Battery stuck at the same voltage

[edliw]

Hi, I have a V3 watchy and updated face with 7Seg using Arduino. All went well besides the problem with battery stuck at the same voltage 3.92V all the time, not changing at all. Updated again, with different faces too, went back to 7Seg, disconnected battery, connected another one etc, no change. always showing 3.92V in About Watchy section:

LibVer: 1.4.13
Rev: v30
Batt: 3.92V
SSID: ****
IP: ***

These batteries are showing more than 4V in my other V2 watchy.