Hi, despite many "battery" related posts here with interesting info on batteries I opened my new H4 (1950mAh battery there, no sd socket) and measured the voltages at the battery connector. H4 freshly charged over night.
My HP34401A meater reads (aprox. 1min between measurements)
1. H4 turned off, no usb cable: 4.212V
2. H4 turned on, no usb cable: 4.153V +/- 2mV
3. H4 turned on, with active usb cable connected: 4.223V
During step 3 with vbat_offset set to 0 the vbat command returned values from 3682-3823.
My current understanding is as follows:
1. the battery gets a little bit overcharged
2. the "vbat" ADC reading is pretty noisy (see the graph below), provided it is done via stm32's 12b ADC, with a 2layer pcb and some decoupling the readings should stay within +/- 10mV, imho.
