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Success! Discharging batteries, heating motor up.

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  • Success! Discharging batteries, heating motor up.

    Success at last! I still have no working brakes, but that would take some of the fun and challenge out of it.

    http://www.youtube.com/watch?v=CykCx1xLEzQ

    I'm using the cheapest car starting batteries I could find, so a full charge got me about 40 minutes of pretty hard run time. I took the kart up to the corner store for an errand, and got more than a few looks. I changed out the original drive sprocket, so it's now geared a bit taller. I guessed correctly that the reason it won't light them up from a dead stop is because of the damned accel curve programmed into the controller. Got to get a programmer and fix that.

    It turns out that by the time the batteries were pretty much flat, the motor had heated up quite nicely. So the battery charge life is the fail safe for not frying the motor. Of course, as you can see, it was being run pretty hard.

    I couldn't stop grinning. Now I'm trying to decide on whether to improve this one, making it faster, or move on to the next one. Maybe add brakes and sell it off to finance another project?

    -Mark
    The curse of having precise measuring tools is being able to actually see how imperfect everything is.

  • #2
    wOOt!

    Very cool. That's got plenty of scoot; the same setup would work pretty
    well for a small electric motoscooter for around town. You may wish to
    use deep-discharge batteries instead; they'll survive much longer than
    regular car batteries. What also helps is not flattening them completely;
    stop at 10.8 volts or so for longer life.

    - Bart
    Bart Smaalders
    http://smaalders.net/barts

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    • #3
      Sweeeeeeet! And you can add braking to the motor. It probably corners like it is on rails huh?
      Jim, By the river enjoying life...

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      • #4
        The Happy look on your face makes me feel good.

        You will be amused to know this new pitt pup has a taste for electrical wiring also like the last one did.

        He has carried more tools outside than I can find. Butch had a whole set of screwdrivers and I never found them.. I guess he buried them.

        I was showing my wife the USB camera mated to a huge lens, Holding the two in my hands getting the focal points close.. THE pup looked at her, then me, then leaned over and pulled the usb plug from the laptop.. if I had not saw it, I would not have believed it. He is jealous of anyone coming close to me.
        Excuse me, I farted.

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        • #5
          Very cool! Thats a a pretty sweet acceleration - how much power do estimate that thing has?

          i need to shoot a few pics of my go-kart

          all made from gas pipe as yours but man...everytime i see a go-kart pic on here it is made about three times heavier than mine. I waiting for mine to fold up in the wind...but it keeps on trucking

          that pipe is pretty good for go-kart frames!

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          • #6
            And the neighbors saying there goes the G-dam kid again.
            Very nice.
            Don\'t ask me to do a dam thing, I\'m retired.
            http://home.earthlink.net/~kcprecision/

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            • #7
              Originally posted by David E Cofer

              You will be amused to know this new pitt pup has a taste for electrical wiring also like the last one did.

              He has carried more tools outside than I can find. Butch had a whole set of screwdrivers and I never found them.. I guess he buried them.

              I was showing my wife the USB camera mated to a huge lens, Holding the two in my hands getting the focal points close.. THE pup looked at her, then me, then leaned over and pulled the usb plug from the laptop.. if I had not saw it, I would not have believed it. He is jealous of anyone coming close to me.
              There goes another proud animal sacrificed on the alter of bigotry, stupidity and ignorance.
              Owners need licenses, not animals.

              Rigger.

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              • #8
                For a moment there I was angry...then I realized that in fact it was not my wife you had caught on camera. She uses the same cornering technique in our driveway, and on our streets, but she has a tendency to not always stop when she should. Nice rig!
                There is no shortage of experts, the trick is knowing which one to listen to!

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                • #9
                  Originally posted by Rigger
                  There goes another proud animal sacrificed on the alter of bigotry, stupidity and ignorance.
                  Owners need licenses, not animals.
                  What??? A little OT here, but I have to say...

