Introduction

This motor controller installed in the Chinese moped-style electrical 🚲 bike (ebike) with 500W motor. It's works correctly, but I decided to take a look how it looks inside:

• Model: TJMM9-AB-YTC2-CK 
• Voltage: 60V
• Low Voltage Protect: 52.5V ±0.5V
• Current Limit: 25±1A
• Date: 2024.05
• Manufacturer: JIANGSU XIECHANG ELECTRONIC TECHNILOGY CO., LTD
• Transistors: 9PCS (UPD 2025/05/31: I believe some of them is serve to electrically stop motor when press brakes or in case of alarm)
• Chassis connection: connected to GROUND

🌟 Related Articles

🛠 TEARDOWN: Brushless Motor Controller  48V  of the Chinese Electrical Bike (Ebike)

Housing

It's aluminum case that used also as heatsink for power MOSFET's.

To disassble it you need triangle screwdriver bit:

Controller has white rubber gasket for waterproof:

Internals

Transistors (MOSFET's) not connected directly to the metal housing:

So their drains isolated with kapton gasket but have some thermo paste for batter cooling:

MOSFETs with EL4N60F marking (9PCS, 3 on each phase):

Looks like this controller use transistor driver based on discrete components (no special IC):

Chinese MCU CXKJ363 MNW9LK 2348:

Common ground connected to the aluminum case (be carefully with positive wires):

All connectors are also waterproof with rubber gasket, which is really good:

It's 2-layer board yellow-mask board with components only on one side:

Pinout of the connectors marked on the silkscreen, which is good:

High current connections reinforced by the open mask and thermo paste

Common ground have special copper buses (rails), that connect different points of the board:

If you want to find out more ways of making PCB suitable for carry high electrical current see the article:

🧱 SMT Metal Copper Sheets (blocks/jumpers) for High Current PCB

Conclusions