New BYD battery: SOC jumps around and it doesn't seem to use full capacity. Is that a fault?

Plain explanation

From the BYD manual for the Battery-Box Premium HVS/HVM: New modules ship at about 30% – SOC starts as a placeholder. SOC calibrates within a full charge/discharge cycle. The rest of the checklist is below; work through it in order. Owners can do the app and visual checks; any work on the wiring is for the installer.

Steps from the source

1. New modules ship at about 30% – SOC starts as a placeholder
2. SOC calibrates within a full charge/discharge cycle
3. SOC jumps are normal – let it run full cycles

Source

Where installers ask this

• BYD Akku entlädt nicht komplett (r/DeutschePhotovoltaik)

General guidance based on the manufacturer's manual or the named source. Always follow the current manual for your exact model and your national code. DC and AC electrical work is for qualified installers only. Not affiliated with or endorsed by any brand named; trademarks belong to their owners.