# curious on battery replacement



## AngerManagment (Jul 10, 2009)

I just wanted to see what most of you guys have been doing on replacing your batteries. I got a used boat last year and I truly dont know how old the batteries are. I think they test OK but i have heard some people say they just replace batteries every 2-3 years regardless of how they test. I just hate to get out there come mid april and find out one battery isnt charging like it should.

Thanks guys


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## bocajemma (Dec 29, 2008)

With you not knowing the age of the batteries I would definitely reccomend replacing one. (assuming there are two or more batteries on board) My personal preference on batteries is to have one starting battery and one dual purpose battery with more than enough cranking amps to start my boat (454 inboard). The only thing typically connected to my starting battery is my starter and lights. My dual purpose runs all my electronics. But if my starting battery were to fail or my alternater were to fail I always have my dual purpose battery availabe at the flick of a switch to get me back to dock safely. I keep both fully charged at the dock with my on-board charger.


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## Gottagofishn (Nov 18, 2009)

I agree with Boca. I don't have a switch to change batteries with but I do have a plug near the starting battery that I can jump from the trolling batteries if needed. I keep that starting battery fresh and replace it before there is ever any question.


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## oarfish (May 12, 2004)

Sam's has Energizer brand marine batteries, cheap (in boating terms) I woud replace them. What size (kind) is your boat ? Is there a selecting switch?


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## Papascott (Apr 22, 2004)

IMHO if you replace one replace them both unless they are completly independant of each other. Personally I like to carry a jumper pack, the little portable ones with the jumper cables on them, for those oh crap times we all have had or will have.


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## SwollenGoat (Apr 13, 2005)

oarfish said:


> Sam's has Energizer brand marine batteries, cheap (in boating terms) I woud replace them. What size (kind) is your boat ? Is there a selecting switch?


+1 on the Sam's club Energizers. 
Mine have worked great and been a good value for the price.


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## papaperch (Apr 12, 2004)

I would test any battery before replacing it. Batteries should be tested with a load on it.

All you need is a multimeter and a car headlight. One of those inexpensive night fishing light that use a headlight encased in styrofoam will do. Do not use LED lights they do not draw enough current. With multimeter take voltage reading on battery. It should be sliightly over 13 volts on a freshly charged battery. Now connect light and take another voltage reading with light on.. If your voltage drops more than 1 volt with light on chances are the battery needs replaced.

Another way is to use a hydrometer which measures the specific gravity of your battery acid. Auto parts stores sell them. A freshly charged battery should give you a reading of
1.270 or better in each cell. Of course this cannot be done on sealed batteries. Then you are stuck with method one.

When you use a hydrometer make sure to check each cell. As it is quite possible to have one bad cell and five good ones. One bad cell will seriously degrade performance. By the way the hydometer is a inexpensive tool.


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