The battery icon on my REM-Fit Active fluctuates (shows various degrees of charge). Why?
The battery icon is an approximation of how much battery you have left. It is normal to have slight fluctuations in the middle of the range. Just be sure when the battery is very low to charge the device as soon as possible.
When your REM-Fit Active needs to be recharged, use the included USB charger, recharge your REM-Fit Active for 8-10 hours. You will see a filling battery animation on the screen while it is charging. Once charged, the battery icon (while the REM-Fit Active is in the charging dock) will show as full.