Solar Panel Battery Charger

[HerringKing]

I have a 12' jon boat that I run with a 45 # thrust minn kota. I'm looking at getting a solar panel charger to put on my boat somewhere. Do they charged while I'm running the electric motor? Does it replace actually charging the battery before the trip or is it just a back up? What size do I need for my small boat?

Thanks for any help

[Gerry Zagorski]

If your intention for solar is to charge your trolling motor battery or extend it's life while using, don't waste your money...

You would need at least 200 watts worth of panels to get any real charging benefit and even @ 200 watts it would take days, not hours to re charge a battery. Not to mention, 200 watts of solar panels would be impractical for a 12 foot boat since they'd be close to the size of your entire boat.

About the only thing most are using solar for on boats is a trickle charge to keep your fully charged batteries topped off over time when the boat is in storage or sitting idle.

[Charlie B]

They are good as a battery maintainer to keep a battery topped off. If you keep your boat in the water at dock or on a mooring they will keep up with self discharge and occasional bilge pump usage or other very light loads but not much more than that. Do the math a small panel is about 15 by 30 inches or so and puts out maybe 15 watts. Even a small 10 amp battery charger puts out a little over 14 volts at 10 amps and that works out to be about 140 watts. So you see you would need about 10 panels to roughly equal a small 10 amp charger...Charlie