MrRobot Posted April 5, 2020 Share Posted April 5, 2020 (edited) How difficult would it be to repair a damaged battery pack? I had a pretty bad crash a couple months ago and haven't been getting very good range since (~20 miles with moderate riding). Took it apart and let it fully charge and found one of the packs is only getting warm in a very small part of the pack. I'm pretty sure the connections to most of the cells was damaged during the crash. Has anyone here attempted such a thing? Any videos or how tos? I know it's very difficult and would require soldering... 😢 Not sure what else to do though. I've already checked connections and tested voltages of each pack individually and they're both giving a good reading I just think only a few cells are actually working in one...or both. 😞 Edited April 5, 2020 by MrRobot Quote Link to comment Share on other sites More sharing options...
Rywokast Posted April 6, 2020 Share Posted April 6, 2020 anything is possible, but im afraid if you are asking, then its not worth the undertaking... you have to know exactly what youre doing and why and playing with batteries is no joke you could seriously injure yourself or start a fire if you dont know what youre doing.. plus the cost to do so probably wouldnt even be worth it in the end.. i really hope the riding youre doing has only been moderate because you have a high probability of cutout with damaged batteries especially with how severe it sounds... im very far from an expert on batteries but i would say the obvious first step would be to unplug everything and take the shrink wrap off, check for visible damage and then test each cell for its output, you would then need to acquire new cells of the exact same make to replace them and do the (de)soldering work making sure each cell is at the same voltage before connecting them.. it may not sound that complicated and you surely would be able to find some youtube videos on repairing battery packs but like i said unless you know precisely what youre doing and have all the right tools it is not a wise undertaking in my opinion, you would be much better off and safer just replacing the bad pack(s) as a whole with official GW batteries https://www.ewheels.com/product/84v-800wh-battery-pack-msx-nikola-monster/ are you certain you damaged the batteries? i mean that would have to be a seriously gnarly crash to do that, ive seen dozens of crashes at 60+ kph and unless the battery actually flew out of the thing it seems very unlikely that it would get damaged.. not impossible though, you said you took it apart but are you sure both packs are connected and theres nothing wrong with the wiring anywhere in the msx? do you have pics? because a battery damaged by physical force should show obvious signs... either way i recommend you dont ride it until its solved Quote Link to comment Share on other sites More sharing options...
Rywokast Posted April 6, 2020 Share Posted April 6, 2020 btw where did you get the wheel from? i would highly recommend you have a professional examine it first because the batteries are by far the most expensive part of the euc and i know it sucks if you had to replace them, but if you got it from somewhere that offers warranty repair you could pay to have them look at it.. or even in the city im in theres electric bike repair shops that would be able to figure out the problem and if they had to be replaced or not Quote Link to comment Share on other sites More sharing options...
alcatraz Posted April 6, 2020 Share Posted April 6, 2020 I don't think the cell get ripped from their terminals. If anything they get dented because they are soft. That would kill a cell group and you shouldn't be able to recharge the pack fully again. The cells arent soldered. They are spotwelded. Do you have any tools at all to your disposal? If you don't the tools will likely cost more than buying a 2nd hand pack. It is also quite time consuming and a bit dangerous to work on lithium batteries. It's a lot of fun to learn though and you can save money in the future by learning how to build a pack. 1 Quote Link to comment Share on other sites More sharing options...
MrRobot Posted April 6, 2020 Author Share Posted April 6, 2020 This is what the seller said. No warranty, bought it from twheels on Ali express. How do I check the BMS for burnout like he suggested? Quote Link to comment Share on other sites More sharing options...
alcatraz Posted April 6, 2020 Share Posted April 6, 2020 "Just" is a bit boldly written here. You'd have to take the shrinkwrap off the pack which is going to clearly avoid the warranty. Check first for obvious external damage. Scuffs, dents, bulges. 1 Quote Link to comment Share on other sites More sharing options...
