't change much at a particular RPM. So doubling the applied voltage (V), having not changed Eg which was likely close to V, will result in a much higher increase in current (I) than the 2 to 1 ratio of V.

This might not be the case if the starting point is at a very low speed or high load or if the resistance was very high. But that wasn't what he was talking about.

Regards,

major


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## major (Apr 4, 2008)

gerd1022 said:


> does increasing the voltage shift the torque speed curve for series wound motors the same way it does for perm magnet motors?


It is similar.


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## engineer_Bill (Jun 24, 2008)

The theoretical discussion, ("argument"), is nice, but what I understood the original question was are you willing to pay a little extra for a reliable 1000 amp controller, answer YES! Build it, test it, publish the specs, and start taking orders. The ratio of voltage and current depends alot on how the motor is wound, as well as the total load. Yes I have measured that the current drops off real fast as the motor spins up, so what! by that time my car is moving down the road. Let me know when I can buy one. Tessaract asked what is the market hole for controllers, we answered a reliable 1000amp controller with a wide input voltage range. If he doesn't like the answer that is OK, but I'm sticking with it.


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## JRP3 (Mar 7, 2008)

Actually the original question was Do you really need 1000A? which is the title to the thread, and the truthful answer is "no". A reliable 700-800 amp controller is probably good enough for 80%, so that's probably a good place to aim for.
His next controller can hit the magic 1000.


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## Tesseract (Sep 27, 2008)

engineer_Bill said:


> Tessaract asked what is the market hole for controllers, we answered a reliable 1000amp controller with a wide input voltage range. If he doesn't like the answer that is OK, but I'm sticking with it.


Actually, what I asked for was data to support the widely held supposition that 1000A is necessary for the average daily driver... I'm not conducting market research, per se - there is already a thread on that subject so why duplicate it?

If it appears I don't like the answer, it is only because it has not been backed up with any data.

Major, you clearly know quite a bit about dc motors... Have you any data that supports the need for 1000A or more in a daily driver conversion?


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## Technologic (Jul 20, 2008)

major said:


> Take a look at post 27, the first link. Mike is able get 1900 amps at 1000 RPM and 1000 amps at 3000 RPM. And I don't think he has smoked his comms yet.


*rubs eyes*

I think the question is "why?" You can pull any amperage at any RPM (theoretically) with enough voltage, and the wrong gearing. But the idea here, in building EVs anyway, is to cut down on that correct?

High amperage draw means harmed battery life, hot electronics, and peutkert effect.


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## gerd1022 (Jun 9, 2008)

major said:


> Hi gerd,
> 
> This isn't necessarily true. For the DC motor, PM, series or sepex, I = (V-Eg)/R. One has to be careful when dealing with a series motor because Eg is current dependent, but if we're talking about reasonable loads, then Eg won't change much at a particular RPM. So doubling the applied voltage (V), having not changed Eg which was likely close to V, will result in a much higher increase in current (I) than the 2 to 1 ratio of V.
> 
> ...


your correct. I just ran my numbers again. I think i was thinking of the current near or at stall, which would double. 

So i know that for PM motors, Eg is proportional to rotational speed of the motor. Do you know the equation for Eg for series wound motors? Is it possible to get the needed motor constant from manufacturers in order to put together a motor duty curve?


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## major (Apr 4, 2008)

Tesseract said:


> Have you any data that supports the need for 1000A or more in a daily driver conversion?


I'm more of a technical guy than a marketing whiz. But I have a 96 volt Jeep with an 11" motor direct drive and would love to have a good 1000 amp controller for it. Maybe 1500. My take on the diy market is that is all over the place WRT system voltage, GVW, motor size and everything else you can imagine. So, is 1000 amps needed for the average daily driver? If he has a multi-ratio tranny, probably not.

Then you could look at it a different way. The Zilla 1K was the gold standard. But many went with Curtis and others. Why? Cost? Or availability? How much are they willing to spend to get a few second blast? 

But I think Mike's data shows that you can in fact use 1000 amps or higher at high speeds. He sees 1000 amps at 90 mph, I think. But then he's on the drag strip. So it is not just for starts. And also that there are DC motors which can take it. And batteries. Is it abuse? Some would call it that. Others say it is just fun. Maybe the thread should have read "Do you really want 1000A?"

Regards,

major


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## major (Apr 4, 2008)

gerd1022 said:


> Do you know the equation for Eg for series wound motors?


 
Hey gerd,

Eg = K*rotational velocity*flux per pole = K*rad/sec*webers = volts

Tem = K*Ia*flux per pole = K*amps*webers = Newton meters

The motor torque and voltage constants are equal in metric units.

K = (p*N)/(2*pi*a)

Where:
p = # of poles
N = # of conductors
2 = 2
pi = 3.14
a = # of current paths

Equations are the same for all DC motors. Tricky part is that flux varies for the series wound motor whereas is constant for the PM.

Sorry, don't know how to make those fancy Greek symbols in this format. And hope I remembered those equations correctly. All my references are still packed away from the move.

Regards,

major


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## gerd1022 (Jun 9, 2008)

great info. thanks major

i think im going to start a new thread to talk about the characteristics of series motors


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## Bowser330 (Jun 15, 2008)

major said:


> ....Others say it is just fun. Maybe the thread should have read "Do you really want 1000A?"
> 
> Regards,
> 
> major


Amen +1

..


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## MalcolmB (Jun 10, 2008)

> i think im going to start a new thread to talk about the characteristics of series motors


I think a lot of people would appreciate that, including me


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## Tesseract (Sep 27, 2008)

major said:


> ...I have a 96 volt Jeep with an 11" motor direct drive and would love to have a good 1000 amp controller for it....


OK - this is a good example of a setup that would probably benefit from having an honest 1000A or more on tap AND that would be relatively common. Or, at least, more common than a twin Siamese-motor drag racing setup. It would be very useful for all EV'ers to see what sort of current your motor demands while accelerating from a stop.




major said:


> ...Maybe the thread should have read "Do you really want 1000A?"


Nah, there's no point in asking if people *want* 1000A (or more) because, of course, everyone does.

Most of us, though, will have to balance wanting more performance with much more prosaic concerns like not snapping teeth off of gears, not exploding batteries, not igniting fireballs across the commutator every time we accelerate from a stop... You know, basic things like that


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## major (Apr 4, 2008)

Tesseract said:


> It would be very useful for all EV'ers to see what sort of current your motor demands while accelerating from a stop.


Hi Tesseract,

The old eJeep is in need of new batteries. And it is not real well instrumented. Just an analog V and I meter. And besides that, it is like below zero F with a foot of snow. It will be awhile before any testing, but I'll let you know.

The eJeep has the original 1979 controller. A Cableform SCR job. Last it ran, a couple months ago, I think I was seeing 600 or 700 amp on accels, battery current. Seemed like something was following me

Regards,

major


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## grouch (Jan 18, 2009)

I'm in the position of a lot of others: I have no certainty of what I need, yet, only vague ideas of limits based on reading the experiences others have generously shared. Therefore, I can't help Tesseract with real-world data, only a wish list. My intention is to put an approximately 2100 lbs (950 kg) electric vehicle safely amongst other traffic. The plan now is to have a (nominal) 120V system using 10 lead acid batteries and an ADC FB-4001a motor. I am sacrificing some range for responsiveness in handling and acceleration (you can't argue with mass and inertia, only deal with them). 

An ideal controller for me would have these characteristics: 

Rugged -- withstand the vibrations and environments the under hood area of a vehicle endures.
Responsive -- able to handle as much power as the batteries can provide, the motor and wiring can stand, and the go-pedal tries to demand. The controller should protect itself. I don't want the controller acting as a fuse in the system. 
User-friendly --
Physical separation of terminals which should not be shorted. If I drop a wrench, it shouldn't be able to cause a short at the controller. (Maybe terminal barrier strips or placing all (+) terminals at one end and (-) at the other?)
Distinctly different, but standardized, connectors for different functions. (If plugging the throttle pot to the KSI terminal could damage the controller, then the connectors shouldn't be physically compatible).
Data collection -- if a microcontroller is involved, there should be provision for tapping into the inputs and outputs it uses in its processing. (If it's reprogrammable without physically swapping chips, I want the source, too).
 
 

Since this is my first post on diyelectriccar, I may as well add a little rant that can give insight to my choice of pseudonymn. I don't like buying magic black boxes. I pay for quality of R&D, design, manufacture and service. In another discussion on here, there was some criticism of Tesseract by a controller manufacturer for opening, examining and reporting on that controller's design. There was nothing revealed that any inquisitive owner of that controller wouldn't be able to find out. That criticism resulted in adding that manufacturer to my personal, permanent black-list. 

I don't know Tesseract and don't know whether he/she is full of hot air or whether there ever will be a controller resulting from this research, but I appreciate the open discussion, sharing of information, and the hope from the stated intent.


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## Qer (May 7, 2008)

grouch said:


> An ideal controller for me would have these characteristics:
> 
> Rugged -- withstand the vibrations and environments the under hood area of a vehicle endures.
> Responsive -- able to handle as much power as the batteries can provide, the motor and wiring can stand, and the go-pedal tries to demand. The controller should protect itself. I don't want the controller acting as a fuse in the system.


Yep. That's very much what we're trying to do. It should be rugged both in software and hardware and it should shut down if there's any sign of trouble. As I've stated earlier in the thread I'm planning to drive a car with one of these controllers myself (you know, eat your own shit) and I definitely don't want a controller that sets the car on fire, runs off with me or happily BBQ itself to death.

Of course, it's totally impossible to guarantee 100% perfection, but we're aiming for it... 



grouch said:


> User-friendly --
> Physical separation of terminals which should not be shorted. If I drop a wrench, it shouldn't be able to cause a short at the controller. (Maybe terminal barrier strips or placing all (+) terminals at one end and (-) at the other?)
> Distinctly different, but standardized, connectors for different functions. (If plugging the throttle pot to the KSI terminal could damage the controller, then the connectors shouldn't be physically compatible).
> Data collection -- if a microcontroller is involved, there should be provision for tapping into the inputs and outputs it uses in its processing. (If it's reprogrammable without physically swapping chips, I want the source, too).


 All valid points. At the moment I can't promise anything but I like input on what features people like since I'm the guy behind the software in the controller. However, I hate to disappoint you but the source will be closed. I can fully understand your point of view (I'm a Linux and open source-nut myself), but in the grim reality the sales has to pay for all the money and time (and blown prototypes, IGBT's ain't cheap...) we're investing.

Sorry, but that's the reality.



grouch said:


> I don't know Tesseract and don't know whether he/she is full of hot air or whether there ever will be a controller resulting from this research, but I appreciate the open discussion, sharing of information, and the hope from the stated intent.


Well, at least I've seen pictures of the prototypes. 

It's actually quite amazing if you think about it. T and I live on different continents, started to talk to each other through the Internet and all our planning and brain storming has been done over the net (mostly in text, but partly on Skype) and even though we've never met we're actually running this project together, and with good progress too. Who'd thought this was even possible 2 decades ago?

But yeah, Tesseract knows his act. We've had a few prototypes up and running and so far it's looking really good. Loads of work left to do, but we're getting there. Then I "only" have to build a car so I can enjoy using it too...


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## engineer_Bill (Jun 24, 2008)

goodpoints by Grouch. I have another brand controller, and two things I don't like, 1 the smaller flag terminals, are too big for spade lugs, and kinda small for screws. The big flag terminals are two close for a good sized bolt with backing nut. The + and - are 1/2" apart, even with batteries disconnected I accidently shorted the cap bank screwing them on. Tesseract may have a point on current. At 72 volts flooring from a stop with the motor I have I only drew 189amps. So far my top speed is 40MPH, at 60-90 amps. I will try tweaking the controller config and pumping up the tires. I calculated a top speed of 50. If I had to do it again I would use 90 volts or more. (1950lb 2004 Hyundai Accent). It looks like with the Raymond SEP-EX fork lift motor just doesn't draw that much current at 72 volts even in 5th gear.


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## grouch (Jan 18, 2009)

Qer said:


> All valid points. At the moment I can't promise anything but I like input on what features people like since I'm the guy behind the software in the controller. However, I hate to disappoint you but the source will be closed. I can fully understand your point of view (I'm a Linux and open source-nut myself), but in the grim reality the sales has to pay for all the money and time (and blown prototypes, IGBT's ain't cheap...) we're investing.
> 
> Sorry, but that's the reality.


Glad you like input. 

How will closing the source help pay for the investment of R&D? It certainly won't prevent any so-called gray marketer from just cloning your work.

If your code is in firmware, it's essentially a part of the hardware and providing the source to users is not much help to them or you. Changing the code requires replacing a chip and is no different than a user desoldering and replacing some other component -- not a practice a manufacturer generally recommends.

On the other hand, if the device is field reprogrammable, it's a general computing device and providing the source allows you to leverage distributed development -- the cooperation of people who expose the device to conditions you can't anticipate or simulate. Withholding the source eliminates the most meaningful assistance from users while posing insignificant hindrance to ethically challenged (to put it gently) competing manufacturers.


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## Wirecutter (Jul 26, 2007)

grouch said:


> Physical separation of terminals which should not be shorted. If I drop a wrench, it shouldn't be able to cause a short at the controller. (Maybe terminal barrier strips or placing all (+) terminals at one end and (-) at the other?)
> Distinctly different, but standardized, connectors for different functions. (If plugging the throttle pot to the KSI terminal could damage the controller, then the connectors shouldn't be physically compatible).
> Data collection -- if a microcontroller is involved, there should be provision for tapping into the inputs and outputs it uses in its processing. (If it's reprogrammable without physically swapping chips, I want the source, too).


 These are very good points, and I wish I'd brought them up. In Qer's case, while he _may_ be developing on an open-source platform, I can see the case for not making his work open source. It's up to him.

