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


Out of Stock Items

Due to an overwhelming demand, some items are now sold out. We are working hard to produce the next batch of these items.

UPDATED: October 18th

We are experiencing unanticipated delays with some raw materials and are now forecasting restocks on or around Oct. 27th-28th.