Looking for advice on older battery bank

[Deegore]

I was given some 155ah marathon agm batteries that are about 5 years old. I tested them by fully charging them one at a time and running a 50 watt air pump until my inverter started beeping.
One battery measured 150ah, one 75ah one 100ah, three at 50ah, one at 20ah and one at 10ah.
I will throw out the worst two.
Are the 50s worth connecting to the bank or will they do more harm than good?
I'm just looking to squeeze another year or two out of them before a buy new batteries.

 

[anadiner]

Completely up to you. Ive seen folks with huge mess of everything from scooter, car to boat batteries all strung together.

Mentality of the more the merrier. So its really your choice.

 

[Supervstech]

An agm battery run until inverter started beeping is SEVERELY depleted, and needs rapid AGM recharging ASAP.
Shouldn’t ever be depleted below 12.0V most inverters cut off at 10V and start beeping at 11V… way too low for lead acid.

 

[Supervstech]

I would get an agm specific charger, and see if they can be recovered. Some chargers have a recovery mode that can reverse minor wear from the mesh… but agm is fairly sensitive to damage. They may be too far gone.

 

[Alphacarina]

I was given some 155ah marathon agm batteries that are about 5 years old. I tested them by fully charging them one at a time and running a 50 watt air pump until my inverter started beeping.
One battery measured 150ah, one 75ah one 100ah, three at 50ah, one at 20ah and one at 10ah.
I will throw out the worst two.
Are the 50s worth connecting to the bank or will they do more harm than good?

I would toss the weakest 5 or 6 - Connecting 50AH batteries in parallel with the other, higher rated ones is gonna pull everything down and soon they'll all measure low. Paralleled batteries should be of equal capacity

Don