Grouch may have been referring to being able to tweak the code in his controller, but I have another angle on it. Sure, it would be cool for users to be able to code-in their own new features, but that would mean it would have to be at least partially open-source. (or "open API". something) But the controller will probably at least have some user-configurable parameters. Don't require the user (or installer - whatever) to have *special* extra hardware for configuration, a la Sevcon or Navitas. Nicer still - don't require special software. Maybe a serial port with a command line menu tree. (so config is not wedded to a hardware platform or OS)

Another slightly OT contribution from the peanut gallery...

-Mark


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## Qer (May 7, 2008)

grouch said:


> On the other hand, if the device is field reprogrammable, it's a general computing device and providing the source allows you to leverage distributed development -- the cooperation of people who expose the device to conditions you can't anticipate or simulate.


There's the other reason why we won't release the software; safety and legal reasons.

Imagine that a guy, let's call him Joe Average, tinkers around in the open source without really being as skilled as he thinks he is (both you and I know there's loads of Joe A's in the open software community) and without realising it he's introducing a bug that means that the controller actually can lock up in some extreme cases. One day, when Joe A is driving his car as usual, the controller does lock up, the motor revs up without control and he rams right into a bus stop bringing total mayhem among the poor sods that were unfortunate enough to be waiting for the bus at this exact spot this very day.

So what will Joe A tell the cops? That he's a total clutz that fucked up and thus is the one responsible for killing and injuring all those people or that there must be a fault in the controller that made him lose control over his car and that he personally is completely innocent? Who will the lawyers go for? Will they hunt down Joe A, that has an average job, a few bucks on his account and a house the bank has dibs on or will they hunt down the company that builds the controller and probably has more assets that can be converted into cash?

I'm sorry, but if you want an open source controller I'm afraid you'll have to look for another hardware platform. Besides, even if you could convince me (not very likely) it would still not be my decision wether the code should be released or not, so it's not going to happen.


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## Qer (May 7, 2008)

Wirecutter said:


> Don't require the user (or installer - whatever) to have *special* extra hardware for configuration, a la Sevcon or Navitas. Nicer still - don't require special software. Maybe a serial port with a command line menu tree. (so config is not wedded to a hardware platform or OS)


That I can at least give an straight answer to! 

It will be an ordinary serial port and it will talk ordinary 7-bit, no parity, 1 stop bit and English in the interface. Speed is not definitely decided yet, but it might be 115.2 kbit, possibly one or two notches lower if the CPU has a problem handling it when the rest of the software is in place. Flow control will be optional but a full serial cable (ie not only RxD and TxD) will be required. And yes, we'll write a guide for those of you that has started to wonder if these last sentences actually were in English. 

We're thinking about if we'll also offer a special software to make it easier for non-nerds to work with the controller, but that will not be instead of a basic serial console but as a complement for those that prefer a GUI. This is, however, not decided yet (someone has to find the time to do one...).

OS requirement are, with other words, whatever you like as long as the computer has a serial port (natively or through USB) and can handle the speed. You might want to avoid using, for example, an old Atari ST or similar since they might have a problem keeping up with the traffic...


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## grouch (Jan 18, 2009)

Qer said:


> There's the other reason why we won't release the software; safety and legal reasons.
> 
> Imagine that a guy, let's call him Joe Average, tinkers around in the open source without really being as skilled as he thinks he is (both you and I know there's loads of Joe A's in the open software community) and without realising it he's introducing a bug that means that the controller actually can lock up in some extreme cases. One day, when Joe A is driving his car as usual, the controller does lock up, the motor revs up without control and he rams right into a bus stop bringing total mayhem among the poor sods that were unfortunate enough to be waiting for the bus at this exact spot this very day.
> 
> So what will Joe A tell the cops? That he's a total clutz that fucked up and thus is the one responsible for killing and injuring all those people or that there must be a fault in the controller that made him lose control over his car and that he personally is completely innocent? Who will the lawyers go for? Will they hunt down Joe A, that has an average job, a few bucks on his account and a house the bank has dibs on or will they hunt down the company that builds the controller and probably has more assets that can be converted into cash?


Sorry, but that's a strawman argument. First of all, anyone can sue anyone for anything, at least in the US. Closing the source is more likely to attract litigation than opening it. Second, any alteration by Joe A renders the device Joe A's responsibility. By your reasoning, GM is responsible for Ken Norwick's overloaded Saturn. If I saw a ladder into 3 pieces, duct tape the pieces back together in the form of a scaffold, is the ladder manufacturer liable for my resulting broken neck when the thing collapses? 



Qer said:


> I'm sorry, but if you want an open source controller I'm afraid you'll have to look for another hardware platform. Besides, even if you could convince me (not very likely) it would still not be my decision wether the code should be released or not, so it's not going to happen.


Perhaps I will have to look elsewhere in the end, as I've had my fill of manufacturers attempting to create artificial lock-in to their products. (See, for example, the recent legal battles between independent automobile service organizations and car manufacturers. See also, http://www.righttorepair.org ). In the meantime, I can't say for sure that I will be looking elsewhere because of a lack of knowledge of the specifics of your design, and therefore I remain hopeful, especially in light of the quality of information posted here by both you and Tesseract.

If the device can be reprogrammed in the field by just interfacing with it and transferring some downloaded binary blob, it's a general computing device and the only reason for keeping the code secret is to maintain and exert control over the user through creation of a dependence on the manufacturer for any future corrections to the code. Such artificial barriers short-change both the creator(s) and the users by inhibiting advancement. That's a completely different situation from a device purchased with firmware in ROM.

You mentioned Linux, earlier. It may be helpful to note that in 1998, proprietary UNIX systems ran 99.4% of the top 500 supercomputers. By 2003, Linux ran on 36.8% of the top 500 and in the latest list, November, 2008, it runs 87.8%. The proprietary UNIX systems had strict licensing terms limiting access to the code and have been left in the dust.

This is all hypothetical at this point, but what isn't hypothetical is the fact that open source development is a superior model than closed, for both vendors and users. Another thing not hypothetical is that I won't pay for a device that remains under programmatical control of the manufacturer -- that's rental, not ownership. If the manufacturer can reprogram it, I require the ability to see how my device is being altered. Trust is something you do when there is no other choice.


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## Tesseract (Sep 27, 2008)

major said:


> The eJeep has the original 1979 controller. A Cableform SCR job. Last it ran, a couple months ago, I think I was seeing 600 or 700 amp on accels, battery current. Seemed like something was following me


Hehe... "well thar's your problem..." You wouldn't draw nearly as much current if you just unhooked that trailer full of firewood from the jeep, you know... 

Those old Cableform controllers are so bulletproof they make kevlar look like saran wrap. They sure do sing, though, don't they? As old as your's is I bet it runs at 400Hz. Have you replaced the input capacitors (if not... you might want to...)?


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## Qer (May 7, 2008)

grouch said:


> Second, any alteration by Joe A renders the device Joe A's responsibility.


Ah, but open source means that there will be lots of third part people that will run the code as ordinary users (as I run, for example, Gnome and OpenOffice without ever read or verified the code myself) and even if I agree with you that if Bob B runs code created by Joe A it's technically not our fault, there's still the risk that by the time the whole legal mess is sorted out we're out of business. Rumors and bad will aren't necessary fair or well earned...



grouch said:


> If the device can be reprogrammed in the field by just interfacing with it and transferring some downloaded binary blob, it's a general computing device and the only reason for keeping the code secret is to maintain and exert control over the user through creation of a dependence on the manufacturer for any future corrections to the code. Such artificial barriers short-change both the creator(s) and the users by inhibiting advancement.


There is the element of market control, of course, since releasing the source means that anyone can clone the software and hardware, produce it cheaper than us and eventually force us out of the business. But there's also the element of software and development control where we can take full responsibility that the code is properly tested, something we can't if the software is developed by a community.

Technically you're right, this controller is a general computer device, but that's not what the vast majority of our potential customers will buy. They will buy a controller and won't care for anything that can't be read in "Users manual", many of them might not even read beyond the chapters "Getting started" and "How to connect the controller". After that it is our hope they'll be busy driving and grinning.

That it's running software in a small computer doesn't really matter. Except for a small minority the average user will see the controller as a box with terminals that run their motor and that's what we're going to sell. To them it doesn't matter if the control is done in soft- or hardware as long as it works.



grouch said:


> The proprietary UNIX systems had strict licensing terms limiting access to the code and have been left in the dust.


Yes, I'm fully aware of the Linux history since I've been running Linux since -96. It's also irrelevant for this discussion. A desktop computer, or a server, is a multi purpose device with various tasks and where the software is constantly improved, changed, fixed after people's needs and a constant movement towards extended functionality. There's no limit, except imaginagion, to what a PC can do.

This is a motor controller, it's main task is to run a DC-motor. It won't do your spread sheets, surf the web or help you in your various daily tasks (except driving your EV, of course), it will run your DC-motor, period. There's no UNIX-style license in the controller because we're not selling an operating system, we're selling a motor controller aimed at vehicles. It's like a modern micro wave oven; you're not buying a computer, you're buying a device that will heat your food. That more or less all micro wave ovens today have a small computer inside doesn't really turn them into a PC...



grouch said:


> This is all hypothetical at this point, but what isn't hypothetical is the fact that open source development is a superior model than closed, for both vendors and users.


If we're talking ordinary computers (ie PC's) I generally agree (although even though the community has tried hard for over 10 years to improve the situation, the sound support in Linux still SUCK!), but in this specific case I don't see how a community would improve the code quality.



grouch said:


> Another thing not hypothetical is that I won't pay for a device that remains under programmatical control of the manufacturer -- that's rental, not ownership.


That's utter bullshit. Our controller will be yours as much as, for example, a Curtis-controller will be yours after you've paid for it. The only difference is that the controller can be improved without it demanding you send it back to us for an upgrade, but it's definitely YOUR controller.

This is not Solaris, HP-UX or Microsoft Windows where the license has tons of paragraphs and situations where the selling part can void the license if you break any of the agreements, the only thing you can do is void the warrant, as you can with more or less anything you buy if you're not following the specifications (like exceeding the input Voltage).



grouch said:


> If the manufacturer can reprogram it, I require the ability to see how my device is being altered.


If you're not happy with us, you can do as Linus Torvalds; DO something about it! There's nothing that stops you (or anyone else) to build a controller that's completely open and where the community is developing hard- and software together. Carpe Diem, go for it, blow some IGBT's and get your hands dirty, have fun! It's a free market!

You can be the motor controller version of Linux if you like, we're more aiming at being the Macintosh.


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## Tesseract (Sep 27, 2008)

grouch said:


> Perhaps I will have to look elsewhere in the end, as I've had my fill of manufacturers attempting to create artificial lock-in to their products....


You need not look far for your open source controller. Mark Hanson released the schematic and code for one to the public domain here: 

http://www.evdl.org/lib/mh/index.html


One other thing: until you contribute substantially to the development and/or funding of this controller you do not have even the slimmest of claims to its source code, much less the justification for the swaggering sense of entitlement you've displayed thus far.

Now, if you have any motor amperage data to report, by all means continue posting. If not, please take your rant somewhere else.


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## JRP3 (Mar 7, 2008)

I guarantee 99% of us don't give a crap about the source code, just give us a powerful controller that doesn't break and has some settings that can easily be adjusted.


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## dimitri (May 16, 2008)

Qer,

please do not waste your valuable time on trolls and get back to that controller software


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## Qer (May 7, 2008)

dimitri said:


> Qer,
> 
> please do not waste your valuable time on trolls and get back to that controller software


**laugh**

Ok, but not tonight. Tonight I'm going out on dinner with my colleges on my daytime job. However, I promise I'll work hard during the weekend to make up for that slacking.


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## Bowser330 (Jun 15, 2008)

JRP3 said:


> I guarantee 99% of us don't give a crap about the source code, just give us a powerful controller that doesn't break and has some settings that can easily be adjusted.


+1 for powerful, reliable, guaranteed controller...

...and lets try to keep the forum/community a little less chippy shall we...we are here to help one another and help the industry as a whole..I agree with Dimitri, please focus on producing the much needed controller as it is in the best interest of everyone...

Looking forward to your product Tesserect/Qer, do you have a timeline for release? quarter/year?


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## david85 (Nov 12, 2007)

I agree too. Open source is a nice idea, but if the controller works well and is reliable, I don't care what is going on inside. The less I know the better LOL.


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## Qer (May 7, 2008)

Bowser330 said:


> Looking forward to your product Tesserect/Qer, do you have a timeline for release? quarter/year?


Definitely 2009. 

Seriously, we're making progress but not as fast as we might've liked. It's as usual, you try to determine the complexity of the problem and do an estimation of how long it could possible take to solve it, then you find out that it's much harder than expected, that you've been seriously optimistic when the plans were laid out and that you totally forgot that you need this and that too.

But the prototype has been up and running, software and hardware, and been able to run some serious current without blowing up. If this would've been a DIY-controller I'd guess that we'd be out driving and grinning by now, but since we actually want to sell this thing and don't want components to shake loose or having to recompile the software to change parameters there's some "packaging" left to do.

In the "packaging" is also included minor details, like, for example, safety, and of course then there's testing, testing, testing followed by field test and some more field test to make sure there's no serious flaws that could cause accidents or that we won't get back 90% of them on warrant issues. So don't expect to be able to start buying the controller in a week or so just because we've been able to run it in a shop...

But we're getting there!


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## Tesseract (Sep 27, 2008)

JRP3 said:


> I think that must be the answer. I asked the question on the EVDL:
> http://www.nabble.com/How-does-a-Zilla-HV-control-high-pack-voltage-to-the-motor--td21435183.html


I finally, and with great reluctance, joined the EVDL and posted what I found concerning this question. Cor van de Water was correct: the armature sees about 95% of the applied voltage. Whether limiting the PWM duty cycle will actually protect the motor from experiencing whatever faults occur during overvoltage remains to be determined. While I am hell-on-wheels when it comes to the electronics here, I admit I am not nearly so knowledgeable about the motors themselves.


