Julian-NZ Posted April 9 Share Posted April 9 Hi Guys Has anybody had any experience in repairing battery packs? One of my friends has a wheel that he's done less than 500km on and a couple of the cells have died. I have the same wheel and have done nearly 7000km. The price of a replacement pack is ridiculous! I'm fine with doing electronics but have never worked on packs this size before. I'd have to buy a 'battery welder' for the tags. Replacing the 'damaged' cells would be a lot cheaper. Quote Link to comment Share on other sites More sharing options...
alcatraz Posted April 9 Share Posted April 9 It's possible but it's tricky because the cells are live while you're working on them. A single cell isn't very dangerous but as your pack grows it becomes very dangerous. Original packs can look quite different. Some are easier to work on than others. If you're working on a pack from a brand that likes to disable your wheel at first sign of problem like Inmotion it might not be worth it. Brand new cells of the same model are matched before they go in a pack. Two different batches of cells can over time create a voltage difference that sets off these alarms. I'd still try to repair it but it might not work as new is what I'm saying. Maintenance free riding that is. And selling it later is a problem because buyers expect it to be plug and play. Quote Link to comment Share on other sites More sharing options...
Julian-NZ Posted April 10 Author Share Posted April 10 Hmmmm - a good point. The battery pack is from a Kingsong S22. 126v might be a bit shocking but....... it's over NZ$2,787.82 to replace! That's more than half the price of a new one! Ouch! Quote Link to comment Share on other sites More sharing options...
alcatraz Posted April 10 Share Posted April 10 I think it's worth fixing but contain your expectations a little and fix it to ride the wheel a lot, not for resale value purpose. Doesn't the S22 come with a smart bms? If that's the case you don't need this next tip. Install balance wires so you can do some monitoring and balancing without taking the wheel apart too much. Quote Link to comment Share on other sites More sharing options...
Julian-NZ Posted April 10 Author Share Posted April 10 1 hour ago, alcatraz said: Doesn't the S22 come with a smart bms? Yes it does have a good BMS. Mine is working just fine but my friend is really fed-up with his wheels. I had to replace a number of parts on his V11. It just didn't want to work properly. In the end he managed to get a warranty replacement. Unfortunately, the S22 is out of warranty period even though he's done less than 500km. Thanks for the suggestions. All help is appreciated Quote Link to comment Share on other sites More sharing options...
alcatraz Posted April 16 Share Posted April 16 How's it going? Encountered any issues yet? You need a spotwelder, nickel strips, spare cells, maybe some hot glue, perhaps heatshrink. Take a pic perhaps. Quote Link to comment Share on other sites More sharing options...
Julian-NZ Posted April 19 Author Share Posted April 19 On 4/17/2024 at 2:20 AM, alcatraz said: How's it going? Encountered any issues yet? It hasn't at the moment. I've been away touring around in our caravan and doing a bit of riding. There are some really great people out there I've also been asking/researching when I can. I'm looking into which spotwelder to get. I have all the other tools already so that won't be a problem. Up early this morning to go for another ride. Looking forward to seeing more beautiful New Zealand. Quote Link to comment Share on other sites More sharing options...
Augety Posted April 20 Share Posted April 20 On 4/10/2024 at 11:38 AM, alcatraz said: 我认为它值得修复，但要稍微控制您的期望并修复它以经常驾驶方向盘，而不是出于转售价值的目的。 S22 不是带有智能 bms 吗？ 如果是这样的话，你就不需要下一个提示了。安装平衡线，这样您就可以进行一些监控和平衡，而不会将车轮拆开太多。 Kingsong's smart BMS seems to be very power-hungry, and if you don't use it, the battery will starve to death after one to two months. The battery will not be repaired without voltage. Quote Link to comment Share on other sites More sharing options...
Julian-NZ Posted April 20 Author Share Posted April 20 4 hours ago, Augety said: Kingsong's smart BMS seems to be very power-hungry, and if you don't use it, the battery will starve to death after one to two months. The battery will not be repaired without voltage. Hmmmmmm - Now what is interesting. It certainly makes me pleased that I have nearly 7000km on my wheel whilst he has less than 500km. I need to tell my wife that I need to ride my wheel even more to make sure the battery doesn't die Quote Link to comment Share on other sites More sharing options...
alcatraz Posted April 21 Share Posted April 21 Augety brings up an interesting point. Smart BMSs take power from the pack to keep monitoring it. What if the dead cell group is in fact the one group that is used to power the bms system. It's almost a design issue then. Maybe it's worth asking Kingsong. Quote Link to comment Share on other sites More sharing options...
Julian-NZ Posted April 21 Author Share Posted April 21 58 minutes ago, alcatraz said: Maybe it's worth asking Kingsong A good point. I'll have to take the battery apart to make sure that the BMS is correctly reporting the voltages. Quote Link to comment Share on other sites More sharing options...
