# Which controller for small autocrosser?



## Guest (Jan 29, 2010)

For racing I'd go with the Zilla Z2K. Go for the top of the line because it is known to live at the race track. It costs money but it is the best for racing. Soliton1 may be ok with a single motor and the Netgain may be good to. Neither the Soliton or Netgain have race proven information. The Zilla does.


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## rickeolis (Aug 13, 2009)

I would consider that. Can my Transwarp 9" handle that using lithium batteries?
Thanks-


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## Guest (Jan 29, 2010)

Need to ask the folks who race with the Zilla and lithium batteries.


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## rickeolis (Aug 13, 2009)

I agree; anyone???

Without a tranny and using lithium batteries, my car should be lightweight, so I hope that will make for good performance. I just don't want to buy weak EV parts.

Rick


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## dimitri (May 16, 2008)

Sounds like you are approaching this backwards, but maybe it only appears so because you didn't provide too much detail about the project goals. You already ordered the motor, does that mean you already have calculated torque and RPM and gearing numbers to make sure your car will accelerate as expected given your motor torque limits and gain max speed as expected given motor RPM limits and your differential's gear reduction since you are planning on direct drive?

I am not an expert or a racer, but direct drive with 9" motor doesn't seem like a logical choice to me, unless the car will be really super light.

Also, given that you calculated max power the motor can handle, have you decided on battery pack size, both voltage ( number of cells ) and amperage ( cell size ) ? How does your power requirement corellate to your range requirement? Since you want to race and street drive you probably need a balance of both power and range, which turns into a dilemma of the pack size. You need high C rates, especially with direct drive, so large prismatic cells are probably a poor choice, so you are looking at lots of small cells. This means $$$$. You'd be tempted to build smaller and lighter pack, but then you lose range.

As you see, lots of questions, decisions, compromises, etc.

I think the question of which controller to buy is probably the last one you need to be asking. It will become obvious once you figure out pack size and power levels ( volts and amps ) involved.

Hope this helps


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## EV-propulsion.com (Jun 1, 2009)

Direct drive probably isn't the way to go-especially since you want to use this as a dual purpose vehicle. 
What kind of top speed are you looking for in racing, and what kind of accelleration do you desire? Direct drive is not conducive for both speed and accelleration (usually one or the other)-sounds like a large AH battery pack will be required because of the current draw, which will not make your car lightweight as you say you are building.
I am not an autocrosser, but it seems like a transmission would be needed.
Mike
www.EV-propulsion.com


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## rickeolis (Aug 13, 2009)

I am building it for lower speed torque in mind. There is no interior at all, no radio, no heater or A\C, etc. It should be VERY light when I get done.
I have a Geo Metro for my normal daily driving and an '87 Corvette to race with now, and this is a new project I am trying to build, so what I need to know is the advantages of one controller brand over the others.
Thanks-

Rick


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## Qer (May 7, 2008)

Note: I am the guy developing the software for the Soliton 1 so I won't touch the controller question with a 10 foot pole since that has been known to be a mine field. Therefore you won't get any controller recommendation from me (even though gottdi's response amuses me ) but just general tips what to think about.

I agree with Dimitri and EV-propulsion, you have to figure out what kind of performance you need before you decide what parts to get, having a controller that can handle kA doesn't make sense if your pack or motor can't handle the power. We know from experience that a WarP 9" can handle 100kW (1000 Amps and 100 Volt) for at least 10 seconds, but we also know that about that time it looks like a good idea to not stand too close to the motor and we've (well, ok, Tesseract has since I'm on the wrong continent) always made sure to run it at low current for some time to re-settle the brushes before next high power run. If you push the motor too hard or too long it might zorch which, btw, is a bad thing.

Also, those 100 kW have to come from somewhere and 100 kW out from the controller means 100 kW in which means that the pack has to handle that power as well. Since Lithium typically don't like discharges above 5C (there are exceptions like A123, but they come with a different price tag) it means that if you have a pack with 150 Volt nominal your battery current will be somewhere around 700-800 Amps (depending on sag and SoC). This translates to around 200 Ah, which, as EVpropulsion put it, "will not make your car lightweight". A higher pack voltage lowers the needed Ah, but it still won't make your car lightweight.

Another thing to consider is transmission. Loads of Amps means loads of torque. Excessive torque means that thing might break. We've tried that too. 

So, do you need a drag racer or is a peppy commuter car enough?