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## TheSGC (Nov 15, 2007)

I really would like to see this controller when it's done. At the end of the day, I too would like to see affordable reliable controllers. 

Anyways, I have a suggestion on testing them: Do your own testing, and then have a "Beta Program" that would allow others with an EV to test the controllers for a few weeks. It would provide you with 



 More realistic info because ever EV is different (i.e. car vs truck, 96 volts vs 144 volts, etc.)
Quick reports on how everyday people would installed it and set it up
And major brownie points
You could have a list of people who have EVs and want to test your controller, and then select a bunch with different EV specs from around the country to get Real World Data. 

As for the subject of Open Source Code, I personally prefer that the code the runs my car NOT be Open Source. I don't want to have the slimmest chance that some dohdoh made a "change" to the software that turns my EV into a runaway missle. While I am a Unix/Linux user, Open Source to me means "Way Too Easy to Screw With".


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## engineer_Bill (Jun 24, 2008)

I don't need open source either, just a serial port to configure min max current, voltage, and throttle type would be fine. If anyone wants to get more involved than that they can design their own.


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## Tesseract (Sep 27, 2008)

*Warning - actual data in this post!*

I did some motor amp testing yesterday with a Kelly KDH14500 in a 96V system, an ES-31B motor in a vehicle of approx. 1800lb GVWR. I used a B&K 369B AC/DC clamp meter that has a max hold function. I clamped it onto one of the motor cables, reset the max hold and had the driver floor the accelerator with the vehicle in second gear while I observed. The tires chirped and acceleration was definitely snappy - certainly comparable to a sporty ICE vehicle. The max current after each run averaged 420A (range of 415-435).

One thing that really impressed me was how much zip you can get out of that ES-31B... a fairly small motor by EV standards. Perhaps having neutrally timed brushes and being wound for 144V is the reason?


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## JRP3 (Mar 7, 2008)

Tesseract said:


> *Warning - actual data in this post!*
> 
> I did some motor amp testing yesterday with a Kelly KDH14500 in a 96V system, an ES-31B motor in a vehicle of approx. 1800lb GVWR. I used a B&K 369B AC/DC clamp meter that has a max hold function. I clamped it onto one of the motor cables, reset the max hold and had the driver floor the accelerator with the vehicle in second gear while I observed. The tires chirped and acceleration was definitely snappy - certainly comparable to a sporty ICE vehicle. The max current after each run averaged 420A (range of 415-435).


 I would extrapolate this to mean much higher current in a heavier vehicle, suggesting the 500 amp Curtis is not enough but 700 or so probably would be.


> One thing that really impressed me was how much zip you can get out of that ES-31B... a fairly small motor by EV standards. Perhaps having neutrally timed brushes and being wound for 144V is the reason?


I do believe neutral brush timing provides greater torque, does the winding negate the need for brush advancement at 144V?


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## Bowser330 (Jun 15, 2008)

Tesseract said:


> *Warning - actual data in this post!*
> 
> I did some motor amp testing yesterday with a Kelly KDH14500 in a 96V system, an ES-31B motor in a vehicle of approx. 1800lb GVWR. I used a B&K 369B AC/DC clamp meter that has a max hold function. I clamped it onto one of the motor cables, reset the max hold and had the driver floor the accelerator with the vehicle in second gear while I observed. The tires chirped and acceleration was definitely snappy - certainly comparable to a sporty ICE vehicle. The max current after each run averaged 420A (range of 415-435).
> 
> One thing that really impressed me was how much zip you can get out of that ES-31B... a fairly small motor by EV standards. Perhaps having neutrally timed brushes and being wound for 144V is the reason?


Can you define "zip" and "snappy" a bit more please...comparable to sporty ICE vehicles? Mazda miatas can do 0-60 in 5 seconds, is that what youre comparing too? "sporty ice"


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## Qer (May 7, 2008)

Bowser330 said:


> Can you define "zip" and "snappy" a bit more please...comparable to sporty ICE vehicles? Mazda miatas can do 0-60 in 5 seconds, is that what youre comparing too? "sporty ice"


The term "zip" and "snappy" are indeed tricky terms to concretize and thus dangerous to use in a technical discussion. There is also the element of environmental effect on the result. For example, a controller, such as this, that is good for 750 Ampere peak will of course move a Beetle filled with LiFePO4 incredibly faster than a Chevrolet S-10 loaded down with lead. Other things, like cabling, gearing, motor etc, will of course also have a general affection to the "snappyness" of the vehicle in question. From that perspective it's of course hard to tell if our controller will be "zippier" than your example of an ICE-driven Miata without knowing what kind of vehicle you're planning on converting. Will it be a motorcycle or a Sherman tank? A VW Golf or a VAN? Will you lead it down for range or not? Will it be powered by a Warp 11 or some old truck motor you found in a scrap yard? Direct drive, automatic gear box or manual? Etc etc etc.

All these parameters will together probably affect the acceleration more than the actual amount of current pumped out of the controller. However it is our firm belief that 750 Ampere will be enough for average commuting and even leave some room for some "zip" and "snap". In fact, we've conducted a very thorough market research to make sure that our product will be in pair with some of the finest EV-products ever produced and I can proudly guarantee that our controller will be snappier than many market leading brands such as this:

http://shorl.com/bopritrereprogri

I hope this will answer your question in a satisfying way and if you have additional questions, don't hesitate to ask so that we can provide yet another adequate answer that will fill your need for information.

Regards

/Qer (Carpe et diam)


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## david85 (Nov 12, 2007)

Qer, just my thoughts so take it for what its worth.

My gut tells me that 750 amps is ahead of what is available right now, but you might be supprised to see how quickly competition can close such a small gap. I don't think paying for extra performance with a motor controller is as likely to be dismissed as say, more expensive batteries. The reason being that a controller is not a wear item and as such is a one time investment. When thought of that way, a slightly higher price is not as unreasonable since many home conversions end up being upgraded later on.


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## JRP3 (Mar 7, 2008)

Qer said:


> In fact, we've conducted a very thorough market research to make sure that our product will be in pair with some of the finest EV-products ever produced and I can proudly guarantee that our controller will be snappier than many market leading brands such as this:
> 
> http://shorl.com/bopritrereprogri


I assume you're referring to this model, and that is indeed impressive, I can't wait! 
http://en.wikipedia.org/wiki/Detroit_Electric#Partnership_with_Proton
http://paultan.org/archives/2008/09/02/driven-detroit-electrics-electric-lotus-elise/


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## Qer (May 7, 2008)

david85 said:


> My gut tells me that 750 amps is ahead of what is available right now, but you might be supprised to see how quickly competition can close such a small gap. I don't think paying for extra performance with a motor controller is as likely to be dismissed as say, more expensive batteries.


Oh, I definitely agree, but both you and I know that many DIY'ers usually look at every single dollar they spend during the conversion and one of the things that I repeatedly have heard in this forum is how expensive every part is. Not that I don't agree, converting a car into an EV is expensive and an investment that usually will take a while to pay itself back (like most big investments).

At the moment there's a sweet spot at 750 Amps that we're hoping will be attractive for the average DIY'ers. It's not a number Tesseract has pulled out of a hat, there's very good reasons for why the controller specs looks exactly as they do and one of the reasons is, of course, price. It would be quite possible to put a noticeable bigger number berfore the capital A, but that would also mean a noticeable bigger number behind the $-sign on the price tag and considering there's many EV-owners that are quite content with, for example, their Curtis controllers I think such a controller wouldn't be attractive for most people. And of course, more Amps in the controller means that the motor and battery pack will have to handle it too which means even more dollars...

That said my personal wish is that this controller won't be the end of this little adventure. On the contrary I personally hope that this is just the beginning of a very fun, and interesting, ride and that Tesseract and I will have the opportunity to provide more shiny toys to all you DIY'ers out there. But this first controller is meant to be pretty basic and is strictly aimed at the average DIY'er that just want an EV that he, or she, can commute with, that works and keeps working without catching fire or creating havoc in general.


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## Qer (May 7, 2008)

JRP3 said:


> I assume you're referring to this model, and that is indeed impressive, I can't wait!


Actually, I was more referring to the more classy version...


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## Tesseract (Sep 27, 2008)

Bowser330 said:


> Can you define "zip" and "snappy" a bit more please...comparable to sporty ICE vehicles? Mazda miatas can do 0-60 in 5 seconds, is that what youre comparing too? "sporty ice"


Sorry, no - I used imprecise language rather than hard data simply because I didn't have hard data. This was informal testing done on a public street and it was only in one gear. The whole point was to see the peak current on acceleration and if said current could cause the tires to break loose from the pavement. The peak current was ~420A and the tires did break loose every time. What would more amperage get you at that point? Spinning tires, would be my guess.

Also, the latest gen. Miata accelerates from 0-60 in 6.5s, not 5s.


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## JRP3 (Mar 7, 2008)

Tesseract said:


> The peak current was ~420A and the tires did break loose every time. What would more amperage get you at that point? Spinning tires, would be my guess.


Or the ability to move a heavier vehicle quickly. It doesn't take a lot to break the tires on a Miata and most conversions come in much heavier. That being said, a reliable 750 amp controller will take over the market. The latest revisions of Logisystems still seem to be blowing up: http://www.diyelectriccar.com/forums/showthread.php/logisystems-latest-repairs-26010.html


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## david85 (Nov 12, 2007)

Words cannot describe how critical reliability is when you consider all the melting controllers out there. Its sad to think that after all these years, the humble curtis is still the best one that is available right now. In that respect, you will not be able to hold pace with demand if your controller proves to be reliable. Not sure if the projected price tag has been discussed yet.


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## Qer (May 7, 2008)

david85 said:


> Its sad to think that after all these years, the humble curtis is still the best one that is available right now.


Yep. Before I got involved in this wild ride Zilla was the way I'd planned to go and only reluctantly did I accept that it would have to be Curtis instead. As far as I know Zilla and Curtis are still the two brands that has the best reputation and I really don't like when things break down, gasser or not...



david85 said:


> In that respect, you will not be able to hold pace with demand if your controller proves to be reliable. Not sure if the projected price tag has been discussed yet.


Neither definite release date nor price is decided yet (as far as I know), partly because that even if we've been able to run the controller at serious current and it's more or less fit to run a car now we're still not quite happy with how some of the components behave. They're not quite enough to satisfy our demands, and we're quite picky. 

After all, the major design goals for us are safety and reliability. This controller would never be developed if it weren't for what you stated yourself, that right now Curtis is the only controller in the market that has a genuine reputation and the Curtis is a bit yesterday. Safety and reliability are also the reasons why you won't see this controller push higher current than 750 Amps. The IGBT is capable to do a bit more (we know, we've tried it) but that also means it's getting awfully close to blowing up (we know, we've tried that too)...

But we're getting there. Eventually.


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## Tesseract (Sep 27, 2008)

JRP3 said:


> Or the ability to move a heavier vehicle quickly. It doesn't take a lot to break the tires on a Miata and most conversions come in much heavier. That being said, a reliable 750 amp controller will take over the market. The latest revisions of Logisystems still seem to be blowing up: http://www.diyelectriccar.com/forums/showthread.php/logisystems-latest-repairs-26010.html


Yeah, the problems Logisystems are having with their controllers are a real bummer. While this may seem to be a weird thing for an eventual competitor to say - their loss, my gain, right? - my take is that spectacular failures of any component used in an EV only serve to reinforce the (generally correct) perception by the public that EVs are nowhere close to being viable.

Anyway, excellent point about more amps being able to move a heavier vehicle quickly. Might I argue the converse, though, in that the heavier the vehicle the less suited it is for conversion? Our informal testing, combined with a survey of the motors and controllers currently available (and proven to work), makes a pretty strong case for a controller capable of delivering 500A continuous and 750A for 2 seconds being more than enough for most conversions up to around 3000lb curb weight. If the conversion weighs more than that, and/or faster acceleration is needed, then you might want to wait for the 1000A/1500A controller we will eventually roll out. Finally, if you are looking to smoke the White Zombie or the Current Eliminator V on the track then you might want to hold out even longer for the 2000A/3000A version...


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## Tesseract (Sep 27, 2008)

david85 said:


> Words cannot describe how critical reliability is when you consider all the melting controllers out there. Its sad to think that after all these years, the humble curtis is still the best one that is available right now. In that respect, you will not be able to hold pace with demand if your controller proves to be reliable. Not sure if the projected price tag has been discussed yet.


Reliability is definitely the most crucial "feature" for a controller... It really doesn't matter what the claimed specs are if the controller catches on fire or only makes it 800 miles or what have you.

As for the projected price of our controller... well, we haven't even nailed down all of the components, much less the labor cost to assemble everything, so it would be tough to even hazard a guess on price at this point! 

That said, we are aiming for the void in the market left by Cafe Electric's exit. Our goal is make a controller every bit as reliable as the Z1K, with a similar feature set (programmable, data collection, built-in heat sink, etc.), and, we hope, at a comparable or better price given the difference in peak current capability. Going by the peak current metric alone, a "fair" price for our 750A controller would be $2000 (75% of $2675). Even though I don't know exactly what components were used in the Z1K, I have seen pics of its guts and from those I am reasonably sure our parts cost will be far higher. However, our labor cost will be far lower, and it is the cost of labor that is the real Achilles heel of manufacturing in America.

Now, I don't know about the rest of you, but I generally don't mind paying more money for better components (and better engineering); paying more for a product because it took longer to put together, though, is not exactly a compelling argument...


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## dwarasim (May 22, 2008)

This is just my option, so please take it with a grain of salt.
I'm looking to do my first EV conversion and have been doing some research. Now, the 750amp controller will be a good fit for my conversion plans (120v - 144v system) with GVW of estimated 3000lbs. A price tag over $1,500 will have me consider Curtis 1231c or 1221c at the lower price and with the reliablity, but not the extra amperage. Is it possible to put together a bare-bone 750amp controller that can just be installed and without any modification from the user at a cheaper price (120v - 144v plug-n-play barebone system)?
Thanks


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## 280z1975 (Oct 2, 2008)

Tesseract,

I've been reading this thread for a while and thought I would finally put in my 2 cetns.

