If I have a spare motorcycle or car battery, and I wire up an off-the-shelf solar trickle charger to it and put the panel in the sun, that will give me a 12v solar power system that won't overcharge, correct?
I know it wouldn't support much of a power draw, but it doesn't need to.
If's it a half-decent charger, that will work perfectly.
Excellent. And is there any reason I can't hook up multiple trickle-chargers in parallel? (equivalent to plugging more than one into a car with multiple cig. ports)
I don't see a major issue with that, but I'm not an expert.
I can tell you our 12x12" solar trickle charger only puts out about 6 watts in full sun. Keeps the battery in our big trailer topped off nicely.
5W should cover what I need, 10w would be plenty.
My H-F panel puts out like 20+ volts in full sun. Don't I need a regulator circuit to avoid overcharging? The instructions (which I did not read before purchase) caution that this is so.
You need a regulator circuit to float it at 13.8-14.2 volts, like an alternator in a car does, this could be as simple as a transistor with a correctly sized resistor on the trigger line(cuts power when voltage passes 14, completes circuit again when it falls below 14). Though 5-10 watts is probably low enough water loss from the overcharging will be negligible, if any.
GameboyRMH wrote: Excellent. And is there any reason I can't hook up multiple trickle-chargers in parallel? (equivalent to plugging more than one into a car with multiple cig. ports)
I assume you mean multiple trickle chargers off the one solar panel to trickle charge multiple batteries? I'd think you can do this, but I don't know why you'd want to - the wattage/current to each trickle charge would be reduced in proportion to the number of chargers connected - 2 equals half the current, 3 chargers equals 1/3 current to each, etc etc. Or do you mean multiple trickle chargers off one panel, all feeding one battery? This would probably work, but I don't know what practical benefit you'd get from it...
I meant multiple panels on one battery - I figure more than one would charge faster when the sun is up.
I notice that some of the panels say they have overcharge protection, guess I'd have to use those to avoid using a regulator between the panels and the battery.
The HF panels are pretty decent for the money, but the control box isn't so stellar. I found that the readings it was giving were a little off from what my multi-meter read. Fortunately, something like this: http://www.amazon.com/SunGuard-SG-4-Controller-Regulator-Morningstar/dp/B000O3O0W2/ref=sr_1_4?ie=UTF8&qid=1404787973&sr=8-4&keywords=sunguard is a cheap solution. You can add on a voltage meter, or just test it from time to time with your multi-meter.
The HF is a great start, but I found that it had quite a bit of a draw on the battery.
I don't think you'd need multiple trickle chargers with multiple panels on one battery. You should be able to wire the panels in parallel, feeding into one trickle charger.
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