External Battery
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.
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.
Synchro-shift
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.
Details & Specifications
Shopping links
Are you looking to upgrade your bike using this component or tool? I've added links to this component's shopping pages. If you make any purchase using the links below you'll support the site - at no cost to you.
