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Old 09-14-2015, 10:54 AM   #2
JohnnieB
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E-Z-GO
 
Join Date: Jun 2011
Location: West Virginia
Posts: 19,654
Default Re: 42 volt EZGO Upgrade to 48 volt

There is a bit of a misconception about higher amp controllers allowing the motor to produce more torque on inclines and hills.

Granted, a higher amp controller allows the motor to draw more amps, but a motor can only draw more amps at RPMs lower than it is typically spinning when going up an incline or climbing a hill. Basically, unless the hill is steep enough to bog the cart down to walking speeds or less, a higher amp controller won't speed it up going uphill.

Of course you need a controller that will pass enough amps to obtain optimal low end performance from the motor, but how many amps a motor draws, which determines the amount of torque produced, is limited by the motor's RPM and the voltage applied.

Upping the pack voltage from 42V to 48V will increase both the upper end torque as well as the lower end torque by 16.7%, so the cart will have a higher top speed and won't slow down to as low of a speed going uphill.

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FWIW: I have a SepEx drive, which doesn't slow as much going uphill as Series drives. I also have very short tires (17" tall), so 42V maxes my motor RPM out on level ground (6500RPM) and with a DCX controller I couldn't go to 48V without the possibility of over-revving my motor. The XCT controller I'm now running has user adjustable RPM limiting, so I can now go to 48V and have the XCT controller limit my motor to my motor's manufacturer's max recommended RPM. With my tire height, my top speed will be about 26.5 MPH due to the RPM limiting, which is done by reducing the duty-cycle of the controller's PWM output, but when I encounter a hill, the controller is going to try to maintain the motor RPM at the max limit by increasimg the duty-cycle of the PWM. If the hill is steep enough, the PWM will reach 100% duty-cycle and then the cart will start slowing down, but it will still be going upwards of 16.7% faster than it would have been on the same hill with a 42V battery pack.
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