After converting 4 bikes to e-bikes, and cycling over 1500 km on my recently converted B'twin Rockrider ST520 with a Tongsheng TSDZ8, I would like to share my installation process and do's and don'ts. My previous conversions are using the TSDZ2 motor. These bikes I built for a few friends, are all are still running strong. One has done almost 10000 km. None of them had any issues. But this TSDZ8 on my most recent project is a different animal. Much better construction and way more powerful. Until now it’s been really great to ride the bike.
I ordered the TSDZ8 motor with the B02N-TS display, and a 48V 20Ah battery in Hailong Max enclosure from pswpower.com in March. I received the materials within about 1 week, very well packaged and it was delivered complete with cables, throttle, brake handles, all screws, spacers, etc.
Installation:
- Remove the old chain, cassette, bottom bracket, front derailleur + shifter, and rear shifter cable.
- Assemble chainwheel on motor, mount motor on bike.
- Install chainguide or re-use front derailleur without cables (use adjust screws to set position) for keeping the chain on in lower gears. Chain will drop otherwise.
- Mount new cassette, install new chain.
- Mount crank arms and pedals. Torque the crank arms down really, really tightly since the arms tend to come loose if undertorqued.
- Install rear shifter cable and a full-length outer shell.
- Install battery. Use M5 threaded blind rivet nuts to create the mounting points in frame if needed. I had to make these mount points.
- Install display, route cable to motor.
- Install brake levers and connect to display cabling.
- Connect speed sensor and bike lights.
- Update motor firmware to test_3.0 from august 2024 using a Segger Jlink programmer. This firmware has the best riding experience and is bug-free (for me at least).
Do’s:
- With a flat piece of wood and some 180 or finer grain sanding paper, remove the paint from the sides of the bottom bracket, where the locknuts of the motor will press against. This will greatly reduce the chance the motor loosens (paint is soft and will deform, so loosen the motor).
- Use extra-strong green Loctite on the following places:
- Both motor locknuts threads. Before applying, remove grease with some soapy water or brake cleaner.
- Between the bottom bracket walls and the motor mounting plate (the small black metal piece). This will improve the torque handling. Degrease before applying.
- Place a polyethylene pad between the motor casing and the bike frame down tube. During assembling, rotate the motor such that it already presses firmly against the pad (so motor points to the front of the bike). After that, torque down the locknuts with a hammer and the provided locknut wrench. This method avoids motor rotation and guides the reaction forces through the frame rather than through the bottom bracket.
- Use a piece of old bike inner tube around the motor wiring harness where all connectors are. This protects them from the majority of dirt and water ingress.
- I removed the AMP connectors from the battery cables to the motor and soldered everything at exactly the right length once all was mounted. I kept the yellow XT60 connector at the motor side to ease removal/servicing of the motor.
- Adapt the charger maximum charge voltage to 52V (4.0V per cell) to greatly improve shelf life. There is a potentiometer in the charger to adjust this voltage level. Use a multimeter to make sure the voltage does not exceed the max charge voltage. You'll lose about 20% of capacity, however the battery will easily last >2 times as long as it degrades much less over time. If you do this, it's important to still ensure the balancing us activated once in a while and this can be problematic if your BMS starts balancing only at 4.0V or higher.
- Ideally, charge the battery only just before when you're going to use the bike, and only charge it for the amount you'll need for your trip. Avoid charge levels above 52V (80% SoC) when you don't need the range that day.
Don’ts:
- Don’t route any cables (signal, power or shifter cables) underneath the motor to avoid cables being squashed when the motor accidentally gets loose. This surely can happen - happened to me and it destroyed my display cable connector. There is some room on the non-drive side to neatly route cables.
- Don't charge your battery to 100% full every day or park the bike with a 100% charged battery. This will cause about 15% to 20% yearly degradation by just letting it sit at maximum state of charge. One of my previous builds still has 90% state of health even though the battery is 7 years old and has done 7000 km. Limiting charge levels and charge time really helps a lot.
I posted this to the TSDZ8 Facebook group as well
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