# controller - motor combos trade-offs



## Yabert (Feb 7, 2010)

For a rare time, it's not about controller........ because each choise can give you over 280 Kw!

But, to build a powerful BMW, you'll need more than just high torque.
You will need power and power = torque x RPM or V x I.
So because a Warp 9 can't take high voltage (+ 200v) his power will be limited at around 100 Kw (maybe 140 Kw at 1400A).

You have the solution at this moment, a motor with interpole who can take high voltage.
If the Kostov 11" can't give you enought power, you can try the Warp 11 HV.

Personnaly, I thinks the best solution will be to try to have good torque at high rpm instead to have high torque at low rpm for the same power....... thus, there will be less stress on mechanical components...


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## piotrsko (Dec 9, 2007)

Tessaract alluded that he was zorching Kostovs, but I'm not sure how. I am therefore thinking that the Kostov I own will be happier if I limit it to 60 minute ratings. That bombshell aside, perhaps the warp 11 HV might be a better deal, but it ain't as cheap as the Kostov.


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## rwaudio (May 22, 2008)

valerun said:


> Hey Guys!
> 
> [if this has been discussed at length already somewhere else on this forum, apologies - please point me to that]
> 
> ...


To add to Yaberts post, I would say a Warp11HV with either controller would give you "enough" torque, and a lot more power. That's the reasoning I used when I bought the 11HV and a Soliton1. That gives you 290ft-lbs and about 300hp with a good stiff battery pack.

The most fun would be an 11HV + 360v 1400A WarpDrive.... But then I know I would break stuff.


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## valerun (Nov 12, 2010)

piotrsko said:


> Tessaract alluded that he was zorching Kostovs, but I'm not sure how. I am therefore thinking that the Kostov I own will be happier if I limit it to 60 minute ratings. That bombshell aside, perhaps the warp 11 HV might be a better deal, but it ain't as cheap as the Kostov.


Piotr - of course it will be happier but there's no fun in running 250A on the motor... also, quite an under-use of Soliton1...


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## valerun (Nov 12, 2010)

thanks guys. I find it kind of weird that there are no reviews / user comments of ANY kind on WarpDrives... PLENTY on Soliton1... 

I definitely know that I want to try 1400A but would be curious to get user feedback first...


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## Guest (Jun 10, 2011)

Lots of gogo gaga over the Soliton1 but they do have a killer product. It is the only controller that can do at this time 1000 continuous amps with proper water cooling. If you can provide 1000 amps all the time the Soliton1 can pump it. That is HUGE. However the there are other players that are going to bring some other excellent things to the board. Some things that are going to be game changers. Serious game changers. It is not all about total grunt power. 

That's all for now. 

Pete


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## Tesseract (Sep 27, 2008)

piotrsko said:


> _Tesseract_ alluded that he was zorching Kostovs, but I'm not sure how....


Err... I'm not sure we actually "zorched" any of the 3 Kostovs we've destroyed so far - ie, had a plasma fireball from commutation failure. Rather, their failing was more from simply pushing too much current through them for too long (as evidenced by field and armature coils actually melting). 

The salient fact here is that Kostov motors are wound for higher voltage and lower current so they are much less tolerant of excursions above 500-600A than, say, NetGain's motors. I'm afraid valerun will soon be learning this lesson the hard way, especially since he's wondering...



valerun said:


> thanks guys. I find it kind of weird that there are no reviews / user comments of ANY kind on WarpDrives... PLENTY on Soliton1...
> 
> I definitely know that I want to try 1400A but would be curious to get user feedback first...


There's one guy on here that's been pretty happy with his NetGain Controls controller and his build thread is here:

http://www.diyelectriccar.com/forums/showthread.php/planning-1969-vw-bug-conversion-plug-43767.html

Despite my obvious partiality towards my own product, I wouldn't mind seeing an honest controller comparison done by a neutral 3rd party. Since you are going to be (if not already are) doing more conversions you might be just the guy to do this. 




gottdi said:


> ... It is not all about total grunt power.


Always trying to stir the pot, eh Pete? 

Still, I completely agree with you here in that there is more to a good EV motor controller than just being able to dish out a lot of amps on command. Of course it's easy for me to agree with you about this because we do have, in my not-so-humble opinion, the absolute best feature set of any EV motor controller on the planet! 

(And kudos to Qer for that!)


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## Guest (Jun 10, 2011)

> Always trying to stir the pot, eh Pete?


Well, not really this time. Teaser maybe but not pot stirring. Game changing feature set and high power too.


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## valerun (Nov 12, 2010)

Tesseract said:


> The salient fact here is that Kostov motors are wound for higher voltage and lower current so they are much less tolerant of excursions above 500-600A than, say, NetGain's motors. I'm afraid valerun will soon be learning this lesson the hard way, especially since he's wondering...


