Solar Battery Charger for 3rd battery/ radio

[psavas]

Morning all!

I have a concept I am trying to work out. We do a lot of hanging out on the "Disappearing Island" and I want to figure out a way to run my stereo directly to a battery that can be recharged/ continuously charged by a solar panel as to not kill my batteries and be stranded.

Has anyone done this? I see solar panels that are all different sizes and wattages. I know my radio needs at least 11 volts to power on. I have found this solar panel here - http://www.earthtechproducts.com/guardian-charge-controller-kit.html that will run 15amps and is only 5.5"x2.5 inches; small enough to be portable or possibly mount to some sort of rod holder.

Any help would be great!

 

[wish2fish]

15 watts not amps?

I can't imagine you could run anything with a solar powered charger of that size. I use a solar panel to charge my boat lift battery. it is approximately 20" x 25". I can easily run the battery down during the day if I do too many ups/downs.

Might be better off with a jump starter.

 

[Lazy Daze]

The 5"... you're looking at the controller specs, not the panel. If you look at the picture, you can easily tell that the panel is not 5". Page down a little further and you'll see the panel specs. 15W is nowhere enough to power a radio. With solar charging, it's not about the volts - that's easy. It's how much power (watts or amps) you can get.

Find out how much your radio draws (amps) per hour and start there. You can guess till the cows come in, but without knowing the specs, it's just that - guessing (and probably wasting money, too).

Get a larger deep cycle (or two) or even a couple golf cart batteries. You might need a dedicated charger for those, though, as the run back in may not be enough to charge the battery by the engine. But since you have a lot of sun down there, and depending on how many days you go before boating again, you may be able to at least use a solar charge to replenish when you're back in the slip.