Will your boat’s batteries survive the winter? You certainly don’t want to wait for spring to find the answer to that question. If your batteries are in fact dead when you try to start the season, they can be brought back to life; it’s not the end of the world. But it’s definitely a hassle you don’t want to have. Here’s some advice from Practical Sailor (for these purposes, batteries work the same way on powerboats and sailboats) about steps you can take to help your batteries last until warm weather.
If you’ve removed the batteries from the boat, store them in a cool place, such as your basement or a garage, where the temperature is not likely to drop too far below freezing. Then you should bring the batteries up to a full charge at least once a month. This may not always be possible, but if you keep the batteries fully charged, you shouldn’t have to worry about the electrolyte freezing.
If you keep a house battery on the boat, take the usual steps to make sure it’s healthy: Clean the posts, fill the electrolyte and eliminate any loads that could cause it to discharge. And then check the voltage and recharging on a monthly basis. Read more:
https://www.practical-sailor.com/blog/Boat-Battery-Winter-Storage-10697-1.html
