@JahFyahh - I still haven't managed to et round to it. I've been really busy since this project and its still hectic here. I'm sure i read a few reviews somewhere, here or google. Not sure.
@Puneit-Thukral
Could you post your full working sketch please?
I'm revisiting some of my 51822 nodes that have sat collecting dust for a long time and thought i might try to get them working again.
@alexsh1 the reason i am using the 18650's is the fact i have a steady stream of them coming in for my large battery packs. I have a couple hundred that aren't dead but just aren't quite up to to the standard i am putting in my big packs.
@4994james or just use internal vcc measurement as described on the same page. That saves you the voltage divider.
I wrote a convenient library to measure vcc internally : https://github.com/Yveaux/Arduino_Vcc