How to get a low voltage, high current controller?

[Chalo]

Hi y'all,

I'm trying to help the good folks at Austin Bike Zoo to troubleshoot a hub motor drive for one of their animals. It has a hefty scooter hub motor rated 1000W, but the RPM per volt is much too high for what they're doing. I've been looking for a controller in the 18V to 24V range that draws at least 50 battery amps.

Everything I've found so far in the correct voltage range is either low powered or a suspiciously tiny/explodey RC controller that probably wouldn't push a big hub motor on a slow heavy beast bike.

It would be great to find a 50+ amp controller that can tolerate 24 volts or lower. But it would also be good to know if there's an easy technique for lowering or eliminating LVC on a big bike controller.

Thanks in advance for any help you can provide!

 

[Vbruun]

The VESC will do it. A cheap and powerful options is the flipsky 75100.
But other models are good as well

 

[Chalo]

The VESC will do it. A cheap and powerful options is the flipsky 75100.
But other models are good as well

Thanks for this lead; I'll check it out.

 

[BalorNG]

Yup, I've been using it for some time, those are not 'explody' unless you try to push volts very close to maximum and/or do regen braking. Not terribly cheap, but actually is for what you are getting actually.

 

[Chalo]

Yup, I've been using it for some time, those are not 'explody' unless you try to push volts very close to maximum and/or do regen braking. Not terribly cheap, but actually is for what you are getting actually.

So as this project has become more tangled, now I've been asked to find a low voltage high power BLDC controller that can run sensorless. So far I've only found Kelly KSL:

https://kellycontroller.com/shop/ksl/

But I'd rather find something that doesn't require programming. Is that possible?

 

[amberwolf]

How much power, at what voltage range? Same as the original post, but just sensorless?



BTW, regarding changing LVC on a typical ebike controller, it depends on how they implemented it. If it is reading a voltage divider from the battery voltage, into the MCU, then you could alter the voltage divider ratio to get the LVC you are after.

But you may also have to change the input to the LVPS that makes the 12/15v and 5v. If it's one that has the big resistor between battery input and the LM317, you could probably just take the resistor out and replace it with a wire, since the 317 should take any voltage it would see on a 24v system...but you can change it to one appropriate to drop any excess voltage across it if necessary.

 

[liveforphysics]

I had bad luck with the sensorless Kellys.

I think the VESC may be the very best of the sensorless control options.

The unfortunate think about many VESC options is they cable them to survive intermittent high burst currents, but not a ton of continuous current. For an application with long continuous heavy loads, I would get the largest current ratings of the VESC options (I don't even know what that is today "250"-"300A"?), and then tune it down to the 50Amps you need to power the application. On paper it should have a much better shot at long continuous current loads than a VESC rated for "50Amps".

Remember to protect them from weather too, many VESC have the same weather protection as an RC motor controller, which is to say getting it wet while its powered up will probably make it glitch or fail.