The proposed 750 peak/500 continuous controller is the most appealing to this (be it at the moment) niche market. It will fit my needs later in the year when I start my build and I will be surly glad to purchase one (even at the 2000 ballpark). I'd pay, some others won't (at first), but when their cheaper controllers die, they will end up switching (assuming your controller proves as reliable as you have claimed, which is fully expect it to do).

I even think there is a definate market for it to be used in mass-produced econo-box type electric cars. If you applied a cheap DC motor system, 100ah LIFEPO batts and a decent light weight shell of a car, you could have a 100+ mile all Electric car for under 15,000 purchase price easy.

-Gregg-


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## JRP3 (Mar 7, 2008)

Tesseract said:


> That said, we are aiming for the void in the market left by Cafe Electric's exit. Our goal is make a controller every bit as reliable as the Z1K, with a similar feature set (programmable, data collection, built-in heat sink, etc.), and, we hope, at a comparable or better price given the difference in peak current capability. Going by the peak current metric alone, a "fair" price for our 750A controller would be $2000 (75% of $2675). Even though I don't know exactly what components were used in the Z1K, I have seen pics of its guts and from those I am reasonably sure our parts cost will be far higher. However, our labor cost will be far lower, and it is the cost of labor that is the real Achilles heel of manufacturing in America.


Certainly you'll have to price your products where you can make a fair profit for your work. For a fair comparison though unless you are building your controller to go significantly higher than 156 volts, (which I don't think you are), then you need to compare it with a Zilla 1K LV, (Low Voltage), which I believe came in just under $2000
http://www.grassrootsev.com/control.htm 
Obviously that's old data since they aren't in production any longer but I believe those prices were valid a few months ago.


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## Qer (May 7, 2008)

JRP3 said:


> For a fair comparison though unless you are building your controller to go significantly higher than 156 volts, (which I don't think you are),


Oh yes, we are! 

It'll land somewhere between the LV- and HV-grading of the Zilla and even though I'm not entirely sure what the maximum Voltage will be in the end everything points at that it'll definitely be noticeably above 156. It'll be the capacitors that decide in the end and since that part of the controller isn't entirely settled (just almost) it's still a number that might change.

But yes, we are. Most definitely.


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## JRP3 (Mar 7, 2008)

Interesting, that's new information I believe  Will the controller be able to limit pack voltage to the motor like a Zilla, so you could have say a 216 volt pack and set the controller to limit the motor voltage to 156, or won't you be going that high?


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## david85 (Nov 12, 2007)

That changes things a little. I assumed that 750 peak and 500 constant would be in the 156V range. If you are going past 200 volts, then the amp rating is adiquate.

156 x 750 = *117 kw* peak power, but...

at 200 volts (for the sake of argument)

200 x 750 = *150 kw* peak power (same as the ACP's system)

156 x 1000 = *156 kw*, so you are already in the butter zone at 200 volts so there is no point going past 1000 amps.

You've done your research


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## Qer (May 7, 2008)

JRP3 said:


> Interesting, that's new information I believe  Will the controller be able to limit pack voltage to the motor like a Zilla, so you could have say a 216 volt pack and set the controller to limit the motor voltage to 156, or won't you be going that high?


That's the plan, yes. However (and this is a BIG however) Tesseract has tried to find out how much that will affect the motor (as you probably are aware of) and so far there's been almost as much answers as there's people replying so we haven't been able to come to a conclusion.

On the other hand, it works for White Zombie. On the third hand, they've blown up a few motors too so maybe it's not something you should do if you want to be sure to reach your destination. 

But the plan is that the software will support it, yes. After all, it's pretty easy. Just calculate maximum allowed duration for the PWM and never pass that value...


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## Tesseract (Sep 27, 2008)

JRP3 said:


> Interesting, that's new information I believe  Will the controller be able to limit pack voltage to the motor like a Zilla, so you could have say a 216 volt pack and set the controller to limit the motor voltage to 156, or won't you be going that high?


The maximum voltage rating of the controller hasn't been detemined yet, but it will be north of 200V. I will say that the 600V IGBT certainly isn't the limiting factor... 

There is a provision in the controller code to limit the maximum duty cycle when the battery voltage is higher than the motor rated voltage, we just aren't sure whether that will actually protect the motor or not. The folks at NetGain seem pretty sure that it doesn't matter if the voltage applied to the motor is chopped or not - 192V is the absolute maximum (170V strongly recommended). I scoped the waveform across just the armature and field during the last round of controller testing and can confirm that the armature does, indeed, see virtually all of the battery voltage. That said, others seem to feel that the true voltage limitation is arcing from the commutator segments to the brushes and that because the voltage from a PWM chopper goes to zero dozens to hundreds of times for each commutator segment as it rolls past a brush that this prevents a fireball from occurring. Otmar saw fit to include this in the Zilla, and it is certainly easy enough for us to keep it in our controller, but we will remove it if it proves to only provide a false sense of security... Unfortunately, I suspect the only way we'll get to the bottom of this is to set up a high speed camera to watch the commutator/brush interface and compare what happens when DC versus chopped DC of the same average voltage is applied. High speed cameras aren't cheap, but this is an important question so if we can't rent time on one we'll probably eventually buy on... and if it turns out we need to change the code, well, that's when being able to download and install firmware updates yourself will come in real handy


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## Qer (May 7, 2008)

Tesseract said:


> and if it turns out we need to change the code, well, that's when being able to download and install firmware updates yourself will come in real handy


Mmm. Another part of the code I'll have to finish eventually. It was trickier than expected (as most of the software for this project ) but, well, it SHOULD work.


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## piotrsko (Dec 9, 2007)

hmmm 400 amps is kinda like 55hp in a bug. My bug wasn't all that fast, but it got the job done, usually on 35 hp. what in the world would I do with 750 peak?? {actually: don't ask}

Hmmm: modular voltage, addressable current, *DIY* software upgrades.

my $.02 HOW COME THE BLOODY THING ISN"T DONE YET????? I'm turning blue waiting, holding my breath.

Do I want one?? DUH, especially if it works as advertised. The threads lead me to believe that this will outperform the Zilla, which is kinda hard to come by anymore.

Hope the business model will support estimated production/demand; and I'll be really pissed off if you guys sell out to GM or Mobile oil.


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## JRP3 (Mar 7, 2008)

Tesseract said:


> There is a provision in the controller code to limit the maximum duty cycle when the battery voltage is higher than the motor rated voltage, we just aren't sure whether that will actually protect the motor or not. The folks at NetGain seem pretty sure that it doesn't matter if the voltage applied to the motor is chopped or not - 192V is the absolute maximum (170V strongly recommended).


A quick search of the evalbum under cafe electric controllers shows a good number of EV's using more than 200 volts, though I saw at least one who did blow up a motor, not sure of the reason. It might be worth your while to search through that and try to contact everyone running a high voltage setup and see what their long term results were. If more than a couple had motors blow that might show a general problem with running high voltage.


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## Qer (May 7, 2008)

piotrsko said:


> The threads lead me to believe that this will outperform the Zilla, which is kinda hard to come by anymore.


Na, let's not exaggerate. Depending on how you look at it we might be more or less in pair with the Zilla 1k, but I wouldn't say we will outperform it. True, our controller will have a continuous current that is 500 (if it's properly cooled) instead of 350 (I believe?) but the Zilla has 1000 Ampere peak where ours will most likely make 750 (just adding a slight reservation here since it's still in prototype state ).

The Zilla series of controllers are still a damn fine breed and it will yet take some time before they're outperformed (especially the 2k). I expect that we will continue to see a lot of Zillas powering DIY-cars for several years to come, probably outliving their initial cars, even if noone ever picks up the production again. That's what you get when you pay some extra bucks for genuine quality.


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## Tesseract (Sep 27, 2008)

JRP3 said:


> A quick search of the evalbum under cafe electric controllers shows a good number of EV's using more than 200 volts, though I saw at least one who did blow up a motor, not sure of the reason. It might be worth your while to search through that and try to contact everyone running a high voltage setup and see what their long term results were. If more than a couple had motors blow that might show a general problem with running high voltage.


Excellent idea... I am doing that same search now. Hmm... seems a lot of these folks have only racked up a couple hundred miles or less on their high voltage EVs.

Alternatively, Qer and I were discussing this and we both found a Casio digital camera at the same time that can shoot up to 1000fps for $600. Given the disparity of opinion on the EVDL (btw - have my two posts on that stupid list shown up? (Jeffrey Jenkins)) I might not be satisfied with any "theoretical" answers from anyone until I've seen the slo-mo footage of a commutator blazing away.

Eye candy attached:


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## JRP3 (Mar 7, 2008)

Tesseract said:


> Excellent idea... I am doing that same search now. Hmm... seems a lot of these folks have only racked up a couple hundred miles or less on their high voltage EVs.


 Remember many of those postings have been on there for a few years and haven't been updated. I'd concentrate on the ones with lower album numbers. I'm evalbum.com/1609 and added about a year ago, for reference.



> (btw - have my two posts on that stupid list shown up? (Jeffrey Jenkins))


Weird thing is I'm sure I read your first post on the list, worded slightly differently, responding to Cor van de Water, but now it's gone and the second one is there. Yeah that list is annoying but hard to beat for experienced EV'ers.
http://www.nabble.com/Re:-How-does-a-Zilla-HV-control-high-pack-voltage-tothemotor--p21659033.html


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## JRP3 (Mar 7, 2008)

> Otmar reported that the commutator seems to respond the same
> whether the voltage applied to it was pure DC or a PWM'ed average.
> George at NetGain seems to think that the upper voltage limit applies
> regardless. These are two very compelling authorities... more data
> are needed, apparently...


Has George taken actual measurements or is he going by theory? He may error on the side of caution to protect his motors, which is not a bad thing. I assume he would have tried running a motor at higher voltage to see what happened. I know I would if I ran a motor factory


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## Tesseract (Sep 27, 2008)

piotrsko said:


> my $.02 HOW COME THE BLOODY THING ISN"T DONE YET????? I'm turning blue waiting, holding my breath.


What can I say... everything takes twice as long and costs twice as much as expected... 

Actually, the power section is pretty much fully functional - the eye candy pic in another post shows the prototype pumping 679A into a block of graphite (at 195V input) - but we want to do substantially more testing before releasing this beast upon the public. Let's just say that we have learned from the mistakes of others in this business... 




piotrsko said:


> ...Hope the business model will support estimated production/demand; and I'll be really pissed off if you guys sell out to GM or Mobile oil.


Learning from the mistakes of others, once again, one of the main design objectives for this controller is to minimize the amount of labor to put it together. Not only does this shift the bulk of the cost over to the parts and engineering (which is "good") but it also means a small operation such as ours will be better able to keep up with demand (compared to a design that, for example, requires laborious hand-matching of dozens of IGBTs).

As far as selling out to some big corporation, well... let's just say if we were greedy we probably wouldn't be making products for EV's... 

We expect to make a decent profit from each controller - don't get me wrong, we are capitalists and this is America, after all (excluding our token socialist/programmer, Qer) - but one thing that really torques me, and I am not a conspiracy theorist, is Chevron buying up Ovonics large format NiMH technology and then pretty much sitting on it... Let's just say that ain't gonna happen.


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## Qer (May 7, 2008)

Tesseract said:


> ...socialist/programmer, Qer...


I strongly object! If I'm a socialist then G W Bush is an environmentalist. 

Bah.

Now, the programmer part can be discussed.


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## Wirecutter (Jul 26, 2007)

Tesseract said:


> What can I say... everything takes twice as long and costs twice as much as expected...


Actually, there's a not-quite-asymptotic formula that would describe the time function. Basically it works out that the last 1% takes 99% of the time.


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## mattW (Sep 14, 2007)

The other advantages of having higher voltage is that it makes two motors in series a possibility. 200+V on one motor is almost definitely overkill but having two 120V motors in series with 750 amps might be an option for those seeking more power. I think you guys are putting your controller in exactly the right market segment. The bottom end (<500A) is pretty crowded and the top end would get a lot less sales. As well as making the controller as reliable as possible it would probably be worth making the controller as idiot proof as possible too. Its hard to work out some times whether some blow ups/failures are flaws in the controller or just too much being in the hands of complete newbie DIYers. I see you are already heading that way with the inbuilt cooling. 

Also I don't know if you have seen this yet but Ian from ZEVA.com.au had been developing a controller with similar stats but has decided he wants to study more before doing it. Luckily for you he has documented a lot of the developtment here.


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## Qer (May 7, 2008)

mattW said:


> As well as making the controller as reliable as possible it would probably be worth making the controller as idiot proof as possible too.


We're trying to, the problem is that there's so many ways you can screw up. 

However, among the things the controller already does is, for example, that it refuses to start the PWM if throttle is applied at power on. This is, of course, to avoid that the car lurches forward when the contactor switches on in case there's a problem with the throttle wires.

I believe that at least someone of the current manufacturers do the same (but I don't remember which one) so it's not like it's really ingenious or unique or so, it rather feels like common sense. 

_Edit: Yeah, yeah, it seems this was fairly more common (read: standard feature) than I thought. At least I gave Tesseract a good laugh and a huge opportunity to tease me for it. I'll never hear the end of it..._



mattW said:


> Also I don't know if you have seen this yet but Ian from ZEVA.com.au had been developing a controller with similar stats but has decided he wants to study more before doing it. Luckily for you he has documented a lot of the developtment here.


Very nice build indeed. Although he's based his build on a bank of MOSFET's where Tesseract went for the IGBT instead. You can probably debate cons and pros of either until the forum database overflows, but it's pretty different roads.

Still, very nice read and he's done a beautiful job. I hope he gets it working, would be a shame if all that work was for nothing.


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## Tesseract (Sep 27, 2008)

mattW said:


> The other advantages of having higher voltage is that it makes two motors in series a possibility. 200+V on one motor is almost definitely overkill but having two 120V motors in series with 750 amps might be an option for those seeking more power.


