Suggestions for BLDC and controller 5kw

General Discussion about large electric scooters and motorcycles and other things with no pedals.
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ReubenH   10 µW

10 µW
Posts: 6
Joined: Sep 12 2020 4:38am

Suggestions for BLDC and controller 5kw

Post by ReubenH » Jun 01 2021 4:51pm

Hey guys
I have a china scooter from about 2009
It's a sit on type, looks exactly the same as what may have a 49cc 2 stroke in it but came electric. It was bought pretty cheap with completely flat lead acid batteries.
I believe the hub motor was rated at 250w. 48v system
The thing was incredibly slow to begin with haha.
I have since upgraded the controller with a high spec china controller (up to 120v 60a foc from memory) which allowed much faster acceleration but top speed was only 35kmh. It drew the full 60a on acceleration but the motor is about at it's limit there.
I then replaced the terrible lead pack with 24s spim08hp cells and I also modified the current sensor in the controller. The motor clearly is too over driven now as a short drive makes the case get up to 60c and we took it apart one day and the windings were toast. Peak power according to bms was 11.8kw. it feels like 1kw is getting to the ground and the rest is turning to heat. I believe battery current peak was 120a.
The top speed was then 60kmh. This is more what I'm aiming for.

I am after a mid drive motor that is capable of putting down much more power. A couple of options that I have been looking at is a qs138 90h 72v.
The other is a golden motor 5kw liquid cooled 72v.
I do have more cells and am thinking about upping the voltage some more to possibly 32s. Probably the better way would be to make my pack 2p so I could draw much more current as it appears 72v controllers and motors are more effective than their 96v cousins. Please let me know what you think.

If there is interest then I can attach pictures and all that. The reason for wanting to go for a chain drive motor rather than a hub is so that with a couple of sprocket changes I could go between laying skids on tarmac to doing a top speed run easily. A hub motor I would have to shoot for the middle ground.

Please also let me know about a suitable motor controller. I'd prefer foc with variable regen but with every controller that I research there are some people that say it's garbage and to go with a different controller, I then research that controller and see similar comments.
I'm not made of money but am willing to spend for high performance.

Thanks heaps

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