I think I will listen to you and major and rewire my Kostov in PFM. Based on what major said, it should give it more tolerance to such excursions. Also, Kostov's own explanation:
-------------
Switching to parallel field mode increases rpm and nominal amp draw while decreasing torque a bit. This, however, doubles the copper cross section in the stator, greatly increasing overload ability. The result is a motor which can survive severe overloads while keeping rpm high.
-------------



Tesseract said:


> There's one guy on here that's been pretty happy with his NetGain Controls controller and his build thread is here:
> 
> http://www.diyelectriccar.com/forums/showthread.php/planning-1969-vw-bug-conversion-plug-43767.html


Jeffrey - you're the best. This is what I call 'class'. And *the* way to create yourself a stellar reputation. Way to go. 



Tesseract said:


> Despite my obvious partiality towards my own product, I wouldn't mind seeing an honest controller comparison done by a neutral 3rd party. Since you are going to be (if not already are) doing more conversions you might be just the guy to do this.


Maybe. Will see. I am still figuring out which way to combine motor and controller capabilities is the best. Apart from obvious WarpDrive/Soliton1+11" combos, there are other configurations - some of them with interesting side benefits:
1. Soliton1 + dual 9" kostovs wired in series. Build a 340V pack and utilize controller and motors to the fullest. Same 300ft*lbs torque as 11" but higher peak power and better thermals. Additional benefit - better space utilization in a car with long under-hood space (any front-engine performance car, e.g., BMW). And dual builds are done by Kostov at a DISCOUNT relative to buying 2 motors separately. Try that with Netgain... 
2. Soliton Jr + dual 11" kostovs wired in series. Again, max the usage of controller. Side benefit is the ability to easily upgrade power by swapping controller. That can get you 550ft*lbs max - that will get things moving.
3. DIY controller (P&S 1000A with modified firmware to implement most if not all of the state-of-the-art features) + any of the above motor combos
4. Soliton1 + dual 11" kostovs wired in series but in direct drive mode. Get some weight back. With 550ft*lbs at the shaft and final drive around 3 for BMW E46s, this would give ~1700 lbs forward force. If traction is maintained, this is ~0.5g acceleration or 0-60 in 5.4 sec. respectable...

So the choice space is substantial.

Anybody cares to comment? Would love to hear informed opinions!

Thanks,
Valery


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## Tesseract (Sep 27, 2008)

valerun said:


> ...Also, Kostov's own explanation:
> -------------
> Switching to parallel field mode increases rpm and nominal amp draw while decreasing torque a bit. This, however, doubles the copper cross section in the stator, greatly increasing overload ability. The result is a motor which can survive severe overloads while keeping rpm high.
> -------------


The text in blue is true but the text in red is... well... controversial, let's say. The overload capability of the _stator_ (field) is higher in parallel mode, yes, but that of the _rotor_ (armature) is exactly the same in either configuration. Personally, I'd rather the rotor have a higher overload capability because it's easier to repair the stator when it turns into a fuse from the over-enthusiastic application of high current... 



valerun said:


> Jeffrey - you're the best. This is what I call 'class'. And *the* way to create yourself a stellar reputation. Way to go.


Aw, hell... I have to be nice to the NetGain Controls guys because their retail operation - EV Source - is one of our best dealers!!!  



valerun said:


> ...I am still figuring out which way to combine motor and controller capabilities is the best....


There are so many combinations of motor(s) and controller(s) that it's unlikely there is a "best" one for all driving conditions. A great setup for drag racing might not survive a 1-3 minute autocross or even a 10 minutes of mildly spirited driving on a highway. Regardless, running a single 1000A controller with a 340V battery pack and two Kostov motors wired in series - with the motor current limit set to 1000A, no doubt - is going to be hard on everything: motors, controller and battery pack.


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## valerun (Nov 12, 2010)

Thanks Jeffrey.

I think I will go with a single 11" 250V Kostov for now (same as in my Fiat) with a higher voltage pack. 

Then will upgrade to dual 9s or 11s Kostovs. I love the fact that Kostov builds you dual motors out of the factory and does not charge more for it! Too bad the next availability date is Aug 20 and then shipment time of 1-2 months...

This BMW is going to be our main show & PR vehicle so have to build it right...

V


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## Bowser330 (Jun 15, 2008)

Tesseract said:


> ....their failing was more from simply pushing too much current through them for *too long* (as evidenced by field and armature coils actually melting)......


Can you please quantify the above? I don't think I would need to draw 1000A from the Soiliton-1 for too long, maybe only a 5 seconds at a time, but i would like to know how long I could until i melted the Kostov 11 HV internals....


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## Tesseract (Sep 27, 2008)

Bowser330 said:


> Can you please quantify the above? I don't think I would need to draw 1000A from the Soiliton-1 for too long, maybe only a 5 seconds at a time, but i would like to know how long I could until i melted the Kostov 11 HV internals....


