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Transforming a $156 scooter into a 20mph wheelchair

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    #31
    Originally posted by Gordy1 View Post

    Your bike shop was definitely correct about needing to upgrade the controller to match the upgrade in battery voltage. Whilst some controllers specifically state that they can handle two or three different voltages, most are designed for only one.

    I just caught up with a mate who is far more intelligent than me...I asked him about how torque relates to power (Watts) in a hub motor, as I didn’t notice any difference when upgrading voltage on a motor. He gave some interesting responses (which I hope I’ve remembered correctly!):
    1. The larger the diameter of a hub motor the larger the “lever arm” (between the centre and the magnets around the perimeter), so the larger the torque.
    2. The wider the hub motor is, the longer each magnet is, which again increases the torque.
    3. The more amps (and/or volts) you can supply to the motor, the greater the torque.

    So by just measuring a couple of things on two different hub motors (which have the same power (Watts)) you can tell which has the greater torque. (Apparently the number of windings within the hub motor also has an effect on torque, but you can’t tell the difference between two motors without opening the motors up.)

    Obviously larger powered/wattage motors get larger in size, so also provide larger torque, but I thought he provided some useful info if you need to compare motors before buying.

    He also said that electric motors have such high torque anyway, than I may not have noticed a slight increase in torque when increasing battery voltage. He’s probably right (as he usually is, but not in a smart-arse way, thankfully!).
    Thanks! Good info. As I see it, current is like torque and power/watts is related to voltage. (in a gas engine, RPM) If one doubles voltage, current necessarily will double if the resistance doesn't change. That makes watts a second order function of I x V, (I is amps). I may be wrong!

    But, theory aside, it's clear I need a 500W motor and 500W controller. One 36V controller is rated 30A. Before ordering a bigger motor, I'll put it into the stock setup. Either it will rip on hills, or it will overheat and I'll need to buy a bigger motor.
    69yo male T12 complete since 1995
    NW NJ

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      #32
      Originally posted by nonoise View Post
      I'm really curious if your system will reverse as it should be a geared motor. Way back when I had to go with a direct drive motor because I wanted to have reverse for my recumbent trike. But those larger diameter motors meant shorter spokes. And short spokes would not stay tight in a small diameter wheel.
      It reverses. It's controlled by a two wire open/closed deal into the motor module. If a pair of Halls and a pair of phase wires were swapped, it would also reverse; doing that would require a Double Position 4 Pole switch and 8 long wires!

      Motors for bicycles have a one way clutch for coasting so they won't reverse.
      Last edited by pfcs49; 8 Dec 2020, 11:32 AM.
      69yo male T12 complete since 1995
      NW NJ

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        #33
        This post is heating up nicely. I like the spirit in here.

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          #34
          Thank you Mr. Sporto for putting me through this site:

          https://ebikes.ca/learn/power-rating...powerandtorque

          a must read for anybody into brushless motors/electric conveyances, and just the thing for empiricists like me!!

          PS: stayed up til 2am Monday crunching the unlikely interface of the original KDX throttle/multi-function display/control to a no-name Chinese/cheap/no instructions motor controller.
          Pretty successful so far! Had to rewire power leg to 36v source and make up KDX multi-plug to Brand X multi-plugs adapters after figuring out who was what. Most functions working except any relating to velocity so no MPH, odometer, etc. (But throttle is good)

          About to re-heat the shop and go out while our first snowstorm blows around. Hopefully I will be able to restore full KDX functionality to a scooterchair that reverses!
          Then I think hacking in the 500W/reversing motor controller will go more quickly and we'll either go uphill better/faster OR melt down a KDX motor
          Last edited by pfcs49; 9 Dec 2020, 2:52 PM.
          69yo male T12 complete since 1995
          NW NJ

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            #35
            This is getting too serious! Had to crack out the cheep scope.

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            However, progress is being made. Now I need to see if I can find the two PWM? Digital? signals (in the two circuits needed for velocity stuff like mph, etc) like the one on the scope, in the new controller which may not be possible. I may have gone as far as can be with this cheep motor box!

            69yo male T12 complete since 1995
            NW NJ

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              #36
              Just like your political views Phil, It looks good on paper.

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                #37
                Originally posted by Tim C. View Post
                Just like your political views Phil, It looks good on paper.

