Battery Anomaly

[Eichfeld]

Hello all,

I have a strange battery problem.
Setup: 16 mightyMax MLD4 batteries, (200 AH @ 12v SLA) Connected to make 800 Ah @ 48V. (4 parallel strings of 4 batteries in series)

This system is about 1 year old. I have been babying it for a year (not letting it get below 80% SOC ) for that time, and all looks pretty good, all batteries in spec.

Recently, i was seeing 1 battery out of the 16 drop to 11.3V to 11.5V when the system is under a 100Ah load (5 kWh or so). The other 15 were at 12.4V. I was at ~90% SOC based on the battery monitor. This did not happen when at ~95% SOC.

When the system dropped back to 60Ah, the voltage of the battery recovered to 12.5V or so, within .2V of the other batteries.

What in the world could be wrong? Sulfaction? A dried out cell?
Ideas?

Thanks much for any advice!
-timothy

 

[Hank Waconda]

Hello all,

I have a strange battery problem.
Setup: 16 mightyMax MLD4 batteries, (200 AH @ 12v SLA) Connected to make 800 Ah @ 48V. (4 parallel strings of 4 batteries in series)

This system is about 1 year old. I have been babying it for a year (not letting it get below 80% SOC ) for that time, and all looks pretty good, all batteries in spec.

Recently, i was seeing 1 battery out of the 16 drop to 11.3V to 11.5V when the system is under a 100Ah load (5 kWh or so). The other 15 were at 12.4V. I was at ~90% SOC based on the battery monitor. This did not happen when at ~95% SOC.

When the system dropped back to 60Ah, the voltage of the battery recovered to 12.5V or so, within .2V of the other batteries.

What in the world could be wrong? Sulfaction? A dried out cell?
Ideas?

Thanks much for any advice!
-timothy

I would say check all your connections....I don't think you can equalize agms. Maybe isolate that battery that is low and charge and test it.