Battery boiling over

[Basil]

Some of you know I have 290 watts solar and with that I have four 125 ah batteries and one 80 ah deep cycle battery.
I am using a Xantrey C35 charge controller set to run on a 12 volt bank. The batteries are not old.
The one that is boiling over in only 1 to 1 1/2 years old. It's the second one next to the + battery.
The two behind it is even older.
Loads are hooked + first battery - end battery so the loads pull on all the batteries. Loads are 1000 watt inverter that
is never really used. The dc ceiling fan ( 1 1/2 amp ) 24/7, New dc 20'' box fan ( Around 2 amps, Day time only ).
When they have been pulled down to 12.3, they all boil over a little when charging back up. I have seen 16 amps
at 13.8 or 13.4 volts. I water them better than my garden. They all have the same amount of water.
They did set floating this winter (Months)and have never been below 12.2 volts.
Is that one of the first signs of a battery going bad? 

[DanG]

Just a tip, not saying its happening to you...

Try and top-off when batteries are nearing full charge and warm.

I've flooded a work bay once by watering a cold battery that had low-voltage disconnected, so when power was restored and battery got charging all the cells merrily dribbled out more electrolyte than I thought was possible. A discharged and cold battery will heat up and expand driving electrolyte levels a long way toward escaping.

[TomW]

Basil;

Actually flowing out of the battery or just spitting some out?

The fluid expands as the gas is created but if properly filled they should not spit out too much.

Not sure what you mean by "boiling over".

Bubbling is common and "good" if not excessive and you keep the electrolyte  level up where it should be.

 can actually hear mine when they are gassing (boiling) and I have some spitting under high charge rates but they should not actually force liquid out in any quantity.

Maybe they are too full or there is a problem with the batteries themselves?

Without more information it is hard to help.

Tom

[Basil]

Tom  DanG

Thanks for the fast response.
This one battery is staying wet on top all the time. Yes, I can hear it / them.
The electrolyte level does go down faster on this one battery.
I have to add water to it more often that the others. Never real low, but lower than the others.
I fill it to match the others and it just gasses / boil out and keeps the top of the battery wet.
 ( Slow process ) but it loses electrolyte. Reminds me of the old batterys I started with.
They gassed / boiled over all the time. The old ones I started with worked fine
but just would not charge as high as new batterys. E