This article will guide you through the step-by-step process to charge the Di2 for 10, 11, and 12-speed groupsets.
Based on my experience as a long-time Shimano Di2 user, I’ll cover the key aspects, such as the location of the charging port, using the correct battery charger, and the frequently asked questions about charging.
Charge 12-speed Shimano Di2 battery
The 12-speed Shimano Di2 uses an internal battery (BT-DN300) and requires the EW-EC300 charging cable.
- Connect the USB-A end to a regular smartphone charger with at least 1.0A capacity.
- Pop open the charging port on the rear derailleur by placing your finger on the notch.
- Connect the magnetic end rear derailleur. Make sure the connection is snug and secure.
- The charge indicator LED on the rear derailleur will light up blue while charging and goes off once charging completes.
Things to note
- The derailleurs will not work during charging.
- This cable can also charge the latest Shimano power meter (FC-R9200-P).
- If the charge indicator LED flashes red, the charging current is insufficient. Find a charger with at least 1.0A capacity.
- If the rear derailleur becomes too hot, stop charging for a while. If it persists, contact your local bike shop.
Charge 11-speed Shimano Di2 battery
The 11-speed Shimano Di2 uses an internal battery (SM-BTR2 or BT-DN110) and requires the SM-BCR2 charger.
- Connect the USB-A end of the cable to a regular smartphone charger with at least 1.0A capacity.
- Connect the micro-USB end of the USB cable to the charger (SM-BCR2).
- Pop open the charging port on Junction A. Depending on your setup, it can be below the stem, handlebar end, seatpost,, or downtube.
- Connect the other end to Junction A. Make sure the connection is snug and secure.
- The charge indicator LED will light up in orange while charging and goes off once charging completes.
Things to note
- The derailleurs will work during charging.
- If the Charge or Error indicator lights up or flashes, there is a problem with the charging. A current of less than 1.0A usually causes this.
Charge 10-speed Shimano Di2 battery
The 10-speed Shimano Di2 uses an external battery (SM-BTR1). Use the SM-BCR1 charger.
- Remove the battery from the bike.
- Insert the battery into the charger SM-BCR1.
- The charging indicator will light in orange and go off once charging completes.
- A full charge will take around 1.5 hours, depending on your battery level.
- Remove the battery from the charger and reinstall it back onto the bike.
This applies to 10-speed (R7970 / R6770) 11-speed (R9150 / R9000 / R8000 / R6870) and 10-speed Shimano Di2 rear derailleurs.
How long does it take to charge the battery to full?
Depending on your battery level, a full charge will take around 1.5 hours (AC adapter) to 3 hours (computer USB port).
Is the shifting working while the battery is charging?
The shifting will not work for the 12-speed derailleur while charging. Shifting will work for 11-speed derailleurs while charging.
Will it continue to charge when the battery is full?
The charging will automatically cut off when the battery is full. The Charge indicator light will go off. If you attempt to charge a full battery, the Charge indicator will not light up, or light up and turn off immediately.
Check your Di2 battery levels regularly to ensure you don’t run out of battery midway through the ride.
Alex Lee is the founder and editor-at-large of Mr. Mamil. Coming from a professional engineering background, he breaks down technical cycling nuances into an easy-to-understand and digestible format here.
He has been riding road bikes actively for the past 12 years and started racing competitively in the senior category during the summer recently.