LoRa Node 151 - battery supply, low power @ 5V supply

I have 3 LoRa Node 151 devices. On all these devices it is not possible to use battery supply. When I disconnect the USB supply, all the devices stop running.
It seems there is no power supply from the battery.
So my 1st question: Is there some action required in the firmware in order do activate supply from battery?

When I use 5V supply, the current consumption is about 500 uA in STOP mode. It should be only a few uA in STOP mode.
So my 2nd question: Does low power mode also work with 5V supply?