Another Golf Cart Question

Re: Another Golf Cart Question

Welcome to the forum.

Your batteries are probably standard GC2's: 220 Amp hours.
Normally that would require a minimum of 11 Amps @ 36 Volts or 514 Watts. Check your charger for exact specs if you want full recharge from solar. You could also minimize the solar to a maintenance level.

The charge controller is limited because many of the inexpensive off-the-shelf controllers can't be set at 36 Volts. You'd be looking at a TriStar 45, for example: http://www.solar-electric.com/trts12vochco.html Pretty large capacity which you'd be using less than half of.

You can do it with three well-isolated 12 Volt controllers, plus 12 Volt panels, but that can be expensive too.

Or you can power up an inverter and use the existing 120 VAC charger, which is somewhat less efficient that running DC direct. In that case you would also need to know the charger specs so that its power requirements are met.

If we know how much power we're trying to get we can cost out some different ways of doing it and then you can compare that to running a line.

Re: Another Golf Cart Question

dhertzel wrote: »

Ok, I hear you. What about a maintenance system? Ballpark cost?

Maintenance is much easier as you only need about 2-3 Amps.
Cost gets tricky because small panels cost more per Watt.
One way to do it: Three 12 Volt 45 Watt panels like this: http://www.solar-electric.com/spm040.html $137 * 3 = $411
And three small charge controllers like this: http://www.solar-electric.com/sg-4.html $30 * 3 = $90
You're at just about $500 there.

Re: Another Golf Cart Question

Tobit wrote: »

Even when factoring in shipping? There are many places on the west coast where you can get 200W+ panels for less than $1/watt. However, to ship them here in the North East, many of the west coast distributors quoted me close to $400 in shipping alone. There are several places, Renogy, for one, where you can get 100W mono panels for $150 with free UPS delivery. I have two Renogy 100W poly panels that work great. Sure they aren't Kyocera or some other well known brand but I haven't had any issues with them.

I was lucky when I found Solarworld 275W panels for $1.22/watt delivered.

Yes; large panels cheaper per Watt but more for shipping on individual panels. Switch it to buying a pallet and the economics swing back. But of course with 'GT style' panels you also need more expensive MPPT controller.

You can just about go mad trying to get the best deal these days.

Panels like the Renogy or Solarworld aren't going to work in this application as singles because their Vmp is not high enough to charge a 36 Volt battery bank. So the smaller, more-per-watt panels work out better for maintenance charging. If you were to go for a 'full charging' system the economics would swing back the other way.