Pylontech US2000C - different SOC after a few days

[grasmax]

After just a few hours of discharging (no charging via solar or city power), the modules have different residual capacities.

"Overvoltage errors" occurred in the module with the lowest remaining capacity.

[mi-hol]

Did firmware updates resolve this issue?

[grasmax]

No.
And I am not satisfied with the pylontech support.

[grasmax]

Power off Juli, 13th 2023 20:00:
613 47,491 ,325-.326 21,5°C
615 46,527 ,324-.326 21,5°C
606 45,466 ,325-.326 21,3°C
843 45,303 ,325-.326 20,5°C

Check at September, 1st 2023 10:00
module number Ah CellVoltage Temperatue Voltage
613 47,468 ,333-.333 18,2-18,5°C 49,995V
615 46,525 ,332-.333 18 -18,2°C 49,982
606 45,464 ,332-.334 18 – 18,2°C 50,009
843 45,301 ,333-.334 18 – 18,1°C 50,008

It is unclear, whether the capacity really has not changed.
Or whether only storage statuses are read digitally and these are only changed when electricity flows in or out.

[mi-hol]

It is unclear, whether the capacity really has not changed.

capacity means column Ah, right?
but I see a slight reduction i.e. module 613 went from 47,491 Ah down to 47,468 Ah

Do I read it wrong?

[grasmax]

Genau DAS meine ich mit gesunder Unschärfe: 0,03Ah in 7 Wochen.
Im Betrieb traten hingegen krasse Differenzen auf, die, wenn man sie nicht bemerkt und ausgleicht, wahrscheinlich zur Tiefenentladung und Zerstörung führen. Beispiel 16.6.2023:
20,6Ah 3,276-.278 19,4°C
24,4 ,276-,277 -->ca 50%
24,7 ,275-,277
15,2 ,275-,277 18,5°C --> ca 30%

[mi-hol]

m Betrieb traten hingegen krasse Differenzen auf, die, wenn man sie nicht bemerkt und ausgleicht, wahrscheinlich zur Tiefenentladung und Zerstörung führen

Es gilt der alte Spruch "Versuch macht klug", die Versprechen des Herstellers stehen dem entgegen

[grasmax]

Stand am Anfang des Test am 6.9.
613 47,468 ,333-.333 18,2-18,5°C 49,995V
615 46,525 ,332-.333 18 -18,2°C 49,982
606 45,464 ,332-.334 18 – 18,2°C 50,009
843 45,301 ,333-.334 18 – 18,1°C 50,008

Stand am 14.9. 0730: seltsam: alle 4 Module zeigen 2/6 LED = 30% an!
613 7,53Ah ,256 - ,258 48,86V
615 12,14 (25%) ,254 - ,259 48,84
606 9,37 ,255 - ,260 48,86V
843 5,46 (10%!) ,256 - ,259 48,86V