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    Loose battery connection

    No sooner than I fixed the last problem than I discovered a new one. The symptom was a dead power circuit from the battery. So I used my brain and a multi-meter to figure how to find the broken wire. I had to cut open the casing to solder inside. And that is when I discovered the wire was broke off held together only by the silicone rubber casing. With my new soldering iron to 797° Fahrenheit [425c] I put some rosin paste flux and solder in there and that is all that is holding the circuit right now. Tape over the outside will not hold it.

    I think I should try to remove the end plate and make a better connection to a new wire. Any ideas could help guys.

    I want to find a connector that will pull apart easier, yet will not need a longer exposed part of the wire. Because there is not going to be more than 1/2 inch. right now there is less than 1/8th inch before the brake.

    On the input wires there was also the same problem but out at the plug. When I buy a new battery I am going to make sure there is not any wiggly pig-tails to fail.

    I can't help but think that these two problems could be related some how.

    Attached Files

    #2
    The input wire broke off again and as I was fixing it the output wire broke again. I do not recommend doing this unless you are desperate like me; this pack is still good it has not run down at all, but I can't fix this kind of thing on the road; working with live wires.

    It is way past time for me to buy a new battery. But Luna does not have a 20Ah [or more] pack with non-breakable connections. Do I have to settle for a cheap one off google? No way I'm buying anything off eBay, unless there is really good support and guarantee. Why doesn't Luna make them? And it needs to be flat and no more than 17.5" long to fit on my bike.


    Click image for larger version

Name:	second wire brake.JPG
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ID:	131622 Can anyone tell me where to buy a pack of long living cells that has a 52v to 60v nominal and at least 20Ah [really I need a 40Ah pack]. I can't find any whole sale supplier of Samsung 29E cells [240cells] so I don't know what cells to use. I don't need a high drain rate cell, because the low drain rate cells last longer and if I build the pack large enough the discharge rate will very low per-cell.

    Comment


      #3
      Bolton looks to have current stock of their 20ah triangle pack. In general Bolton seems to have a good rep, seems like I read one bad review of that pack but it didn't really give any context so not sure what the person was doing with it or expecting it to do.
      https://boltonebikes.com/collections...ithium-battery

      Em3ev looks like they also have stock of their triangle. I have an older version that I got used that has been working great for me so I would consider them again.
      https://em3ev.com/shop/50v-14s6p-small-triangle-pack/

      This is also one I considered at one point but its more of a rack mount.
      https://ebikes.ca/shop/electric-bicy...7-lim-kit.html

      As for repairing yours if that was me I would carefully go at what I assume is 3d printed ABS around that nub with a dremel like tool till I have enough exposed again to solder onto then after its soldered go nuts with hot glue and other random stuff I have laying around to make sure those wires can not flex at all. On my bikes I have my packs in the Luna zip tie triangle bags with the magnet mounted inside the bag. When I am running any of my wolves either the V1 like yours or the V2's I set a 3d printed handlebar stand down at the bottom to make sure the battery can't slide down and put any pressure on the wires. After seeing yours there I am not going to go out and put some hot glue around that point where yours failed just to hopefully move the stress point a bit further out if it does get stressed.

      Comment


        #4
        and yet another wire broken off. Good thing I have a n excellent soldering iron.

        Comment


          #5
          OK I may try grinding off enough stuff to get more wire exposed thanks.

          Comment


            #6
            I am going to have to add a new connector to the charger and some how keep it from sparking. this looks like good info:

            scriptasylum.com/rc_speed/nospark

            Precharge Calculator | Sensata Technologies

            Click image for larger version  Name:	Input-capacitor-pre-charge-cable.jpg Views:	59 Size:	67.0 KB ID:	147485
            Last edited by jawnn; 02-27-2022, 11:58 AM.

            Comment


            • AZguy
              AZguy commented
              Editing a comment
              XT90S (vs XT90) have the pre-charge resistor integrated for your convenience

            #7
            I discovered that if I plug the charger in first wait a few seconds while the capacitors charge there will not be a spark when pluging in the battery. But then the spark happens at the AC outlet. so I am going to order the right size resistor and put it in the new connector and shorten the main positive prong to it will not spark because the second positive will touch first with resistor. photos later.
            Last edited by jawnn; 02-27-2022, 11:49 AM.