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## Guest (Jan 29, 2010)

Anyone here using the Soliton1 or the Netgain at the track? I'd be interested in the information from the runs. 

Pete


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## rickeolis (Aug 13, 2009)

Hi Qer, I really appreciate the input.
I had posted a while back with my desires for this project and nobody had much to say, but you are asking the questions I need to know:
I want the car to be quite powerful for each lap up to 5 minutes, without damaging any related parts (Batteries-motor-controller)
I would like performance specs similar to that of a Spec Miata, such as 0-60 under 5 seconds, top speed does not need to exceed 90 MPH, and on a daily drive should last at least 50 miles...
If you don't think the Warp 9 is the way to go, I would like to honestly like to know what kind of motor\controller package would be good.
Thanks again!

Rick


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## EV-propulsion.com (Jun 1, 2009)

I think to get anywhere near this performance you will have to go to as high a voltage as possible, maybe using the high voltage warp11 (up to 288 volts) with a Soliton ? A transmission would still help, especially with using a warp 9 (& up to 176 volts).
mike
www.EV-propulsion.com


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## Batterypoweredtoad (Feb 5, 2008)

What rear gear ratio are you using?


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## Qer (May 7, 2008)

Ok, I'll bite, despite risking being flamed to crisps. 

"0-60 under 5 seconds, top speed does not need to exceed 90 MPH" is not simple to achieve and you WILL be pushing things, probably even blowing things (batteries, motors, possibly even controllers) becasue that's what racing's about. To quote Plasmaboy: "...we blow things up, so you don't have to."

Anyway, the White Zombie does the 0-60 in 2.9 seconds and has a top speed at 1/4 mile of 114 mph. It achieves that with a Zilla 2kA and a siamese WarP but (and this is a big but) it can't keep it up! Drag racing is about seconds (with the possibility to cool things down between runs), you're talking minutes and pushing these kinds of kW for up to 5 minutes will be torture for the whole electric circuit.

So let's start from the beginning; batteries. As EVpropulsion already stated you want voltage, preferably north of 200 Volt, but you also want Ah because the maximum power you can drain by the pack is of course W=V*A and your maximum continuous Amps will be Ah*C. For currents that are getting awfully close to continuous I don't think you want to use more than 3C which means that 200 Ah will give you 600 Amps top and if you want more power you have to raise the Voltage. Your pack will be huge unless you go with A123, but then the price tag will be monstrous. You want to keep an eye on the pack temp too and might even have to cool it with fans because even though increased temperature has the advantage of reducing internal resistance and increasing it's efficiency it'll also kill it in the long run.

Then there's the next step, controller. I think you have two options, Zilla or Soliton (with a possible third alternative, Netgain). Zilla has a peak power of 1kA or 2kA but continuous Amps are "only" 300 versus "over 600". I dare say that since you're talking serious performance your choises are Zilla 2kA versus Soliton (I haven't seen any claims about Netgain so I really can't give you any hints about that one), the Zilla 2kA definitely wins on peak current but according to the specs it might eventually drop down to 600 Amps. For drag racing this is obviously not a problem but, again, seconds versus minutes. I can't really tell you which one's the better one for you because that depends on how long the Zilla will stay above 1kA, how much current you really need and for how long.

Now; motor. With those performance numbers I'm afraid you'll blow up the TransWarP. It will be too much Volt and too much current for too long. You probably want a siamese build since that cuts the power per motor in half which will drastically increase the chance that you make it to the end. You might also want to consider forced cooling too, ESPECIALLY if you go direct drive, since the motors won't get much air flow at all at low rpm's but you'll still force a LOT of current through the motor and thus generating insane amount of heat. If you want to go with the high voltage version or not I'm not competent to tell you, I'd say Major is the guy that can give you that answer. With a siamese the Zilla has an edge since it can do series/parallel shift. It's on the todo-list for the Soliton (and Netgain I think?) as well, but there's no ETA for when...

Finally, transmission. I think direct drive is a bad idea all considered, because you probably want to keep the RPM high to be as nice as possible to the motor(s) and that means you'll have to keep the gear box. Since you probably don't want to wait a second or two when changing gears you probably also want to keep the clutch. But now's the question, can your transmission handle the torque? Pushing 1kA through one motor will give you a torque in the 200 Ft/Lbs-range, using a siamese setup in serial mode will mean 400 and increasing it to 2kA in serial mode will be somewhere in the 800-range! When will the transmission (or it's mountings) snap?

One thing's for sure, you better have a big wallet.


