Di2 Battery Holder (Rubber) for 25.4 mm Cannondale C3


This battery holder is for Shimano Di2 internal SM-BTR2 and BT-DN110 batteries. The battery fits inside the seat post and typically requires a seat post made specifically for Di2. This holder allows the battery to be held securely within a 25.4 mm Cannondale C3 seat post. It will also fit other seat posts with the same inside diameter.
Weight:  11-12g

Battery Holder Sizes

Other Di2 battery holders for 25.4mm seat posts are available in polypropylene for a wider variety of seat posts.  This model is only available while supplies last.

Why use a holder instead of tape or foam?

Ad hoc solutions using tape and foam have multiple issues. The net result is often a damaged or stuck battery.

Problems with Tape or Foam:

  • They don't protect the delicate battery connection
  • Tape or foam can shrink, causing the battery to fall out
  • They can cause the battery to overheat
  • Tape, especially, can fuse to the inside of the seat post


Returning Customers Please Read

Free Replacement Quarter-Turn Insert

If you had previously purchased a Garmin mount between May 2021 and February 2022 you may be eligible for a free quarter-turn insert replacement. Please read this article to see if your mount is affected.