HI All. I have a Kodak OG10 inverter running 4 x Pylontech 5000 batteries. Connected 2 batteries per string. 3 of the batteries is 2 years old and 1 is a year old.

String 1 running 1 x old (slave) and 1 x new battery(Master) is the problem. String 2 is running perfectly together (Both Slave). Everything is controlled via Solar Assistant.

This morning, I noted that Battery 1 is @ 12% state of charge and charging, while battery 2 is at 3% and discharging. Battery 3 and 4 on 15% and 16% and charging

Why would 1 battery be at 3% while the rest is more or less on the same SOC, and why would it be discharging while the rest is charging.

I can confirm all batteries does charge up to 100% when charging

 

 

 

 

 

Edited February 6, 20251 yr by battlingpilot
Amended images

9 hours ago, battlingpilot said:

HI All. I have a Kodak OG10 inverter running 4 x Pylontech 5000 batteries. Connected 2 batteries per string. 3 of the batteries is 2 years old and 1 is a year old.

String 1 running 1 x old (slave) and 1 x new battery(Master) is the problem. String 2 is running perfectly together (Both Slave). Everything is controlled via Solar Assistant.

This morning, I noted that Battery 1 is @ 12% state of charge and charging, while battery 2 is at 3% and discharging. Battery 3 and 4 on 15% and 16% and charging

Why would 1 battery be at 3% while the rest is more or less on the same SOC, and why would it be discharging while the rest is charging.

I can confirm all batteries does charge up to 100% when charging

 

 

 

 

 

Might be a bad cell in that Pack 2 - the max and min voltages are way out compared to the other batteries. When you charge them to 100% how long do you let them balance?

On 2025/02/06 at 8:47 AM, battlingpilot said:

HI All. I have a Kodak OG10 inverter running 4 x Pylontech 5000 batteries. Connected 2 batteries per string. 3 of the batteries is 2 years old and 1 is a year old.

String 1 running 1 x old (slave) and 1 x new battery(Master) is the problem. String 2 is running perfectly together (Both Slave). Everything is controlled via Solar Assistant.

This morning, I noted that Battery 1 is @ 12% state of charge and charging, while battery 2 is at 3% and discharging. Battery 3 and 4 on 15% and 16% and charging

Why would 1 battery be at 3% while the rest is more or less on the same SOC, and why would it be discharging while the rest is charging.

I can confirm all batteries does charge up to 100% when charging

 

 

 

 

 

Battery 2 is at 48.5v while the others are are 48.4v which is likely why 2 is discharging into 1 since it has a higher pressure (and perhaps into 3 and 4, althoug not to sure by what you mean that they are on different strings since the word string is an American term for items connected in series).

The system seems unbalanced when comparing SOC and Volts between the battery packs. When last ware the batteries charged to full based on cell voltages for the cells in each pack to balance and for the SOC measure on the BMS to reset to 100%?

 

Edited February 7, 20251 yr by I84RiS