BYD HVS/HVM connected but the inverter won't charge or discharge it. What do I check?

Plain explanation

From the BYD manual for the Battery-Box Premium HVS/HVM: Check the configuration against BYD's latest Compatible Inverter List (V2.19 or above) and make sure the inverter is configured correctly. Check the app configuration was completed and the firmware is the most recent one. The rest of the checklist is below; work through it in order. Installer only: DC and AC work on a live PV system is dangerous, so owners should note the code and call their installer.

Steps from the source

1. Check the configuration against BYD's latest Compatible Inverter List (V2.19 or above) and make sure the inverter is configured correctly
2. Check the app configuration was completed and the firmware is the most recent one
3. Terminal resistor: one tower, plug it into the IN port. Parallel towers: OUT port of the master and IN port of the last slave
4. Inverter not showing battery SOC and temperature? Confirm the PIN / cable configuration for your inverter model, replace the comm cable (min. CAT5, better CAT7). Fronius and SMA: check the enable signal
5. Connect the Battery-Box directly to the house ground bus, not over the inverter casing or other devices
6. Relay closed? Check for output voltage in Be Connect 2.0 / Be Connect Plus, or whether the inverter shows the battery voltage
7. Defined restart: battery off (LED button 5 s), inverter DC off, AC off, wait 1 minute, battery on, AC on, DC on (Kostal only: pull the PV strings before waiting and reconnect them after battery on)

Source

Where installers ask this

• Fronius Gen24 + BYD: battery no longer charging? (r/fronius)
• reddit.com/r/DeutschePhotovoltaik/comments/1vjn81v/
• reddit.com/r/fronius/comments/1i11q4t/
• reddit.com/r/DeutschePhotovoltaik/comments/1pfn6m1/
• reddit.com/r/DeutschePhotovoltaik/comments/1ckxc0b/

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.