Is it usual for batteries to drop 20% in 2 mins?

I have 20kWh Lion batteries on a Multiplus II 5kva 48v Every night at the start of cheap rate the batteries start charging they jump from 35% SOC to 55% SOC after 2 mins of charge. Then the moment charging stops they drop from 100% to 80% immediately. This system has been in for only 1 month, but it just seems very odd. Is this normal or to be expected? any ideas on what is going on? Much appreciated.

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Matthias Lange - DE ♦ commented · Oct 02, 2022 at 08:10 AM

We need more information about your System.

What components do you have? What batteries? Settings? Wiring?

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busta999 Matthias Lange - DE ♦ commented · Oct 02, 2022 at 08:20 AM

New to all of this so apologies if doing something wrong.

MultiPlus-II 48/5000/70-50 230V

Leoch - 48-100TCAN Lithium (LiFePO4) Pack - (51.2V/100Ah/5.12kWh)

Victron Cerbo GX - Control & Monitoring Hub Victron GX Touch 70 - Control & Monitoring screen

Victron Lynx Distributor - Modular Fused Busbar (Inc. fuses)

Victron Lynx Power In - Modular Busbar Victron VE.Bus Comms Cable 1,8 m VE.Can to CAN-bus BMS type A Cable 5 m RS485 to USB interface 5m

25mm Black Battery cable

70mm Black Battery Cable

Battery Isolator 300A

What additional config do you require, the Victron is set to Auto for BMS and it is using the Leoch BMS.

Looking the displays for each of the 4 5kWh batteries you can see three have an SOC of say ~ 72% +/- 2% and one, the top one is showing an SOC of ~53%.

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