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    Permobil C350 question, need more speed

    Recently acquired C350 that I will be converting for street use (cane holders, lights, flag, etc.). 5 MPH speed not fast enough for me. Want 8 or more MPH.
    Question: Will reprogramming speed it up or will I need different motors and controller then programed?
    Before I talk to a tech, I need as much info as possible because I usually have to "hold their hand".

    My C500 will do 10 MPH so I can handle the speed, although it can cause a "pucker" moment at times. I just want the stability of a rear drive C350 at speed.
    Attack life, it's going to kill you anyway
    Steve Mcqueen (Mr Cool)

    #2
    Originally posted by Gearhead View Post
    Recently acquired C350 that I will be converting for street use (cane holders, lights, flag, etc.). 5 MPH speed not fast enough for me. Want 8 or more MPH.
    Question: Will reprogramming speed it up or will I need different motors and controller then programed?
    Before I talk to a tech, I need as much info as possible because I usually have to "hold their hand".

    My C500 will do 10 MPH so I can handle the speed, although it can cause a "pucker" moment at times. I just want the stability of a rear drive C350 at speed.
    Top speed on the C350 is ~6.5MPH with the "high speed upgrade" option. Me thinks you're SoL.

    Comment


      #3
      Had a good reply but forum kicks me often.
      In short, I too think I'm SoL based on my research.
      Guess I was looking for a magic bullet
      Attack life, it's going to kill you anyway
      Steve Mcqueen (Mr Cool)

      Comment


        #4
        LiFeP04 battery conversion would give a voltage increase so potentially more speed if you could get the control system to give it to the motors but Permobil won't supply OEM software to let you set the chair as you want it. Depending upon how chair was set up you might not be getting 100% power/speed in the programming but you need software to check, more money to Permobil dealer to get from you. Personally I wouldn't buy a Permobil because of this, look after the programming of my R Net chair and Dynamic Controls chair myself. Both with LiFeP04 batteries and increased voltage to motors.

        Comment


          #5
          Originally posted by Gearhead View Post
          Had a good reply but forum kicks me often.
          Many forums have timeouts to automatically log users off after periods of inactivity. Typing a message is "inactivity" in the software's eyes (your browser sees your activity but the forum software doesn't). I think the "Remember Me?" checkbox on the login page puts a cookie on your machine to work-around this timeout (at least, that's how it is at other forums in which I participate).

          If you are "kicked out" when you click the button to "post" what you've just typed, you can often IMMEDIATELY click on "Back" (in your browser) to return to the web page in which you were typing your reply. SELECT all of the text and copy to your computer's clipboard. Then, when you are "kicked out", you can log back in, find the thread in question and just PASTE your reply into the page and click on "Submit Reply" -- before the timeout has a chance to dump you.

          Alternatively, you can "Preview" your post frequently as each "Preview" is seen by the forum software as "activity" (thus prolonging the timeout)

          In short, I too think I'm SoL based on my research.
          Guess I was looking for a magic bullet
          You can probably hack something together as a DIY solution. The problem, there, is that you have no guarantees that the "final product" will be reliable -- because you don't know the design limits of the "stuff" you're working with. E.g., to go faster, you need to push more POWER into the motor/drivetrain. But, there are INefficiencies involved -- how much additional heat will be dissipated in the motor? How much in the gearbox?? Are there stability issues with the mechanics of the chair, itself? (if you can push it to 8MPH, what about 15MPH? 30MPH?? where's the limit -- and, WHAT is the limiting ISSUE/component?)

          [E.g., you can run nitrous oxide and avgas in your car -- but I'm not sure how long the engine will last with that higher rate of "combustion"]

          Comment


            #6
            Your right. Can't type fast due to hand function so timmer is what's kicking I think.

            Yea, Permobil keeps their programming and tools closely guarded.
            I have a dongle that I used on my M300 to get 8 MPH. Problem is it must have other chairs downloaded in it via it's USB port. This requires tech's username and password which I'm sure is tracked by Permobil. A lot of study and programing other chairs has given me confidence in changing the settings. Motors can be rewound or adapt a better motor but exceeding amp rating of controller can be a problem. 8-10 MPH would make me happy. My C500S goes 10-12 which can be tricky for a front drive. Permobil says they never made a chair that fast. Ha ha. Programming it is via push button sequences on ESP module in the base. Old chair with user accessible programming.
            Rear drive at speed is more stable verses front drive I've read. Would like to test that myself. Going a few miles to my local, small downtown is fun + good for me.

            Going next week for face to face doctor evail for new chair. I want the F3 for the forward tilt. Hope I can get 8 MPH version if they offer it. It will be primarily a house chair.
            Attack life, it's going to kill you anyway
            Steve Mcqueen (Mr Cool)

            Comment


              #7
              Originally posted by Gearhead View Post
              Yea, Permobil keeps their programming and tools closely guarded.
              You can understand their argument(s) for doing so. OTOH, it just makes the TCO (Total Cost of Ownership) higher. Gotta wonder what a "direct to user" seller could do if they really wanted to "disrupt" the market. Granted, there will always be a need for "providers" to address specific needs of users where there is a fair amount of "sales support" involved (education, fitting kit to needs, etc.). But, I suspect there is also a fair bit of "overhead" that is incurred when it need not be.

