Power Hat cannot detect input current

I have noticed an issue with the Power HAT.

I came home to find all LEDs of connected devices flickering. I pulled power to it to investigate.

The attached battery was drained even though it was connected to the wall via 12v power supply.

When I use the python power_api it cannot detect input current but it can detect the voltage correctly.

My assumption here is that since it cannot detect the input current it thinks there is no current so it starts to drain the battery and once that runs out it flickers since it can’t get enough power to the devices.

I reset to factory settings, and have reset the MCU but it still cannot detect the input current. It seems to work okay without the battery attached.

Anyone seen this?

Hi @cecil ,

About your question, please help to confirm the following information:

  1. What is the software and Power Python API version?
  2. Make sure that the current supplied through the input is sufficient. For the 12V input voltage, the minimum is 1.5A.
  3. What is the output of get_input_current?


Hi, thanks for the response.

  • Firmware version 0.3.22
  • Software version: 0.4.2
  • get_input_current: 0.0 (which it can’t be if the device is on)

This is what is reported in the power UI. There is no battery connected at this time, and I just tried a different power supply to make sure that wasn’t the issue.

Can you test it using the official Raspberry Pi adapter, please?
Does the input current appear to be ‘0’ as before?

Also, note that you should not use it without a battery.

So this Pi has gone out to production, its currently in the field. It has a backup battery. I have a staging Pi setup that is connected with an official 5v 2a charger, I can add a backup battery to it and see if I get this result, though I doubt it.

My current theory is that the bq25703a TI IC is detecting overvoltage of the battery and as a result it is “bleeding” the battery to prevent damage. So it temporarily discharges the battery to lower its voltage.