How do I check the battery charge level?

10-speed and 11-speed Di2

Press and hold any of your shifting buttons for at least half a second. The colour and the amount of flashes of the junction box LED indicates how much charge is left.

Of course the LEDs cannot flash if the battery is completely empty, which is why a more accurate approximation would be:

• Green for two seconds: more than 75%
• Green, flashing 5 times: 50% – 75%
• Red for 2 seconds: 25% – 50%
• Red, flashing 5 times: less than 25%

Please note that when you have 10% or less charge remaining, the front shifting will cease to function. You’ll be stuck in the chainring you selected.

Depending on your firmware version, it’ll also display flashing lights to indicate the shifting mode you’re in.

12-speed Di2

For 12-speed Di2, both the button and the LED moved to the rear derailleur.

Checking the main Di2 battery charge level is really easy - you just press the rear derailleur button.

Pressing the button for 0.5 seconds or less will turn on the LED, indicating the remaining battery charge.

• Solid green: 100% - 51%
• Flashing green: 50% to 26%
• Red: 25% to 1%
• Off: 0%

If you'd like to check your (wireless) shift lever battery, press-and-hold both of the shifter's buttons for about 0.5 seconds.

The lever's LED will then switch on, showing you a rough battery level indication:

• Green: 11% to 100% battery
• Red: 1% to 10% battery level
• No LED: 0%

Once the (CR1632) battery reaches 10%, you've got about a month to replace it. It'll go completely flat after that.

Changing the batteries is really simple, and only takes a couple of minutes. Read all about this in the Replace Wireless Shift Lever Battery Guide.