Yep... that was my thinking in the beginning but somewhere along the way I sort of forgot about that advantage. When your controller has such a huge surplus of voltage capability (i.e. - all of the parts in the power path are rated for 600V) then it seems, well, wasteful to only run it at 144V or so... Thanks for reminding me of this!




mattW said:


> ..As well as making the controller as reliable as possible it would probably be worth making the controller as idiot proof as possible too. Its hard to work out some times whether some blow ups/failures are flaws in the controller or just too much being in the hands of complete newbie DIYers. I see you are already heading that way with the inbuilt cooling.


That has been the primary design goal all along: make the controller as ummm... "fault-tolerant" as possible (to be diplomatic about it... ).

Some of the "faults" I've seen or heard others commit:


accidentally applying battery pack voltage to the key switch input
same, but with the throttle input
connecting battery pack to motor out and one of the batt terminals (rather than B+ and B-)
connect motor to the wrong battery terminal (e.g. - to M and B- instead of M and B+)
And lots more, of course. One of the things I don't like about any of the existing controllers out there, including the Zillas, is that they don't incorporate the main power contactor inside. I am really trying hard to cram the very popular EV200 (I believe) sealed contactor from Tyco into our controller so it will then be able to protect against serious wiring faults.




mattW said:


> Also I don't know if you have seen this yet but Ian from ZEVA.com.au had been developing a controller with similar stats but has decided he wants to study more before doing it. Luckily for you he has documented a lot of the developtment here.


That guy, bless his hard-working heart, appears to have come up with the most labor intensive controller layout possible. Not only that, but you will never get a bank of 10+ MOSFETs or IGBTs to hard switch* synchronously. He seems to recognize that fact, at least intellectually, but plodded ahead with that type of design anyway. 

* - soft, or quasi-resonant, switching will let you do this, but it is considerably more complicated and some methods are very dependent on the load characteristics.


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## piotrsko (Dec 9, 2007)

been goofing off and looking at published torque curves for some of the major imports. 

at about 2500 rpm, a typical 3 liter ICE is getting about 50 hp and perhaps 70 lb ft of torque assuming about 175 hp at peak rpm. I just don't see your average EV'er sidestepping the clutch at 6 grand in his ICE car.

when I translate 400 amps @ say 144 V I get about 75 hp using conservative electronic theory {I X E /750). Much more HP than what the ICE being replaced makes. Even running 72 v packs you still get 35 hp, which once again is what the bug used to run at full throttle and 3600 rpm ON THE FREEWAY at 65 mph. Now somebody may have changed the wattage to hp chapter since my theory books were published, but........


Ergo, I am still confused as to why someone would need much more current than that. BTW, with proper technique, the bug could smoke the tires on 35 hp.


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## JRP3 (Mar 7, 2008)

Every bug I've ever been in was an underpowered dog. Most EV's come in heavier than bugs, certainly if they use lead acid.


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## Bowser330 (Jun 15, 2008)

piotrsko said:


> ... I am still confused as to why someone would need much more current than that. BTW, with proper technique, the bug could smoke the tires on 35 hp.


Well for one...not all of us want to drive Bugs...and smoking tires means youre not moving as fast as you could be if you had better grip or a better setup, so I dont see that as a plus..

And two, its been discussed at length throughout the thread that "the people" want the power "available"...not that they will use it all that often...but available is what we want...

What I am confused about is why some in the EV community seem to think that underpowered EV drivetrains can "compete" with overpowered ICE drivetrains...ICE development is predominantly pushing for more and more power in every new design...75 HP for few seconds isnt going to cut it...The EV motors have the potential, so do the controllers, so do the batteries, and Im proud to say so do the members on this board, many of which are seriously smart people who are willing to do whats right for the community not their pocketbooks..., so with all that said, why stunt the future research & development?


This is where Tesla has it right...Make something comparable if not better...To be honest the Tesla is a bargain for the performance (0-60 is in serious supercar territory, cars that sell for 200K$+) ...If the Tesla car had the branding, say if the failing Aston Martin worked a deal with Tesla Inc. and released the car with Aston Martin branding, advertising, and dealer network, i feel it would have been a greater success....

But i digress, back to the controller thats coming out in 2009....750Amps woo hoo!!


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## piotrsko (Dec 9, 2007)

actually I believe y'all missed the point

75 EV hp or more is WAY more hp and associated torque at 2500 rpm than what most of these people are REMOVING from the donor car. This, in theory should make the EV accelerate FASTER than what the ICE did when it is in the car. OOOH performance improvement. now OTOH, 75 hp at 65 mph doesn't really cut it with a Cd of >.6, but once again, most of the driving is going to be city streets where you cant get to 65.

IMHO, a clean hand built car with a low Cd, under 1800 lbs would just plain fly.


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## JRP3 (Mar 7, 2008)

piotrsko said:


> actually I believe y'all missed the point
> 
> 
> IMHO, a clean hand built car with a low Cd, under 1800 lbs would just plain fly.


Actually I think you missed the point. Most people are not doing a hand built car under 1800 lbs, they are converting existing vehicles with lead acid batteries that weigh much more than that and may not have a great Cd, that's the reality.


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## piotrsko (Dec 9, 2007)

so in fact you are telling me that it is required to have at least 117 Kw or more to accelerate what ever vintage iron one converts?

seems wasteful


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## JRP3 (Mar 7, 2008)

Required? No, but if it makes for a better vehicle then why not? EV's often have a reputation of being slow, and they often are, yet need not be.


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## Bowser330 (Jun 15, 2008)

piotrsko said:


> actually I believe y'all missed the point
> 
> 75 EV hp or more is WAY more hp and associated torque at 2500 rpm than what most of these people are REMOVING from the donor car. This, in theory should make the EV accelerate FASTER than what the ICE did when it is in the car. OOOH performance improvement. now OTOH, 75 hp at 65 mph doesn't really cut it with a Cd of >.6, but once again, most of the driving is going to be city streets where you cant get to 65.
> 
> IMHO, a clean hand built car with a low Cd, under 1800 lbs would just plain fly.


I agree with you piotrsko...I totally agree that If something like this were made..

http://www.greencar.com/features/vw-235-mpg-car/

VW says 2010, although i dont see whats stopping them now...since they already have the prototype...

the thing runs on 8.5HP!!!!


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## Technologic (Jul 20, 2008)

Bowser330 said:


> VW says 2010, although i dont see whats stopping them now...since they already have the prototype...
> 
> the thing runs on 8.5HP!!!!


that car likely has a Cd of like 0.2 or higher... it's no where near as efficient as they could have made it.


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## DIYguy (Sep 18, 2008)

as quoted.....

"Measuring in at 4.1 feet wide, 11.4 feet long, and just over 3 feet tall, the car features an amazing drag coefficient of just 0.159...even more wind-cheating than the slippery GM EV1 electric car's 0.19 Cd."


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## JRP3 (Mar 7, 2008)

It's pretty hard to judge a car's cd by looking at it, plus since it's so small the cdA is probably really good. However it probably takes a year to accelerate and would be a hazard on today's roads.


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## JRP3 (Mar 7, 2008)

DIYguy said:


> the car features an amazing drag coefficient of just 0.159...even more wind-cheating than the slippery GM EV1 electric car's 0.19 Cd."


See what I mean?


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## Technologic (Jul 20, 2008)

JRP3 said:


> See what I mean?


 
lol I was actually quite close, just by looking. 

You can tell if you have a good sense of fluid dynamics... there's lots of room to improve the body shape. I could see 0.05 being quite possible without many modifications. (namely getting rid of the weird shapes over the tires and moving the wheels inward some and make the entire body a single fluid unchanging neutral wind shape)


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## JRP3 (Mar 7, 2008)

Technologic said:


> I could see 0.05 being quite possible without many modifications.


You mean better than any vehicle ever produced?
http://en.wikipedia.org/wiki/Automobile_drag_coefficient
I don't think it would be that easy.


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## Technologic (Jul 20, 2008)

JRP3 said:


> You mean better than any vehicle ever produced?
> http://en.wikipedia.org/wiki/Automobile_drag_coefficient
> I don't think it would be that easy.


Well the aptera is 0.11, namely because of the large structures for wheels coming out.

Air drag is the shape, but often area is worked on more to get down (like on the shell car)

All you need is for no wheels to extend below and have a teardrop car with the wheels sticking out a few inches from the entire shape... it should be easily possible, area would just be needlessly high.

However, they easily could have gotten the VW to 0.11 or so.... easily... just removing the two protruding additional flows over the wheels would have cut it significantly (and putting side guards on the wheels)

0.05 might be seen if they dropped the body and housed the wheels in the continuous body shape, using an elastomer plastic for the body would help absorb slight waves of turbulence too.


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## 280z1975 (Oct 2, 2008)

Technologic said:


> Well the aptera is 0.11, namely because of the large structures for wheels coming out.
> 
> Air drag is the shape, but often area is worked on more to get down (like on the shell car)
> 
> ...


Tecnologic,

I the .05 CD you speak of is VERY much harder to achieve than you suggest. Just look at the lowest CD I could find from a quick search on WIKI.

http://en.wikipedia.org/wiki/File:Nuna3atZandvoort1.JPG

It has a CD of .07 and has all the attributes you speak of, but still isn't at the .05 mark (and I am sure they made very little compromises to the shape for passenger comfort). I am not saying the .05 is impossible, but I think it's a LOT harder than you make it out. 

The other big factor people don't speak of here is the surface area of the cars, which makes just as big of a factor. So I always like to know of the CDA of a car, not just the CD.


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## david85 (Nov 12, 2007)

Technologic said:


> that car likely has a Cd of like 0.2 or higher... *it's no where near as efficient as they could have made it.*


They never are. The tail being chopped off nearly flat might also be a problem.


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## Technologic (Jul 20, 2008)

280z1975 said:


> The other big factor people don't speak of here is the surface area of the cars, which makes just as big of a factor. So I always like to know of the CDA of a car, not just the CD.


Well frontal cross sectional area is actually the most important factor up to a point. For instance a standard 9 sq meters of SUV frontal area vs something like 0.8-1.2 sq m for a tandum or well designed 2 seater. Efficiency will increase (at least at effectively high speeds where wind resistance makes up most of the power useage). Effectively at highway speeds you could see 9 times more efficiency assuming the motor's power curve is efficient at the RPM used.

The nuna solar car isn't exactly what I had in mind (it also was built around the necessity to have large flat areas), the wheels extend out too far (think about if you cut the wheels off the aerofoil would be about 0.03 or so... at least that's what my fluid CAD simulations of similar shapes show.

They couldn't remove the wheel shapes in the nuna because a person had to lay inside it. 

At any rate, the VW certainly isn't the best shape I could think of... the Frontal cross sectional area is actually about 10%-15% too large as well... just my 2 cents though, it's still better than ice conversion like the volt 

Also the VW I believe has a tranmission, a totally unnecessary feature in a car that light/efficient (basically just a big waste of power, if they just made it an EV with a direct drive it'd boost efficiency by 2-3 times the amount)

Say you had an SUV getting 12 mpg that had a CDA of 0.45 x 9 sq m x 4000lbs vs a car that was a 2 seater, 1 sq m x 0.12 cd x 1000 lbs (a fairly easy achievement with a bit of planning). The car could effectively have 10,500% more efficiency as gas powered, or around 50,000% more efficient at highway speeds using electricity... (assuming a rather moderate power to wheel efficiency of 80%).

General efficiency based upon potential energy of gasoline, but definitely funny to look at.

1 such car would effectively be more powerful than 500 Lincoln Navigators

This is why the Chevy Volt and other cars upset me so much. The efficient car described above could be made for a production cost of around $4000 in parts, if you wanted a range of 200-300 miles anyway.


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## Bowser330 (Jun 15, 2008)

Search for the Loremo, it has a pretty low cd and its somewhat normal looking, however still on the smallish-side...

one of the contributers to drag is turbulence of the air and one way to improve it is miniature fins to "organize" the air flow around the car...

The technolgy is used by Mitsubishi on the lancer...










Its also being installed onto wind turbines for increased efficiency...

http://www.whalepower.com/drupal/

We are way off-topic though, so lets get back on...Controller updates?


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## Tesseract (Sep 27, 2008)

Bowser330 said:


> ...
> 
> We are way off-topic though, so lets get back on...Controller updates?


Ya think? I leave you folks to your own devices for a day and look what happens!

And what I was doing most of yesterday was trying to work out the various mechanical/assembly details. We are actually wrestling with a bit of a dilemma at the moment: *Will customers accept a larger controller size (we are talking at least 11" wide by 16-18" long by 4-6" tall) for the benefit of using only film capacitors on the DC input, rather than electrolytics? *

It's a bit of an arcane technical question unless you are really familiar with electronics, but the benefit of going with film (polypropylene) capacitors versus electrolytics are: they don't "dry out", which leads to controller failure and they have extremely low losses, which reduces ripple and voltage spikes, allowing the controller to handle a higher motor amperage and battery pack voltage.

The downside? The film capacitor alone is some 10" in diameter and 3" tall... it's scary huge. But, it can handle 400A of ripple current _continuously_ with only a 10C temp rise - that means this one capacitor will happily operate at the worst case duty cycle of 50% with the motor current at 800A without limit. Like I said, electrically it really brings on the dropped-jaws and drooling, but mechanically it's a bit daunting...


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## Dalardan (Jul 4, 2008)

Personally, my father've always been saying to me "the bigger, the better" so just for this point, he'd trust more a huge controller..... Ok, let's says it's not a valuable argument.

From what I've seen in other's setups, there is some room around their controller in the motor bay. I don't know if it would allow for a 11" wide controller, but if the contactor and the heatsink are included, it might get really interesting. Maybe the controller could, with the additional size, include the shunt and provide an output for the amp meter display? Include the high amp fuse with an external access (to be sure no one ever open it...)? Be able to switch the polarity of the motor thus removing the contactors for reversal? I'm just shooting ideas that would make more palce under the hood thus allowing for a bigger controller.

