Solar battery charger info please

[Pappy24]

Need to keep a 12volt deep cycle battery charged on the boat. Used for VHF radio/stereo/cabin lighting. Confused on what size solar charger and do I need a controller? Thanks for any insight and boat safe. Thanks

 

[H20Rat]

Re: Solar battery charger info please

First of all, why is your battery going dead, and how dead? Are you just trying to give it a maintenance charge, or is your charging system not keeping up for some reason? Without more info, the correct answer could be 1 sq foot of solar cell to cover the top of your boat with cells...

 

[Jim Hawkins]

Re: Solar battery charger info please

It depends. If the solar will be the only source for recharging this battery then you will need to figure several things. How much sun do you get, what is the drain on the battery? If you need to charge the battery as opposed to just keeping it topped off when not in use then you will need a charge controller.

What is the load on the battery, how many amps are you drawing and for how long (average)

Also to recharge a 12V battery you should have at least 14.4V and a full charge would be 12.8 V with the charger disconnected. You should not let your battery discharge below 12.4 V if you can help it or you will shorten the life of the battery considerably.

A small 1' sq. solar panel is meant to keep a battery topped off when not in use and does not require a controller but it will not work to charge a battery under load.