Ring doorbell 2020 release won’t fully recharge

This is my second winter to have my Ring doorbells (2020 release). I am using the battery since it is not hardwired. This year, we’ve had a few cold snaps (windchill down to -45 C). I read that the battery drains fast in the cold weather. True! I’ve tried recharging my devices a few times but one never gets above 12% charge and the other never above 20%. Until the cold weather happened, I never had a problem getting a full recharge. I left the devices recharging with the USB cable for 2 days and they would never fully recharge. Does anyone have any suggestions as to what I can or should do (besides moving to a warmer climate ;-) )? Thanks for your help.