First build, 1991 Honda CB250, sanity check requested.


1 µW
Hello! I've been stalking all of you while planning my own build in the shadows. I think I've learned a lot from this forum. However, this is my first automotive project. I'm planning on a QS-138 70H V3 motor, a far driver ND72360 controller and a 60-80Ah 72v battery. The image below is how I want to mount all of them. It's still very rough. I want feedback on if it looks reasonable before refining it. I'm going to have two mounting brackets. The left holds the motor controller and will bolt into the lower motor mount. The right mount just holds the rest of the motor. I'll link the two halves together somehow. The battery will sit atop the two mounts and I might make slits in the mounts for straps to strap the battery down. Thanks!


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Staff member
As long as your mounts also replace the structural support the engine used to do, and the controller and motor are not able to pass their heat to the battery (instead passing it to the environment around them, the airflow, etc.), it's probably ok.

I'd also recommend making sure the mounts prevent twisting of the motor relative to the frame so it does'nt cause chain issues, and the motor output sprocket is centered on the same spot as the original engine's so that it has the same chainline (or you may end up having to modify the frame or the swingarm).

Regarding controller, mtoro, and battery--do you know the maximum power you'll need to do the job the bike has to do for you? And how long it will need to do that? And the range you want at a certain performance level? If those havent' been defined yet, you'll want to do so, so you can then make sure the parts you want to get can do that job. :)


1 mW
I'm planning on a QS-138 70H V3 motor, a far driver ND72360 controller and a 60-80Ah 72v battery.

Why such a weak controller with that motor? At least get a ND72850 ( ND72850 | far-driver ) and make sure your battery pack can provide the amps that this controller can take. You'll be much happier with the performance. And you can always program it to lower power levels if needed.
Read through the other build threads with this motor what they feed it in amps. EScooter/EMotorcycle Build Threads
Or if you want to stay with a small Controller, take the ND72680
On the picture you see on the right side the ND72680 and the ND96850 , and on the the left side sabvoton 72150 and 72260.
The Farduver ND72680 is really small.


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