a spark and a pop while riding and he stopped riding to check it out. Found battery not charging, removed BMS right away. Brings it here, we test each balance terminal and all seems well, untill we check voltage at the charge port and get wonky readings. some of the cells are reading low when checked using the +batt terminal.
open it up to find exactly what I expected. a loose wire due to a cold solder joint. Fortunately, the wire was secured enough that it didn’t go anywhere (which could have shorted it out) so I replaced that solder joint and all other such nonsense that I could see. Set up the new BMS and ready for testing. Sadly my phone can’t connect to the BMS Bluetooth, but light and connection attempts let me know the magic smoke is still inside. the story continues…
Not me. I mock up my nickel and do all the soldering on a silicone mat then transfer the soldered “harness” to the battery and weld. Even for balance wires, I solder wires to little tabs, then weld the tabs. This way I can take my time with the solder and make sure it’s well and properly heated all the way through without stressing about heat transfer. I only solder to pre-welded battery as a last resort. Did it on my CGT mod due to space constraints. But it still works fine.
How are the copper braids connected to the nickel atop the battery - Did you spot weld them with the copper above? Based on my understanding you should always have the more resistive metal on top. But maybe it works because the braid is stranded.
P group replaced. Fixed the weak ass main power cable connection (all 50 amps going through .15x8 nickel folded over). Added welds to every connection I moved. Glued, kapton, harness tape, harness again over balance, double heat shrunk with a layer of 1/8 rubber on the deck side in between. BMS working and cells balanced.
Are LG MJ1 18650 3500mAh 10A good for a 12s8p pack ? I was thinking of the Samsung 30Q but the “short” cycle lifespan had me thinking twice. Aiming for 2 60A motors that would not run max power to save range
Yeah, they work great. Just don’t draw more than 80 batt amps, I’m using a batch of them for a range extender project. They’re perfect for range over power.
Resuming work on this 12s2p HG6 battery. Doing something a bit different with the other side. I found thinner copper braid…lol but it’s a bit to thin for my taste. However it spotwelded really nicely and holds via spotweld slot better then the other stuff. So on this side of the battery I will be doing 4 strips of copper braid on each series connection with a layer of nickel over it as well
Series connection between two sides made of 12awg silicone wire…lol, I know my soldering skills need some skill added. I soldered the wires to the nickel strips off the battery and then welded the strips to the battery terminals
Yeah, I saw that one, I just don’t like the triple stacking of the batteries. With the smaller pack, they are in 5S1P packs that I can connect together.
Haven’t been in use yet, still chilling in a drawer until my friend is willing to put in the time and effort to fix it. His shitty board isn’t looking so hot anymore and the battery (a 10s1p from a Blitzart that he LITERALLY FOLDED IN HALF MIND YOU) is toast…about 3 miles per charge now. I was gonna use these to make a battery for a old hub board but I got a different battery for that one
He wrapped it in duct tape and then put it on a bunch of bolts…you can see scratches on the now exposed cells…
Ha, nice. Yeah, I was thinking that these could be good for a budget hub build. I’m gonna buy the LiFePO4 pack from them so thought I might as well tack on these 18650 ones as well.
