Review on 🔌 MakerHawk USB DC-DC Voltage Buck Regulator Step Down Power Supply Module - 9V 12V 24V to 5V Dual USB Output - Buck Voltage Board 3A, 6-26V, Car Charge Charging Regulator (4pcs) by Lequon Kirkpatrick

I bought this UPS for my Raspberry Pi 4 to keep my 2.5" external hard drive from spinning during a power outage. It handles the Pi's current demands for about a day and runs great on both 5V 4A microUSB and battery. The issue only occurs once a day, but it's annoying: It randomly turns off a few hours after the batteries show full charge on the onboard LED display. When I turn off the device, the LED indicator turns off. When I plug it back in, the LEDs say the batteries are low. Disconnect power from the 5V microUSB source and put the Pi on battery until it dies (no LED refresh). HAZARDOUS battery failure (resulting in fire or explosion). Yes, I've tried without a disk and it still shuts down randomly. I also tried connecting the Pi's USB-C input to the UPS's USB-A output. This didn't seem to help much as it would shut down after a power outage and in fact after plugging it back in I could see that the batteries were low according to the LED indicator. I will test this on my Pi 3 to see if it works better. I hope this is a firmware issue and can be fixed in the future. Batteries: 2 new Samsung INR18650-25RM MicroUSB power supply: 4A @ 5V