Solar charger for boat batteries

Thinking a solar charger for my 3 boat batteries. Do Rainy Lake houseboat annually, hate running and listening to a 4-cylinder gas engine to charge 3 batteries. Also, we have a pontoon on a 15-acre lake with no plug in by the water. And shoot at a 6-stand shooting coarse we have to pull batteries to charge them. Wondering how many watts you would need to charge 3 batteries in a reasonable amount of time. I very often fish alone, or with one person and always the dog in a 18.5′ boat. If it’s not too physically large. It could be in the boat while I’m fishing, maybe use a seat base mount. Rainy is the primary interest, a small one would do the pontoon and rotate through the thrower batteries.

stevenoak wrote:

Wondering how many watts you would need to charge 3 batteries in a reasonable amount of time.

Very difficult to answer this question because everything depends on what you consider a reasonable period of time AND how deep do you discharge the batteries before you start charging them?

The pontoon on a small lake is easy. Any decent solar charger will work, all the way down to 3-5 watt models if it’s just for the starting battery. I use these small units on my tractor at my hunting property and they keep the battery topped up and ready to go.

Charging deep cycle batteries on a trip is more complicated. All depends on how much you discharge your batteries during use. If you’re fishing all day most days then you’ll need an option that will work in the boat, but you also need a lot of watts which means a big panel.

If you’re mainly a morning and evening guy and the boat is tied to the houseboat during the peak sun hours, then you can go bigger on wattage and panel size.

A 30 watt panel is something like 30×15 inches and that will produce only 2.5 amps at peak power, so likely the reasonable average charge rate is going to be only 1-2 ahr charge rate on average. Which is pretty slow. That’s kind of a good benchmark, you have to see how big of a panel you’re willing to have based on your fishing and size limits.

Would work on your remote lake but would no way produce enough amps on a weekly trip. The panel size you would need to charge your battery in a short amount of time would be bigger then your boat. As grouse has said you would need more information to determine recharge and discharge amount on your other locations.