Accuracy of measurements

Has anyone done an assessment of the accuracy of the measurements provided by the UPS HAT v2?

I’m comparing the measurements provided by my UPS HAT with multimeter readings and the accuracy leaves a lot to be desired:

  • the USB-C input voltage is 5.13V but the HAT reports input=4.736V
  • the battery voltage is 3.527 but the HAT reports 3.543
  • the battery is charging but the battery info does not report the charge current, which is odd
  • the input current is ~1.7A @5.1V and the system current is reported at 0.7A, which means the battery is charging at significantly less than 1.37A, yet the docs state “Parallel Charging up to 3 Amps while powering the system.”
  • the battery has now been charging for a while (>30 minutes), the voltage is now 3.75V, but the “battery level” is still reported as “1”, I believe the level is in % and 3.75V is certainly not 1% anymore
  • a bit later… the battery is fully charged. I had set “battery_max_charge_level” to 95, however, the battery charged to 4.19V, which is 99%+, so the “max charge level” does not seem to function?
  • “battery_health” says “91”, what does that mean? how is that calculated?

Am I missing something?