Is there a big price difference between an array of electrolytics and a huge polyfilm capacitor? If it's in the hundreds, it might be not that interesting...

Dalardan


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## JRP3 (Mar 7, 2008)

It will provide some challenges for some smaller conversions but it really depends on where you actually end up. If you can keep it to the low side, 11x16x4 it's not too bad, but if it's closer to 12x18x6 that's taking up some real volume. For comparison the biggest curtis is 7x12x4.

*Maybe a mod can strip out the off topic drag stuff into it's own thread?


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## dimitri (May 16, 2008)

*



Will customers accept a larger controller size (we are talking at least 11" wide by 16-18" long by 4-6" tall) for the benefit of using only film capacitors on the DC input, rather than electrolytics? 

Click to expand...

*Wow, that reminds me of MetricMind's AC150 beast, I hope the price won't be as huge 

I think its a tough pill to swallow for many people, who are pulling their hair to cram more batteries under the hood.

How will this change effect the price? I have a feeling this capacitor is not cheap and you need more aluminum now to house it....

As a project manager I begin to worry about your endeavor, seems that ideas still keep coming, I hope you don't loose control and keep your eyes on the end goal and hands wrapped around it. After all, this controller must be affordable to be successful.


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## Tesseract (Sep 27, 2008)

dimitri said:


> I think its a tough pill to swallow for many people, who are pulling their hair to cram more batteries under the hood.


That's my feeling, too, hence, why I asked!




dimitri said:


> How will this change effect the price? I have a feeling this capacitor is not cheap and you need more aluminum now to house it....


Using this capacitor compared to a mixed bank of electrolytics and box film capacitors won't affect the final price, or not by much, anyway. While it is much more expensive ($200 in single quantities ) than the 10 capacitors used in the Kelly KDH12600 (approx. $35) it is not too much more than 32 capacitors reported to be used in the lower-amp rated Curtis 1221C (approx. $112). When you compare based on ripple current rating, though, it would take approximately 100 electrolytics of the type used in the Kelly to equal this one, at a corresponding parts cost of ~$350.




dimitri said:


> As a project manager I begin to worry about your endeavor, seems that ideas still keep coming, I hope you don't loose control and keep your eyes on the end goal and hands wrapped around it. After all, this controller must be affordable to be successful.


The design process is occasionally ugly, Dimitri. Perhaps I should refrain from providing updates at all? Just spring the controller on the market when it gets done?


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## Tesseract (Sep 27, 2008)

Dalardan said:


> ...
> From what I've seen in other's setups, there is some room around their controller in the motor bay. I don't know if it would allow for a 11" wide controller, but if the contactor and the heatsink are included, it might get really interesting. Maybe the controller could, with the additional size, include the shunt and provide an output for the amp meter display? Include the high amp fuse with an external access (to be sure no one ever open it...)? Be able to switch the polarity of the motor thus removing the contactors for reversal? I'm just shooting ideas that would make more palce under the hood thus allowing for a bigger controller...


Thanks for the excellent observations, Dalardan. One of our original design objectives was to incorporate the main contactor and, of course, the heatsink into the controller itself. Reversing contactors, though, we won't include because not everyone will need them, they take up lots of space and add quite a bit both to the parts and labor cost of the controller. That said, the controller will have outputs for activating not only reverse contactors, but also to switch between series/parallel mode.

Since a motor current sensor is needed for the controller to operate, we also thought it would be nice to make the signal from it available externally. Just add an appropriately scaled voltmeter to see motor amps in real time.

No fuse inside the controller, though, mainly because it would require a lot of effort on our part to protect the customer from shock or other injury during replacement.... it's best to just leave that outside the controller


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## dimitri (May 16, 2008)

> The design process is occasionally ugly, Dimitri. Perhaps I should refrain from providing updates at all? Just spring the controller on the market when it gets done?


No, please continue to feed us with info  Some more eye candy wouldn't hurt either  and more progress updates, please...


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## Jimdear2 (Oct 12, 2008)

Tesseract,

Just a quick thought, I have seen some very large capacitors in my brothers sound system that were stand alone, wrapped in its own heat sink and cooling jacket. They were phisically about 2 inchs in dameter (not including fins) and 8 inches long. He says the make much bigger. The prices he gave me (as I remember) weren't too far off what you have been mentioning

Would it be possible to use something like that with a remote mount instead of inside the controller. I don't know if the external wiring would cause problems (don't know enough), but remote mount should help with cooling loads.

I am liking what I am reading about your controller, and the thought you are putting into it. I don't have a clue about the electronics, but the planning and forethought is impressive.

If we build EV equivalent to the V8 mini rod pulling tractor next year (my health and age permitting) we will be talking to you.

Jim


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## Bowser330 (Jun 15, 2008)

Make the controller reliable and powerful and people will figure out a way to fit it....

Some of our fellow members that have gone with other brands have had them malfunction over and over...This is pretty sad...and, I, given the choice, would not buy from that manufacturer in the future.. I am sure many would agree with me on this...

Plus the popular 9" dc motor is tiny compared to even some of the small ICEs out in many donor cars..So i think its a non-issue...


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## JRP3 (Mar 7, 2008)

Someone mentioned the AC Propulsion unit, which is huge. If I could get my hands on one, I'd make it fit. Point being if the unit is good enough you can make it work. I don't know the dimensions but here is a comparison of a Raptor and a Zilla, though of course the Zilla has the separate Hairball interface.









I think a thinner unit with a larger foot print would be better than the Raptor design.


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## Bowser330 (Jun 15, 2008)

speaking of high-amperage controllers and the heat that is generated by them, why couldnt this waste heat be converted back to electricity by using a sterling motor or even the ever inefficient thermoelectric unit?

better than nothing right?


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## dogstar74 (Dec 6, 2008)

I know very little about the engineering side of things, but I seems that it's far easier to make two small objects fit odd sized spaces than one large object. But I too believe that if it's powerful and reliable, people would rather leave the oldest child at home and strap that into the car seat instead! 

I am following this production with great anticipation. 

Aaron


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## Technologic (Jul 20, 2008)

Bowser330 said:


> speaking of high-amperage controllers and the heat that is generated by them, why couldnt this waste heat be converted back to electricity by using a sterling motor or even the ever inefficient thermoelectric unit?
> 
> better than nothing right?


It would be more efficient to simply pump the heat into the cabin during the winter. 

You'd have to recitify the DC and use batteries that are ok with trickle charging, and it's still a really really diminishing returns kind of idea (maybe 5-10w recaptured?)


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## Tesseract (Sep 27, 2008)

Jimdear2 said:


> ...I have seen some very large capacitors in my brothers sound system that were stand alone, wrapped in its own heat sink and cooling jacket...Would it be possible to use something like that with a remote mount instead of inside the controller. I don't know if the external wiring would cause problems (don't know enough), but remote mount should help with cooling loads.


Yep - it would be possible to use that sort of capacitor (heat sinked electrolytic) in a controller but it absolutely must be mounted as closely as possible to the switches (whether they be a bank of MOSFETs, IGBTs or a single IGBT module). The more inductance (ie - the longer the wire) between the capacitor and the switch the less effective the capacitor will be at smoothing out the current pulses drawn by the controller.



Jimdear2 said:


> I am liking what I am reading about your controller, and the thought you are putting into it. I don't have a clue about the electronics, but the planning and forethought is impressive.


Thanks for noticing that! I sometimes feel a little bit like Sisyphus around here, always pushing that rock up the mountain only to have it roll back down at the end of the day... 



Jimdear2 said:


> If we build EV equivalent to the V8 mini rod pulling tractor next year (my health and age permitting) we will be talking to you.
> 
> Jim


Hope you are still doing fine by then because we plan on rolling out twin module (1500A) and quad module (3000A) versions after getting the single module version working perfectly.


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## dogstar74 (Dec 6, 2008)

We'll Make it fit, don't worry!


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## Qer (May 7, 2008)

Technologic said:


> It would be more efficient to simply pump the heat into the cabin during the winter.
> 
> You'd have to recitify the DC and use batteries that are ok with trickle charging, and it's still a really really diminishing returns kind of idea (maybe 5-10w recaptured?)


I'm gonna pick some numbers out of a hat as an example of what you can expect.

Let's say there's a voltage drop of 2 Volt over the IGBT and the battery current is 100 Ampere from a 120 Volt pack at cruising. That means the car is using 12 kW power from the batteries to move and of those the controller is wasting 200 Watts, probably more because of the diode so let's say 300 Watts instead. That's somewhere around 97-98% efficiency.

Now, 300 Watts through a Sterling motor, let's be nice and say that the Sterling motor has 70% efficiency (I doubt you can get that high in reality) and that the alternator has 90% efficiency, that means that you get less than 200 Watts back. That means the range will increase a whopping 1.5%! Except that you now have to carry a Sterling engine and alternator in the car too which adds weight...

Yeah, I also think that it's better to use the heat from the controller to heat the compartment in the winter. 

But why are we discussing this in the 1000 Amp thread...?


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## JRP3 (Mar 7, 2008)

Love it, gives a whole new purpose for hood scoops 


dogstar74 said:


> We'll Make it fit, don't worry!


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## Tesseract (Sep 27, 2008)

dogstar74 said:


> We'll Make it fit, don't worry!


*That's* hilarious!


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## JRP3 (Mar 7, 2008)

Tesseract said:


> Hope you are still doing fine by then because we plan on rolling out twin module (1500A) and quad module (3000A) versions after getting the single module version working perfectly.


How big will those be  Might have trouble fitting them in a vehicle.


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## Bowser330 (Jun 15, 2008)

JRP3 said:


> How big will those be  Might have trouble fitting them in a vehicle.


HAHAHAHA...

but seriously...twin and quad module? Is this a new idea or something you've been sitting on?

Why hasnt this been mentioned yet!!!


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## Qer (May 7, 2008)

Bowser330 said:


> Why hasnt this been mentioned yet!!!


Ehm. It has. Tesseract dropped a while back that we're planning a 1500/1000 and a 3000/2000 Amp controllers too. Both with serious input Voltages too (same technology) and, of course, with matching price tags...


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## Bowser330 (Jun 15, 2008)

sweet!


..


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## Qer (May 7, 2008)

Bowser330 said:


> sweet!


You don't even know the price tag....


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## Jimdear2 (Oct 12, 2008)

Tesseract said:


> Yep - it would be possible to use that sort of capacitor (heat sinked electrolytic) in a controller but it absolutely must be mounted as closely as possible to the switches (whether they be a bank of MOSFETs, IGBTs or a single IGBT module). The more inductance (ie - the longer the wire) between the capacitor and the switch the less effective the capacitor will be at smoothing out the current pulses drawn by the controller.
> 
> Thanks for noticing that! I sometimes feel a little bit like Sisyphus around here, always pushing that rock up the mountain only to have it roll back down at the end of the day...
> 
> Hope you are still doing fine by then because we plan on rolling out twin module (1500A) and quad module (3000A) versions after getting the single module version working perfectly.


Thought wire length might be a problem with remote mounting of capacitors, sometimes wild shots work sometimes they don't.

To often people dont see what a pain it is to make something completly new that requires original thought. We all need to step back and look at the effort.

You had to go and say that. Now I'm just going to have to keep going long enough to put one togeather. I still have the frame and axles from my abandoned triple motorcycle engined tractor. 

Now lets see, cut away the old mounts and connecting drives, then the motor(s) goes there, batteries there, Controller. . . . Hey! Didn't I see an 8 to 1 ring and pinion for the 9 inch? Hmmmmmmmm. 

Keep on keeping on,
Jim


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## gv2ev (Jan 27, 2009)

david85 -asked for pic of controller in converted car. there is a pic of 156v/500a controller on website($1400). this unit is approx 11 x 7 x 4.
depending on build(v/a)72v-240v/500a-1000a, size may vary . gv2ev.com has pic. site is new and still under constuction. will get pic of a few models together to show difference in size between ours/zilla/raptor/curtis. doesnt everyone need 1000a?! 
thank ypu for your interest,
joshua


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## Tesseract (Sep 27, 2008)

Bowser330 said:


> HAHAHAHA...
> 
> but seriously...twin and quad module? Is this a new idea or something you've been sitting on?
> 
> Why hasnt this been mentioned yet!!!


Well, mainly because we're trying really hard to not come across as shameless opportunists here, plugging products that are not yet available!

Anyway, yeah, we've been sitting on this, not only for the above reason but also so we don't give the competition any good ideas!




JRP3 said:


> How big will those be  Might have trouble fitting them in a vehicle.


The plan, which might not survive contact with the "enemy" (i.e. - the special capacitor) is to make the layout for the 1 and 2 module controllers the same as this reduces labor cost AND makes it possible to upgrade from the 750A controller to the 1500A controller by simply adding the second module. The 4 module controller is a special beast all to itself, though, because it will be capable of slinging around a _megawatt_ of power. 

That won't be an off the shelf product, for sure...


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## engineer_Bill (Jun 24, 2008)

The film capacitor sounds good. There are a lot of good reasons to go with film instead of electrolytic. I haven't seen controller size be a factor in installation. Batteries still take up a lot more room. the controller can be stashed anywhere. The more components you put in the controller, (main contactor, shunt, etc...), the less expensive and much less trouble to install, (and less chance for an inexperienced person to mistake). But the more cost and bigger size for controller. I think you are on the right track I would like to try one. Film capacitors are big and expensive which is why they are used sparingly in most designs. having a bullet proof controller is a good use of them. And should be well marketed if that is the path you choose.


