# Electric Motor Choice



## major (Apr 4, 2008)

Those would be 6.6" dia (possible 7.2, but I doubt it) and maybe 70 pounds each. Sorta like a golf cart motor on steroids. There was a Prestolie model looking like that with a helical gear cut into output shaft. That'd be tough to work with. And two motors? I think for that money, you'd be able to find a bit larger single motor and make conversion a whole lot easier.
Regards,
major


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## Cutlass_442 (Nov 21, 2019)

Thanks for the information, I'll check back in with the guy to get a more accurate description. And I plan on using two DC motors because my cutlass weighs around 3500 lbs and I'd like it to be able to travel at 70 mph with out too much trouble for around 100 miles.


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## skweeks_n_leeks (Dec 29, 2019)

Cutlass_442 said:


> Thanks for the information, I'll check back in with the guy to get a more accurate description. And I plan on using two DC motors because my cutlass weighs around 3500 lbs and I'd like it to be able to travel at 70 mph with out too much trouble for around 100 miles.


You can do that with one motor if it’s the right size and type. Battery pack and controller will typically be your limiting factors.


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## Cutlass_442 (Nov 21, 2019)

I have been reading a lot of conflicting information about what is the best method. If my car were smaller, one motor would be ok but mine is just so heavy. I imagine 1 9" or an 11" motor could move it but not quickly.


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## skweeks_n_leeks (Dec 29, 2019)

Cutlass_442 said:


> I have been reading a lot of conflicting information about what is the best method. If my car were smaller, one motor would be ok but mine is just so heavy. I imagine 1 9" or an 11" motor could move it but not quickly.


There are plenty of pickup trucks In the 3500-4000lb built with single GE 11” motors. There is a popular Jeep XJ that was about 3800lbs prior to conversion running a single 9”. A guy built a F250 and that called for 2 motors. I am currently building a 2wd F150 with a single 11.5” motor that weighs 187lbs. My truck is only 3300lbs prior to stripping. My drivetrain is 750lbs alone. You’ll get to 70 mph with proper gearing and controller. You want to advance the motor, have a battery pack of at least 120-144v and continuous amps around 500. That’ll allow hopefully around 72kw or almost 100hp. The torque is why conversions are fun though. If you don’t want DC look into a Nissan Leaf.

Edit: The 100 mile range will be heavily dependent on batteries. For the truck I’m building it’s a lead sled for around some land. Top range of 30 miles but will do 60mph. You’ll definitely want to look into packs from a Tesla, Leaf, or Volt to get that range.


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## Cutlass_442 (Nov 21, 2019)

Really? Thats amazing! What GE motor are you using? I did a quick google search for an 11" GE motor and I found a GE 11 frame but its small. That would great not to have to use 2 motors. Thanks for the info!


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## Duncan (Dec 8, 2008)

I'm using an 11 inch Hitachi motor

I'm really impressed with the way it goes - it's rated at 10 Kw but if you treble the speed - as you will at 60 mph - then that would be 30 kw - the fan will be moving three times as much air so 60 kw would look sensible

My car is about as aerodynamic as a brick flying sideways - so a pickup would not be any worse and it takes about 25 kw for 60 mph

Pickup would have more frontal area - but it should still be OK


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## skweeks_n_leeks (Dec 29, 2019)

I got mine out of an old Clark forklift. There are a few eBay sellers that have great options. Search industrial forklift motor. Here’s what you want to look for: that it is series wound, has the capability for a front and rear bearing, an output shaft, and something over 100lbs. In most cases your freight will be about the same cost as the motor. Check out my Motor A or B thread on here for details of the motor me and another member on here are both using. Both motors were under $500. I wouldn’t spend more than that on a used one.


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## ElectriCar (Jun 15, 2008)

Cutlass_442 said:


> Thanks for the information, I'll check back in with the guy to get a more accurate description. And I plan on using two DC motors because my cutlass weighs around 3500 lbs and I'd like it to be able to travel at 70 mph with out too much trouble for around 100 miles.


I blew my Advance 9” running 80mph for about 10 miles. Ran it at high rpm for cooling and it wasn’t hot when it let go. It would peg the speedo at 85 and still be pulling hard! Had it set for 700A max. 165V pack. Starting up a Kostov 11 any day. Haven’t had it running since 2013 so I’m getting excited about it! Hope it’s a better motor. I don’t think the current killed that motor but I blew 2 of them and they both let go exactly the same way, starting after a stop. It started to pull for a second each time then nothing.


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## ElectriCar (Jun 15, 2008)

Duncan said:


> I'm using an 11 inch Hitachi motor
> 
> I'm really impressed with the way it goes - it's rated at 10 Kw but if you treble the speed - as you will at 60 mph - then that would be 30 kw - the fan will be moving three times as much air so 60 kw would look sensible
> 
> ...


Curious how you calculate that. I have a 91 S10 with 50 Calb 200 batteries and it easily did 85 and still pulling hard. But I blew it running 80 for 10 miles. 😂


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## Duncan (Dec 8, 2008)

ElectriCar said:


> Curious how you calculate that. I have a 91 S10 with 50 Calb 200 batteries and it easily did 85 and still pulling hard. But I blew it running 80 for 10 miles. 😂


From your comment your motor did not overheat!! something else killed it

Logic
10 kw - 200 amps and 48 volts and 1400 rpm
Three times that rpm at the same current will give the same amount of heating (200 amps) but three times the power - so it is the same in terms of heat at 30 kw
At the higher rpm's the fan will be shifting more air so it will be able to cope with MORE heat

60 kw at three times the rpm is roughly equivalent to 10 kw at the lower rpm in terms of heat load

I'm greedy I don't feed my 11 inch Hitachi with 200 amps

I feed it with 1200 amps and up to 340 volts


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