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Battery mounted on the rear bike rack is a bad idea...

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    Battery mounted on the rear bike rack is a bad idea...

    I mounted my shark pack on a rear bike rack. Even with velcro straps and putty to absorb the shock, it is still too much. I broke or seem to damage my battery pack because of the shock of going from concrete to grass. Opened up the pack, the BMS is broken as the cells are still measuring voltage but not the bms...Unfortunatly, Lunacycle stopped selling BMS?...Good thing I have a spare battery pack :rolleyes:


    The shock is very smoothed out when the battery is between the wheels, so being mounted on the downtube is better...

    The point of this post is to warn anyone else thinking to mount the battery on a rack. Dont make my mistake.

    #2
    Hi, was the BMS was physically broken?

    Comment


      #3
      No, I tested the positive and negative on the battery output (the 4 terminals outside of the shark pack) and there was no voltage. Also, there was voltage with the Positive inside the pack to the grounds, but not on the BMS.

      I am not sure how physical shock can dismay the circuitry of the BMS. The cells seems to be good (not conclusive as I did not tested each cell). I will be breaking the pack apart once I get myself a spot welder to salvage and make my own.

      Comment


        #4
        You may just have tripped the BMS and it can be reset, those are the exact symptoms of a tripped BMS. The Shark packs have a nasty habit of tripping out with the least provocation. Here is the procedure
        http://lunacycle.com/jumping-your-lu...-battery-pack/

        Comment


        • hammonkey
          hammonkey commented
          Editing a comment
          You saved my battery!!!!! Thank you thank you thank you!!!!

        #5
        battery on downtube is also bad idea well atleast for those who do offroad / trails, i damaged mine and now i put my battery in my backpack and its upside down orientation.

        just to give you an idea, here is what happened to my downtube mounted bottle battery pack.

        I opened the base where the switch is located: Click image for larger version

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        shattered pieces inside making annoying sound.

        not to mention the top part where bms is installed: https://1drv.ms/v/s!AkfKtrEULtPWsDvfjUaFf4MGptMW
        because of that lots of problem will arise, errors everywhere and for a noob like me? oh man sleepless nights :(
        Last edited by pcliteuser; 08-11-2016, 10:10 AM.

        Comment


        • hammonkey
          hammonkey commented
          Editing a comment
          I agree, backpack is probably the best/safest route. Although, the wire should be connected where it can come loose easily if the rider happens to fall off. But thats also risky if the wire ending are exposed.

          I say the downtube is good place because the shock coming from the tires (either front or back) gets less intense because of a fulcrum effect? I am not a physicist but it seems to dampen the shock. I also put a huge blob of putty underneath the battery mount.

        • edrios3
          edrios3 commented
          Editing a comment
          I also broke the battery plastic tabs since then I use 3 pieces of velcro one on top in the thinner part of the battery another one connecting the top one the one on the lower part of the battery this prevent vibration

        #6
        I have been worried about this. Every once in a while the bike gets a heck of a jolt. Maybe I can suspend my pack under a luggage rack..........hummmmm

        Comment


          #7
          I followed OpimiusPrime's suggestion by jump starting it with the anderson connectors...Its alive!!!

          Comment


          • OptimusPrime
            OptimusPrime commented
            Editing a comment
            Glad I could be of assistance!

          #8
          I use two layers of a 1/2" thick yoga mat under my batteries to protect them. The mat is similar to this one.

          http://www.amazon.com/Crown-Sporting...t_sims?ie=UTF8

          The actual one I used is no longer available. This one says 3/4" thick but the reviewers say it is only 1/2".

          I've used it to add 2" height to my motorcycle seat, and I am thinking of adding a couple of layers to my bicycle seat.

          I use allsport vinyl which stretches four ways to reupholster my seats.

          Comment


            #9
            Originally posted by pcliteuser View Post
            battery on downtube is also bad idea well atleast for those who do offroad / trails, i damaged mine and now i put my battery in my backpack and its upside down orientation.
            I think that some cases are better than others. I find the Dolphin to be most durable and mine have survived several falls and drops. I have 4 with varying cells. Much stouter build than the others.

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              #10
              My Luna Dolphin on the downtube would rattle on bumps. I lived with it, thinking the cradle was loose on my bike, but my wife complained when I put it on her bike. Turned out the foam padding inside the case had shrunk, and the batteries were moving. Yikes. I repacked it.

              When I first installed the BBS02 on another bike, I would mount that repacked Dolphin on the rear rack with bungee cords. It did indeed smack the rack on bumps, so I put thawed out soft freeze packs under it, and everything in a battery bag. That worked out until I bought a rack battery.



              Comment


                #11
                Some rubber padding under the mount is useful. Some packs shipped with rubber mounts.

                Comment


                  #12
                  Rubber mounts would be a good thing to have by default for all post mounted batteries

                  Comment


                    #13
                    I like somewhat high density foam, similar to the yoga mat stuff, with a super thin layer of aircraft plywood (scrap pieces, multi ply, very strong for it's weight, plus free) over the foam. The plywood handles the mechanical loads, spreads it out anyway, of the 3 straps that secure my padded bag from my bikes horizontal tube. It's a compromise between binding a battery down tight enough to not slop around, and experience g forces, versus the securing method itself causing damage. Movement is the enemy, but restraining that movement properly is the trick. 2000+ miles plus now, with a lot of very rough trail riding, so far so good.

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