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## toddshotrods (Feb 10, 2009)

There are so many things to address here I didn't even try quoting, because the quotes would dominate my whole post. I'll try to just address subject matters, instead of exact wording or posts.

*Autocross*
I am building an autocroser as well, and also plan to sprint down the drag strip. What kind of autocross are you running in that lasts 5 minutes!  That seems like an awfully l-o-n-g time for an autocross race, and more like a short road course. The autocross races I watched at the local Goodguys car show here in Columbus were completed in less than 30 seconds by the fastest cars, and still under a minute by the slower ones.

The biggest point with this subject, in your case, is weight. Even a stripped down unibody car is going to be too heavy to effectively compete in an autocross race without a transmission - or - rear end gearing that is too steep to do anything more than city driving. Those gears may also come back to bite you in the autocross because it won't want to stretch out on the final straight. You will punish your motor and batteries running direct drive, because off the apex of every turn you're going to be asking them for max current to make up for not having enough gearing.

My project, by comparison, is being scratch-built and purposely designed to run direct drive. I am shooting for a final weight of 1200lbs with A123s. I am also using an 11-inch motor, which is capable of a ridiculous amount of torque for a 1200lb vehicle. The goal is that I won't be stressing the motor and batteries so much off the apex because it will actually have more torque than I can succesfully apply. The vehicle is also a dedicated race and show car, with no real-world expectations other than an occasional trip up the street for fun. That allows me to (hopefully) afford A123s. It looks like my pack will be around $15K, and under 500lbs.

I don't mean to go on about my project. I am trying to give you an idea of how the project was planned. Unless we are missing critical details, your plans seems to be a mix of components and ideas that will likely result in disappointment. You have a production street car that you plan to convert to an EV racer/driver, with a mild performance-oriented powertrain combination. It sounds like you will ultimately break a lot of parts, and eventually kill the motor and/or battery pack. Shoving enough current through to repeatedly accelerate the steel-bodied car will stress the batteries and motor, and the high torque loads delivered electric motor style (instantaneously - like a hit of nitrous oxide) will stress the driveshaft and rear end.

*Transmission*
As noted, running direct drive with a relatively heavy vehicle is probably asking too much from your motor and batteries - in an autocross race environment. If you were just drag racing you could manage it. The converted Powerglide (do a search here) might be a nice option if you don't want to shift, and want a more futuristic "feel". They can be built to withstand over 1200lb-ft of torque and live to tell about it. There are also a number of racing manuals that can handle high-torque racing applications. When I was considering using a transmission, one thing I found appealing is that you can use dog-engagement race transmissions that can be shifted without a clutch. Because an EV can simply select the appropriate gear from a standing start and accelerate without use of the clutch it opens the door for using these transmissions. Whatever route you plan to go, if you choose to use a transmission, be prepared to pay the piper. You need a really stout transmission race transmission because the street models aren't designed to handle the repeated shock of instantaneous torque hits. The phrase "nitrous-ready" is a good thing for an EV racer's parts.

*Controller*
I'm not pitching for anyone - yet - but have a couple favorites. I have been enamored with Zillas since I first learned about EV drag racing, and then along came a spider named Soliton. I like the Zilla's track record and relentless ability to slam as much current as your batteries can muster up on the motor. I like the Soliton's hi-tech build and ability to deliver whopping doses of current until someone screams "Uncle!" I am split between which one makes the most sense in an autocross race. Until there's a 2K Soliton, the Zilla will win likely continue to dominate at the drag strip, but autocross is a different animal. It's unproven whether one could even get 2K amps into the motor and on the ground, and you're definitely not going to use any substantial amount of current continuously. You're on and off the pedal, from apex to entry point. I watched some 500-700hp muscle cars (with road-race suspension underneath) go through the cones at the aforementioned Goodguys event. They struggled to successfully apply the ramp up of torque their ICE powertrains delivered - even with really wide, sticky, rear tires. The ones who got a little overzealous with that application ended up doing nice little 360s. One guy just enjoyed the moment, kept his foot in it for a couple turns, then emerged from a cloud of tire smoke. This would be even more challenging with an e-motor that's capable of full torque whenever you ask for it.

I look forward to that challenge but, as I pointed out, spent a lot of time designing for the intended mission.


