Maintenance free battery maintenance ???

Moody Blue

Captain
Joined
May 24, 2004
Messages
3,136
I have a DEKA Marine Master starting battery that is the maintenance free type. My motor, a 1992 40HP mariner, puts out 15-17V when running flat out. I have been told that this high charge voltage could boil off the water in the battery and that I should check it frequently. From what I can see, this battery is completely sealed. I could try and pry off what looks like a factory installed cover but it looks quite permanent. I don't want to boil the battery dry but I also don't want to try to open something that was not intended to be opened. Any suggestions ?
 

briannh1234

Petty Officer 1st Class
Joined
May 19, 2003
Messages
233
Re: Maintenance free battery maintenance ???

If it's trully sealed then there's nothing that you can do to maintain that battery. If the high voltage is really bothering you then you could install an accessory to pull the voltage back down. (Something that uses alot of watts, like those electric coolers) Some people have also resorted to installing a voltage regulator.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
Re: Maintenance free battery maintenance ???

Rod, Sometimes the manufacturer used a sticker to cover the access to the cells. You can slit it with a razor and then have access to the cells. Also, if you look for the vents on each cell (it must have these) it may give a clue as to where the access is located.<br /><br />You can also install a zener diode to shunt the excess voltage to ground. Ideally you would want a 13.5V (or therabouts) heavy duty zener. I'm not sure where you could find one, maybe a google search would turn up something.
 
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