Battery status for the Guition JC8012P4A1 (ESP32-P4, battery version)

What I'd like

On the JC8012P4A1 battery version, expose the battery status as entities in Home Assistant:

• battery level (%) and/or voltage
• whether the screen is running on battery or on USB power
• whether it is charging (if the hardware allows it)

Related

Wish #21 concluded that the 4848S040 cannot read its battery state. This request is about the JC8012P4A1 (ESP32-P4), a different board with its own power circuit, so its schematic may be worth checking separately.

Why

• The screen keeps running on battery when USB power is lost, but there is no way to see this in Home Assistant.
• With a battery level you could automate charging with a smart plug in front of the USB power supply (e.g. charge between 20 and 80 %), which is kinder to the cell than sitting at 100 % on a wall panel all the time.
• A "running on battery" state would also be useful as a power-failure warning, and to dim the screen or go to standby earlier to save power.

My setup

Board	Guition JC8012P4A1C_I_W_Y1 (10.1", speaker + battery version)
SKU	10153002-V3 (Tessera detects it as jc8012p4a1v3)
Firmware	Tessera 0.60.0 / ESPHome 2026.9.0
Manager app	0.4.97

I don't know whether this board routes the battery voltage to an ADC pin of the ESP32-P4 or has a readable charger IC. If it does, I'm happy to test!

Thanks! 🙏