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## rickeolis (Aug 13, 2009)

Hi guys,
This is great input, I really need it.
Ok, so I agree that 5 minute runs are too long in AutoX, maybe 2 is more realistic. Also, I am looking at a 1500 pound car or lighter when done, which is why I opted or the 9" motor. I can move up to the 11" if needed, I thought about it many times...
As for the performance spec's, the Tesla can do a much quicker 0-60 time (3 seconds??) and is capable of 100 miles. As long as I keep the weight down, I think my spec's (0-60 in 5 seconds and 50 miles), is doable. It's a direct drive too.
A tranny, clutch, shifter, pedals, linkage, and related mounting hardware would add hundreds of pounds, and that alone should help me keep the need for enourmous torque down.
A stock 1979 RX7 weighs about 2400 pounds, minus 12a motor at 350 pounds, minus tranny and clutch and linkage (250 pounds), minus gas tank (40), exhaust system (60), radiator and lines (40), A\C unit and heater (70), entire interior (150), steel motor mounts (30), radio and speakers (20), stock lead\acid battery (50), etc. gets me down less than 1300. Then I can cut out lots of unnecessary heat shields, brackets, battery tray, lines and hoses, but I will also get aggressive about certain panels and brackets.
Given all that, I will then add in the new motor and controller and batteries. No idea how much it will weigh realistically, but I can get it weighed. I still think it will be less that 1500...
This is much lighter that Metros and Festivas using lead acid battreries and still doing 8 second 0-60's and up to 65 MPH for 70 miles using 400 amp controllers. I think 1200 amp controllers and lithium batteries should get me where I want. I could be wrong though...

Rick


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## Bowser330 (Jun 15, 2008)

For performance either drag or autoX you will need the following:
(1) High power battery pack (with high C rating) e.g. A123, Kokam, Headway
(2) Dual motor or large single motor e.g. siamese 8/9, Warp11HV, or 13"
(3) High amperage controller e.g. Zilla, Soliton, Netgain
(4) Best donor you can find e.g. weight, handling.

RX7 is not a bad choice, good luck and report back your performance numbers!


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## rickeolis (Aug 13, 2009)

Thanks Bowser,
I know about the A123s but not the Kokam or Headways. I need to look into that.
Guys, why the high voltage motors over the 144 or 156 volt models?
Thanks again!

Rick


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## Bowser330 (Jun 15, 2008)

rickeolis said:


> Thanks Bowser,
> I know about the A123s but not the Kokam or Headways. I need to look into that.
> Guys, why the high voltage motors over the 144 or 156 volt models?
> Thanks again!
> ...


Simple answer:

Because John Wayland's and Dennis Berube's dragsters have high voltage.

Complex answer:

Higher voltage allows for more amps to be drawn at higher rpms. example: 144V will allow 500A to be pulled up until 2000rpm and 288V will allow 500A to be pulled up till 4000rpm... if 500A to a motor is 150ftlbs, then which would you rather have?....

150ftlbs @ 2000rpm = 57hp
or...
150ftlbs @ 4000rpm = 114hp

So lets say you wanted to build a 320V pack that can pulse at 2000A peak

1500 Headway cells will cost about 26K$USD for 320V 150A (15C pulse)
13.33C = 2000A peak
It will also weigh 1013 lbs for the pack

320V*150AH = 48kwh
if your lightweight, aerodynamic car, got 250wh/mile then 48kwh = 192mile range (100% DoD)


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## Qer (May 7, 2008)

Just an addition to Bowsers post:

Even if you "only" have a WarP 9" that will probably zorch if you get close to 200 Volt it still makes sense to have a higher pack voltage since this means sagging will have a lesser impact. Pulling hundreds of amps out of a pack will make the voltage drop pretty drastically and if you don't have a margin that means your top rpm will suffer.


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## DavidDymaxion (Dec 1, 2008)

Sounds like a great project. I plan to autocross my conversion, too, but it's much heavier than yours.

Don't forget about current multiplication. At low rpm, your controller will buck up the current. The motor current could be 3 times the battery current, for example. Your I^2R heating is going to be 9 times higher, plus with the lower rpm the motor's fan won't move as much cooling air.

Also, don't forget the torque curve falls off faster at high rpm for series DC than for AC.

I have autocrossed about 50 times. The top speeds vary hugely, from 1st gear courses (40 mph in my car) to 3rd gear courses (~80 mph). If you do a single gear ratio, you'll be heating your motor more on the slower courses than you would with a transmission, plus have less acceleration (unless you have a really strong pack, controller, and motor(s)). Remember, you don't compare directly to drag racers. They go for < 15 seconds, and the "course" is repeatable, and they spend very little time at low rpm.