Rywokast Posted April 6, 2020 Share Posted April 6, 2020 (edited) well the bms is a small pcb soldered or connected with plugs to the battery inside of the shrink wrap.. unless theres obvious physical damage im not sure how you could test it... and not sure what difference it makes, unless he is able to sell you a direct replacement? Edited April 6, 2020 by Rywokast Quote Link to comment Share on other sites More sharing options...
alcatraz Posted April 6, 2020 Share Posted April 6, 2020 (edited) It sounds to me like the seller has had claims for faulty bms before. Could it be a result of the crash? Hard to say... You haven't mentiones the wheel model, which would help tell us if you're dealing with a hardcase or merely a shrinkwrapped pack (common). If a warranty claim is out of the picture then you might find the problem by taking the heatshrink off and measuring the cell group voltages with a multimeter. But I gotta warn you that both if you have a bad bms or bad cells, it's a job for a somewhat skilled person. You can't rush a fix unless you've done it before. Edited April 6, 2020 by alcatraz Quote Link to comment Share on other sites More sharing options...
Rywokast Posted April 6, 2020 Share Posted April 6, 2020 (edited) 4 minutes ago, alcatraz said: It sounds to me like the seller has had claims for faulty bms before. Could it be a result of the crash? Hard to say... You haven't mentiones the wheel model, which would help tell us if you're dealing with a hardcase or merely a shrinkwrapped pack (common). i assumed he was talking about the MSX per his nametag, in which case a faulty bms other than from impact would be a true rarity... i dont believe gotway has ever had anything but perfect history with their batteries.. plus the seller said in the convo gotway, so i think gotway has only ever done shrink wrapped Edited April 6, 2020 by Rywokast Quote Link to comment Share on other sites More sharing options...
MrRobot Posted April 6, 2020 Author Share Posted April 6, 2020 (edited) Gotway Msx 84v 1600wh and it's almost exactly a year old. Looks shrink wrapped Edited April 6, 2020 by MrRobot Quote Link to comment Share on other sites More sharing options...
alcatraz Posted April 6, 2020 Share Posted April 6, 2020 Well, how about taking the panels off and checking that both packs are still hooked up. You can power the wheel up (not ride it) with one pack connected and check its voltage in the wheellog app. Then power off and swap to only the other pack. If they both show 84V (100%) or thereabout the packs are probably fine. If you can't get over 79-80V lets say after charging there's a problem. Also don't forget that the charger could be malfunctioning. Quote Link to comment Share on other sites More sharing options...
MrRobot Posted April 6, 2020 Author Share Posted April 6, 2020 (edited) What about the fact that the one pack only is warm in the very middle after charging for 6 hours? I'm pretty sure the other pack was warm all around but I need to verify this. I also could ride with only the suspected damaged pack plugged in to verify it is indeed much weaker. Both packs are indeed hooked up. Tested charging with both the stock charger and ewheels quick charger. Both packs show ability to charge up to 84.5v (testing voltage with ewheels charger charging each pack individually) Edited April 6, 2020 by MrRobot Quote Link to comment Share on other sites More sharing options...
Rywokast Posted April 6, 2020 Share Posted April 6, 2020 (edited) 15 minutes ago, MrRobot said: What about the fact that the one pack only is warm in the very middle after charging for 6 hours? I'm pretty sure the other pack was warm all around but I need to verify this. I also could ride with only the suspected damaged pack plugged in to verify it is indeed much weaker. Both packs are indeed hooked up. Tested charging with both the stock charger and ewheels quick charger. Both packs show ability to charge up to 84.5v (testing voltage with ewheels charger charging each pack individually) well thats probably the bms heating up lol.. wait both packs are charging to 84V? so whats the issue then.. just the range is noticeable less?? did you check the voltage after that range test? if both packs can be charged to 84V then it seems your issue is elsewhere.. can you describe any behaviors outside of the norm exhibited? because while i dont know your personal situation a heavier rider, going hard in cold weather 20 miles is feasible for an MSX to start getting speed warnings.. but if this is totally out of the ordinary for you say you normally can do twice that range then theres a problem for sure, but it doesnt seem to be the batteries themselves, which would be good because they cost far more than anything else to replace.. however im not sure how something on the main board could cause that? i mean i guess its possible i just have no clue what it could be you could only replace it to see... but you did firstly try with only one pack and then with only the other to make sure all connections are good and its actually registering them both fine? Edited April 6, 2020 by Rywokast Quote Link to comment Share on other sites More sharing options...
MrRobot Posted April 6, 2020 Author Share Posted April 6, 2020 Yeah just the range being about half of what it used to be. This was just a theory that some cells went bad or were disconnected somehow. Previously I thought it was just the cold weather affecting the range but it's warming up now and not improving. 50-60f for recent tests. If I ride until 25% or so it's around 72-74v on the ewheels charger. I didn't ride that long today so I can't give you an exact number. Quote Link to comment Share on other sites More sharing options...
