Cerbera Posted July 4, 2022 Share Posted July 4, 2022 (edited) Hey everyone Had an interesting crash with my much loved (but possibly nearing the end of its useful life) Gotway MS3V yesterday, and annoyingly didn't have any phone with me, so wasn't logging stuff. The wheel is about 5 years old, and apart from a few tyre and inner tube changes is still all original parts, which I periodically inspect for structural integrity / signs of wear. Yesterday I went for a 7 mile ride up and down some extremely challenging hills, all of which seemed to go very well. I started off with 5 lights, still had 4 by the time I got to my destination. I paused a few times on the way back to check the battery status, and as I got near home it was holding the low end of 3 lights. Previously with 3 lights on the rack I would have little hesitation powering up my steep driveway, though probably wouldn't try and do it very fast. On this occasion I was perhaps a little overconfident, thinking 'nearly made it home!' and as I approached the final 30 yards to my house the wheel suddenly went massively saggy, twisted under me, and kicked me off backwards while it helpfully rolled into my parked car !! So relatively low speed crash (under 15 kph), good armour and recently arrived TSG PASS Pro, so nothing hurt, and 1 of us walked away unscathed, which was nice. But this had relatively bad consequences for the wheel, and the green motor wire had become detached - ie one end of it popped out of the connector to the motherboard. Now, horrified at the thought of having no wheel for the daily shops run (the only thing that makes shopping fun), despite a slight lack of resources I attempted a direct-solder repair - ie removed the connector, soldered the wires back together as well as I know how, and lacking any immediately available heat-shrink, wrapped it all thoroughly in electrical tape, and offset the connection away from the other motor wires to avoid accidental contacts should my temporary insulation plans fail. And so far the wheel seems back to normal and didn't sustain any other damage in the crash. I have walked it around via the handle for at least 20 minutes without a loss of balance or anything catching fire ! So, Question no 1, if you'd be so kind... Now, I would not be happy to just continue wheeling on this rather 'Heath Robinson' arrangement, but I have a Begode Master on pre-order which should be here in around a month from now. Do you think I will get away with the current solution for about a month of short daily shopping trips on easy cycle path type terrain (with full armour) while I wait for that new wheel to arrive, or have I done something most of you wouldn't even consider a passable temporary solution / option ? What might be the primary danger of my solution, and how likely do you guess I might be to run into problems in the short month of life I still would like out of this wheel ? Question 2 if you don't mind, is 'what do we think is most likely to have caused the crash' ?. Almost 100% sure it wasn't rider-error other than possibly going slightly too fast uphill for current battery status. Guess I'm just looking for some confirmation that this might be expected behaviour from a battery pack that is 5 years old and has about 3000 k on it that has just done a rather speedy and tortuous ride up the Hampshire hills and back ? Only alarms I got on the whole ride were the occasional second level beeps I have set to 32 kph (occasional), but at no point did I get any pedal dipping, or hear any of the shorter beeps that signify overload or temperature problems or anything like that... I guess I am just generally canvassing opinion as to whether you guys would risk running it for that last month given the situation... Cheers guys CBR Edited July 4, 2022 by Cerbera Quote Link to comment Share on other sites More sharing options...
Chriull Posted July 4, 2022 Share Posted July 4, 2022 8 minutes ago, Cerbera said: Yesterday I went for a 7 mile ride up and down some extremely challenging hills, 8 minutes ago, Cerbera said: twisted under me, and kicked me off backwards Sounds like an overheat tiltback that threw you off? There was beeping before? Do gotway tilt back after overheat alarm was "ignored"? 10 minutes ago, Cerbera said: despite a slight lack of resources I attempted a direct-solder repair - ie removed the connector, soldered the wires back together as well as I know how, Gotway started with motorwire connectors because soldered motor wires got too hot, so they desoldered themselves... Like they use fiberglass insulation sleeves around the motor wires, as normal insulation melts... So 12 minutes ago, Cerbera said: wrapped it all thoroughly in electrical tape should withstand not too much temperature. If you drive without hard accelerations and avoid challenging hills this repair could stand for this month? Set in the phone app some low motor current alarm. 16 minutes ago, Cerbera said: or hear any of the shorter beeps that signify overload or temperature problems or anything like that.. But it was a tiltback that threw you off backwards?! 18 minutes ago, Cerbera said: twisted under me, and kicked me off backwards Or you mean some strange behaviour by twisting? Like wheel not balancing anymore as one motor wire came loose and you fell backwards? 20 minutes ago, Cerbera said: went massively saggy, Take a thourough look at the big capacitors! They are very (over)burdened in such situations. Once they "bloat" or their legs melt wheels can feel saggy, too. 1 1 Quote Link to comment Share on other sites More sharing options...