There are various ways to attack the problem:


AC -- it's a bit more efficient and has a broader torque curve
Light weight
Keep the tranny to optimize for the speeds
Extra cooling
Twin DC motors or a single big motor


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## rickeolis (Aug 13, 2009)

Based on suggestions here, I've decided to go with the NetGain controller for one reason: I can start with 144 or 156 volts to run the Warp9" now, but if it looks like I need to move into the Warp-11" HV, the controller allows me to add high voltage in later.
This way I can go ahead and buy the HD plumbing kit too and should not have to replace the controller whether or not I go with different batteries or motors.
I also plan on being dramatic when it comes to shedding weight off of the car...
More to follow-

Rick


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## EV-propulsion.com (Jun 1, 2009)

One thing to add, if you use the soliton, you won't have to purchase any controller add ons in the future. It is ready to operate from 12 volts to 342 volts.


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## rickeolis (Aug 13, 2009)

That's true, but for the extra $1200.00 it's hard to do right now.
I agree that I think it's the best of the 3, but a bit $$$ for me at the moment.

Rick


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## Bowser330 (Jun 15, 2008)

http://www.evsource.com/tls_warp9.php

1000A = 237 ftlbs of torque

Thing is, with 160V, whats the maximum rpm you can pull 1000A?

By the looks of this comparable 168V Kostov 9" graph...

http://kostov-motors.com/files/productattachments/817455860674b455566486badd21c31d_9-168V.pdf

The *bold* data is data that came from the graph and the underlined is data that was assumed in accordance to the trend... Looks here like 1000A will only be available until 900rpm..

Amps RPM *
250* *5000* 
*300* *4750* *
400* *4000* *
500* *3500* 
*650* *3000* 
720 2475 
820 1950 
920 1425 
1020 900


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## ngcontrols (Nov 4, 2009)

Bowser330 said:


> http://www.evsource.com/tls_warp9.php
> 
> 1000A = 237 ftlbs of torque
> 
> The *bold* data is data that came from the graph and the underlined is data that was assumed in accordance to the trend... Looks here like 1000A will only be available until 900rpm..


This is a really good point. Torque (which is in relation to current) will fall off as the RPMs increase. But because speed is increasing, horsepower can still increase. 

Series wound motors (and possibly other types of motors, but I'm limiting the discussion to series wound) will draw whatever current is necessary to produce a certain speed (which is a function of the specific motor) for a given voltage. That is, apply 12V to the motor, and it will "want" to spin at a certain RPM. With no load on the motor, it will draw very little current to do that. As you increase the load though, it will still want to spin at the same RPM, but will require more current to do that. 

When you get into racing, it gets more complicated than this. For one thing, your battery pack is sagging under the load (assuming lead-acid - other chemistries might exhibit this more or less), so the maximum available voltage is diminishing. 

The attached data file is from a test run with the WarP-Drive. The pack is 240V, the controller is set up for 1200A, and the clutch slips with too much power applied. It's has an ImPulse 9 motor. You see that as the data starts out, motor amps are decreasing, motor voltage is increasing (and consequently motor RPM - sorry, this graph doesn't have RPMs), but motor power is increasing. You see some weird stuff after the shift to the next gear takes place, because the throttle had to be feathered to keep the clutch from slipping!


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## rickeolis (Aug 13, 2009)

I've been looking at the Headway batteries as well as Thundersky... Given what I want to do, and that I want the best of both (power&most miles), what style should I consider buying?

Thanks so much for the input everyone!

Rick


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## Bowser330 (Jun 15, 2008)

rickeolis said:


> I've been looking at the Headway batteries as well as Thundersky... Given what I want to do, and that I want the best of both (power&most miles), what style should I consider buying?
> 
> Thanks so much for the input everyone!
> 
> Rick


*Headway pack:*
320V
150AH
48kwh
2250 max pulse amps
100% Range @ 250wh/mile = 192 miles
Weight: 1013lbs.
Cost: ~25.5K$

*Thundersky pack:*
320V
200AH
64kwh
2000 max pulse amps
100% Range @ 250wh/mile = 256 miles
Weight: 1320lbs.
Cost: ~22K$

Thundersky is cheaper, with nearly the same peak amps, and 60 more miles of range, but 300 more lbs...


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## dimitri (May 16, 2008)

Bowser330 said:


> *Thundersky pack:*
> 320V
> 200AH
> 64kwh
> ...


Those numbers you quoted mean squat for performance EV. There is no way in hell TS will do 2000 amps, what's the point of saying "pulse" if pulse is 10 ms, can you press the pedal and release it within 10 ms? 

