Onboard Charger only charges two of four batteries

[Kurtbowman]

I’ve owned the boat for 4 years. Batteries 1 year old. I use the boat every weekend. The last two weekends the two port side batteries are dead when I arrive. I swap them with the starboard batteries and the charger will charge them quickly and fully. What could I be missing?

 

[roscoe]

Details on how the batteries are hooked up, what they are hooked up to, and any switches, breakers, or fuses in the circuit.?

Have you put a meter on any of the charger leads to see if it is working?

 

[Scott Danforth]

welcome aboard

since we can not see how your batteries are connected, or how the charger is wired, or what kind of charger you have, we can only guess.

if batteries are going dead within a week, you have a serious power drain issue or you have dead cells in the batteries. pull the batteries and have them load tested, and check for power draw. assuming this is a slipped boat, with the only house load being a bilge pump and with a properly maintained boat, batteries should be able to go months before needing a charge.

if your charger used to charge all 4 batteries, and now it doesnt, did the charger die? (hook a meter up and check), or are the batteries that far gone it killed that bank of the charger?

 

[Silvertip]

Does this boat have a trolling motor perhaps? If so, a dual bank charger would likely charge only those two and the engine is left to charge the other two. If the boat has an ACR and/or a dual battery switch setup this complicates things and as was mentioned, our crystal ball is in the shop so we can't see your boat. Pictures, diagrams, details needed.