Ditch Shimano’s proprietary EW-EC300 Cable: 4g USB-C Adapter for charging semi-wireless Di2’s on the go

If you’re running a 12-speed semi-wireless Di2 groupset on multi-day tours, you’ve probably experienced the frustration of Shimano’s EW-EC300 charging cable. While your GPS, lights, phone, and radar all charge with standard USB-C cables, your Di2 system demands its own bulky proprietary solution.

The EW-EC300 Problem: One More Cable to Carry

Every bikepacker knows the drill: you’ve carefully optimized your charging setup with a single power bank and USB-A to USB-C cable for all your devices. Then comes the Di2 system, demanding its own 69g proprietary EW-EC300 cable that:

• Adds unnecessary weight: 69g of cable just for one device
• Takes up precious space: Bulky design eats into limited packing volume
• Creates range anxiety: What if you forget it or it breaks on a 1000+ km tour?
• Breaks your charging system: Forces you to carry a second cable type

Simple Solution: Use Your Existing Charging Setup

How to Use

1. Connect your existing USB-A to USB-C cable to the adapter
2. Plug into your power bank (any 5V USB output)
3. Connect the 4-pin connector to your Di2 rear derailleur
4. Charge alongside your other devices (full charge in ~3 hours)

Reliability & Durability

Built to the same connector standards as Shimano’s original EW-EC300, the RRSKit Di2 charging adapter features a weatherproof design tested for outdoor conditions. The same 4-pin interface ensures reliable charging every time, while the compact design eliminates cable stress points that can fail on long tours.

Perfect for Long-Distance Cycling

This adapter is essential for multi-day tours exceeding the 12-Speed semi-wireless Di2’s 1000+ km battery life. It’s particularly valuable for bikepackers, gravel riders, and long-distance cyclists where every gram and cubic centimeter of space matters.

By eliminating Shimano’s bulky EW-EC300 cable, this simple RRSKit Di2 charging adapter streamlines your charging routine and saves significant weight and space. Used by hundreds of cyclists worldwide, it’s the kind of upgrade that makes you wonder why you didn’t switch sooner.