With the launch of Dura-Ace 9100 came new firmware offering road riders Synchronized Shifting options between front and rear derailleurs. A short while later this technology was made available to Ultegra 6800-series and Dura-Ace 9000-series riders who have the latest Di2 battery.
The new battery (BT-DN110/BT-DN110-a) contains a memory chip that can handle the processing power required to deal with the multiple shift patterns and customizations that Synchronized Shifting brings, offering you the choice to suit your gear positioning to your personal riding style.
If you’re planning on putting this battery in your seatpost you will probably also want a seatpost battery mount. You can easily find those on Amazon, Chain Reaction Cycles or eBay, All major manufacturers make them.
It is possible to mount this battery outside the frame, if your bike or seat post does not support internal mounting. You can use the external case SM-BTC1 to mount it outside the frame. It also doubles as a 6-port Junction B.
Read how to install the BT-DN110 internal battery in your seatpost in our Di2 internal seatpost battery installation guide.
There are two different versions of the BT-DN110 Internal battery available, the BT-DN110 and BT-DN110-A. The latter is grey, not black, newer and slightly better built. The functionality of both batteries is the same.