golf cart charger for power supply?

[kra]

I have a 36 volt 25 amp golf cart battery charger
would this work for a power supply?
I have three 150 oz./in. motors to run on an almost finished cnc router
unipolar motors 1.7v. and 4.7 amp
would 36 volts be too mutch for these motors?
thanks for replies,
Randy

[ViperTX]

Originally Posted by kra I have a 36 volt 25 amp golf cart battery charger would this work for a power supply? I have three 150 oz./in. motors to run on an almost finished cnc router unipolar motors 1.7v. and 4.7 amp would 36 volts be too mutch for these motors? thanks for replies, Randy

It might work...kinda depends on whether it can continuously supply 36 volts at 25 amps. You could try it...open it up and look at the circuitry....if it doesn't have any large capacitors on the output....I suspect that the output is rather a chopped AC cycle then true DC with little ripple.

No, just current limit the motors.

[Al_The_Man]

Many of these chargers are just straight full wave rectification with 120hz ripple, with some fitted with a voltage sense circuit that folds back once the battery voltage comes up to a certain level. You may be able to use the main components if you do not want it as a charger.
Al

[kra]

thanks for your responces
this was just given to me and I haven't looked inside it yet
Randy

[papagolf]

I know this is an old thread but I was pondering the same idea. I was wondering if anyone successfully converted a golf cart charger to a cnc power supply. The one I have is older and the voltage control is shot so basically I have a transformer and two fat diodes. I was thinking that a 20A full wave rectifier and some fat capacitors would do the job. My problem though is that the charger currently puts out 42v expecting a 36v load of batteries. Any thoughts on how I could limit its output?

Thanks!

[mike_Kilroy]

All 4 of my 36v golf cart 20 & 100 amp charges are simply variations of constant voltage transformers with timers on them to prevent over charging. No filtering to speak of. Not a good choice for this. Go to Galil, a-m-c.com, newark, digikey, etc, and buy a small cheap 20-80v filtered output dc supply meant for this.

[sch]

I think the golf cart charger, suitably packaged would be acceptable,
depending on the amperes expected of the supply. Any DC supply
consisting of xformer, diodes and capacitor will drop the voltage
when loaded depending on the load and to some extent the size of
the capacitor. There is an excellent discussion on the gecko site
of parameters involved in this: how to size the supply voltage,
current and capacitor(s) depending on the load. You can look under
the FAQ listing on their forum here or at their website. If you expect
to draw 15-20 amps, you will need a pretty large cap to support this.
Simple way to drop voltage is with series diodes in the output, each
diode absorbs 1.2-1.5v depending on the current, of course the
diodes will need to be rated well above the expected current draw but
diodes are cheap and the result better than a fixed resistor. Gecko
doesn't recommend regulated power supplies for motor drive purposes,
just good filtration.