Re: AGM battery equalisation


greatketch@...
 

Paul,

I won't comment on the West Marine brand specifically, but MOST AGM batteries can not be safely equalized.

But... you are likely being mislead by your instruments.  Your battery meter measures the [Amps into the battery] and [Amps out] multiplies by an [efficiency factor] and subtracts to calculate [Amps used], and then divides by the size of the battery bank that was entered when it was setup.  Very small errors in this calculation can add up over time to cause the meter to miss report the state of charge. There is no way this kind of meter will actually measure a decline in capacity of the batteries, in its calculation it ALWAYS uses the battery capacity that was initially entered into its memory.

Best thing to do is to fully charge the batteries. Plug in to shore power and run the battery charger overnight at least, if that is possible. Then reset the meter to read 100% charge.  Your only real way to measure the capacity of the batteries is to draw them down, and watch the voltage drop.  If the voltage is lower than it used to be when the meter reports a "50%" state of charge, then that reflects a decline in capacity.

Bill Kinney
SM160, Harmonie
Georgetown, Great Exuma Is., Bahamas


---In amelyachtowners@..., <sharongbrown@...> wrote :

Hi all,

I have what seems to be a charging issue with my West Marine AGM92 batteries. They do not seem to be accepting a charge past about 75% capacity. They are 4.5 years old. Am I correct in that these batteries can be equalised? Would this solve the problem? If so would anyone know for how long equalisation should be carried out for and at wht voltage?

Cheers,
Paul
Ya Fohi - Amel 54 #98


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