What is the battery cutoff voltage current consumption condition of the pi-juice

[JustEnoughDucks]

Hello,

I am making a device where I am using a pijuice zero, a pi 4, and a custom PCB in between (just due to low pijuice stock and plentiful pijuice zero stock). I am using the pijuice 12000mAh battery as I have a screen attached which sucks away a lot of power.

I have a concern about the sleep current of the pijuice relative to the battery voltage. I have measured with a Keysight 1147B current probe that the power off current of the pijuice is on average 1.65mA. Though a bit of error with non-invasive probes.

This is generally fine for a solar UPS where the battery will get recharged automatically, but for other applications it is possible that it keeps sucking battery until the battery is fully drained.

My question is how far will the battery drain? In the hardware section of the documentation here, it says that the cut-off voltage is 3V. Is this internally regulated through the battery or will the Pijuice continue pulling ~1.65mA under 3V? It seem as though the charge controller/DC-DC has a "supplemental mode" where it will continue operation until the battery is at 2.5V (which is in the danger zone for battery degradation through deep discharge). Is this only in the case of an overcurrent case, or can this also happen due to battery discharge after it has reached 3V?

The LDO then also has quiescent current that is quite high (~25 to 50 uA estimate based off of the component marking since there is no part number in the schematic) because it is always on until the battery is deeply discharged. I have measured the 12000mAh battery discharged to an open circuit voltage of <3.0 results in a 2.7V on the 3v3 net. There is still some source of battery drain that might be a still-active STM32 since the drop-out voltage of VDD is 2V, and it seems as though the battery will feed the LDO until it is deeply discharged and possibly damaged (if it is sitting on a shelf for a year for example)