Cheat Sheet: 12-speed battery checks
To check a shift lever battery, press-and-hold both buttons on that shift lever for 0.5 seconds or more.
The LED on the shift lever will then indicate the battery status.
- Green: 11% to 100% battery
- Red: 1% to 10% battery level
- No LED: 0%
If your shifter LED turns red, you have about a month to go before it’ll go completely flat - buy a new CR1632 (Amazon | eBay) and replace that battery as soon as possible.
Here is more information on checking and changing wireless shift lever batteries.
Check 12-speed main system battery status
To check the 12-speed main battery charge, press the button on the rear derailleur for 0.5 seconds or less.