No charge controller?

Volvo Farmer · June 2012

Just wondering what you folks thought of this... I recently got a used golf cart with six T105 type batteries in it wired for 36V. I scrounged up what I believe to be three 50W solar panels that will fit on the roof. I think I'm going to get somewhere between 2.5 and 3 amps out of these panels. So I'll be charging at something lower than c/30. Do I even need a charge controller? I might use a little water, but is there any way I'm going to hurt full batteries charging at this rate for 5-6 hours/day?

I suppose if I actually run the batteries down 50%, there's no way they are going to get fully charged, even if I let them charge for two weeks between uses. Anyone have an opinion on that? Golf cart charger is a major load on my off grid system!

waynefromnscanada · June 2012

Re: No charge controller?

With such a small charge current, you probably don't need a controller. On the other hand, if you actually use the batteries to power anything, they're not going to get recharged, and that will kill them.

Cariboocoot · June 2012

Re: No charge controller?

There are some other threads on the forum regarding charging 36 Volt golf carts from solar panels. Most of them were dealing with larger panels, but the basic inequity still remains: a lot of battery with a little panel.

Let's see what we can find:

http://forum.solar-electric.com/showthread.php?9193-36-volts

http://forum.solar-electric.com/showthread.php?9680-Charging-36V-golf-Cart-battery-bank-with-3-12V-panels

http://forum.solar-electric.com/showthread.php?10309-Solar-Power-for-EZ-GO-Golf-cart

mike95490 · June 2012

Re: No charge controller?

Generally, raw panels do not have anti-backfeed diodes in them, they rely on the charge controller to do that. So with 5 sun hours, and 12 night hours, you may DISCHARGE the batteries, unless you put a diode in, or disconnect at night.

Look for about a 10 A Schottky diode to do the job http://www.solar-electric.com/blocdiod8amp.html

No charge controller?

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