# Rebirth style twin motor setup?



## electron bom (Dec 4, 2014)

Rebirth's page has been down for a while and I'm not sure if they even exist anymore. I'm wondering about the possibility of cramming another 11" motor into my car. Please opine. Schematics are warmly welcomed 

Here is my single motor setup. I'll have even more room if I tube frame the front, but I have no means to fabricate a motor coupling piece.


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## Karter2 (Nov 17, 2011)

I guess anything is possible with enough time and money !......
...but why ?
That 11" could probably be massaged to double its output without the added extra weight of a second motor and associated hardware that would likely make it handle like a greased Sumo wrestler on a water bed !


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## electron bom (Dec 4, 2014)

Karter2 said:


> I guess anything is possible with enough time and money !......
> ...but why ?
> That 11" could probably be massaged to double its output without the added extra weight of a second motor and associated hardware that would likely make it handle like a greased Sumo wrestler on a water bed !


 Great metaphor. I know you're right, it would be quite heavy. However, the idea of running them in series and obtaining twice the torque for a given current is extremely appealing.


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## jwiger (Oct 18, 2014)

It doesn't really look like you have the transmission to frame rail clearance for and adapter in there. Does that 11" have any upgrades yet?


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## electron bom (Dec 4, 2014)

Motor is stock. Frame rail will be tubed if a second motor ends up going in. My controller is capable of providing ~370V, but is capped (along with my Li pack) at 1000A. Second motor appears to be the most cost effective way to achieve big torque (500ftlbs) without generating massive heat. My intention in creating this thread was to gain insight on the nuances (cost) of implementing a 2nd motor. I know rebirth's kit was pricey, perhaps it could be done for less.


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## major (Apr 4, 2008)

electron bom said:


> Motor is stock. Frame rail will be tubed if a second motor ends up going in. My controller is capable of providing ~370V, but is capped (along with my Li pack) at 1000A. Second motor appears to be the most cost effective way to achieve big torque (500ftlbs) without generating massive heat. My intention in creating this thread was to gain insight on the nuances (cost) of implementing a 2nd motor. I know rebirth's kit was pricey, perhaps it could be done for less.


The motor is only capable of about half of your battery voltage, so get a 2000 Amp controller. You can limit your battery current to 1000 Amps and get double your torque. I suspect you'll keep busy repairing the tranny, but if you solve that, you may need to boost motor cooling. 

major


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## Duncan (Dec 8, 2008)

If you want twice the torque why not look at sticking another one of those units in the back?


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## electron bom (Dec 4, 2014)

So, no one likes the idea of a rebirth style twin motor kit?

-Possibly cheaper than a high power 2000A controller
-Retain gearbox for multiple ratios
-Less average heat per motor for a given torque output
-More tq/ampere
-More weight
-Design difficulty

Three or four pros and two cons. Am I missing something?


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## palmer_md (Jul 22, 2011)

Evwest has built a lot of dual motor setups. Mostly for the Curtis ac but also for netgain systems. I have a dual netgain 9" setup built by them. I'm sure it will handle dual 11" for the same design. You might give them a call to see how much. They don't list it on the website but I know they have the original CAD files to duplicate it.


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## major (Apr 4, 2008)

electron bom said:


> So, no one likes the idea of a rebirth style twin motor kit?
> 
> -Possibly cheaper than a high power 2000A controller
> -Retain gearbox for multiple ratios
> ...





> -More tq/ampere


 This will be the same for 2 motors with one 1kA controller as for 1 motor with a 2kA controller.


> -Less average heat per motor for a given torque output


 This doesn't mean much unless you're overheating the single motor which is unknown.


> -Retain gearbox for multiple ratios


 This would appear to be much easier (less costly) by a long shot using a single motor.


> -Possibly cheaper than a high power 2000A controller


 I would think the 2kA controller would be less expensive than the additional motor along with the all the special hardware to install it.

I don't see any reason to use 2 motors unless you intend to use two 2kA controllers and use a battery capable of such a system.

I'm basically a motor guy. I generally like bigger and more motor. So use 2 motors if that is your objective. If speed and budget are your objectives, two motors with a single 1kA controller is counterproductive.

major


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## electron bom (Dec 4, 2014)

palmer_md said:


> Evwest has built a lot of dual motor setups. Mostly for the Curtis ac but also for netgain systems. I have a dual netgain 9" setup built by them. I'm sure it will handle dual 11" for the same design. You might give them a call to see how much. They don't list it on the website but I know they have the original CAD files to duplicate it.


Thanks for the tip 



> This will be the same for 2 motors with one 1kA controller as for 1 motor with a 2kA controller.


Admittedly I've never supplied 2000A to a Warp 11 before, but I think I can only agree with that statement if we ignore the effect of temperature on resistivity.


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## electron bom (Dec 4, 2014)

major said:


> I'm basically a motor guy. I generally like bigger and more motor. So use 2 motors if that is your objective. If speed and budget are your objectives, two motors with a single 1kA controller is counterproductive.
> 
> major


I appreciate your insight, I understand its backed by significant experience.


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