How Do I Top Off and Equalize A Battery?

[Arlou52]

I read that I should use a generator once every 10 days to top off my 12 volt (two 6 volt in series) 280 Ah AGM battery bank, and about once every month run an EQ charge. Can I use an automotive 50 amp charger to top off rather than a generator? How long should I charge it and what indicator am I looking for to know it’s topped off? How exactly do I run an EQ charge with a charger if I can do this?

[Mike90250]

STOP. Get the manual for your batteries. AGM batteries are seldom "equalized". They sometimes can be given a poor mans EQ by using a long Absorb cycle. Your battery manual/spec sheet is the authority if you want to retain the warranty.

AGM are sealed, and the cells have a catalyst pack that recombines the Oxygen gas and the Hydrogen gas back into water and is reused by the cell. When overcharged the catalyst cant's keep up, pressure builds, the case swells, and then the relief vents are supposed to pop open and release the gas. Gas released, will never be returned as water, and so the cell looses capacity.

The scheme I use for my NiFe batteries, is to run the generator in the early AM, and bulk charge the batteries, That is efficient use of fuel, and then by 9am, the batteries are on solar for the long absorb cycle.

[Sunking]

I read that I should use a generator once every 10 days to top off my 12 volt (two 6 volt in series) 280 Ah AGM battery

AGM huh?

[AL1952]

STOP. Get the manual for your batteries. AGM batteries are seldom "equalized". They sometimes can be given a poor mans EQ by using a long Absorb cycle.

So most controller sold that have an AGM preset automatically DON'T try to EQ a battery? I saw one that looked like it did an EQ on AGM that didn't make sense except it may be a long absorb cycle.

[Mike90250]

I have no idea what crazy ad copy comes from charge controller companies, nor how all their gear works ( or doesn't )

AGM batteries do not get EQ'd like flooded batteries do. The factory battery manual/datasheet should cover what the care & feeding would be. Match that with the data from the charge controller you are considering.

[Sunking]

OK I am going to jump in here. Yes you can EQ a AGM battery. However it is not the same as FLA or even the same voltages. In fact same voltage as the normal charging voltage. Here is a short article from the the folks who invented the AGM battery for military (Concorde). Lifeline is their consumer line. Concorde makes the worlds best AGM battery.. In the article they tell you their batteries can be EQ provided you have their permission and follow their instructions to the letter.

In a nutshell what they are saying is their are some applications that do not allow the user to fully recharge their battery each day after use. The give an example with a customer who has a sail boat and batteries wer only lasting two years. With their help was able to get 5 years with a proper EQ procedure.

Like I have said for years, you cannot fully recharge a battery on solar unless the system is grossly over sized or under utilized. You have to have a genny for weekly full Saturation Charges and periodic EQ charges. Having said that a EQ charge on an AGM is nothing more than a full Saturation Charge. It does not raise th evoltag elike you would a FLA battery, you just run the charger for a full 24 hours on your GENERATOR. Solar cannot do that.

Bottom line is EQ does not have any real meaning. Depends on battery type. It is just a voltage like Float, Bulk, Absorb. They can all be the exact same voltage.