External Battery

External Battery

Non-series components SM-BTR1

The Shimano SM-BTR1 is the Di2 external battery. While external battery mounts have changed over the years, the battery has stayed the same. The only external battery is still the SM-BTR1. Most bikes these days will be equipped with internal batteries such as the BT-DN110.

It weighs about 70g, has a rated capacity of 500 mAh / 3.7 WH and a rated voltage of 7.4 V. You charge the battery by taking it out of the bike and putting it in the SM-BCR1 external battery charger.

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When storing the battery away for a long period, remove it when the indicator is at the half-way level (for the FLIGHT DECK) or when the green indicator is flashing (for the SM-EW79A) in order to prolong its useful life. It is recommended that you check the condition of the battery about once every half a year.


Note that this older battery can be made synchro-shift and BluetoothLE compatible. You will need to use it in combination with the current generation BM-DN100 battery mount.


  • Model code: SM-BTR1
  • Series: Non-series components (NON)

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View the External Battery Mount (BM-DN100-S, BM-DN100-L, BM-DN-100-I)

BM-DN100-S, BM-DN100-L, BM-DN-100-I

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View the External Battery Mount (deprecated) (SM-BMR1 / SM-BMR2)


External Battery Mount (deprecated)

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