Cerbera Posted July 4, 2022 Author Share Posted July 4, 2022 (edited) 14 minutes ago, Chriull said: But it was a tiltback that threw you off backwards?! 14 minutes ago, Chriull said: Or you mean some strange behaviour by twisting? Like wheel not balancing anymore as one motor wire came loose and you fell backwards? Yes the twisting ! It was definitely not tiltback that threw me off - the wheel twisted under me like balance had just failed. I suppose it could be possible that the motor wire didn't come off in the crash as I previously assumed - maybe it did get hot enough to melt the solder there ?! But I suspect not, as it continued rolling and balancing (as much as it can with no rider) until it hit the parked car. On restart we only had horrible loud clonks, and no balance at all, as we'd expect with 1 motor wire out. But the fact that it got all the way to the car makes me think that wire came off in the crash. However, you have made me think twice about that ! 14 minutes ago, Chriull said: There was beeping before? Do gotway tilt back after overheat alarm was "ignored"? I didn't hear any warnings at all related to temperature or overpower during the whole ride. Mine has never ever done a tiltback that wasn't related to speed, and given that I never go faster than 32kph on it so I stay well within its comfort limits I have never had a overtemp event in the entire time I have had the wheel, so don't actually know if it tilts back with overtemp ! I live in the UK, which doesn't get very hot, and I am a very light rider (9 and a bit stone, fully armoured), so overheating is almost never a problem for me, although it does have to be said it is not that often I do challenging hills runs either ! 14 minutes ago, Chriull said: Take a thourough look at the big capacitors! They are very (over)burdened in such situations. Once they "bloat" or their legs melt wheels can feel saggy, too. Yes I looked carefully at those, and they both seem 'as new'. Thank you for your thoughts ! I shall wait to see what a few more poeple think, but I tend to agree with you that I should be OK for a month as long as I don't do anything overly speedy or overtemperature-baiting ! CBR Edited July 4, 2022 by Cerbera 1 Quote Link to comment Share on other sites More sharing options...
Arbolest Posted July 4, 2022 Share Posted July 4, 2022 Hi there! First off, super glad to hear you've gotten so much faithful service out of your machine up till now! I still have parts of my original MSuper V3S+ is use today in one of my Frankenstein wheels and love it to death! As to your issue here, for question #1 I'd say ride on with caution and respect! No more hardcore hill climbing for the poor thing, but daily trips should be no problem assuming the control board is still ok! I have solder-repaired my motor cables twice in the past (different wheels, and only to add extra length) and have had no issues with them. That said, I mechanically strengthened the connection before soldering it by TIGHTLY winding a small solid copper wire around the two cables before soldering. This means that JUST IN CASE it gets super hot and the solder melts, the wires won't come apart easily. If possible, I would go back with some heat shrink to cover that joint when you can (double up on it if you have generously-sized heat shrink tube) instead of leaving it with just electrical tape. While the tape will probably suffice for normal riding without major issue, why take the chance? Also, good idea keeping the wires physically separated. I do the same thing in all of my wheels with some simple nylon zip-ties. Cheap, easy and effective. For question #2, This sounds a bit to me like one of your main capacitors may have given out. You'll be able to tell if it is either bloated/exploded, or if one of the legs looks like it has melted or disconnected. Another reason would probably be the motor wire disconnecting, but when that happens, the wheel wouldn't get saggy, it would jerk to a halt pretty quickly and "thumpily" and probably wouldn't have the power to "kick you off backwards". You stated that it is balancing fine, but you need to try it with some weight on it. Like, hold on to a wall or rail/pole and give it a sharp lean/tilt in both directions. If it still feels soft/saggy or weak, then definitely look at the capacitors closely. In any case. If it's working, it's working. I would just reinforce your soldered connection a bit, electrically insulate it as well as you can, and rebuild your trust with the wheel. Just remember to stay sensitive to changes in its riding dynamics, and take it easy until your Master gets here - that one should be able to take all of your craziest hill-climbing demands and then some! Good luck! 1 Quote Link to comment Share on other sites More sharing options...
yoos Posted July 4, 2022 Share Posted July 4, 2022 1 hour ago, Cerbera said: expected behaviour from a battery pack that is 5 years old and has about 3000 k on it 5 years is considerable but not particularly old. If it still charges to 84V it is probably healthy. If your range has not decreased to inconvenient levels then I see no need to replace the battery. 3000 miles (let alone kilometers if that's what you meant) is not that much either. I have 3700 miles on my 1000Wh battery meaning almost twice your cycle count. It's still healthy. Your battery will easily last until your master arrives. It's the other parts of the circuit discussed by others that I would worry about 1 Quote Link to comment Share on other sites More sharing options...
Cerbera Posted July 4, 2022 Author Share Posted July 4, 2022 Thank you guys - that does put my mind at rest to some degree, though will take all of your precautionary advice and do a loaded balance test by a fence before I take it out anywhere I'd hate to have to walk back from I perhaps could have chosen better words for how it kicked me off - I didn't mean to imply I was tipped off it by the pedals - the whole thing just stopped balancing, and down I went. But I didn't think forward motion was possible with the green motor wire out, so like @Arbolest suggested I would have expected it to be unable to continue rolling the 10 odd meters to the car before it fell over if that wire had come out before it impacted. Quote Link to comment Share on other sites More sharing options...
