Winter Battery Cae

[PrinceWilliamSound]

I have a Ranger 31 in Alaska and would like information on battery care during winter. We have a winter temperature range of -20 to 40 degrees F. The batteries are AGM. Do I need to be concerned about low temperatures below freezing on AGM batteries? Since the battery banks are located in the side compartments on either side of the engine compartment, they would be exposed to colder temperatures than the engine room and cabin of the boat where I would have my space heaters. Would that be a problem for AGM batteries? Would keeping their charge up with the boat's battery charger be adequate or should I provide separate heat to those compartments? Thanks for any information on winter care of AGM batteries. The boat will be stored in our backyard and have power on board.

John Schoen
Anchorage, AK

 

[knotflying]

Battery capacity is reduced by 50% at -22 degrees F – but battery LIFE increases by about 60%. Battery life is reduced at higher temperatures – for every 15 degrees F over 77, battery life is cut in half. This holds true for ANY type of lead-acid battery, whether sealed, Gel, AGM, industrial or whatever.

 

[PrinceWilliamSound]

Thank you. I am assuming that with heat in the engine room and the batteries on trickle charge (in the storage on either side of the engine room) that this should be adequate to maintain the batteries over winter.

John

 

[knotflying]

I would think so. I know the batteries on the 31 are difficult to get to and removing them would not be fun. However, if you are really concerned you can always take them out and bring them home. Quite frankly, I always took the winter layup as an opportunity. I would remove them and clean up all the terminals and the battery storage area in the spring and then reconnect everything. If you are leaving them in for the winter, I would pull the fuses on all the 24/7 items. Granted you will be doing a trickle charge, but one never knows. If the boat is covered and no water can get in the bilge I would probably pull the fuses on the bilge pumps also. If one goes crazy and engages, there goes a battery!