Rywokast Posted April 6, 2020 Share Posted April 6, 2020 1 minute ago, MrRobot said: Yeah just the range being about half of what it used to be. This was just a theory that some cells went bad or were disconnected somehow. Previously I thought it was just the cold weather affecting the range but it's warming up now and not improving. 50-60f for recent tests. If I ride until 25% or so it's around 72-74v on the ewheels charger. I didn't ride that long today so I can't give you an exact number. you know honestly that doesnt sound that off to me.... if i do the conversion because i dont speak your language haha thats about 50f outside and i have a regular route that is 25 miles, now on that i will get home and it will be at the same, within 72-74V which is like 40% ish for a KS18XL.. so you know what for an MSX depending on your weight thats actually not really outside the norm... i do ride hard though and if you say its normally twice as much and youre taking it easy then something is fishy Quote Link to comment Share on other sites More sharing options...
MrRobot Posted April 6, 2020 Author Share Posted April 6, 2020 I'll do another more in depth test with each pack individually in the coming days and see what happens. Supposed to warm up to 70 degrees so that would be a good time to see if it's still weather related. I weigh 205 pounds and average around 25mph when riding. 1 Quote Link to comment Share on other sites More sharing options...
Rywokast Posted April 6, 2020 Share Posted April 6, 2020 if cells were bad you would not be able to achieve 84V (i think your charger exaggerates the cells shouldnt go over 4.2V each.. if you turn it on and check the app it should reflect this, 20 x 4.2 = 84) so you can rule that out.. which is good.. if you are absolutely positive that both packs are working as in with only one at a time connected the wheel operates and both can charge to 84V then you can move on to the next thing... i would be looking at replacing the board, im not sure how that can relate tbh, but thats really the only other aspect of the wheel that it could possibly be lol Quote Link to comment Share on other sites More sharing options...
Rywokast Posted April 6, 2020 Share Posted April 6, 2020 1 minute ago, MrRobot said: I'll do another more in depth test with each pack individually in the coming days and see what happens. Supposed to warm up to 70 degrees so that would be a good time to see if it's still weather related. I weigh 205 pounds and average around 25mph when riding. yea see im 120 and average the same though i do ride quite a bit at the top end 30 mph on my 18XL, but thats obviously not my average speed.. i really dont think thats unusual i would do some more tests without replacing the board... Quote Link to comment Share on other sites More sharing options...
Rywokast Posted April 6, 2020 Share Posted April 6, 2020 (edited) because im not kidding, optimal conditions no wind summer day i can do 105 km on my KS18 before i get to the point i dont want to ride any more (10% battery) for safety reasons... there is a huuuuge difference that nature can make, wind resistance, inclines, temperature.. any season that isnt summer here the temperature is drastically lower and its very often quite windy.. that can cut my range in half from the summer lol Edited April 6, 2020 by Rywokast Quote Link to comment Share on other sites More sharing options...
MrRobot Posted April 6, 2020 Author Share Posted April 6, 2020 OK I'll do more testing. Thanks for all the technical feedback @Rywokast and @alcatraz! 1 Quote Link to comment Share on other sites More sharing options...
Rywokast Posted April 6, 2020 Share Posted April 6, 2020 Just now, MrRobot said: OK I'll do more testing. Thanks for all the technical feedback @Rywokast and @alcatraz! hopefully it helps.. a board change would be a last resort but again, i dont think its a problem.. if the board were damaged in some way it would very likely either be visible, or it would exhibit other symptoms of being damaged.... and you wouldnt want to find out what those are lol. i dont know how much you ride you know if you ride every single day and then charge the battery to 100% w/e but you know youve said you had it one year.. its not out of the ordinary that you would lose 15% or more range capacity in that amount of time... very regular charging and bad charging habits could shorten the lifespan by quite a bit over time.... perhaps it is just this event that had this brought to your attention.... i know if i had a bad crash like that i would be extremely paranoid that something could be wrong Quote Link to comment Share on other sites More sharing options...
alcatraz Posted April 6, 2020 Share Posted April 6, 2020 (edited) I'd charge both packs up fully and let them sit for a while disconnected from eachother, like overnight. Then hook them up one by one and see if the voltage is kept the same (by multimeter or in the wheellog app). Note the voltage drop from the evening before. Are they both similar? Edited April 6, 2020 by alcatraz Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.