To use the correct LiPo battery, I would like to know what the charging capacity of the Wireless Paper board is. In other words, what capacity battery do you recommend? I couldn’t find that in the datasheet.
Charging capacity Wireless Paper board
I’m not sure about optimal battery capacity, but the schematic shows that it uses a TP4054 charging IC.
Do with that what you want - and maybe share your wisdom if you know the answer 
Thanks for helping. According to TP4054 info (see below) it has a programmable charge current up to 800 mA So it depends on how Heltec has set this up. I don’t see it yet 
If you’ve got one close by, you can just hook up a battery and USB cable and check the charging current. If you don’t have one, I could give it a shot as it’s on my desk.
I hadn’t thought of that. I measure roughly around 175-180 mA, which is in any case far too high for the 145 mAh battery I intend to use.