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Should battery cells be equalized?

The July 4th holiday weekend sent me into super busy mode so sorry for not posting in a few days. I received an email from a reader today though that asks a good question that I’ll bet a few of you may have.

Dave writes in:


I saw a product advertized as “Battery Equaliser 12 Ounce # BE12oz” which is to increase battery longevity… what do you think?

I have two four year old 8D wet cell batteries and these things are expensive! Cat 3208

120 amp alternator with internal regulator…
Dual Pro 4 stage charger when on shore power…



Well I’m not familiar with the specific product that Dave mentions but I can certainly answer the question about battery cell equalization in a general sense.

Battery cell equalization is one of those maintenance items that where if a little bit is good, more is NOT necessarily better. In fact, this is someting that if overdone, can destroy your batteries. Also, it is something that should never be done with sealed batteries of any type.

Battery equalization is a controlled overcharge of the battery that induces a really violent electrochemical reaction inside the battery’s individual cells. The purpose of this is to literally rattle sulfate particles that accumulate on your battery’s cell plates over time, off the plates and back into the liquid electrolyte. By doing this, you effectively remove these unwanted particles, which act as insulators on the cell plates and reduce the plate’s effective surface area. This reduces the battery’s potential capacity. So, cell equalization is done periodically to maintain what amounts to parity among the cells inside your battery. I don’t recommend doing this any more than once or twice during a typical boating season. Any more frequent than that and you risk damaging the cell plates.

Modern battery chargers will often have this function as a manual selection or automatic function that requires user intervention to activate. Read the manual for the charger to make sure you get it right and do not do it too often!

Personally, I prefer using the PulseTech products I discussed last week over this functionality. It does exactly the same thing in an on-going manner and does not induce the violent reaction that can be damaging to the cell plate material. Each to his own on that count.

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