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## david85 (Nov 12, 2007)

gv2ev said:


> david85 -asked for pic of controller in converted car. there is a pic of 156v/500a controller on website($1400). this unit is approx 11 x 7 x 4.
> depending on build(v/a)72v-240v/500a-1000a, size may vary . gv2ev.com has pic. site is new and still under constuction. will get pic of a few models together to show difference in size between ours/zilla/raptor/curtis. doesnt everyone need 1000a?!
> thank ypu for your interest,
> joshua


The administrator has set up a seperate thread for you. Please post your info here: http://www.diyelectriccar.com/forums/showthread.php/1000a-controllers-available-27132.html

Look forward to any info you have.

Thanks


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## Bowser330 (Jun 15, 2008)

+1 Nothing wrong with Healthy competition...


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## Bowser330 (Jun 15, 2008)

Qer said:


> You don't even know the price tag....


Updates???

.
.


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## Guest (Feb 5, 2009)

I really don't know that I need 1000 amps. But that isn't the stopper in controllers at this point. There seems to be a 156 VOLT ceiling on them.

I need higher voltage. I have good acceleration, but top speed is limited by voltage. I am currently running two parallel strings of 108 volts. I would like to put them in series. But there isn't anything out there for DC motors in that range. The Warp9 is rated up to 192 volts, but I can't get there from here.

A 200 kW controller at 200 volts would be fantastic. But realistically, 150 kW at 200 volts would probably be overkill. 700-800 amps at 200 volts would be a unique product on the market.

Kelly tells me they're working on a 400v model - still 2-3 months away.

Jack Rickard


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## DIYguy (Sep 18, 2008)

jrickard said:


> I really don't know that I need 1000 amps. But that isn't the stopper in controllers at this point. There seems to be a 156 VOLT ceiling on them.
> 
> I need higher voltage. I have good acceleration, but top speed is limited by voltage. I am currently running two parallel strings of 108 volts. I would like to put them in series. But there isn't anything out there for DC motors in that range. The Warp9 is rated up to 192 volts, but I can't get there from here.
> 
> ...


I am going to look at my 800 amp 192 volt (1100 amp/250volt IGBT rated) controller tomorrow. Electrocraft will make u a 1000 amp unit if you want also. u can get there from here...


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## Qer (May 7, 2008)

Bowser330 said:


> Updates???


Well, nothing revolutionary yet. There's progress both in soft- and hardware, Tesseract et al are moving towards a working prototype that will be driveable (ie not falling into pieces if the car hits a speed bump...) and I'm right now working on the user parameter settings.

So far we haven't had any serious show-stoppers (just the average pit-falls...), which I think is pretty good considering that building a reliable controller actually has been a LOT harder than I anticipated. Still a long way to go until something can be produced and sold, but considering the size of the work force I still think we're moving quite rapidly forward. 

My admiration of Mr Otmar keeps growing btw. I think that noone that hasn't digged this deep into the technology behind a controller can quite grasp what he managed to do and as I've understood it he did it mainly by himself too. 

Impressive.


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## Tesseract (Sep 27, 2008)

I finally called NetGain (the parent company is an authorized distributor) and asked for the current vs. time data for the WarP motors. The answer I got might be surprising... all of the WarP motors have the same current rating. Yep. Doesn't matter if it's an 8", 9", 11" or a 13". The reason is because they all use the same size copper "wire" which determines ampacity. Larger motors simply produce more torque per amp...

Anyway, the specs are:

2000A for 10 sec.
1000A for 20 sec.
450A for 5 min.
220A for 1 hr.

Keep one important point in mind, though: you don't get to cram 2000A through a WarP motor for 10s AND run it at 220A for 1 hour immediately afterwards... This is because the 2000A for 10s already raised its internal temperature to the maximum! 

Which raises an interesting theoretical point: a controller capable of exceeding any of these current vs. time limits will hasten the destruction of the motor, and NetGain might not feel obligated to honor the warranty!


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## david85 (Nov 12, 2007)

.....so this implies that a warp 9" can stand up to 2000 amps? Yikes.

I can't help but wonder if using the same winding size results in a performance compromise from one motor to the next. Could this by why the 8" has lower efficiency than the 9"?

We need liquid cooled motors.


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## JRP3 (Mar 7, 2008)

1000 amps for even 10 seconds should be enough to get you moving pretty well


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## Tesseract (Sep 27, 2008)

Yeah, yeah... hold your horses, you two! Just because a motor can tolerate 2000A doesn't mean it is producing proportionally more torque at that current than it would at 1000A or even 500A. The reason why is because any material with a magnetic permeability greater than 1 (ie - air) will saturate when the current flowing per turn reaches a critical point. An increase in the current flowing through a coil (ie. - the field and armature of a motor) after saturation no longer results in an increase in the strength of the magnetic field produced by said coil. In other words, the amps are getting wasted (literally, as heat).

The key question is, at what point do each of the WarP motors saturate? If we knew this then we would know for sure at what point to stop throwing more current at the motor. 

Eventually we will build or buy a proper dyno and be able to test this ourselves... (our fearless leader forgot to bid for a perfect dyno on eBay and has been in a real sulk about it ever since he saw it sold for the minimum bid to the single bidder...  )


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## gv2ev (Jan 27, 2009)

Gentlemen,
yes that is an interesting point, in as much as motor life is concerned. given an electric motors longevity, even with considerable degradation, i would expect at least 100,000 miles before needeing a fresh one. i paid $3,000 for the last warp 11. i think 100,000 miles would be an acceptable trade-off. it would also appear that a 2,000a controller really only serves a useful purpose of drag racing( if thats useful). for daily driving, given those stats- maybe 1500a is about tops.


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## JRP3 (Mar 7, 2008)

More Power!!!  I'd guess that 1000 amps is well within reason since these motors seem to perform well with a Zilla 2000 amp controller in drag racing situations, and they also perform better with a 1000 amp controller than a 500 amp controller. From what I've seen most motors are controller limited.


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## major (Apr 4, 2008)

Tesseract said:


> Just because a motor can tolerate 2000A doesn't mean it is producing proportionally more torque at that current than it would at 1000A


Hey Tesseract,

Yes it does. Torque is the product of armature current and flux. In the series motor, flux is current dependent. Prior to saturation, torque follows the square of current. After saturation, flux stay pretty much constant and so torque becomes directly proportional to current. So, 2000 amps would get you twice the torque as would 1000 amps. And, I don't know the saturation characteristics for these particular motors, but for your purposes a decent guess would be 300 amps for saturation. Actually could start down around 200, but depends on the design particulars, like field turns and size.

Regards,

major


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## Tesseract (Sep 27, 2008)

major said:


> ...Prior to saturation, torque follows the square of current. After saturation, flux stay pretty much constant and so torque becomes directly proportional to current. ...


I was hoping you would chime in on this...

This is more or less what I was trying to say earlier; you just added some detail and worded it much better than I did! My point, essentially, was that you don't get the same increase in torque per amp after saturation as you did up until that point. I figured a motor would behave much like a gapped-core transformer, softly saturating over a range of current.

I wonder if all the WarP motors saturate at the same amount of current That is, do they all have the same number of field and/or armature turns (I assume it does not matter whether the field or the armature saturates, the effect is the same, correct?).

So, more turns allows a motor to run at a higher voltage, but also causes it to saturate at a lower current. No free lunches...


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## major (Apr 4, 2008)

Tesseract said:


> I figured a motor would behave much like a gapped-core transformer, softly saturating over a range of current.


The saturation curve (flux vs NI) starts as a straight line called the air gap line. Obviously due the air gap reluctance only. Then it sees a fairly sharp knee as the iron starts to saturate. After that, flux continues to rise very slowly with increasing NI and this slight increase in flux diminishes as NI continues to increase. But there is a definite knee in the curve. Don't have a good example to post up.



> I wonder if all the WarP motors saturate at the same amount of current That is, do they all have the same number of field and/or armature turns (I assume it does not matter whether the field or the armature saturates, the effect is the same, correct?).


Most well designed motors will see saturation of the magnetic circuit begin at the root of the teeth in the rotor. This is the bottleneck in the magnetic circuit. And it is the field mmf contribution which is responsible. The armature mmf only distorts the field. It actually can cause saturation localized in the pole tip. But that is a whole different animal.

I don't think you can characterize a family of motors by a single saturation value. Don't need to anyway. With any decent controller current limit, it is a safe bet the motor will saturate.

Regards,

major


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## Technologic (Jul 20, 2008)

major said:


> The saturation curve (flux vs NI) starts as a straight line called the air gap line. Obviously due the air gap reluctance only. Then it sees a fairly sharp knee as the iron starts to saturate. After that, flux continues to rise very slowly with increasing NI and this slight increase in flux diminishes as NI continues to increase. But there is a definite knee in the curve. Don't have a good example to post up.


Major,
What purity of Iron do they use in common DC motors?
Could a motor design be used with ultra high purity iron (99.999%) that would remove all saturation (since the saturation point of such pure iron is over 5T and almost infinitely high the purer you get).

Also have any motors you've encountered used ultra high saturation materials such as Cobalt alloys (I can not for the life of me remember their names anymore...)... Some of them have 3-3.2T saturation points though they are more expensive.

What would be the advantages to a material that could not be magnetically saturated, besides just straight efficiency gains? Obviously saturation on the teeth is due to thickness of the material, since more magnetism can be carried by thicker ferromagnetic materials.

Thanks in advance for satisfying my curiousity.


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## piotrsko (Dec 9, 2007)

new questions:

40 years ago in electronics for USAF, I was told that when saturation hits, current flow becomes stable and will not increase up to the insulation breakdown point in voltage. Thats how we turned down the runway lights, big coil and went to some percentage of saturation with a couple of amp power supply. Anything change in the last couple of decades?

where is this leading to, some sort of super motor? LN2 cooling, perhaps

most commercial rotors that I've played with are some form of either cold roll or hot roll steel, probably 1018, 1020 with poor homogeneous controls for impurities. cheap, easy to form/punch, readily available.

Won't the coil saturate on its own anyway, or will that point be high because of the core?


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## Technologic (Jul 20, 2008)

piotrsko said:


> new questions:
> 
> 40 years ago in electronics for USAF, I was told that when saturation hits, current flow becomes stable and will not increase up to the insulation breakdown point in voltage. Thats how we turned down the runway lights, big coil and went to some percentage of saturation with a couple of amp power supply. Anything change in the last couple of decades?
> 
> where is this leading to, some sort of super motor? LN2 cooling, perhaps


LN2 cooling won't help you much unless you plan to use laminated superconductors.

Likewise major's explanation was accurate. As the coil spins and saturation occurs in the iron around the motor (poles etc) saturation once it hits a wall will in turn linearize the current to torque because there is a single factor effecting power output not saturation and coil movement in the gap.

I imagine stopping saturation in a motor with more pure iron would have positive outcomes towards efficiency at high torque outputs.


----------



## major (Apr 4, 2008)

Technologic said:


> Major,
> What purity of Iron do they use in common DC motors?


Most motors use electrical grade silicon steel laminations probably grades M-27 thru M-47, depending on the cost. These are engineered alloys. Maybe getting into the 1.5 T range. Higher induction would mean higher torque density for the machine. Cobalt alloys have been around a long time, but few are willing to pay the price. Ultra pure iron is a new one on me. Sounds like a troublesome material. Like clean room stuff.

Regards, 

major


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## Technologic (Jul 20, 2008)

major said:


> Most motors use electrical grade silicon steel laminations probably grades M-27 thru M-47, depending on the cost. These are engineered alloys. Maybe getting into the 1.5 T range. Higher induction would mean higher torque density for the machine. Cobalt alloys have been around a long time, but few are willing to pay the price. Ultra pure iron is a new one on me. Sounds like a troublesome material. Like clean room stuff.


Well certainly the 99.995+% stuff will be clean room conditions to get it in rods at that purity consistently.

Silicon steel (I assume low carbon) would work, but certainly not be ideal. 99.95% or so purity iron is relatively common (with a 3T or so spec), just impossible to find in China (I've looked before for other purposes).


----------



## Bowser330 (Jun 15, 2008)

Qer said:


> Well, nothing revolutionary yet. There's progress both in soft- and hardware, Tesseract et al are moving towards a working prototype that will be driveable (ie not falling into pieces if the car hits a speed bump...) and I'm right now working on the user parameter settings.
> 
> So far we haven't had any serious show-stoppers (just the average pit-falls...), which I think is pretty good considering that building a reliable controller actually has been a LOT harder than I anticipated. Still a long way to go until something can be produced and sold, but considering the size of the work force I still think we're moving quite rapidly forward.
> 
> ...


Indeed Mr. Otmar does demand respect and so do all who invest their time and effort to produce a new product to this market...

Thanks for the update, and we look forward to more and your prototype's test results.


----------



## Tesseract (Sep 27, 2008)

Technologic said:


> Major,
> What purity of Iron do they use in common DC motors?
> Could a motor design be used with ultra high purity iron (99.999%) that would remove all saturation (since the saturation point of such pure iron is over 5T and almost infinitely high the purer you get)....


Huh? It is well established that the practical maximum flux level is 2.16T for 99.99% pure iron. Somehow I doubt pushing that one more significant digit out will get you over double the saturation level.

Perhaps you are thinking of permeability? That does increase dramatically with purity in iron. A permeability of 10^6 is achievable at the same 99.99% purity level whereas the typical silicon steel used in 60Hz transformers tops out around around 10^4.


----------



## Technologic (Jul 20, 2008)

Tesseract said:


> Huh? It is well established that the practical maximum flux level for pure iron is 2.16T for 99.99% pure iron. Somehow I doubt pushing that one more significant digit out will get you over double the saturation level.
> 
> Perhaps you are thinking of permeability? That does increase dramatically with purity in iron. A permeability of 10^6 is achievable at the same 99.99% purity level whereas the typical silicon steel used in 60Hz transformers tops out around around 10^4.



I believe you're incorrect about this Tesseract, I suggest you model the properties in FEMM to see for sure though. http://femm.foster-miller.net/wiki/HomePage

Permeability does increase, but permalloy and other expensive high magnetically dense materials still lack the permeability and saturation points of pure iron.

I wish I still had all of the sources from years ago when I was studying this, but finding saturation points of ultra pure iron is not a googleable thing.

