tpbrady
Guru
I have 6 FireFly batteries arranged in 2 banks that are performing strangely.
Under a 20 amp load on a single bank with a theoretical capacity of 348AH, after about 4 hours drawing around 20 amps (81 amps on the Smart Shunt), I start getting low voltage alarms and the voltage under load has dropped to 11.57. After removing the load the voltage recovered to 12.57V in just a few hours indicating greater than 80% SOC.
This morning I continued the recommended recovery procedure which involves drawing down a fully charged battery to 10.5v and fully charging it. I put a 12 amp load on one bank which should draw the batteries down to 10.5v resting in around 30 hours. To speed the process up, I switched the bank over to running the inverter putting a 20A load with the starting voltage of 12.5v while running the 12A load already on the bank. With combined load of 32A on the bank, the inverter switched off within 20 minutes when the battery voltage reached 11.5v. The battery voltage quickly returned to 12.3v with the 12A load attached.
It seems that a load greater than 20A but less than 32A pushes the battery bank over a cliff where the voltage drops quickly. I have not seen this before. The batteries are 3 years old.
Tom
Under a 20 amp load on a single bank with a theoretical capacity of 348AH, after about 4 hours drawing around 20 amps (81 amps on the Smart Shunt), I start getting low voltage alarms and the voltage under load has dropped to 11.57. After removing the load the voltage recovered to 12.57V in just a few hours indicating greater than 80% SOC.
This morning I continued the recommended recovery procedure which involves drawing down a fully charged battery to 10.5v and fully charging it. I put a 12 amp load on one bank which should draw the batteries down to 10.5v resting in around 30 hours. To speed the process up, I switched the bank over to running the inverter putting a 20A load with the starting voltage of 12.5v while running the 12A load already on the bank. With combined load of 32A on the bank, the inverter switched off within 20 minutes when the battery voltage reached 11.5v. The battery voltage quickly returned to 12.3v with the 12A load attached.
It seems that a load greater than 20A but less than 32A pushes the battery bank over a cliff where the voltage drops quickly. I have not seen this before. The batteries are 3 years old.
Tom