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I'm researching motors and controllers for a small EV build and am confused about what I'm reading about what seem to be very high current golf cart controllers. People on golf cart forums are talking about upgrading their controllers from 300 amps to 400 amps or higher and getting improved performance. These are carts running on 36 or 48 volts. This would put the motors north of 20hp max, far higher than these motors are actually rated. For the motors these things run, I wouldn't think they'd pull more than about 150 amps, nor that the batteries could even put that out, so I don't understand how performance would improve. This is relevant to me because I am looking at controllers in the 80-110amp range to power a a motor around 5-10hp and this has me wondering if I'm way under powered.
 

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Continuous fortunately is not the same as peak.
If a DC motor is rated for 10HP, you can get 30-40Hp through it for a minute or two.
You'll want more amps because of the way motors work - specifically back EMF.

At low speeds, the motor voltage is low, so to get lots of power you need high motor amps - P=VI.
Then at higher speeds the volts increase so you use less motor amps for the same power.

Battery amps stay the same for the same power.

Hope that makes sense :)

-Isaac
 
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