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Ebike project, update 3: Bling Bling

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  • Ebike project, update 3: Bling Bling

    As this is a major update and has some big images I decided to put it as a separate thread.

    The chassis for the ebike drive is finished except for the battery holders. It's working out exceptionally well and the weight is excellent. The entire assembly including the drive system, all parts of the chassis/rack and the cargo box as well total 19 lbs (8.6 Kg), batteries not included.

    All material is 6061-T6511 with some 7075-T651 in a few places. The highly perforated rear crosspiece will also serve as the tailight assembly. It will contain a left-right continous cycling ultrabright LED attention getter.

    I also bought a more comfortable cruising seat. The tires will be replaced by ones with much lower rolling resistance since I don't intend to use it off road.









    The last pic shows where the batteries will mount, not with tape...

    The cargo box is something I built about 35 years ago. It has served as a cooler most of that time but I have recently removed the insulation to use it as a general purpose storage box for the vehicles. The frame was designed with this box in mind. The cargo box weighs about 4.5 lbs (2 kg).

    Electronics and rapid charger will go in a small box that mounts between the batteries at the front of the frame under the cargo box.
    Last edited by Evan; 06-22-2008, 07:34 AM.
    Free software for calculating bolt circles and similar: Click Here

  • #2
    Evan, have you come across these?
    http://rfdesign.com/military_defense...atteries-0607/

    Iwonder when they'll become available at consumer prices
    Just got my head together
    now my body's falling apart

    Comment


    • #3
      Those batteries sound really promising. I chose valve regulated gel cells because they have the best cycle characteristics of any of the lead acid family and are much cheaper than exotic stuff like lithium-polymer. The main thing with gel cells is that they absolutely must be charged correctly or they will die. As long as they are treated well they can withstand hundreds of full discharge cycles unlike even so called regular consumer grade deep cycle flooded cell batteries.

      I could get a lot more range from this bike just by changing the motor to a more efficient design. However, I am interested to see how well this performs as is. The cost of this project has been minimal, the most expensive item is the two batteries at $50 each. All together I have less than $200 in this project.
      Free software for calculating bolt circles and similar: Click Here

      Comment


      • #4
        Yup, I'm with you Evan.
        I have a supply of VRLA (glass matt, starved electrolyte) from a mate. 12V 7AH

        I'll name no names, but his company regularly turn over stock, rather than take the risk of putting a dud into service. I get them for a nominal price.

        From my experience, they have at least as much service life as one purchased "new" from the usual, low-turnover retailers.

        I may go your route of the big rim pulley, but I've also been given a couple of hub motor/wheels. With minor mods, I can do something like the "clip-on" front wheel shown elsewhere on this site.
        The hub motors are 36-48V tho.
        No biggie, I guess I'll just run 4 of the smaller 12v 7AH batts.
        Maybe use switching instead of PWM controller.
        Just got my head together
        now my body's falling apart

        Comment


        • #5
          I'm going to switch these batteries between 12 and 24 volts to give a "Turbo" mode when it really needs the extra snoose. The starter motor will withstand that pretty well with the cooling I have implemented. It would only be used for very short periods such as getting across a busy intersection. I considered buying 6 volt cells but the price/performance ratio was poor.
          Free software for calculating bolt circles and similar: Click Here

          Comment


          • #6
            Do you intend to use some form of PWM in between those voltages, or just use the go, whoa, go faster?
            Just got my head together
            now my body's falling apart

            Comment


            • #7
              I'm building a PWM controller. I'm ordering a handful of IRF3710 hexfets. They are rated at 100volts and 57 amp continuous current and only cost 75 cents a piece. I'll use maybe ten or so in parallel as that will make it a 500 amp controller with a pulse rating of about 2000 amps.
              Free software for calculating bolt circles and similar: Click Here

              Comment


              • #8
                Woohoo! sweet.
                Where you get FETS at that price?
                Just got my head together
                now my body's falling apart

                Comment


                • #9
                  Leave it to Evan to make a silk purse out of a sows ear. again.

                  Comment


                  • #10
                    Right here Lin. They have an excellent selection of components.

                    http://www.futurlec.com/TransMosIRF.shtml
                    Free software for calculating bolt circles and similar: Click Here

                    Comment


                    • #11
                      Thanks Evan
                      Card in hand, I'm off
                      Just got my head together
                      now my body's falling apart

                      Comment


                      • #12
                        Bling bling! boy I'll say, nice attention to detail, I noticed you didnt weld the aluminum but mounted it by bolts on that upper frame, How are those holding in the hollow tube end? did you build some kind of wedge piece or are there welded caps on the ends of that square pipe that I cant see?

                        Comment


                        • #13
                          The bolts fasten to 1.5 x 1.5 x .75" aluminum plugs that are a pound in fit. A flush 10-24 screw on the bottom also makes sure they stay put. I've never had one come loose as they cold weld in place.
                          Free software for calculating bolt circles and similar: Click Here

                          Comment


                          • #14
                            I like it. So are you going to make a wind generator or use solar to charge your batteries?
                            Wow... where did the time go. I could of swore I was only out there for an hour.

                            Comment


                            • #15
                              Naw, just a treadmill for the bear-dog
                              Just got my head together
                              now my body's falling apart

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