Battery charge/discharge cycle

First my system setup is as follows

(4) MPP LV6548 two in parallel for split phase 240 volt operation
(24) 12V 100AH LPF batteries configured in two banks of 4s3p each, all four inverters connect to the same bus bars, thus all four share the 2 battery banks
I have (36) 260-watt solar panels configured into three 6s2p configuration. One of the inverters does not have solar connected.
The inverters configuration: SBU, with back grid set at 46V and back to discharge set at 53V


I recently set up an Orange-Pi with Solar Assistant and noticed that my batteries are cycling quickly, that is they discharge over +/- 4 hours and then recharge via the utility grid. The recharge time is relatively short. I find this odd since the power demand at night is low and even though I am trying to use only 50 to 60% of the battery capacity. I should have over 30kWh of capacity, but it behaves like it has much less capacity. I have checked that the individual battery groups (4s) are working, and that none of the battery BMS's have shut down a battery. The oldest batteries are 19 months old and the newest are 13 months old. Hopefully this is just operator error and not an equipment issue. Any thoughts or suggestions would be welcome.

blbaker88 said:

(24) 12V 100AH LPF batteries configured in two banks of 4s3p each,

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Ouch, this is a bad idea.
Do you have 6 battery balancers connected to the 6 strings?
If not, then you have to be the battery balancer.
Because your batteries are out of balance, and this has reduced your capacity.

So much money for a decent set up, seems short sighted not to get native 48v batteries that have BMS monitoring/comms.

what’s your PV charging voltages set to? 52v could be 30% or 85% in SOC.

Have you had any over voltage protection happen on any of the strings?

Do you have a shunt for the system? how else is it determining SOC?

740GLE said:

So much money for a decent set up, seems short sighted not to get native 48v batteries that have BMS monitoring/comms.

what’s your PV charging voltages set to? 52v could be 30% or 85% in SOC.

Have you had any over voltage protection happen on any of the strings?

Do you have a shunt for the system? how else is it determining SOC?

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I am all about the data - I think I would want 6 shunts - one per series string.

And I would want a class T on each series string in case one battery in a string shorted and the other 5 started dumping current into it.