Charging a Di2 battery buried inside a seatpost used to mean pulling the post, disconnecting the battery, and hoping nothing got damaged in the process. Shimano's SM-BCR2 charger eliminates that hassle by plugging directly into your junction box, whether that's a bar-end SM-EW90, a stem-mounted unit, or one of the newer EW-RS910 junctions hidden under your stem faceplate. The battery stays where it is, and power flows through the existing E-Tube wiring to top off the cell.

The charger pulls power through a standard USB connection. Plug it into a wall adapter that supplies at least 1 amp, and a full charge takes about 90 minutes. A laptop USB port works too, though the lower current output stretches charging time to around 3 hours. Two indicator LEDs keep you informed: an orange light that stays solid during charging and turns off when complete, plus an error light that blinks if something in the system needs attention.

Beyond charging, the SM-BCR2 doubles as a PC linkage device for Shimano's E-Tube Project software. Connect it to a Windows computer and the software reads every component in your Di2 system, displaying firmware versions and allowing updates across the entire network from a single connection point. The same interface lets you customize shift settings, configure Synchronized Shifting patterns, and run diagnostics when something isn't working right. If a component becomes unresponsive after a failed update, the SM-BCR2 connection often provides the path to recovery.... Read More