# Motor Selection



## Ziggythewiz (May 16, 2010)

That motor should be fine. Go 144V. I recommend not merging into oncoming traffic.

Most DC motors don't like spinning too fast. Best is usually around 3000 RPM so you'd want at least 4th gear for hwy, maybe even 5th for passing power.

You probably can't do 50 hwy miles on the 100AH cells with much room to spare, but depends what the car weighs and especially how aerodynamic it is.


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## Yabert (Feb 7, 2010)

dsscrusher said:


> The motor at 144v, will do 5600rpm correct?


No, that depend of the load on motor. It will do 5600 rpm when developping 30 lbs-ft of torque, but as low than 3600 rpm at 100 lbs-ft of torque.

I also think that the small Kostov 9 can do a very good work in a small car like a metro. The 100 lbs-ft of torque at 500A will give you better performance than stock engine. Don't hesitate to go for 144v instead of 120v.


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## dsscrusher (Apr 3, 2008)

Thanks for the feedback.

So to keep the RPM down and less shifting, I could use a different Metro tranny. The stock one has the highest final drive ratio, there are other versions of this tranny that have a lower final drive. I can redo the numbers but I probably could get the rpm down to 3500 in 3rd. In that case I could keep it in 2nd or 3rd all the time. I had planned on picking up a second tranny because I will probably buy a parts car and do all my mock up on it, while driving my car on gas. It may take a while to work on those battery boxes and motor mounts. Not to mention $.

I was leaning to the 144v range. My Cd is 0.32 and my frontage is 20 sq. ft. The plan is to block the grill, make underpan, mirror delete, and even a kamback, along with low RR tires, and synthetics all around. I would like to squeeze into the 50 mile range because I am not sure my work will let me charge. The facility installed all of these IPLC (IPLC dot com) units that restrict voltage and current based on outside temps for block heaters only.


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## dsscrusher (Apr 3, 2008)

Just curious though, I could go with the ADC FB1-4001 but not sure why one over the other. The 9" Kostov seems to have more torque, smaller in size and weight, and is cheaper than the ADC. For a small car I don't think the Warp or Impulse Netgain products are needed.


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## Ziggythewiz (May 16, 2010)

Yeah, just make sure you get the specs on whatever motor you plan to use. The RPM I use my 6.7" at would kill a 9".


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## mora (Nov 11, 2009)

I run my 9" 220V Kostov at 144V and regularly do 5000rpm in third gear (continously, keeping up highway speeds). If its flat road I'll change to fourth gear. Been doing so for two years, no problems. I have limited my motor amps to 400 and battery amps to 270. It does fine but acceleration suffers after ~3000rpm. I can't go faster than 80mph in fourth gear, rpm just won't rise. Higher voltage would help to keep motor amps high at higher rpms but Open Revolt won't handle more than 144V safely. Battery amps at 100km/h (~60mph) are something like 120. My car weighs ~2200lbs. Your 50 mile goal will be realistic if you choose next battery Ah level. 130Ah maybe? Otherwise 50 mile drive will push batteries to the limits.

If you can make your clutch handle the torque at 500 motor amps during acceleration you will likely accomplish your "better than stock acceleration" goal.


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## dsscrusher (Apr 3, 2008)

My drive is flat as well. Weight would be more around the 1800-1900 lbs. Based on textbook numbers from stock. I will be removing as much weight as possible. And if I can, only charge at home. One challenge is the size of 130ah batteries. I plan on putting batteries under the rear seat like dtbaker has done. Because I need to insulate the battery boxes, I don't want too many locations. So I will probably going to use the spare tire trunk space as well.


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## Yabert (Feb 7, 2010)

dsscrusher said:


> The 9" Kostov seems to have more torque, smaller in size and weight, and is cheaper than the ADC.


No, yes and yes.


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