The boat’s been winterized, you’re removing all of your belongings and wondering “what in the heck do I do with my batteries”?
Marine Batteries need to be maintained throughout the winter. How you maintain them depends on how your boat is stored. If you want the batteries to last the winter and the boat to fire up first thing in the spring follow these simple steps.
For a boat stored on land with the drain plug removed you can take your batteries out of the boat and store them indoors in a heated environment checking them monthly and charging if necessary. Removing the battery from the boat is fine as long as the boat isn’t in danger of collecting water in the bilge and needing the bilge pump to run. It’s not a bad idea to remove the battery boxes with the batteries in order to safely store them preventing anything from falling on the battery and shorting it out.
I use this type of meter to check my batteries charge while they are out of the boat. You can also use a multimeter to check the charge. If you need to charge a battery do not charge it inside of your house. Batteries off gas while charginging and could cause an accumulation of explosive gas inside your house.
If your boat is stored in the water (as mine is every other year) you will need to keep the batteries in the boat to insure the bilge pumps and other systems function. I use my shore line connection and leave my smart battery chargers running all winter. If you don’t have this option at the very least you need to stop by the boat bi-monthly and check / charge the batteries with an approved marine battery charger. I turn off all the breakers and switches for 12 volt powered things I don’t need. Basically I just leave the bilge pumps connected.
Remember! If the batteries die you are at risk of sinking when the bilge pumps fail. It’s also a good idea to stop by the boat after foul weather and insure everything is ok.
As batteries become discharged the electrolyte will have a higher freeze temperature. This can lead to the battery bursting or internal damage to the battery. A fully charged battery has a much lower freeze temperature than a discharged battery.