Upgrading from an older BT-DN80/BTN2 battery unlocks features most riders don't realize they're missing—Synchro Shift, Semi-Synchro Shift, and wireless customization through the E-Tube Project app all require the newer chip that lives inside this battery. The Shimano Di2 E-Tube BT-DN110 Internal Battery is the current cylindrical internal battery for wired Di2 systems, built around a lithium-ion cell with a memory chip capable of handling the shift pattern logic and Bluetooth pairing that the earlier batteries physically cannot support.

If you're running a wired Di2 groupset—Dura-Ace R9150, Ultegra R8050, 105 R7000, XTR Di2, XT Di2, or GRX Di2—this is the battery you want. It slides into a standard seatpost or frame-specific internal mount, and the cylindrical shape at 17mm diameter by 160mm long fits the vast majority of Di2-compatible frames and posts on the market. If your frame or seatpost doesn't allow internal mounting, the SM-BTC1 external case houses it outside the frame and doubles as a 5-port junction.

Charging happens through the junction box using the SM-BCR2 charger, so the battery itself never has to come out for routine top-ups. Shimano rates the battery for up to roughly 2,000 kilometers of shifting on a single charge depending on how often the front derailleur fires, and when the charge runs critically low the system prioritizes rear shifting while locking out the front derailleur—a clear signal to plug in without stranding you in the wrong gear on the way home.