Winter AGM battery storage

[max from alaska]

I have a 2014 R27 with AGM batteries. Would appreciate guidance on the best way to maintain the batteries during outdoor winter storage. My goal is to best preserve their performance and life.

Temps often are subzero here in Alaska. I prefer not to remove the batteries or disconnect them.

I have been leaving the shore power plugged in and the battery charger on all winter.

 

[Ralf H]

Hi Max,

The first thing I would recommend would be to check the manufacturer recommendations on how low of a temperature the batteries can operate in. If the low temps fit in that range, you should be ok to leave them in the boat and charging with the charger. Just make sure they are inspected regularly, along with all other electrical equipment you have in use. Having said that, the best would still be to remove them and keep them in a more temperate area for storage and maintenance. But if that will not work, then the above should keep them in good shape. Hope this helps.

Cheers,

Ralf

 

[knotflying]

My choice would be to remove them and apply a trickle charge as needed. I used to remove them and join all four in parallel and checked the voltage monthly. If the voltage dropped a little I would hook up a trickle charger to top them off. Removing them once a year gives you the opportunity to clean up the storage box and clean up all connections at the same time.

 

[allanrs74@gmail.com]

Max,
I store my R-27 in Soldotna with no heat or electricity, so I have no choice but to remove the batteries to a warm garage in Anchorage where I can keep them charged and warm. The first time I removed them I very carefully labeled each wire and post and took some photos. It now takes me about an hour to remove and install them but I have peace of mind that nothing will happen to the batteries over the winter.
Do you know who's tug overturned on the Seward Highway last weekend on the black ice?

Regards,
Bob Allan
2016 Annie M R 27C

 

[Mantra]

Hey Guys and Gals; I've got a similar question so thought I would start on this thread and see where it goes. I'm also in AK with a Ranger 31, I've got 6 batteries that are not going to be removed. The boat is stored outside, all winterized but I'm concerned about the batteries when the temps start dropping below 10 degrees. Is anyone running cabin heat? I'm not trying to keep the temps on the batteries above freezing but I'd like to keep them from freezing. The boat is plugged in. I've considered some type of heat in the battery compartment; incondensent light or battery blankets. I'd like to hear about what other people are doing and what seems to work besides pulling the batteries and putting them in the garage.

 

[max from alaska]

Ralf - thank you for the input. My batteries are the Universal Power Group UB121100 which Fluid Motion uses. I called the manufacturer and they said to charge at 32 F or higher, and not to go below 5 F during storage. These values are on the battery spec sheet as well. The gist of what I gleaned from the conversation was that the batteries won’t freeze if fully charged, but at colder temperatures the charging process is compromised and, if partial charge results then the partially charged zone is susceptible to freezing which could damage the battery. The biggest concern is about a fully discharged battery freezing, then exploding if an attempt is made to charge them while frozen. I can see why the temperature limits are set at conservative values.

Bob - I don’t know the owners of the overturned tug but there’s a discussion on Alaska Tugnuts