Hi all.

I've got a weird SOC reporting problem with my 3 Hubble AM5 units and am looking for some guidance.

Initially, I only had two Hubble AM-5 units installed (with a Sunsynk 12kW 3-phase inverter), and everything worked perfectly - the SOC readings seemed accurate. However, two months later I added another AM-5, and since then the reported SOC has been inconsistent. The batteries would charge to 100%, but during the night they would discharge and when the inverter switched over to Eskom (SOC was below required for that time period), the reported SOC of the batteries would drop, like in the picture below. When the inverted switched back to the batteries later in the night, the reported SOC would go up again. Sometimes this drop could be as steep as 20%.

I initially suspected the batteries were unbalanced, but even after allowing ample time for them to balance, the issue persists. During charging, I've noticed that two batteries sometimes display their third SOC indicator (on a four-level scale), while the third battery is still at its second indicator.

Due to the overcast conditions in February, the batteries failed to charge to 100% for several days. One morning, the reported SOC suddenly dropped from roughly 30% to 0% - a situation that doesn't seem normal.

I have already updated the battery firmware, with the issue persisting. Could it be that the battery I added later has a faulty cell?

Thank you for any assistance.

The balancing is definitely one of the first things to check. It also take a couple of hours usually for multiple batteries to balance. For interest's sake what were the SOCs of the batteries before adding the 3rd? How close was the 3rd to the other 2?

The other thing to check is how they are connected to each other and the inverter - the positive and negative lines must be the same length to prevent working on battery more than the other(s)

On 2025/02/23 at 10:06 PM, stefanb said:

Hi all.

I've got a weird SOC reporting problem with my 3 Hubble AM5 units and am looking for some guidance.

Initially, I only had two Hubble AM-5 units installed (with a Sunsynk 12kW 3-phase inverter), and everything worked perfectly - the SOC readings seemed accurate. However, two months later I added another AM-5, and since then the reported SOC has been inconsistent. The batteries would charge to 100%, but during the night they would discharge and when the inverter switched over to Eskom (SOC was below required for that time period), the reported SOC of the batteries would drop, like in the picture below. When the inverted switched back to the batteries later in the night, the reported SOC would go up again. Sometimes this drop could be as steep as 20%.

I initially suspected the batteries were unbalanced, but even after allowing ample time for them to balance, the issue persists. During charging, I've noticed that two batteries sometimes display their third SOC indicator (on a four-level scale), while the third battery is still at its second indicator.

Due to the overcast conditions in February, the batteries failed to charge to 100% for several days. One morning, the reported SOC suddenly dropped from roughly 30% to 0% - a situation that doesn't seem normal.

I have already updated the battery firmware, with the issue persisting. Could it be that the battery I added later has a faulty cell?

Thank you for any assistance.

Did you make the new battery the master and the older 2 the slaves. Charge batteries normally and then run only 1 battery at a time to 100% and then disconnect it and connect the 2nd and after disconnecting the 2nd connect the 3rd. Ensure the switch settings are correct when doing this. Then connect all 3 after changing the switch settings for more than one battery as per the battery manual. Check and see if things improve.