Ebike USB-C Charger

Ebike batteries are large but don’t typically provide phone charging. I built a charger that taps directly into the 48V battery to provide USB-C output for my phone or laptop while riding.

Design

I used a buck converter rated for 48V-54V input, with a USB Power Delivery controller. The controller negotiates 5V to 20V output depending on what’s plugged in.

The converter efficiency is high enough that it doesn’t noticeably affect range.

Result

It works as intended. I can charge my phone at full speed from the bike’s battery.