This one is for a permanent-ish node mounted on a pole isolated from external power sources, so I am trying to find best way to use solar panel.
Yes, that would make sense. If I undestood correctly (link my output from solar charger and battery to the xiao USB input) but … that solar charger outputs 3.7V - 4.2V voltage (same as battery) I assume it is a problem if I supply that to the USB of the xiao board, that normally expects 5V no? Or maybe USB power source on these boards accept under 5V?
In this case, isn’t it better to solder my 3.7V - 4.2V output (mentioned in text scheme above) to the 2 xiao battery pins? I am thinking I can/should place a diode to prevent xiao “charging” this external power source (solar+charger+battery).