              Even the mechanical design of the chairs seems like it doesn't make much of an effort to keep maintenance/repair costs as low as they might be.

              I have a dongle that I used on my M300 to get 8 MPH. Problem is it must have other chairs downloaded in it via it's USB port. This requires tech's username and password which I'm sure is tracked by Permobil.
              Web based service? (how else would they know of your use -- unless they can query the chair, directly?)

              I'd considered approaching chair manufacturers/dealers for access to programming equipment for the chairs that I refurbish. But, figured that would be a wasted effort. And, given the high number of chairs that come in, its relatively easy to just pick which ones are "most driveable" and discard the rest -- no dicking around with programming, required!

              Motors can be rewound or adapt a better motor but exceeding amp rating of controller can be a problem.
              A well designed motor driver should protect itself from all sorts of potential failures -- motors can stall, short out, etc. in normal use. But, you're still dealing with a bag of unknowns...

              8-10 MPH would make me happy. My C500S goes 10-12 which can be tricky for a front drive.
              I'd think it also would require some changes to the "controls" to ensure a twitch doesn't leave you in the middle of a crowded roadway!

              Going a few miles to my local, small downtown is fun + good for me.
              I've noticed a couple of wheelchair-bound young kids at a (school) bus stop down the road. I'm hoping to find some powerchairs with smaller seating units that I can offer to them so THEY can drive down to the local park, etc. (instead of relying on adults to push them there).

              Going next week for face to face doctor evail for new chair. I want the F3 for the forward tilt. Hope I can get 8 MPH version if they offer it. It will be primarily a house chair.
              Good luck!

              Comment


                #8
                Fast FWD chair will lack stability and you might need to reprogram the FWD settings and gyro settings if it has them. Gyro isn't easy to configure especially if you use dynamic. You could replace all the Permobil control system with a 120A R Net system but would probably need new motors. Try asking on wheelchair driver forum, there is a large knowledge base there.

                Comment


                  #9
                  Possible to increase tire diameter?
                  69yo male T12 complete since 1995
                  NW NJ

                  Comment


                    #10
                    Originally posted by pfcs49 View Post
                    Possible to increase tire diameter?
                    Oooooo! Clever man! Speed indicated on the display would, of course, be wrong -- but you could make mental adjustments for that. Ditto for distance traveled (note to self: how does chair know how fast wheels are actually moving??)

                    Practical problem would be finding wheels that had the same bolt-hole positions...

                    Comment


                      #11
                      I don't know what sensible oversizes might be available, but the wheels for my ZX-1 are very simple, are two piece (inner and outer halves, pretty bi-symetrical) mild steel, with flat, drilled centers, no tapered seats like a car.
                      A wheel like these would be real easy to mod. It could be easily re-drilled for a different bolt pattern. A cylindric aluminum spacer could be made and drilled/tapped for attachment to the new wheels; the aluminum could be plunge cut and drilled to mount it to the wheelchair's drive hubs. Something could easily be welded onto the wheels if needed.
                      I hunch that the drive flanges may all have the same bolt pattern? Maybe not! Being the same would imply intelligent design
                      69yo male T12 complete since 1995
                      NW NJ

                      Comment


                        #12
                        Originally posted by pfcs49 View Post
                        I don't know what sensible oversizes might be available, but the wheels for my ZX-1 are very simple, are two piece (inner and outer halves, pretty bi-symetrical) mild steel, with flat, drilled centers, no tapered seats like a car.
                        The "rims" are split -- outer and inner -- held together with three sets of two screws (hidden beneath the "hubcap"/wheelcover). Otherwise, the foam core tires would be a real PITA to remove! A large aluminum "hub" (?) sets between the rim and the mounting flange on the motor shaft through which the wheel fastens to the motor.

                        Increasing the diameter of the wheel -- while leaving it in the same seating plane -- would interfere with the anti-tip rollers, as well as the support arms for the front casters. I'd have to drag out a ruler to see just how much clearance is available -- but, not likely to be the several inches required to increase the circumference ~two-fold (assuming the high speed upgrade motors aren't installed).

                        So, you'd have to move the wheels outboard of their current locations, a bit (might also be needed o clear the chair's frame!)

                        A wheel like these would be real easy to mod. It could be easily re-drilled for a different bolt pattern.
                        You'd have to preserve the existing mounting holes to align with the "four lobed" mounting flange on the motor. But, if the bolt circle is enough larger than the existing one, you could drill the rim just a bit outside of the existing bolt-hole circle (the whell is three-spoked so this limits where you could butcher it -- unless you replace it entirely)

                        A cylindric aluminum spacer could be made and drilled/tapped for attachment to the new wheels; the aluminum could be plunge cut and drilled to mount it to the wheelchair's drive hubs. Something could easily be welded onto the wheels if needed.
                        It might be easier to find a "bell shaped" wheel (where the mounting surface is offset to one side or the other -- the Permobil wheels mount on their centerlines) and arrange for the deeper portion of the hub to be outboard (thus shifting the centerline of the tire out).

