Bafang Ultra M620/G510 Controllers: CAN vs UART, 48V vs 52V

If your Bafang Ultra mid-drive has a dead or damaged controller, replacing it is usually a straightforward fix — as long as you order the right one. The Bafang Ultra M620 controller (also called the G510 controller) comes in four versions, and they are not all interchangeable. This guide breaks down the two things you must get right: the communication protocol (CAN vs UART) and the voltage (48V vs 52V).

What the M620/G510 controller does

The controller is the brain of your Bafang Ultra mid-drive — it manages power delivery between your battery, motor, and display. All of our genuine OEM units are rated at 30A for roughly 1000W nominal (up to 1500W max) output, and every one is brand-new OEM Bafang, shipped fast from the USA. Whether you're repairing a fault or restoring your bike to full factory performance, a fresh OEM controller is the reliable path.

Step 1: CAN vs UART — the protocol must match

Bafang Ultra motors communicate over one of two protocols: CAN (CANBUS) or UART. These are not cross-compatible — a CAN controller will not work with a UART system and vice versa. Before you order, confirm which protocol your motor and display use. Newer and higher-integration systems tend to run CAN, while many earlier builds use UART, but you should always verify rather than assume.

Step 2: 48V vs 52V — match your battery

Pick the controller voltage that matches your battery pack. If you run a 48V battery, use the 48V controller; if you run a 52V battery, use the 52V controller. Running the wrong voltage class can cause performance and protection issues, so this one is simple but important.

The four versions

• M620/G510 Controller — 52V 30A CAN
• M620/G510 Controller — 48V 30A CAN
• M620/G510 Controller — 52V 30A UART
• M620/G510 Controller — 48V 30A UART

Don't forget the sync step

After installation, the new controller must be synced (calibrated) to your motor before it will run correctly. This is done with Bafang's BESST software. It's a quick procedure once you have the tool set up, but skipping it will leave the bike running poorly, so plan for it as part of the install.

Still not sure which to pick?

The short version: match the protocol (CAN or UART) to your motor, match the voltage (48V or 52V) to your battery, and sync with BESST after install. If you're unsure which protocol your Ultra uses, our team can help you confirm before you buy so you get the right part the first time. Shop the Bafang Ultra M620/G510 controllers or email sales@hpcbikes.com.