Gbo Posted September 5 Share Posted September 5 Although this is an old post I am interested in rebuilding a pack or replacing the bms on my v12 I think the cells are ok they all measure 3.8-3.9v and 92.4v in total but the bms won’t wake up. So I’m thinking bms problem maybe. The bms is available on Aliexpress for £145 and a new battery is over £700. But although I am quite technical I have never played with batteries so any guidance would be good. Thanks Glynn 1 Quote Link to comment Share on other sites More sharing options...
alcatraz Posted September 6 Share Posted September 6 10 hours ago, Gbo said: Although this is an old post I am interested in rebuilding a pack or replacing the bms on my v12 I think the cells are ok they all measure 3.8-3.9v and 92.4v in total but the bms won’t wake up. So I’m thinking bms problem maybe. The bms is available on Aliexpress for £145 and a new battery is over £700. But although I am quite technical I have never played with batteries so any guidance would be good. Thanks Glynn How old is the pack? How many km? If it's perfectly balanced maybe the bms isn't completely dead. Might be worth repairing. See if you have somebody in town. Let's say you get a new known working bms and it doesn't work after installing. It's a risky deal. I'm not saying you shouldn't go that route, but it's not risk free. If only Inmotion had instructions on how to swap it. Which terminals to connect first and so on. A battery is always live so there's always the question, how to avoid damage upon installation? Then perhaps you need to connect it to the wheel without the other pack, test it, update firmwares etc, charge it to 100% and when both packs are individually at 100% you connect them both at the same time. That's my guess. Quote Link to comment Share on other sites More sharing options...
Julian-NZ Posted September 6 Author Share Posted September 6 @Gbo I'm interested to see how you get on with your repair. I haven't done anything to my friends wheel as he's been too busy to think about it. You'd definitely need a battery welder. Quote Link to comment Share on other sites More sharing options...
alcatraz Posted September 6 Share Posted September 6 3 hours ago, Julian-NZ said: You'd definitely need a battery welder. He's keeping all the cells. Usually you don't need a spotwelder if you just swap the bms. Quote Link to comment Share on other sites More sharing options...
Gbo Posted September 6 Share Posted September 6 @Julian-NZ have you looked at welders? Quote Link to comment Share on other sites More sharing options...
Gbo Posted September 6 Share Posted September 6 Sorry didn’t see Alcatraz post until I sent the last one. The bms on the v12 is spot welded to the cells I’m not sure how the others are connected but I will definitely need to split about 13 plates and re weld. I was going to try and use the original plates but weld in different spots than original. The next question is is it better to use a tiny drill to remove the spot weld (obviously being very careful not to penetrate a cell or cause any shorts, or lever them off and tear the weld. Has anyone tried this before? When I have done car (automobile) body work repairs in the past ii have used a flat ended drill to drill through the spot weld on one side to split the panel for replacement. 1 Quote Link to comment Share on other sites More sharing options...
alcatraz Posted September 6 Share Posted September 6 Are you sure the nickel strips aren't soldered onto the bms curcuit board? That's the usual on most packs. Quote Link to comment Share on other sites More sharing options...
alcatraz Posted September 6 Share Posted September 6 You don't solder onto the cells because the heat can damage them, but on the bms side you don't have that problem so solder is usually used. Quote Link to comment Share on other sites More sharing options...
Gbo Posted September 6 Share Posted September 6 They are definitely spot welded onto the bms Quote Link to comment Share on other sites More sharing options...
alcatraz Posted September 7 Share Posted September 7 13 hours ago, Gbo said: They are definitely spot welded onto the bms I just saw a picture. You're right. But you don't need to spotweld here. It's optional because there isn't heat sensitivity at those connections. In fact, disconnecting spotwelds is troublesome so you'll damage the nickel strips anyway. You might need to prolong them using extra nickel strips. If you don't want to have to tear strips again then solder. 1 Quote Link to comment Share on other sites More sharing options...
Julian-NZ Posted September 7 Author Share Posted September 7 On 9/6/2024 at 9:53 PM, Gbo said: @Julian-NZ have you looked at welders? Yes. It's best to get a better quality one. Quote Link to comment Share on other sites More sharing options...
Gbo Posted September 7 Share Posted September 7 9 minutes ago, Julian-NZ said: Yes. It's best to get a better quality one. Kweld seems to get good reviews. But you need a car battery or super capacitor board and power supply Quote Link to comment Share on other sites More sharing options...
alcatraz Posted September 8 Share Posted September 8 I got a spotwelder because I built a pack many years ago. Haven't used it since. It's just taking up space. A soldering iron comes in handy occasionally, and costs peanuts, takes up no space. Just saying, why complicate things. Quote Link to comment Share on other sites More sharing options...
Gbo Posted September 8 Share Posted September 8 13 hours ago, alcatraz said: I got a spotwelder because I built a pack many years ago. Haven't used it since. It's just taking up space. A soldering iron comes in handy occasionally, and costs peanuts, takes up no space. Just saying, why complicate things. Thanks for the advice I will give soldering a try first. I have a bms on order so we will see if it works Quote Link to comment Share on other sites More sharing options...
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