Tom McQuinn wrote:
Since several of you are expert in electronics and engineering, can
anyone take a quick look at this and tell me if this unit would be
advisable to use between the 12V solar panel (13 watt) and a 12V gel
cell? [...] http://store.solar-electric.com/sg-4.html

I don't think I'd call myself an expert, but I have hooked up PV solar
panels before and IMHO this looks like it would do the job. It's even
somewhat sanely priced, something of a rarity in the solar power world.

On the other hand, I also agree with Vaughn Simon. The solar panel you
have is effectively a 1 A charger. If your gel-cell is bigger than
about 10 Ah, and you use some power from it every night, you'd be
hard-pressed to overcharge it with that solar panel alone.

If you have a digital voltmeter, you can check it out at home. Set up
the solar panel and battery, then measure the voltage at the battery
terminals on a sunny afternoon. If it never goes over about 14.80 V,
you're most likely not going to overcharge the battery.

Matt Roberds