TS will sag like crazy at 3C, so you will lose voltage and power. Also, even though TS claims 3C continuous, they really won't last if you do it all the time.

IMHO, for this type of project you pretty much looking at cylindrical cells or those new prismatic A123 if you have deep enough wallet.


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## Bowser330 (Jun 15, 2008)

dimitri said:


> Those numbers you quoted mean squat for performance EV. There is no way in hell TS will do 2000 amps, what's the point of saying "pulse" if pulse is 10 ms, can you press the pedal and release it within 10 ms?
> 
> TS will sag like crazy at 3C, so you will lose voltage and power. Also, even though TS claims 3C continuous, they really won't last if you do it all the time.
> 
> IMHO, for this type of project you pretty much looking at cylindrical cells or those new prismatic A123 if you have deep enough wallet.


very valid points...
If it were me I would go with Headway...

13.33C gets you 2000A with the 150AH pack I described earlier...

And they are rated at 15C in minutes not miliseconds, you probably would need only seconds not minutes, so its a nice buffer to have...

26K$USD is also not bad considering you get 134 mile range @ 70%DoD

People can spend up to 6K$ on a LA pack that gets 30 mile range @ 70%DoD...thats basically a 26.8K$ for comparable range and longevity...


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## Lucas POD (Feb 3, 2010)

I'm REALLY happy to find this thread. 
I've been kicking around the idea of making a EV auto-xer for a while. (I already do some autocrossing with an ICE car).

I've got some comments / questions:

Have you ever autocrossed before? Admittedly the ones I do are on the small /short side, but they are 30seconds to a minute. Getting up to 2 minutes would be a heck of an autox course.

Removing tranny clutch and linkage is 250lbs? Really?
RX7's were always pretty light cars and without much torque. I'd think they'd have pretty lightweight components too. I'd have guessed closer to half of that 250lb figure. My confidence level on that isn't super high though.




rickeolis said:


> This is much lighter that Metros and Festivas using lead acid battreries and still doing 8 second 0-60's and up to 65 MPH for 70 miles using 400 amp controllers.
> Rick


Who is doing this? Don't get me wrong, I'm not doubting you. I'd just really like to see some data points on cars that aren't setup for achieving maxiumum range - which seems like 99% of the EV's out there.

If anyone knows of some other links that might be helpful to an EV autocrosser, please do post them.

Finally, Thanks to all the super knowledgable guys who are taking their time to educate the rest of us!

Scott


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## rickeolis (Aug 13, 2009)

Hi Scott, OK, a rough estimate for weight, but that's everything related to the tranny system. (Tranny, bellhousing, arm, pressure plate, disk, T\O bearing, flywheel, master\slave cylinders, lines, shifter, pedals, brackets, crossmember, etc) Plus I never have to worry about clutch problems,  and in autocrossing, the huge time advantage of not having to shift would be quite an asset.
In the past, I have won regional events using a WRX and have since gotten into road-course racing at a local paved track with my Corvette.

As for batteries, the type of racing I am looking to would be on and off over and over and rarely all the way to the floor for very long. On a typical auto-x track there is rarely but one long straightaway for less than an eighth of a mile.
Since I am running 156 volts, I could get away with half the range, weight and cost of the 320 volt packs... I just don't know what to expect from the different styles. So, the Headway's release more amperage faster than Thundersky's? What about A123's?

Thanks again everyone!

Rick


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## toddshotrods (Feb 10, 2009)

I like your project, and am looking forward to comparing notes with you and the other EV auto-Xers here. I am just having trouble understanding how you're going to get your car down to 1500lbs with a full EV powertrain. I am shooting for 1200lbs with the bare minimum amount of composite skin (T-bucket body) over a tubular chassis. You have a full steel unit-body. Even with A123s, from the numbers, it looks more like your race weight will be around 2500lbs. That's pretty light for an EV, and should still make a competitive racer. That's about where the White Zombie is. I'm bringing it up because that is critical to determining what specific components (_e.g._ motor, batteries, controller, etc) you'll need to be competitive.


