Scooter derived Wheelchair system that needs reverse

I fabricated this from a 350W 36V KXD scooter. It works great, is easy to mount up/detach, and I can throw it into my car and take it into the city.

Because I’m in a wheelchair (paraplegic since 95) it really needs a reverse. I tried every combination of the motor legs and no dice. I tried disconnecting the small multi-plug to the Halls sensors and still NG. I think if I moved the sensor signals around to reverse their vision, it might work but that’s a lot of switching! Besides, I need more torque around these hills so I’m thinking 500W wheel-hub, bigger controller and bigger battery (range is only 5 mi) so I might as well consult the knowledgeable people on this site!

Are there controllers that will do the logic for reverse (assuming brushless motor/sensored) and providing a simple switch scenario?

Writing this got me thinking: if I reverse the sequence of Halls signals (swap 1 & 3) would that alone get my motor running backwards? Or do I have to do that as well as switch a pair of phases? (I realize that with fixed timing the motor may not run real well backwards but I only need it for maneuvering, mainly on flat ground)

What motor controller are you using?

How do you control the throttle? Which specific part do you use for that?

Everything electrical is original KXD scooter as supplied:

The full number on the controller is JP-SINSZ21D1809077 The throttle is a 90* thumb deal which I expect is a potentiometer.

Certainly the throttle control could be changed to accommodate a different controller.

You could try switching the hall and phase orders simultaneously with a large multipole switch but the phase wires carry heavy current levels and overall it might not work, and if it does, it may be unreliable and/or dangerous. You’d also probably be better switching it while turned off.

If you wanted to change out the motor controller to a VESC-compatible one, then it can probably be made to work.

Does the throttle have 3 wires coming from it or only 2? Do you have a photograph of the throttle?

Is buying a new controller in your budget? Maybe $200?

The throttle is part of the display which also has multiple functions as well as some simple programming choices (80% or 100% per; hard start/soft start; kph/mph, etc) It is possible that the throttle signal is a digital command. I’d have to remove the battery compartment and break out the multi-meter to get some idea of what goes on. The display/throttle is available new for 20 bucks.

After I buttoned the damn thing back up, it occurred to me that possibly inverting the Halls signals might make the motor reverse. I realize timing would be ~40* off but reversing is low impact short duration and intermittent use.

Do you have a link for that?

Above is throttle/display for my 350W scooter with 3 Halls sensor

And I’ve included this listing which is the same manufacturer and perhaps clarifies some questions:

So I’ve done a lot since this post. This scooter is unbelievably cheap but is, I hunch, fairly sophisticated. I’v found and ordered a couple motor controllers that have a reverse function. I’ve married one to my motor and controller BUT!!! Seems the cheap KDX scooter is pretty smart! The Multi function Display (MFD) and throttle assy has a 6 wire cable: B+, ignition, ground, throttle (.8-3.6V), TXD, and RXD ( Transmit and Receive, digital signals). Fortunately the throttle signal is analog so that works, but any speed related function is not available now, which IMO is not acceptable! Also, the brake control seems to be a Halls based variable signal from ~.8-3.5V. It is on a separate 3 terminal plug to the controller. (and, of course, the KXD has nice/small JST connectors!(upload://5y6gZA2AOKBL7nPcnZotPWo0eq9.jpeg)

and the chinese controllers have grossly big Hillichi? w/ 1/4" wide spades making mating a PITA!)

All these aftermarket chinese controllers seem very similar (I have 4). I have had a scope all over this aftermarket one and am not finding anything like the TXD and RXD signals the MFD/throttle wants.

Also, they all heave a H brake and a L brake circuit. L Brake I can activate by grounding the (yel) wire; H brake has no response to voltage or grounding. How do I implement these and what’s the deal with H Brake which seems inactive??

Here are the two controllers. Note that the smaller original one has TXD & RXD legs

I assume I need a digital data stream to enable my MFD? I ordered a paired controller and MFD/throttle which looks identical to my KDX scoter’s one EXCEPT it has 5 instead of 6 circuits. I assume it’s analog and may work off the yellow/grn stripe “display” wire which outputs DC in proportion to speed/throttle?

I’d love to understand how they expect you to handle brake functions and velocity information on these cheap chinese controllers! HELP!!

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