I have no idea how long a Kostov 11 HV (ie - the 250V version) will take 1000A because we never tested one. The older 9" Kostov (similar to the current 144V model) caught on fire after ~14 seconds at 1000A, so that's my only hard data point. Other Kostov 9" failures occurred with the vehicles in operation and so it's harder to pin down any hard numbers.

And just a reminder: if you set max motor current to 1000A then you will push 1000A through the motor whenever you floor the throttle and still have more battery voltage than back EMF. Seb managed to fry (as in, utterly destroy) two K9/144V motors wired in series with a 288V nominal pack. He was driving at 70-75mph on the highway at the time, IIRC and it took several minutes to kill them. This was not at all surprising to me - I told him he really ought to wire those K9s in parallel - but replacing those motors with twin WarP-9s, also wired in series, gave a massive increase in performance from launch, as well as much cooler operation on the highway. Here's a quick video of Seb launching full throttle: 

http://www.youtube.com/watch?v=DcdyYlDEd_o


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## Bowser330 (Jun 15, 2008)

Tesseract said:


> Here's a quick video of Seb launching full throttle:
> 
> http://www.youtube.com/watch?v=DcdyYlDEd_o


isn't there a feature in the soliton-1 that makes better use of the power? Seb is just spinning the wheels and wasting energy but going nowhere....I thought there was a feature that you can adjust to get the launch just right...something about limiting amps/torque in the low rpm range, like a sort of traction control...


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## Tesseract (Sep 27, 2008)

Bowser330 said:


> isn't there a feature in the soliton-1 that makes better use of the power? Seb is just spinning the wheels and wasting energy but going nowhere....


Sort of - you're probably thinking of the motor current ramp rate setting which can be used as "poor man's" traction control. It doesn't detect wheelspin, however, so if you set the ramp rate high enough (typically above 1000A/s) then it is trivially easy to get the wheels to break loose whenever you floor the throttle.


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## valerun (Nov 12, 2010)

Tesseract said:


> Sort of - you're probably thinking of the motor current ramp rate setting which can be used as "poor man's" traction control. It doesn't detect wheelspin, however, so if you set the ramp rate high enough (typically above 1000A/s) then it is trivially easy to get the wheels to break loose whenever you floor the throttle.


yeah, 2000A/s does it for me pretty reliably ;-))

anyway, Jeff - so are you (or Seb) saying that dual Warp-9s are SO much better than dual 9" Kostovs??? I am getting worried. A 4000lb BMW is not a 2300 Fiat so these motors will have to work that much harder... Could you pls let me know your honest opinion? Pls PM if makes more sense.

V


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## Tesseract (Sep 27, 2008)

valerun said:


> ...so are you (or Seb) saying that dual Warp-9s are SO much better than dual 9" Kostovs??? ...


Sort of, but given that the WarP-9 is more expensive, slightly larger and much heavier than the K9/144V motor, it's not exactly an apples-to-apples comparison. They really are different enough that I wouldn't treat them as interchangeable.

According to the performance graph for the K11/250V motor you'll get ~135Nm of torque (~100lb-ft) at 400A, and since the motor is well into saturation at this point, torque will increase approximately linearly with current (e.g. - expect about ~340Nm/250lb-ft at 1000A). How *long* the K11/250V can take either amount of current is not real clear to me and finding out the hard way is an expensive proposition.


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## Bowser330 (Jun 15, 2008)

Tesseract said:


> Sort of - you're probably thinking of the motor current ramp rate setting which can be used as "poor man's" traction control. It doesn't detect wheelspin, however, so if you set the ramp rate high enough (typically above 1000A/s) then it is trivially easy to get the wheels to break loose whenever you floor the throttle.


The soliton-1 also has throttle deadband and 50% throttle settings, which combined with the slew rate can be customized to give a torquey EV a really great launch...Sort of like the launch of the VW Bug, i think it had twin K9's... that thing just took off...with very little spin...


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## DavidDymaxion (Dec 1, 2008)

An 11 inch Kostov is only about 180 pounds, something like 65 pounds lighter than the Warp11. Also there are many comm bars (good for voltage but less good for high current). Some space is taken up by the interpoles (less space/mass to handle higher currents in the fields and armature, but helps do higher voltage). Just from eyeballing it, the brushes and commutator are a bit smaller, too.

Short story, it seems the Kostovs are designed for less current but higher voltage.

I did not have accurate instrumentation on my old Kostov 11 inch, but from battery sag I estimate I ran as much as 1000 A through it for 1 minute, and 500+ A for regen for ~3 minutes (doing tow regen). The motor would get warm doing that!


Bowser330 said:


> The soliton-1 also has throttle deadband and 50% throttle settings, which combined with the slew rate can be customized to give a torquey EV a really great launch...Sort of like the launch of the VW Bug, i think it had twin K9's... that thing just took off...with very little spin...


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