Generator, and AC to DC conversion

by Mike
(San Antonio, TX)

Generator for a AC to DC Cart

Generator for a AC to DC Cart

I want to power a small electric cart with a generator. I have a Honda 3000 watt generator that I take camping. It's very quiet and has electric start. I want to power an electric golf cart off of the generator, not with golf cart batteries. How could I convert the 120 volt AC to 36 volt DC to replace the batteries?


Hi, Mike!

Dan, our motor man, says:

"I think a 3 Kw generator is too small. This equates to a 4 HP motor. IF it were a decent generator I might say OK but these were not meant for this kind of loading.

I would need to know more about what the intent for the vehicle is i.e. range, speed, etc.

36 VDC will take an industrial charger more than likely. These are generally a 230 volt single phase or 230 or 460 volt 3 phase unit.

If insistent on this setup, I would recommend a 120 V VFD if you can get it in 3 or 4 HP rating and a 3 or 4 HP motor. Geared way down to avoid overload. It can work but the golf cart is going to go real slow."

I'm curious myself, Mike, why don't you want to use batteries?

Regards,
Lynne

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starstarstarstarstar 		your all nuts
by: Gen tech

The generators you described by nature run at governed 3,600 rpm and have a voltage regulator to increase and decrease voltage as the load is applied.
Just for Sh##s and Giggles I will take this seriously.. Understanding typical gold cart motor is 36vdc 7,500watts or about 10Hp.

-Strike one on the load.

Now we have AC to DC..

First: Take a 240vac (or 120) to 48vdc Using a step down transformer. 7.5Kw plus %20 9000w so basically 10KVA to bring it in the range of 48VAC.
Second: That voltage has to be rectified to DC, take the peak voltage and divide by the peak KVA. Somewhere around 208A which the next step up would be 300A worth of diodes to bake a bridge rectifier.That's 8 or doubling it to 8 diodes.
Third: you can't just dump this right into a motor your going to need a buffer or capacitor to absorb , maintain and shield the circuit of voltage and current rushes.

The weight of these items alone ,Generator, transformer is in excess of 200-300lbs and the dollar expense you already bought a gas powered golf cart twice over.
Rating
starstarstarstarstar 		batter charging
by: okie

get a 36 volt cart chager they come in 120 and plug the chager into your generator .
Rating
starstarstarstarstar 		ac to dc for bike
by: tony

i have an ac generator rated at 120 vac 800w/900 max, the specs say 2 hp. i need it to run a dc bicycle wheel hub motor which requires 36 vdc @10 amp/hours (whatever those are)my kaput lithium ion batt always put out 42 vdc, so i'm thinking i should go with 42.my own crude calculations tell me that i'll only require 450 watts. any suggestions?...and how does one go about it?
Rating
starstarstarstarstar 		36 volt generator
by: bubba clark

I too need a 36 volt generator for my golf car. I'm planning to run it off the batteries but if I go very far I need a generator to be sure I can get back home.

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