            Comment


              #8
              Originally posted by jawnn View Post
              [COLOR=#00331a][FONT=Comic Sans MS]The input wire broke off again and as I was fixing it the output wire broke again. ]
              It broke again because you didn't fix it right the first time. Solder has decent conductivity for connecting conductors but it doesn't have enough tensile strength to hold 2 butt ends together the way you attempted, especially if the thing moves/jiggles around after you put it back into service. It's called poor joint configuration but the average guy doesn't learn that unless in the welding trade and even then you pick it up only after years of on the job experience.

              Couple tricks I learned over the years:

              Sweat as much solder as you can into each butt end, let them cool, then carefully drill a small hole into each butt end the deeper the better, push a short length of solid copper wire (eg. 12 gauge from house wiring) into one hole. If you want an elbow then bend the solid wire to whatever angle you want then just slide the other butt end onto the solid wire. Now sweat the solder in. If you kept everything good and clean the solder will sweat down the solid wire in both directions. Now wrap the joint with clean copper foil and sweat solder between the foil and the wire. Alternatively just lay short lengths of solid wire against the joint and sweat them on.

              Mechanics and especially millwrights use and often have copper foil. They use it to shim between mating surfaces and they'll call it shim stock. It comes in thicknesses from about 0.010" to 0.200" if I recall correctly. You can get it at crafts stores too. It will have surface oxide on it so clean that off before attempting to sweat solder on it. If you truly know how to flow/sweat solder you don't need a fancy high dollar iron. Those are for working printed circuit boards. A $20 50 to 80 watt iron from a hardware store will do the trick. Those pistol grip models with an on/off trigger are crap don't even consider one.

              Another trick o' the trade. If the solder cools to a dull finish it's a bad joint with low tensile strength and reduced conductivity and perhaps full of porosity. Redo it or regret it. It must be bright and shiny after it solidifies to be a good joint. To achieve that you need to keep the joint absolutely still as it cools. You need to clamp both sides of the joint in perfect position before you heat and flow the solder. If you hold it with your fingers you'll jiggle it and the joint will have reduced conductivity and strength. You also need to tin both sides of the joint.

              Hot glue is good for holding the wire in position to prevent stress to the joint. Epoxy is even better but don't use JB weld because it contains fine iron powder for extra strength and it conducts electricity.

              Comment


                #9
                That is a good idea to drill out a hole for a solid copper wire then I can use my 30awg wire to wrap the new million strand wire before soldering. Good thing I learned about using good resin paste flux. As well as buying a digitally controlled soldering iron.

                I did put a lot of gorilla tape over the front end so it won't move and come loose again. But epoxy would be the best.

                Comment


                • AltaBrad
                  AltaBrad commented
                  Editing a comment
                  You probably figured this out already but I'll mention it just in case you didn't.... be careful how deep you drill into the wire exiting the battery pack. You might drill into, well, who knows where that wire goes and what you might be drilling into. From your photo it looks like you have about 1/4" of wire and you would think there would be at least another 1/4" of wire inside before it attaches to a circuit board or whatever but ya never know. I think if you can sink a 1/4" deep hole you would get sufficient strength especially if you can reinforce on the outside of the wire and immobilize that first few inches so it doesn't get stressed. 3/8" deep would be even better.

                  Another way to reinforce the outside is find few inches of small bore plastic pipe that will slide over the 10 ga wire. Once it's in place work epoxy or silicon caulking compound down the pipe. Silicon cures only when exposed to air so it would take a week before it would cure all the way through 3" of pipe. Epoxy doesn't need exposure to air in order to cure so it would cure in a matter of hours. Hot glue would be plenty strong enough but it hardens when it cools so you might not get much down the pipe before it hardens up and plugs the pipe. Maybe if you heat the pipe enough to keep all the hot glue liquid until the pipe is stuffed full? An ordinary BIC cigarette lighter might be adequate. A swirl jet lighter (the kind that produces a nice blue flame) would do the job. Keep a wet rag handy so if something catches fire you can smother it quickly.
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