Winter Battery Care For Your Boat

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So, you have had your boat winterized, your cover is ready to be put on, but wait… Did you remember proper battery care? It’s important to take proper care of your battery during the off-season in order to save yourself a lot of money in the spring because you have to purchase a new one. Nobody wants to have all of the kids loaded up in the boat, excited for the first day on the lake, and…click…dead battery….


*Note: these recommendations are for boats not stored in the water (land, lift, facility, etc) for the winter months. Boats that are stored in the water must have batteries hooked up for bilge pumps, heaters, etc.

During or after your winterization:

  1. Perform regular maintenance including removing corrosion
  2. Charge the batteries one final time. This will ensure they’ll completely recharge next season and reduces the risk of a frozen battery during the cold winter months.
  3. Disconnect terminals to remove all loads from the batteries. All electronics have parasitic loads that cause a “vampire draw” even if they are powered off. Batteries also discharge themselves, so combined with the draw, it’s enough to leave you with a weak or dead battery in the spring. *Make sure you’ve trimmed your motor down to storage level (100% down) before your disconnect!
  4. Remove batteries, storing them in a cool, dry place where they won’t freeze. (We recommend on a wood surface, in a garage or storage facility)
  5. Ideally, trickle charge batteries with a marine charger or charge them monthly. This will prevent discharge over time and will help your battery life last longer. Fully charged batteries are much less prone to freezing as well.
  6. To make charging easier, make sure to store your batteries where they are easy to access.
  7. Confirm that your charger is designed for your battery type. See the information below in choosing the right charger.

Other tips for battery longevity:

  • The maximum safe discharge for a battery is 80%
  • Don’t mix old batteries with new ones
  • Install a battery switch for quick “turn off” during the boating season – this will make a world of difference in your battery life.

Worried your battery might be failing? Ask our Service Department about load testing!

As we said above, if your boat is not stored on the water, the best plan is to take your batteries to a dry, semi-conditioned space (ex. The garage). Regardless of where your boat is stored for the winter (water or land), if you do leave your batteries in the boat, make sure the battery cables are tight and free of corrosion. Coat the connections with a corrosion inhibitor, and leave them hooked up to a marine charger with a float setting OR leave them completely disconnected and mark your calendar to make sure to charge them once a month.

WARNING: DO NOT use an automotive charger for extended periods of time! Batteries that are left on an automotive trickle charger for a long period of time run the risk of boiling off the electrolyte, or possibly exploding. It is very important that your charger be marine-specific. **This is a very important point especially for gel and AGM type batteries.

Marine batteries today perform best when they are charged using a marine “smart charger.” These chargers vary the charge and match the charging voltage to what the battery can accept. Our parts specialists at all locations will always be happy to assist you in finding the perfect charger for your application!

If you’re looking into buying a charger, you’ll want to look for the following features:

  • A 3-stage charger with bulk, absorption, and float stages (or 4-stage with pre-float stage) and battery type selection
  • The output of 25-40% of the battery bank capacity (in amp-hours)
  • Temperature sensing for adjustment of charger output
  • An equalization phase for use with flooded cell batteries
  • Ignition protection (if charger to be installed in an engine compartment)

As always, give our parts and service professionals a call for any assistance needed in picking a battery, charger, or having a battery switch or charger install completed!

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