Well you can try using plummers paste. When you put small ammount onto the nickel tabs and apply solder it will pull solder towards it and act as a catalyst. The problem is they have to be copper or nickel. If tabs are from aluminum you are out of luck...PatrcioEV-ATX wrote: ↑Sat Jun 10, 2023 4:18 pm I have Tesla batteries out of a B250e, and they are working just fine, except that lately the voltage sense wires have been coming loose. This makes my BMS useless and I can't charge.
I tried soldering them back to the plates, but I'm just using regular electronic solder and it is NOT sticking to the metal that connects all the individual cells. Do I need a special kind of solder? Any other suggestions of how I can connect these sense wires? I don't want to have to take these battery boxes apart again.
"Welding 0.1 to 0,12mm nickel strips..."muehlpower wrote: ↑Sat Jul 08, 2023 9:47 am how about a spot welder like this one? Could also solve the BMS cable problem with the M3 modules.https://www.ebay.de/itm/354684344125?ha ... Sw9mVkJVss
Nice! Did you use anything to prevent the screws from coming loose over time? FWIW, you can get electrically conductive Loctite or epoxy. I think even a dab of non-conductive epoxy over the tops of the screws would go a long way. You could drill another small hole adjacent so the epoxy has something better to grab onto than just the smooth aluminum. I'm super paranoid about battery connections coming loose over time. Let's just say I have some experience with such things.PatrcioEV-ATX wrote: ↑Mon Jul 10, 2023 1:25 pm I fixed these by drilling and tapping very small holes right next to each wire and screwing in flat head screws that clamp the wire to the plate. Got the car all back together on Saturday and the BMS was happy. Was able to drive and charge. Fingers crossed!
I didn't and I share your concern about the long term. But at this point, it's done and back together so I'll deal with it if it becomes an issue. Fortunately, I made several small installation changes because of this that will allow me to more easily access the front battery box in the future - should need arise.nubster wrote: ↑Tue Jul 11, 2023 7:23 pm Nice! Did you use anything to prevent the screws from coming loose over time? FWIW, you can get electrically conductive Loctite or epoxy. I think even a dab of non-conductive epoxy over the tops of the screws would go a long way. You could drill another small hole adjacent so the epoxy has something better to grab onto than just the smooth aluminum. I'm super paranoid about battery connections coming loose over time. Let's just say I have some experience with such things.
Noted. While it's easier to get in, it's not easy.nubster wrote: ↑Wed Jul 12, 2023 6:26 pm Right on. Glad you're back up and running!
If I may make one final suggestion: Simply adding some "witness marks" with a paint pen or the like would allow you to easily detect if any of them are coming loose just by visually inspecting. Would your changes to access the battery box allow you to add some marks quickly?
Either way, I'd suggest periodically checking on them just to be sure. The issue that may arise could be the car catching fire during the middle of the night. A garage down the street from me recently caught fire due to a loose e-Bike BMS connection, which was only 48v (according to my neighbor who knows them). I don't mean to be a worry wart or annoy you about it, but I think it's important to stress the safety aspect.
