# Two TransWarP 9s vs TransWarP 11 for performance car



## noahmrogers (Nov 9, 2008)

Please forgive me if I'm at bit of a newbie when it comes to the understanding of ev systems. Just getting started at this. 

I'm looking to build a performance/daily driver ev on a budget. Budget here will be defined as 15k total including a cheap donor car. I can do any fabricating myself and I'm very familliar with cars; my cost is simply the parts. I'd like to go transmission-less because I feel that it would be more efficient and practical with a higher powered conversion. I'm concerned more about acceleration than top speed.

My original plan was to use a single TransWarP 9. After doing a bit of research, I don't believe this will provide very much power. Maybe enough for a daily driver, but not nearly enough for a sports car. 

I've been taking a look at Mike Willmon's Pinto, and reading around on running two 9 inch motors in series. Correct me if I'm wrong, but this type of setup would require double voltage while in series, and then double amperage when switching to parallel to feel the full effect of the dual motor benifit. This means I'd have to run twice as many batteries to get that kind of voltage, which is when I started looking into the transwarp 11. 

The 11 has a 10% worse power/weight ratio IIRC, but less batteries means the car will be several hundred lbs lighter overall. Also, I can buy the 11 kit from grassroots which does make things simple. http://www.grassrootsev.com/cpacks.htm This 11" kit any good?

Back again to 9" motors... It seems difficult to find good examples of series/parallel switching and the horsepower benifit it would provide, whereas the 11" motor would be a sure shot easy 100+ horsepower. 

Grassroots advertises the logisystems as 1000 amps. I don't suppose I could run 1000 amps through a transwarp 11 and live?  Once I figure out my power level and motor choice, I'll choose batteries to suit. I'd like a 35 mile range without sacrificing performance. The donor car will be something along the lines of a 2000-2500lb two seater.


Cliff notes: 
Two 9's means more batteries, more cost, and a far more complex system. Do these downsides outweigh the benifit of being able to switch from series to parallel at higher speed? 

Is not having a transmission the right way to go for this kind of conversion?


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## madderscience (Jun 28, 2008)

I suspect its gonna be a challenge to do anything with a dual motor setup and stay under $15K. 

What makes you think a transwarp 9" is not enough? what spec are you looking at? Be aware that the motor's rated horsepower is a continuous number (unlike how gas engines are rated), and the peak horsepower can be several times that value without any damage to the motor. Also be aware that the motor is only one part of the equation. The controller, batteries, cables, and contactors all have to be chosen to handle high power loads in a performance conversion.

I don't know exactly how much performance (in terms of acceleration or top speed) you are really shooting for but a single transwarp 9", coupled to a good controller (1000 amps or up) and a high voltage, high power, low weight battery (read: expensive) in a light car should give pretty decent performance. You will have to sacrifice range if you are using lead acid batteries to keep the weight down. 

The only EVs I know of that use a dual motor with series/parallel switching are built for the drag strip.

Your best shot is to try an emulate 'white zombie" or similar EV drag cars.
http://www.plasmaboyracing.com/whitezombie.php

Good Luck.


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## noahmrogers (Nov 9, 2008)

The transwarp 9 will max out at around 100 horsepower I would think. That's not even close to stock.

I'd like to have better than stock acceleration, and ideally 90+mph, though I'm not so worried about top speed.

I'm wondering how many amps cars like white zombie and the crazyhorse pinto are actually drawing? It looks to me like both of these cars use parallel to deliver higher voltages and increase RPM for a higher trap speed. 

I think that the TransWarP 11 will be perfect for my purposes. I don't really need the high end "parallel" acceleration, and the 100lbs that the 11 will have on the 9 will be negated by the power. 

Seems like most of us are limited by these low amperage controllers...


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## kek_63 (Apr 20, 2008)

If I read your post correctly, I'm not sure you fully understand the series/parallel shift. The battery pack is not shifted, just the motors (or, more correctly, the wiring between the battery pack and motors). Theoretically you could do a series/parallel shift with only one battery a few contactors and 2 motors.

Full amperage-1/2 pack voltage to each motor for tremendous "1st gear" torque.
1/2 pack amperage-full voltage to each motor for higher "2nd gear" speed.

White Zombie and Crazy Horse are using the big Zillas - 2000 amps!


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## JRP3 (Mar 7, 2008)

Unless you can get your hands on a Zilla there is a serious question whether or not there is another controller on the market that can survive a Warp11. You'd certainly need to consider a transmission to keep amp draw lower.


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## noahmrogers (Nov 9, 2008)

I was considering running multiple battery packs, and switching them from series to parallel for maximum potential. It would take a ton of contactors, but it wouldn't be too hard to set up, and it could improve acceleration. It would be an interesting experiment. 

There seems to be a lot of benefits associated with dual motors, though this seems unintuitive to me. I would think that ideally a single motor would be better. I suppose what series/parallel allows is twice the power with only one controller. That means if I had a Zilla, I could run two 11s.... haha

By far the most cost effective sporty EV seems to be the 9 with a transmission. With higher power, and relatively low (<100mph) speeds, seems to be where that transmission benefit is lost.

I wish there were a cheaper motor option than the warp 9's... But I feel I need to be wary of spending money on mysterious forklift motors.


Can anyone give me a recommendation on lead acids for a 30 mile range? I would like to use the full 156v the logisystems is rated at. That's 13 batteries, and I'll probably need 150 ah at least. 
I don't understand how Mike's pinto gets a 25mile range with 32ah. And does he switch the battery packs to series when he switches the motors to parallel? It's listed as a 360v pack. 

Cliffs:
11 is ruled out due to lack of good controllers
two 9's or a 9+tranny are my best options.


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## joseph3354 (Apr 2, 2008)

noahmrogers said:


> Can anyone give me a recommendation on lead acids for a 30 mile range? I would like to use the full 156v the logisystems is rated at. That's 13 batteries, and I'll probably need 150 ah at least.
> I don't understand how Mike's pinto gets a 25mile range with 32ah. And does he switch the battery packs to series when he switches the motors to parallel? It's listed as a 360v pack.
> 
> Cliffs:
> ...


john wayland explains the series/parallel shift in a youtube video,from what i understand in series mode each motor only gets half of the full pack voltage.when shifted to parallel each motor then gets full pack voltage which would nearly double rpms.the battery pack is always in the same configuration,the shift is made with the controller(zilla and a hairball).hope this helps.


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## noahmrogers (Nov 9, 2008)

joseph3354 said:


> john wayland explains the series/parallel shift in a youtube video,from what i understand in series mode each motor only gets half of the full pack voltage.when shifted to parallel each motor then gets full pack voltage which would nearly double rpms.the battery pack is always in the same configuration,the shift is made with the controller(zilla and a hairball).hope this helps.


I was assuming that 360 volts to each motor would blow them both as they are rated for maybe 200 max are they not? I'm guessing running them at half amperage saves them after they are switched?

I've been looking into battery life, and it appears that though a lithium pack costs maybe three times as much to start, it's life cycle is three times as great. Also, it's 1/3 the weight. Let's keep on topic though. 

Would it be possible to set up a system for switching between parallel and series under load? Parallel ought to be more efficient, and under light acceleration, why not use it?


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