Top 10 Tips for Keeping Your Boat Battery Charged

Captain Toby

From the Desk of Captain Toby

Ugh! Stranded with a dead or dying battery. We have all been there whether on a car or a boat. Unfortunately, the battery problem on a boat is usually much harder to rectify than on a car.

Many problems are avoidable with common sense maintenance and a few handy tips.

Boat Batteries: The Facts

  • Extreme heat or extreme cold will shorten boat battery lifespan.
  • If the battery has been fully discharged, it may never recover or retain charge effectively.
  • Battery life tends to expire at the end fairly quickly and without much warning.
  • Even brand new, fully-charged batteries that aren’t connected to anything will discharge over time.
  • While all new batteries have a guaranteed shelf-life, a small percentage will be duds.

Captain Toby’s Boat Battery Tips

  • Check the shelf life of your battery. Replace when due. It’s smart maintenance.
  • Make sure your battery is always fully charged when not in use.
  • Always check that the terminal’s connections are tight and corrosion-free.
  • Smear grease or Vaseline around the terminals to stop any corrosion.
  • Monitor the battery voltage. If your battery is below 11.9V, you’ll have problems.
  • If your battery is reading more than 15V, it’s overcharging and will be irreparably damaged. It may even explode.
  • Solar panel chargers are inexpensive and can help keep a battery charged.
  • At the first inkling of trouble — like slow cranking when starting — take action. Don’t put it off. The next time will be too late.
  • If in doubt, get your batteries checked at an auto battery center.
  • If still in doubt, replace your batteries!

Toby Kilner is the Head Technician for Boat Fix with over 30 years of 24/7 experience of diagnosing and fixing mechanical problems at sea.

Over 60% of Boat Fix alarms are from low battery voltage.

Scroll to top