Hi friend.
The H801MPWD board is an AC power board, consisting of an AC power unit and a monitoring unit. The board supplies power to the device and supports the lead-acid battery for power backup. The AC power unit provides overcurrent protection, output overvoltage protection, short circuit protection, and over-temperature protection. The monitoring unit provides comprehensive management for the power system and storage battery and also provides certain environment monitoring functions.
If the PMU blinks red or red ON, see the following figure:

Thanks.