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## Lucas POD (Feb 3, 2010)

rickeolis said:


> a rough estimate for weight, but that's everything related to the tranny system. (Tranny, bellhousing, arm, pressure plate, disk, T\O bearing, flywheel, master\slave cylinders, lines, shifter, pedals, brackets, crossmember, etc)
> Rick


Okay, but just as a point of reference, I've pulled transmissions out of small cars before. All in all, including the shifter, the bell housing, release bearing fork, cross shaft, carrier and bearing... all that jazz...and they have been not too tough to carry - like 75 to 90 lbs ... I'd guess that's the majority of the weight of the system. That's a long way off of 250lbs. I'm not trying to argue with you, but I just want to make sure you are being realistic, if not conservative with your weight expectiations.



rickeolis said:


> Plus I never have to worry about clutch problems,  and in autocrossing, the huge time advantage of not having to shift would be quite an asset.
> Rick


Very true, but that is going to cost you something too. In this case, bogging down the motor at low RPMs is going to be very tough on the equipement and very costly in terms of how much energy / power you are going to demand from your batteries.

You go direct drive, and its basically like using 4th gear. (assume if you have a 5th - it is an overdrive ratio) You keep that stock rear end gear ratio and close to stock cirumference tires . . . that is asking A LOT of a system to have good acceleration at the low end.




rickeolis said:


> In the past, I have won regional events using a WRX and have since gotten into road-course racing at a local paved track with my Corvette.
> 
> Rick


Cool, glad to hear that you have some experiece on that front too.

I'm really looking forward to reading more on this type of thread.

scott


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## EV-propulsion.com (Jun 1, 2009)

Since you are intent on going without the transmission, maybe two motors with series / parallel switching may help. We have never tried this, but maybe someone who has experience doing that can help. You may be able to get power and speed to some extent..........


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## rickeolis (Aug 13, 2009)

I'm going to work on getting the lowest gearing I can come up with, racing profile tires, and then cutting down weight to less than Metro like spec's and see what I think when I get it on the road.
Thanks-

Rick


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## CFreeman54 (Jan 14, 2009)

Hi Rick. I'm doing a similar thing with a Pontiac Fiero, aiming for both drag and autocross while still being street legal. I think my car was originally 200-300 pounds heavier than the early RX-7, but I agree with Todd that maybe your weight projection is a bit optimistic. Keep in mind if you go with bigger motor (dual 9 or single 11 or 13") your putting back at least 230 lbs with that, and then you need about 700 lbs or more in batteries to get the voltage and current you need. I'm even going with fiberglass/carbon fiber replacement body panels and I am still estimating a finished weight close to stock. I did keep the tranny/clutch so that adds about 150 lbs that could be eliminated with direct drive.


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## rickeolis (Aug 13, 2009)

So, I placed my order for the NetGain controller 1200 from a Colorado based reseller because they are the closest to me.
Called Evolve: http://www.evolveelectrics.com/
My TransWarp 9" should also be getting here in just days now too.
The next purchase will be batteries and I still haven't looked into A123's very well yet.
I also ordered a new hall-effect style throttle.
More to come-

Rick


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## rickeolis (Aug 13, 2009)

OK, so this is my progress so far:
  I have received the 9" TransWarp, and my nice NetGain 1200 amp controller.
 I pulled the driveshaft out of the RX7 and brought it to a local driveline specialist who made me a BEEFY new one that will bolt onto the Mazda rear end and go right into the back of the e-motor.
 I spent the last few days removing unnecessary parts from the car: Gas tank, fuel lines, exhaust system (heavy!!), shielding from that system, Mazda motor mounts, radiator and shroud, more interior junk etc.
 This weekend's goal is to mount the new motor.
 More to come- (I do need to get pic's)

Rick


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## Lucas POD (Feb 3, 2010)

Any news or updates on your build?
Did you get actual weights of any of the parts you took off?


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## Lucas POD (Feb 3, 2010)

ngcontrols said:


> The attached data file is from a test run with the WarP-Drive. The pack is 240V, the controller is set up for 1200A, and the clutch slips with too much power applied. It's has an ImPulse 9 motor. You see that as the data starts out, motor amps are decreasing, motor voltage is increasing (and consequently motor RPM - sorry, this graph doesn't have RPMs), but motor power is increasing. You see some weird stuff after the shift to the next gear takes place, because the throttle had to be feathered to keep the clutch from slipping!


Hi ngcontrols ...

I downloaded that PDF file and was trying to look at it.
The formatting is kind of screwed up.
Wondered if you'd consider sharing the actual spreadsheet that generated this data.

Also . . have any others to share?

