David Nebenzahl wrote:

On 2/26/2009 11:26 AM David Nebenzahl spake thus:

Told a guy I'd do some research for him into a small simple solar system
for use in maintaining the charge on a 12 volt automotive battery.

Update: I'm going to recommend this small charger from Harbor Freight to
the guy:

http://www.harborfreight.com/cpi/cta...emnumber=41144

It's a 5-watt[1] panel for $37. Should be good for starters to see how
he likes the idea, and to figure out how to mount it, etc. (The vehicle
is a truck with a camper shell.)

Thanks to all those who answered with helpful advice. To those who
warned of dire consequences of overcharging, I don't think we have to
worry about that with the relatively small currents here. Keep in mind
I'm not designing a mil-spec system, but a solution for someone who
currently has to drag his batteries (physically) to be charged
regularly; this should make life better for him.

[1] Yes, I know, advertised power output: the actual output (under load)
is probably close enough for our purposes here.


You should really get a meter on the battery in question and find out
what the standby load on it is. Then you can get a better idea of what
sized panel would be needed to keep up with it.