Unless my memory is appallingly bad, I believe things like 99.995% pure iron don't reach saturation to well past 3T... 

What limits flux saturation is impurities... you can model this with steel as well. Likewise it's not a linear relationship with flux saturation... a small amount of impurities can make large differences towards the end of the spectrum of purity.... same thing happens in steel as well.

It's been well over 3 years since I was designing speaker motors though, so it's possible I'm confusing saturation and permeability, but I doubt it. Permeability doesn't matter too much in motor design (not traction motors but speaker motors)


----------



## DIYguy (Sep 18, 2008)

Im still tryin to figure out how to "saturate" this _*controller*_ thread with enough "flux" to get my iron hot....?? 

may be better for the motor discussion?? lol


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## Tesseract (Sep 27, 2008)

Technologic said:


> I believe you're incorrect about this Tesseract, I suggest you model the properties in FEMM to see for sure though. http://femm.foster-miller.net/wiki/HomePage
> ...
> I wish I still had all of the sources from years ago when I was studying this, but finding saturation points of ultra pure iron is not a googleable thing....


I may well be wrong, but you are the one making a claim that is _not_ supported by what a quick search on Google or Wikipedia turns up...

That is to say, 

"Extraordinary claims require extraordinary evidence" - Carl Sagan

I'll also echo DIYguy's sentiment that you start your own thread on this rather than hijack this one. Really, Technologic, is it impossible for you to stay on topic in a thread unless it is one you started?


----------



## Technologic (Jul 20, 2008)

Tesseract said:


> I may well be wrong, but you are the one making a claim that is _not_ supported by what a quick search on Google or Wikipedia turns up...
> 
> That is to say,
> 
> ...


You all were commenting on saturation of materials, I was just asking major a question.

Not as if I have continued this past that.

I'm not making any sort of "extraordinary" claims, merely commenting. If I cared about proving such a thing these days I would model it in FEMM myself, but I've given up motor designing years ago.

Neither wikipedia or any google links I could find commented on ultra high purity iron... just steel and low carbon steels saturation points (which of course are low since they have upwards of 3% carbon).

I was more curious if motors ever used permalloy etc, since their curie temp is also rather high.


----------



## piotrsko (Dec 9, 2007)

Likewise major's explanation was accurate. As the coil spins and saturation occurs in the iron around the motor (poles etc) saturation once it hits a wall will in turn linearize the current to torque because there is a single factor effecting power output not saturation and coil movement in the gap.

so I take it that this linearity will allow more current, or is the torque increased due to the single factor? Or does coil movement negate saturation? I see where as the air gap becomes less, you would get less saturation because of the coupling effect, but Major's explanation tended to end at saturation. Possibly my Pooh-bear mind cannot grasp this concept sufficiently.

I imagine stopping saturation in a motor with more pure iron would have positive outcomes towards efficiency at high torque outputs.[/quote]

I do not believe you can stop saturation, you CAN merely delay onset to effect higher gauss levels, once again through higher currents...

steel/iron based materials may not be your answer


----------



## Technologic (Jul 20, 2008)

piotrsko said:


> so I take it that this linearity will allow more current, or is the torque increased due to the single factor? Or does coil movement negate saturation? I see where as the air gap becomes less, you would get less saturation because of the coupling effect, but Major's explanation tended to end at saturation. Possibly my Pooh-bear mind cannot grasp this concept sufficiently.


I'm not sure if you would get less saturation in the steel if you reduced the air gap width, certainly not how it usually works. Saturation is based upon flux density and thickness of the material. 
Coil movement doesn't negate saturation, coil movement switches back EMF polarity etc. The torque from the motor will increase once the poles are saturated only according to the amperage of the drive coil itself, not proportionally to the increase in flux in the steel and increase in of magnetic power in the coil together.



> I do not believe you can stop saturation, you CAN merely delay onset to effect higher gauss levels, once again through higher currents...
> 
> steel/iron based materials may not be your answer


You can't stop saturation, but you could potentially remove it's flux saturation point outside of the normal operating range of the motor... that's all I was curious about.


----------



## Bowser330 (Jun 15, 2008)

DIYguy said:


> Im still tryin to figure out how to "saturate" this _*controller*_ thread with enough "flux" to get my iron hot....??
> 
> may be better for the motor discussion?? lol...


hahahahahahaa


----------



## ElectriCar (Jun 15, 2008)

Meanwhile, back on the farm... Do we need 1000A controller? 

First of all, thanks for asking. I've been looking for something stronger than the Curtis 1231 for my next possible project. However I'll very likely go with AC for various reasons.

In reference to your question though, I'll give you my perspective and some data so that maybe you can answer the question. And whatever it takes to make it happen, there's real potential out here for it. *The real question for you as an OEM is "Will a viable market materialize?"* I'm an electrical contractor and most contractors I know aren't very concerned about pollution and our country's oil situation to try and convert a vehicle themselves. I OTOH do and did!

Scenario I: Though not viable at this time for me, it is one application to consider. *Converting a 7000lb four door F250 diesel pickup. *If I did replace the diesel with electric I'd need 500ft/lbs of torque to match it's ability. I would need to trailer a load of about 3500-7000 lbs. 

I converted an S10 instead for short trips that don't require such an animal. When I do need the truck, many of the trips would not be practical or possible today due to mileage limitations with electric power. However the S10 does it's job very well as a replacement and I seldom drive the diesel anymore. 


Scenario II, a much more viable option that I'm contemplating but not finding the hardware in a price range that is practical, is *converting a Ford E250 van with an estimated loaded weight of 7500 lbs as it is now. *

We do a lot of work within a range of 10-15 miles from the office. It would do a ton of environmental and economical good if I had one as it is an aerodynamic horror story with it's boxy shape and ladder rack on top. The photo in the link is not mine nor does it have a ladder rack. The ladder rack alone drops the mileage by 1-2 mpg I believe. Overall the mileage of this thing is about 11-11.5 mpg if that can somehow be translated.

For reference:


S10 weighs ~ 4200 lbs
144V system comprised of US2200 232ah, 6V batteries.
Curtis 1231C
Advanced FB1-4001A - 9" motor
Pack wired parallel 1/0 cable throughout the pack with some under hood wiring of 4/0 and 2/0 single cables
Crimped connections with 80% of them soldered as well
Amp meter installed on motor circuit
I don't know about other S10 conversions but I've seen 460A on the Paktrakr monitor for a second or so in first gear but that was hammering it from a stop. It may be more as the monitor has a sampling/display time delay.* On a normal start however I routinely see near 400A. 

*As far as scenario II, the Curtis and 9" motor combination on the S10 just won't work for the van, which also tows up to 3500lbs occasionally but towing with an EV van isn't a necessity.

Hope this is the type data you were looking for.


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## Tesseract (Sep 27, 2008)

ElectriCar: you, my friend, _need_ 1000A. The rest of these yahoos D) so far merely _want_ 1000A.

But even then it makes more sense to me to go with a motor wound for a higher voltage and lower current, rather than vice versa.

Still, you have to admit that a F250 diesel dually is a terrible choice for a conversion, especially given the battery, motor, and, sadly, controller technology that is readily available (the 2 module version of my controller will do 1500A peak, 1000A continuous, but it isn't ready yet, nor are there any motors I am aware of that can handle that amount of current continuously, anyway).




ElectriCar said:


> Amp meter installed on motor circuit
> I don't know about other S10 conversions but I've seen 460A on the Paktrakr monitor for a second or so in first gear but that was hammering it from a stop. It may be more as the monitor has a sampling/display time delay.* On a normal start however I routinely see near 400A. *
> ...


Hmm... need you to clarify one thing. Do you have two current meters or did you install the current sensor for the PakTrakR in the motor loop, instead of the battery loop (where it is supposed to go if you want to actually keep track of your battery life)?

Which is another way of asking, is the 400A you see routinely motor amps or battery amps?


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## piotrsko (Dec 9, 2007)

Mr tessaract, sir:

could the use of two paralleled controllers on a motor with one controller running the "field" and the other running the armature generally reduce to 1/2 the current required by either controller?


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## major (Apr 4, 2008)

piotrsko said:


> Mr tessaract, sir:
> 
> could the use of two paralleled controllers on a motor with one controller running the "field" and the other running the armature generally reduce to 1/2 the current required by either controller?


Hi piotrsko,

I don't think Mr.tesseract sir will object if I address your proposal.

The controller he is designing is intended for series wound motors. Series wound motors are the most common type of DC motors used for EV car conversions. The series wound motor implies that the armature and field are in series with each other, meaning they have equal (and the same) current. Power conversion takes place in the armature. The field establishes the magnetic means for this power conversion to take place. Consequently, the power consumed in the field is very much less than the power converted in the armature. Since both the armature and field have the same current, this means that the voltage across the armature is several orders of magnitude greater than across the field.

For example, on a 100 kW series motor, the power for the field may be only 1 to 2 kW. So your proposed control method would not work well.

Now there are controllers which do control DC motor similar to what you propose. But not for series wound motors. They use separately excited (SepEx) motors. From the 100 kW example, there is a 98 kW armature controller and a 2 kW field controller. But now the armature and field current need not be the same. You have a high current armature control and a low current field control. Both are in the same control box and programmed to work together. The separately excited wound motor resembles more of the shunt wound motor than the series wound motor. However, as you can see from the example, the armature control section is still the big beast.

Regards,

major


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## ElectriCar (Jun 15, 2008)

Tesseract said:


> ElectriCar: you, my friend, _need_ 1000A. The rest of these yahoos D) so far merely _want_ 1000A.
> 
> But even then it makes more sense to me to go with a motor wound for a higher voltage and lower current, rather than vice versa.


Yea, I know more voltage means less wiring weight and cost. And less peukert as well. My next project will have lithium and I want a high voltage with regen as well. This S10 with lead is the first and last one I'll do that way! Lead is NOT the way to go even if you have to pay double for lithium.



Tesseract said:


> Still, you have to admit that a F250 diesel dually is a terrible choice for a conversion, especially given the battery, motor, and, sadly, controller technology that is readily available (the 2 module version of my controller will do 1500A peak, 1000A continuous, but it isn't ready yet, nor are there any motors I am aware of that can handle that amount of current continuously, anyway).
> 
> 
> 
> ...


Yup, motor amps. I'm not sure of the pack amps so I'm thinking of another ammeter for just that.

And no, the F250 is not practical but the vans just may be. I've not worked out all the details yet. The weights I used were "as is" approximations right now. 

Eliminating an iron block 302 and it's 30 gallon gas tank (200lbs when full) while adding enough lithium to go maybe 40-80 miles would change the weight but not sure by how much. I've no idea what a 302 or the new pack would weigh. 

I'd also like to go direct drive with no tranny as that's a $2000+ rebuild job!

Now here's my question to you. Any work being done on an AC system? That is the way to go I feel and I don't think it's all that complex really but I can't believe there aren't more of them on the market.


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## Tesseract (Sep 27, 2008)

ElectriCar said:


> I'd also like to go direct drive with no tranny as that's a $2000+ rebuild job!
> 
> Now here's my question to you. Any work being done on an AC system? That is the way to go I feel and I don't think it's all that complex really but I can't believe there aren't more of them on the market.


No, AC controllers aren't all that complex, there's just 3x as many parts inside them! I personally don't think the advantages outweigh the disadvantages when it comes to 3-ph. AC induction vs. series dc in EVs. Now, switched reluctance motors have definitely caught my eye. The motors are very simple to construct, possibly even by a DIY'er, and the controller is only twice as complicated as one for series dc. Regeneration is a breeze, too. The one downside seems to be the torque is "coggy", like a stepper motor (which they most closely resemble), but as EV drivetrains have considerable inertia this shouldn't be an issue at all.


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## Tesseract (Sep 27, 2008)

major said:


> ..
> I don't think Mr.tesseract sir will object if I address your proposal.


Nope, no objection from Mr. tesseract... err, sir.




major said:


> Since both the armature and field have the same current, this means that the voltage across the armature is several orders of magnitude greater than across the field.


I can confirm that there is something like 5V out of 100V across the field of an ES-31B (wound for 144V with neutral brush timing). I haven't yet done the same test for the WarP 9 we just got in (not installed in a vehicle) but I imagine the field voltage to be even less a percentage of the total voltage as a result of the advanced brush timing - is my supposition correct?


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## major (Apr 4, 2008)

Tesseract said:


> but I imagine the field voltage to be even less a percentage of the total voltage as a result of the advanced brush timing - is my supposition correct?


Not sure the percentage has anything to do with brush position. That will alter the torque/RPM relationship, but converted power to excitation, probably not. From one motor design to another, there may be lots of other differences affecting that ratio. 5% sounds on the high side. I would have thought 2 or 3% more typical. It is load dependent of course. At stall it is about 50/50. But we usually talk in terms of like the one hour rating.

Regards,

major


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## piotrsko (Dec 9, 2007)

wasn't sure the correct name for the motor was shunt.

so there isn't a great advantage to exciting the field with a different source. My original thought was to excite directly from the traction pack, with fixed voltage.


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## major (Apr 4, 2008)

piotrsko said:


> My original thought was to excite directly from the traction pack, with fixed voltage.


That is what you do with a shunt motor. But, for a number of reasons, shunt motors suck at vehicle propulsion. So to get around those problems, they use SepEx motors and controls. All the power comes from the battery pack into the SepEx controller. The controller separates it into different voltage and currents to the armature and field, while monitoring each and making them work together in the proper proportions.

At the present time, there are no sources for SepEx motors and controllers suitable for on-road EVs. However, lower voltage/power SepEx systems are widely used in golf carts and industrial vehicles, like forklifts. SepEx systems offer advantage over series motor systems like contactorless reversing, speed regulation and regenerative braking.

Unless you rewind the fields, it is impractical to use a series wound motor as a SepEx. Even then, for the higher voltage/power applications, commutation becomes problematic, so interpoles are required in the motor.

Regards,

major


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