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My boat is a 2005 220 Sundeck,...

Guest Contributor

My boat is a 2005 220 Sundeck, 5.0L Mercruiser, very low hours (bought last year with just over 100 hours in 15 years - older couple who didn't use it much and kept it really nicely, stored in dry dock).


Getting it ready for the season (late, long story) and I think my battery is bad. Cutoff switch was properly turned off over the winter  when the boat was professionally winterized late September (Pacific NW). When I tried my first start the system beeped several times and then the gauges reset. Same happens when try moving the trim - it moves, slows down as though the battery is close to dead, then the same beeping/resetting.


Battery looks easy to change and I'm reasonably handy. Want to get on the water and not waste more of the short season here. Am I being too aggressive/missing something? I can find the same Interstate battery locally, plus other equivalents marine batteries (e.g. Optima at Autozone).


Guest Contributor
Check the battery voltage and compare to a "voltage / % charge" chart. (google it) That will tell you the state of the battery. If its below about 60% charge it with a smart charger. If it drops below 12.4 volts after a few days, the battery is shot. Initially, if its below 40%, just buy a new battery. Batteries need to be maintained over winter, not just left in the boat. Auto Zone makes the best marine batteries today.

Guest Contributor
Thanks, perfect advice. Battery was shot, bought a new one, boat fired right up. And got to use my multimeter which I'd forgotten I had.