The Shimano BT-DN300 is the dedicated internal battery for Shimano's 12-speed electronic road groupsets — Dura-Ace Di2 R9250, Ultegra Di2 R8150, and 105 Di2 R7150. Designed to mount cleanly inside your seatpost or frame, it delivers a reliable power supply for the entire Di2 system while keeping the bike looking neat and uncluttered. With approximately 1000km of range per charge and a charge time of just 1.5–2 hours via USB AC adapter, the BT-DN300 makes electronic shifting genuinely hassle-free.

Highlights

• Three SD300 ports: Connects directly to Di2 components without a junction box — front derailleur, rear derailleur, and one spare port for satellite shifters or other accessories.
• Charges via the rear derailleur: Uses the EW-EC300 Di2 charging cable connected to the rear derailleur port — no separate charging socket on the battery itself, keeping internal routing clean.
• Approx. 1000km range: Exceptional battery life means you can go weeks or months between charges depending on ride frequency.
• Lightweight and compact: At just 52g the BT-DN300 adds virtually nothing to overall bike weight, and its slim profile fits most modern internal-mount seatposts.
• Rechargeable lithium-ion: 7.4V nominal voltage, 500mAh / 3.7Wh capacity with a Li-ion cell built to Shimano's quality standards.
• Operating temperature range: Functions from −10°C to 50°C, suitable for year-round riding in Australian conditions.

Charging & Cable Notes

The BT-DN300 does not have its own external charging port. Charging is done via the rear derailleur (RD-R9250, RD-R8150, or RD-R7150) using the EW-EC300 Di2 charging cable (sold separately). A full charge takes approximately 1.5–2 hours with a USB AC power adapter, or around 3 hours from a computer's USB port. Charging should only be performed between 0°C and 45°C.

Installation & Port Management

The BT-DN300 is installed internally — typically inside a compatible seatpost or frame void. All three SD300 ports must have either an EW-SD300 wire or a dummy/blind plug attached; leaving any port open will prevent the system from functioning. The battery ships with three blind plugs, a battery adapter, snap ring, wave spring washer, and two washers. Note that most battery holders made before 2022 may be incompatible or require modification due to the redesigned SD300 connector block.

Compatibility & Fit

The BT-DN300 is exclusively for Shimano 12-speed Di2 road groupsets and uses SD300-type connectors — it is not compatible with 11-speed Di2 systems (different port type and firmware). Compatible groupsets: Dura-Ace Di2 R9200 series, Ultegra Di2 R8150 series, 105 Di2 R7150 series. Compatible rear derailleurs for charging: RD-R9250, RD-R8150, RD-R7150. Requires EW-SD300-I power cable and EW-EC300 charging cable (both sold separately).