Hi guys,

I'm stumped and would appreciate some advice on my solar installation. 

I have 2x Growatt SPF 5000 ES inverters connected to 2x Averge (Leoch) 100Ah 51.2V Lithium batteries. I also have 20x 415W solar panels connected.

Batteries talk to the inverters via BMS (CAN) and the system ran faultlessly for 1 1/2 years. Recently the system started tripping the power. Instead of allowing the system to switch from battery to AC at night, the system would switch off completely. I discovered that the batteries were not discharging at the same rate. The one battery (master) would run down completely to cut-off point and the inverter would switch-off and go into fault mode. I decided to do a manual changeover at night before the batterties are drained until I've resolved the problem. In sunshine the Master battery will resume charging but the slave never charges. I think the system is only running off the Master battery at the moment. The Slave remains at 60% SOC. If I manually switch the system off at night the master battery will charge the slave (equalise) until the point where cut-off is reached on the Master battery. I updated both batteries' firmware and BMS seems to work as the combined battery SOC is displayed on the inverter. Ave of the 2 batteries. 

Any ideas?

Edited February 18, 20251 yr by Henryc

Do they share the batteries or are they connect to there own battery?

I would start by testing the batteries individually, i.e. connect what you now have as the slave as a single primary battery. Then monitor the behavior.
Or switch your two batteries around, i.e. configure your Slave as Primary and the primary as slave and monitor.

On 2025/02/18 at 3:15 PM, Henryc said:

I have 2x Growatt SPF 5000 ES inverters connected to 2x Averge (Leoch) 100Ah 51.2V Lithium batteries. I also have 20x 415W solar panels connected.

Is the 2x Growatt inverters parallel configured?

@Henryc

The assumption here is that you have the 48100S model battery. It has a RS232 port. From the Leoch manuals I have read, you can use PBMS Tools V2.5 to monitor each battery individually - also meaning these batteries actually have a Pace BMS). You should get screens like this:

Check the Alarm, Protect & Fault Status first, as any OV/UV alarms will indicate Over/Under Voltage etc.

If none, then check and observe the VoltDiff parameter during a full charge/discharge cycle....Yes, you need lots of patience, as this parameter mostly only goes haywire during times when batteries are stressed, not when idling/floating.

If it is a Voltdiff problem, just check which cell/s is the offending weak cells. You would need to replace those cells and balance them before re-assembly. You also preferably need to balance the whole battery before re-commissioning the whole battery pack.

If all looks OK, however, look at SOH parameter. Depending on age, this could be 90-80%, age/usage dependent. Mine are still at 100% after 4 years of hard work, so I would not expect your to be much lower. 

Another reason could be chronic undercharging & lack of balancing, as the battery manufactures tend to set the limit of this too low, and the cells never get's the chance to balance properly, hence the VoltDiff being high.  That can be set under the Systems Config page. 

From what I can see, these batteries is LiFePo4 type, so you must read up on what values to use for balancing to kick in earlier. Batteries with NMC cells e.g. Hubble AM-2's have completely different values.

Hope this helps.

On 2025/02/19 at 4:07 PM, Sidewinder said:

From the Leoch manuals I have read, you can use PBMS Tools V2.5 to monitor each battery individually

I received PmodToolsV3.0.13 to monitor and change settings in LEOCH 48100S packs. It supports RS232 but monitors only the pack it is connected to. For monitoring the entire battery bank I was referred to PmodbusToos V1.20. This slightly different software supports RS485 and can monitor all packs connected to the RS485 bus individually by selecting the appropriate pack number. I have 3 48100TB and 3 48100S all connected parallel and on the RS485 bus. But on the 48100S packs it was necessary to change the protocol with PmodTools in order to activate the RS485 ports. I installed a RS485 data line (approx 7m) from the battery shack to my office where I monitor the batteries and inverters.

Edited February 23, 20251 yr by Beat