Best Way To Keep A Boat Battery Charged Without Access To Shore Power

Updated 08/18/2026 | Published 08/12/2026

Question:

how can i use a battery maintainer to keep my boat batteries charged while it is in a storage unit with no available AC power? Can i use an inverter connected to the 12 V battery that produces 120VAC power and then just plug the battery maintainer power cord into its AC oultet? Seems like this scenario would not work. ??? Thank you

asked by: Dave E

Expert Reply:

Hey Dave, thanks for reaching out. Your gut is right. An inverter connected to the same battery that you're trying to maintain isn't going to accomplish anything. The inverter takes 12V DC from the battery and converts it to 120V AC, then the maintainer converts that 120V AC back to DC and sends it right back to the battery. Every conversion loses some energy, plus the inverter itself draws power just sitting there. The end result is a battery that slowly discharges rather than maintains itself.

With no AC power available, go with a 12V solar battery maintainer instead. A small solar panel with a built-in charge controller connects directly to the boat battery and keeps it topped off whenever sunlight is available. The Bright Way Solar Battery Charger # BRW54FR is what I recommend. It comes with a 7.5 watt solar panel and a 16' cord. That'll be the best setup for keeping a boat battery charged when you don't have access to shore power.

What kind of boat do you have? What is your storage situation like?

expert reply by: Jesse M