                        I hunch that the drive flanges may all have the same bolt pattern? Maybe not! Being the same would imply intelligent design
                        Ha! I've never thought of even checking that -- despite the number of wheels I've removed over the years!! I will have to take a look on Monday...
                        Last edited by automation; 18 May 2019, 8:47 PM.

                        Comment


                          #13
                          "You'd have to preserve the existing mounting holes to align with the "four lobed" mounting flange on the motor. But, if the bolt circle is enough larger than the existing one, you could drill the rim just a bit outside of the existing bolt-hole circle (the whell is three-spoked so this limits where you could butcher it -- unless you replace it entirely)"

                          I have no idea how power chair wheels are mated, but the ZX1 wheels are 4 lugs. If the new/different flange has 4 lugs, you simply redrill the lug holes 22.5* from the old ones.
                          Minilite used to supply alloy wheels for dual applications with 8 lug holes so they fit the Triumph Spitfire/Herald Lotus 7 as well as the Ford Cortina etc pattern. This was handy; now you could upgrade your Super 7 with the beefy wider ford rear and discard the twisted Herald unit, and all your wheels still fit!)

                          If your hubs have only 3 lugs it still is likely you could find room to redrill it for 4 lugs, but two would be close to one another. I wouldn't let it bother me; the speeds and loads are so low that fatigue wouldn't be an issue. Also, given the implementation of the simple ZX-1 wheels, One could resort to rotating the two halves so the original holes are shuttered, and redrlling for the new hub geometry. It wouldn't matter if the new lug went through an old hole, the other hole would locate/index the wheel to the hub and the flat/un-champhered lug nuts would be supported well enough. The way the ZX wheels work, they come apart whenever you remove the lug nuts, the tire pushes the wheel halves apart, so rotating them back to original indexing is simple.
                          69yo male T12 complete since 1995
                          NW NJ

                          Comment


                            #14
                            REVISIONS: After blowing all this smoke, I went out to measure the OD of the 3.00x4 knobbies on the ZX1.
                            The OD id 10.25"
                            I mis-remembered! And I had assumed the wheels were the same diameter.
                            The outer halves of the wheels are alloy with no place to drill a second set of lug holes, however another pair of inner steel rims may be able to be paired making a drab but malleable part.
                            There's a hole @22.5* from adjacent lug holes for the tire tube but solid inserts would resolve the issue if you wanted to re-drill the holes

                            Then I Googled the Permobil info: they show that the nominal 3.00x8 supplied tires have an OD of 14" (and they look much taller than mine in the photos of the 350)

                            So if you want to do tractor pulls, put my tires on your chair!
                            So I wonder what larger wheel/tire sizes might be available?
                            Intersting conundrum. As an old racer fabrication/machinist type, if a tire of the proper OD is available, it's not a big problem to solve.
                            As a normal consumer, it might be pretty difficult to find a fabricator that was economical.

                            EDIT: Googled 3.00x9 tires and found these exist:https://www.walmart.com/ip/Greenball...waArI3EALw_wcB
                            Comes with nice, malleable steel rims so modification would be easy. I'm assuming the 19 refers to OD which would be 1.36 times the original, so 6mph becomes 8.16mph.
                            You'd need to space these out, but the chair would look like a nasty SOB with these!

                            and now, a list of tire specs from Campus Scooters:
                            https://www.campusskooters.com/tire-...nversion-chart. 10" might be a hit?

                            and from Electric Scooter Parts:
                            https://support.electricscooterparts...ead-tire-sizes
                            and what's available:
                            http://www.electricscooterparts.com/tires.html

                            I'm done1 Time for bed.
                            Last edited by pfcs49; 19 May 2019, 12:02 AM.
                            69yo male T12 complete since 1995
                            NW NJ

                            Comment


                              #15
                              I have no idea how power chair wheels are mated, but the ZX1 wheels are 4 lugs. If the new/different flange has 4 lugs, you simply redrill the lug holes 22.5* from the old ones.
                              The flange on the output of the gearbox looks like a four-leaf clover -- one threaded hole in each of the "leaves". The bolt circle is about 2" in diameter... maybe 3?

                              But, as it's a four-leaf clover, there's no "meat" between the "leafs" where you could locate another (tapped) hole. You're essentially stuck with this four bolt-hole arrangement.

                              So, the solution is to mount "something" to those four bolt holes and then drill new holes in that "something" to accept whatever wheel you want to mount in place of the stock wheels. One obvious choice is to mount the rim from the original wheels to the motor flange and, somehow, adapt the body of that "wheel" to whatever your new wheel needs.

                              This can be a win as it gives you an offset from the normal line of the wheel -- further outboard to help clear the anti-tip and front caster arm.

                              I'll take some photos, Monday, as I've got the wheels off a Permobil chair, currently (though it's a mid-wheel drive chair -- I recall because I was amused that removing the batteries left the drive wheels FLOATING above the floor when the chair was unoccupied)

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