Originally Posted by deadtoaster2
So basically what you are saying is that when you begin to go up the hill it would go up to the max current rating of the motor. Once that was reached the motor would begin to overheat and if the motor had a thermal sensor it would set off the little light? However this could be fixed simply by slowing down and trying to get the amps down much lower? By slowing down the rpm's would drop and you would get more torque which would push you up the hill no problem but at a much slower speed?
In an ICE you would downshift to get more torque at a higher RPM, could you do the opposite and up-shift with an electric motor to get lower RPM's, more torque and less amperage draw?
Thanks for answering.
thats not really what he's saying. Just because you're going up a hill doesn't mean you'll automatically max out the controller amps. It all depends on how much current the motor wants per RPM (see the motor torque curve). If you need xxxftlbs of torque to go up a hill, it will correlate to a given xxxAmps.
If 400A is what the motor "wants", and the controller is a good controller, it'l throttle back so that it stays ONLY at 400A and doesn't go past that. If the motor is rated for LESS than 400A, it might start to heat up and smoke. Its best to match the two together, or at least have the motor handle everything the controller can throw at it.
Slowing down RPM's make the torque increase, but higher torque = higher amps. It would push you up the hill at slower speed, but at a higher current. Amps is torque, volts is RPM.
You still downshift with an EV. Upshifting would cause you to lose almost all your generated torque. Best thing to do is to use the transmission to keep the motor in a good spot so that the Amp draw at low vehicle speed is lower.