What to Do with Your Batteries During Winter Storage

By: Michael Fowler Mechanical Foreman, Somerset Yard

Battery charging has always been a controversial topic. For many years it was recommended to remove batteries from the boat and store them inside with a trickle charger. This proves costly, labor-intensive and sometimes damaging to batteries and their boats. Furthermore, moving these heavy batteries can be dangerous to the technicians handling them; particularly on bigger boats with large, complex battery banks.   

Another approach is using an onboard or portable charging system, which allows owners to keep the batteries on their boat. However, this approach can also damage the batteries and even invites the possibility of an explosive fire. Furthermore, few boat yards (Bristol Marine included) will even allow a vessel to be plugged in unattended due to fear of fire hazard.

What many boat owners don’t realize is that heat and vibration (rather than cold winter temps) are what shortens the life of a battery.  With that said, what is the best way to keep good batteries safe over the winter season and in good working condition in the spring? We at Bristol Marine are taking the advice from an article out of “Ed’s Boat Tips”. Ed Sherman is an author and well known instructor for ABYC (American Boating & Yachting Council) which sets electrical, mechanical and other system standards for the marine industry. Ed’s recommended approach is as follows: bring batteries to a full charge (ideally shortly after haul out), and disconnect the negative terminal. Make sure you don’t leave them hooked up to a charger all winter! This can be dangerous, and will damage your batteries. Once charged, the self discharge rate of the batteries will keep them up to snuff until June for sure.  

With such controversy over the subject, we are listing towards Ed’s educated advice. These simple steps are the best, most cost-effective way for preserving the life of your batteries and helping ensure the safety of those handling them.  For more detail, read Ed’s full article on batteries here.