Voltage of 5V pin when only connected to battery

It’s an epaper display that works from 3.3V to 5V. It does work at 3.3V but it has an high deep sleep power consumption.

If instead I provide an higher voltage power consumption drops. I’m not sure why, I was advised to try this by the manufacturer.

The difference is substantial: with both Xiao and screen in deep sleep current goes from [email protected] to ~100uA@4V

Max current is 6mA during updates