Check this thread ,https://forum.seeedstudio.com/t/xiao-nrf52840-recharging-3v-18650-battery/268260/2?u=pj_glasso second post has the link for it, plus good info related to Batt.
HTH
GL 
PJ
Check this thread ,https://forum.seeedstudio.com/t/xiao-nrf52840-recharging-3v-18650-battery/268260/2?u=pj_glasso second post has the link for it, plus good info related to Batt.
HTH
GL PJ