Battery Equalization

Discussions regarding electronics, gear and other equipment of maintenance issues that ARE NOT SPECIFIC to a certain PDQ model yacht
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phild
skipper
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Posts: 85
Joined: Fri Jul 14, 2006 4:54 pm
Location: Marblehead, MA (36094)

Battery Equalization

Post by phild »

I'm looking for member experiences with "equalizing" wet cell batteries. On the one hand I understand that equalizing on a regular basis (not sure what regular is?) will extend battery life and improve performance. On the other I read about the potential for gasing and explosion concerns, especially for maintenance free or sealed batteries!

Assuming equalizing is a good thing:
1) How often should it be done? How long does it take?
2) Is shore power required? Do the engines need to be running or are the solar panels sufficient?
3) Are all batteries equalized - both start as well as house?
4) Have the results been noticeable?

Thanks!
Phil and Mary DiDomenico
s/v Arabella
36094

"There is more to sailing than ropes and winches, cleats and bulging sails. There are faraway places and the everchanging light, and the silence, and a great peace at the bottom of your soul." - Mate
duetto
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Location: ICW (32043)

Re: Battery Equalization

Post by duetto »

hi phil,

first let me say that i'm not an expert on this, though i have done it a couple of times.

i believe it is usually done to "blow off" the sulfation that accumulates on battery plates which have been on a low charge voltage for an extended period of time(i.e. winter storage or at a dock on charger for long periods). i don't believe sealed batteries, even if they are wet cells, are a candidate for equalization. i think that you'll need a charge source which has an equalization function built in which means the ability to raise the voltage to somewhere around 16V. i think this means a battery charger. i have done it while anchored using our genset. our charger at the time was a prosine 2000. not sure i can say it was good or bad but we're still using the same sam's club exide golfcart batteries. i would recommend just doing house bank. it takes about 15 mins to do and you should be monitoring the specific gravity of the battery and battery temperature.

hope this helps.
john & diane cummings
duetto mv34 #23
Tanah-Keeta
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Re: Battery Equalization

Post by Tanah-Keeta »

I performed an equalization cycle several times on Tanah-Keeta.

I had the Heart Freedom 20 charger/inverter.

The instructions with the charger were to top off all cells first, then start the equalization cycle. This is an automatic function that the charger controls once initiated. The cycle lasts for 6-8 hours and the power required is enough to charge the batteries at 15-16 volts. For me, this required shore power. You do not have to remove the battery cell vents but you should open the compartment for venting and make sure no ignition sources are close.

Make sure that any voltage sensitive equipment... like your fridge or freezer are turned off.

You should test the specific gravity of each cell and record the value before the cycle begins and do it again afterward. You should find the initial measurements having large deviations and the final almost all the same. If not, buy new batteries.

This should only be done on wet cell vented deep cycle batteries.... not maintenance free, glass mat or auto batteries.

You should do this about once per year or when you see a wide variance in cell to cell specific gravity.

Let me know if you have other questions.
Ron McDaniel
TK III 34108
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