Scott


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## rickeolis (Aug 13, 2009)

Well, I've built the car up now: I have the NetGain 9" motor installed in the transmission tunnel of the RX7; I have acquired some 4\0 cables to run from the battery pack to the controller and then to the motor; and I have setup my Netgain 1200 AMP controller in it.
I am now working on getting a set of batteries. It looks like I'll be going with a set of 26650 style ones from Headway or A123, but I haven't placed an order yet.
I did put 4 car batteries in series, and drove the car about 40 feet... One of those batteries was older than I thought and it went out on me during the test, but at least it ran. It was very quiet!
There is no doubt that I need to put really low gears into the rear-end, but I need to get the thing running before I address that.
More soon-

Rick


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## DavidDymaxion (Dec 1, 2008)

That is great, congrats on getting it to move!

How did you decide on 4/0 cable? That's what I'm using, but some of the NEDRA guys thought it was overkill.


rickeolis said:


> Well, I've built the car up now: I have the NetGain 9" motor installed in the transmission tunnel of the RX7; I have acquired some 4\0 cables to run from the battery pack to the controller and then to the motor; and I have setup my Netgain 1200 AMP controller in it.
> I am now working on getting a set of batteries. It looks like I'll be going with a set of 26650 style ones from Headway or A123, but I haven't placed an order yet.
> I did put 4 car batteries in series, and drove the car about 40 feet... One of those batteries was older than I thought and it went out on me during the test, but at least it ran. It was very quiet!
> There is no doubt that I need to put really low gears into the rear-end, but I need to get the thing running before I address that.
> ...


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## Lucas POD (Feb 3, 2010)

Wow - you are really moving along. That's great. Congrats.



rickeolis said:


> It looks like I'll be going with a set of 26650 style ones from Headway or A123, but I haven't placed an order yet.


I'm very interested in what you learn about this. When I finally learned about the lack of high C capability in the prismatic Lithium cells, I was a little dejected.

But the specs on Headways look nice. (I know - battery salesmen are worse than damn liars) 

What is it that makes the cylindrical packages tolerate the high charge / discharge rates so much better? Does the cylindrical shape help keep them from bulging or something? Is there a drastically different chemistry.

Keep me updated on what you consider buying .. . never know, may be able do a small group purchase and get a slightly better price.

Scott


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## rickeolis (Aug 13, 2009)

Yeah, I'm having a hard time getting quotes for the batteries for this project, but I'm getting there.
I agree that ThunderSky's don't have the 'C' rating I'm after, so it looks like I might be looking for DeWalt packs to pull A123's from!
The 4\0 cable idea came from the fact that I was talking to the guys from NetGain who make my controller, and they said I did not have a large enough set of cables from the controller to the motor at first. So I went out to buy a set of 2\0 cables, but the place I bought them gave me a really good deal on 4\0 and I bought them. Better too much than too little!
The car itself needs some work, so I'll be taking pic's soon as I do more to it.

Rick


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## toddshotrods (Feb 10, 2009)

rickeolis said:


> ...it looks like I might be looking for DeWalt packs to pull A123's from!...


I'm seriously giving that more and more consideration. I want to know for certain I have real A123s. Other than scoring some inside connection, this seems like th only way to be sure. From what I have read, you have to buy and test them to find out whether they're real - it's too late then!


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## rickeolis (Aug 13, 2009)

Well, I hadn't updated this post in a while, and wanted to do so to put a time stamp on where I stand. It's June 2010 now and I am waiting for my controller to return to me from the manufacturer who had a recall. I have since bought a hefty relay switch, a full set of 2\0 and 4\0 cables, and have begun to do some wiring.
The one choice I have made that will certainly make this project better than I had planned on originally is to buy a full set of A123 batteries. I though that they would be out of my price range, but have since found a way to do so without breaking the bank. So, I currently have many of the 26650 style batteries now and am getting more each week towards my goal as calculated for my needs to race this car.
I plan on putting them in packs in series for 165 volts of 50 batteries each, and then add 6 of these packs in parallel to increase the range as needed.
The car itself still needs some work, but I am putting all the funds right now towards making it functional in the drive train first.
I just recently had to replace my wife's minivan, so that has slowed the progress of this project, but I gives me plenty of time to wire the battery packs up and create my trays to house them in.

Rick


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## Ryan800 (Apr 15, 2010)

I think that putting indivitual cells in parallel then building a series pack out of those is better paralleling 165V strings because the cells will stay more balanced. This isn't coming from experience, just something I've read on here that you may want to double check.


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## rickeolis (Aug 13, 2009)

I agree with this too.
I am actually working on just that on another thread.
Thanks!



Rick


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