Turn on the module (it does not need to be connected to a basestation/remote)
Connect the shutoff to a USBC charger or powerbank (5V)
Observe the LED, it will to a slow fade in while charging
When the LED remains off, the charge cycle is finished, this will take around 1h - 1h 30min, depending on the battery state and USBC charger used.
Note: When the shutoff is powered via USBC it will now drawer power from the battery, only the charging circuit is connected to the battery.
Troubleshooting:
Q: The LED flashes rapidly when I connect the USBC charger
A: Turn on the shutoff before connecting the charger
Q: The led keeps fading and never remains off
A: If the USBC charger used can not deliver the right amount of current, the charging circuit will slow the charge process.
or the battery might be damaged (voltage <3.0V), if this is the case discard the battery and replace it.