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                  #38
                  I'm glad somebody's paying attention.
                  69yo male T12 complete since 1995
                  NW NJ

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                    #39
                    My son is using an old power chair and turning it into a remote snow plow for his driveway. He has a snowblower but loves to build things.

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                      #40
                      I haven't been posting, but I've been playing with things.
                      I modified & lengthened the original wiring of the KDX scooter, marrying the original JST multi-plugs to the big sloppy Dupont connectors that the Chinese seem stuck on in such a way that I can swap controllers easily. I mounted a (provided) travel bag above the Volvos from Hell battery plate and now the motor controller and second battery reside there.

                      I have 36 and 48V controllers now that have a reverse function, and just tested the first one (36V/17A) on my test hill that nearly stalls the original KDX deal. It should have slightly more grunt than the original; it doesn't It does, however, back up nicely now
                      I will try the 50A controller next. It will have much more torque but may melt down the motor!

                      I revised the lower latching setup. I'm almost satisfied; the only negative now is ergonomics and easily rectified (move the tightening knob up 3" for easier accessibility) It is easy now to latch-up to the chair, as far as I can tell, easier and quicker than any of the commercial deals.

                      I just ordered a digital volt/amp/watt-meter that also calculates and displays watt-hours; it will be small enough to stick it at the top of the parcel bag.
                      I had been road testing using an inductive clamp on ammeter on the battery wire and watching the voltage on the scooter's MFD. Hard to read the ammeter and harder still to remember peak amps/volts while hill-climbing.
                      This new deal was just $17! and has freeze frame memory when power cuts off which will be great! I'll retest this latest shitty motor controller and I'll have the data when it cuts power when it goes under-voltage and shuts off!

                      Then I'll try the 50A controller which, discovered when bench testing it, doesn't have electric brake, just motor shut-off when presented with a brake signal which really sucks! Fortunately I've already fitted a cable brake or this would be a suicide machine. It is quite unsettling to see how this deal picks up speed downhill! It REALLY takes off. It is interesting to find out how downhill some flat looking pavement is; there's stretches that look perfectly flat where the chair will get going scary fast unless I lay on the brake!

                      And, I'm getting my feet wet with programmable more esoteric controllers which afford great flexibility, having full digital capabilities enabling me to select and adjust many parameters including regenerative braking parameters, upper and lower limits for starting torques, velocity, power cutting by battery voltage and motor or controller temperatures. Who woulda' thought the Beetle doctor would need this??!



                      Attached Files
                      69yo male T12 complete since 1995
                      NW NJ

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                        #41
                        Originally posted by Lavender lady View Post
                        My son is using an old power chair and turning it into a remote snow plow for his driveway. He has a snowblower but loves to build things.
                        When we were building the pond, I got the ZX1, some rope, and a big milk crate lined with window-screen. I would drive up to the upper driveway and shovel about 70lbs of round-stone gravel into it and then pull it down to the hose-bib in the lower area where I'd rinse all the quarry process out of it, then pull it to the pond and dump it. Altogether, nearly a ton of stone. The ZX1 performed like a bulldozer. My arms! Not so much, but I got it done. /Best exercise in a looooong while. Even got a tan! And pretty well ground the bottom off the crate.
                        69yo male T12 complete since 1995
                        NW NJ

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                          #42
                          Phil Hunt
                          I've been testing stuff and it's testing my patience! I think I need to go with one of the programmable motor controls like the Flipsky. I put a dashboard on the scooterchair so I could see peak current/(low) cutoff voltage as well as consumption. The first MC I tried was 17A (original is 16A) and has reverse. It was near useless; the motor was noisey with any load. I blamed myself, thought I screwed up phasing/timing when I took the motor apart, but putting original MC in, and it's fine. Re-installed the 17A one and did re-learning and got the same result, so moved on to a 30A reversing controller which was shitzoiid, shutting off an counterintuitive times of low demand. Basically unusable; it was 19* out so I spent only a little time with it!!

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                          On the side of the dash, cruise control button and 3 speed switch. Backup switch is on the left handlebar. Need to find out what I'll need to program a Flipsky. I hunch it will NOT be a Mac which is, of course, all I have!!

                          https://flipsky.net/collections/elec...eed-controller
                          69yo male T12 complete since 1995
                          NW NJ

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                            #43
                            i think ur having a blast i do not understand all the technial stuff but you can sure tell ur having fun

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