This timelapse video of the SM-BTC1 Di2 External Battery Holder for Internal Batteries (SM-BTR2 / BT-DN110).
It isn't really used nowadays, but used to be a popular solution to install Di2 batteries on mountain bikes.
[ Ссылка ]
![](https://i.ytimg.com/vi/MpcGR23O7Rw/mqdefault.jpg)
This timelapse video of the SM-BTC1 Di2 External Battery Holder for Internal Batteries (SM-BTR2 / BT-DN110).
It isn't really used nowadays, but used to be a popular solution to install Di2 batteries on mountain bikes.
[ Ссылка ]