                  I don't consider Mr Cofer bigoted, stupid, or ignorant. I also don't believe he mistreats his dogs in any way, unless spoiling them counts somehow as mistreatment. If you've followed some of the history - the guy just seems to wind up with mischievous dogs. I get a laugh out of his screwdriver-stealing, wire-chewing dogs. Seems ironic that an electrician's dog likes to tear up wiring.

                  -Mark
                  The curse of having precise measuring tools is being able to actually see how imperfect everything is.

                  Comment


                  • #10
                    Originally posted by JIMofalltrades031
                    Sweeeeeeet! And you can add braking to the motor. It probably corners like it is on rails huh?
                    That it does, that it does. The controller has regenerative braking, but don't think the power returned to the batteries amounts to very much. It's more like using the batteries as a big load to dump braking energy into.

                    The handling is very crisp, almost twitchy. It feels to me a lot like the karts I've ridden at a local track. Frankly, I'm absolutely delighted that it came out so well.

                    I was thinking of trying to clock the max speed, and maybe get a measurement of lateral acceleration. I don't know what I'm getting in the lateral, but I know it's a lot. The automotive press measures lateral G by seeing how fast a vehicle can go and stay within a circle of certain diameter, I believe. "Drifting" also doesn't count. Maybe I can setup a test like that?

                    I've already got the second battery on the charger - they should all be good by tomorrow evening. My head is swirling with new ideas, now. Should I make another, or make this one "stronger, faster, better"? This thing is such a hoot.

                    -Mark
                    The curse of having precise measuring tools is being able to actually see how imperfect everything is.

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                    • #11
                      I am still fairly new to the world of high-speed internet, and I must say some of these videos are too cool! Somebody pass the dramamine!!!

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                      • #12
                        suggestion, It looks like the CG is low enough to not be a concern but a seatbelt and roll bar may be a good idea. Looks like a lot of fun! Is that a golf cart motor?

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                        • #13
                          mouthy jerk

                          Rigger,
                          Do you have to work at being a loud mouthed prick or does it come naturally?. I have read many, many of David Cofers posts and One thing is for certain, he is neither ignorant or stupid!, I, and I am sure many others enjoy reading Davids folksy posts and knowledgeable answers. You sir, on the other hand, have contributed exactly precisely nothing of any value to this forum. Do us a favor and spend your time on Adrians page, you two will make a loverly couple.
                          "four to tow, two to go"

                          Comment


                          • #14
                            Originally posted by Rigger
                            There goes another proud animal sacrificed on the alter of bigotry, stupidity and ignorance.
                            Owners need licenses, not animals.

                            Rigger.

                            I'd suggest checking the attitude at the door. David is very kind to his animals and if you took the time to look up the history you'd know that. He's also a very helpful guy, the kind you shouldn't judge too quickly.



                            Cool go-cart!

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                            • #15
                              Originally posted by BillH
                              suggestion, It looks like the CG is low enough to not be a concern but a seatbelt and roll bar may be a good idea. Looks like a lot of fun! Is that a golf cart motor?
                              Yup. Bought it off FleaBay from a guy that got a pallet of them. Folks he got it from develop golf carts or burden carriers or some such.

                              Well, yeah, I guess it lacks some essential safety features, like roll cage, seat belts, or even brakes. I doubt I'll need a roll cage unless I hit a curb sideways, though. It's very heavy and low, and the tires aren't the grabbiest. It likes to slide, and so do I.

                              The brake disc and caliper have been on the kart all this time, but I don't have an actuator (pedal or handle) or a cable rigged up. With such a tight turn radius combined with a live axle, it stops pretty neatly by just doing "S" turns, believe it or not. I'll probably do some preliminary tests on the mechanical brake to see if it has the needed power. I'm skeptical, and I've been thinking about going hydraulic anyway - it's easier to route hoses than a cable or rod actuator.

                              I went ahead and sprung for the programming pendant for the controller. I want to see what the kart will do when it actually thinks it's supposed to go fast, rather than keep from spilling golf clubs.

                              -Mark
                              The curse of having precise measuring tools is being able to actually see how imperfect everything is.

                              Comment

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