Cerbera Posted July 4, 2022 Author Share Posted July 4, 2022 (edited) Corollary question: Presuming it passes the 10 minute 'by a fence test', and some general wheeling about in the driveway, would you then tie yourself to it (bungee rope or similar) for a subsequent town ride, in the hope of limiting its travel if it did dump you again ? Or is the perceived wisdom these days that we are better off not doing that so to minimise secondary injury to ourselves ? I would not ordinarily ever use a tether when I have full confidence in the machine. Edited July 4, 2022 by Cerbera Quote Link to comment Share on other sites More sharing options...
Cerbera Posted July 4, 2022 Author Share Posted July 4, 2022 (edited) Well, it passed its fence tests, then I went into town (untethered) very slowly, and slightly faster back again, all the while riding my most gracefully balletic best (no harsh stops / hard accelerations) and all seems fine. No unusual behaviour at all in that run, and as soon as I got it back home I took the cover off, and felt the wires to see how hot they were. And they weren't at all, which I took to be very good news ! Here's some pics of my bodge (promise it is actually soldered under that blue tape!) and capacitors, which I reckon also look fine. Cheers for the advice everyone... CBR Edited July 4, 2022 by Cerbera 2 Quote Link to comment Share on other sites More sharing options...
alcatraz Posted July 5, 2022 Share Posted July 5, 2022 This is offtopic but 80v capacitors on an 84v wheel? Or is this a 67.2v wheel? So the green motor wire came loose? Quote Link to comment Share on other sites More sharing options...
alcatraz Posted July 5, 2022 Share Posted July 5, 2022 Those capacitor solder joints look odd. Do you see that? It's like it softened, and hardened. And there isn't enough solder. Just a guess. 1 Quote Link to comment Share on other sites More sharing options...
yoos Posted July 5, 2022 Share Posted July 5, 2022 8 hours ago, alcatraz said: This is offtopic but 80v capacitors on an 84v wheel? Or is this a 67.2v wheel? Good catch! I thought the MS3 was a 84V wheel, but apparently it was discontinued before I ever saw an EUC so I am by no means a specialist . It's definitely a very bad idea to use a 80V capacitor on a 84V device (just like a Mosfet it can blow/short at voltages higher than the specified 80V). Quote Link to comment Share on other sites More sharing options...
Arbolest Posted July 5, 2022 Share Posted July 5, 2022 If I remember correctly, the Msuper3 was a 67v wheel, while the MSuper V3S+ was the 84v wheel. An easy way to tell them apart is the side panels. If they are essentially perfectly flat all the way up the sides then it is the Msuper3, while if it has a raised pocket/bulge over the battery packs, it's the V3S+. Anyway, that's probably why the board uses 80v capacitors. (Just a guess on my part, I've never seen the board for an original MS3) 12 hours ago, alcatraz said: Those capacitor solder joints look odd. Do you see that? It's like it softened, and hardened. And there isn't enough solder. Nothing to worry about. Those older style boards actually had two very-close-together holes for one leg of each of the caps, probably to accommodate two different capacitor types/styles/brands based on whichever was required/available at the time. That's why one of the solder joints on each cap looks a bit funky. 18 hours ago, Cerbera said: Well, it passed its fence tests, then I went into town (untethered) very slowly, and slightly faster back again, all the while riding my most gracefully balletic best (no harsh stops / hard accelerations) and all seems fine. No unusual behaviour at all in that run, and as soon as I got it back home I took the cover off, and felt the wires to see how hot they were. And they weren't at all, which I took to be very good news ! That is good news! I hope the ride and the many I'm sure will come after it will set your mind at ease a bit. Build your confidence in the machine back up over the next few rides and get back to enjoying it! After looking at the pics of your board and your testimony, I'm still not entirely sure what caused the accident, but it's sounding/looking more like a one-time fluke or possibly just a temporarily overtaxed battery. I don't personally believe you will need to worry much about the repair if you ride normally until your new wheel arrives, so I think you can relax on that front. Just remember to listen to your wheel when it tells you something! Good luck! 1 Quote Link to comment Share on other sites More sharing options...
alcatraz Posted July 5, 2022 Share Posted July 5, 2022 1 hour ago, Arbolest said: Nothing to worry about. Those older style boards actually had two very-close-together holes for one leg of each of the caps, probably to accommodate two different capacitor types/styles/brands based on whichever was required/available at the time. That's why one of the solder joints on each cap looks a bit funky. Interesting, but I was referring to the lack of solder. If you look closely there's like a crater around the legs. Quote Link to comment Share on other sites More sharing options...
Tawpie Posted July 5, 2022 Share Posted July 5, 2022 16 minutes ago, alcatraz said: Interesting, but I was referring to the lack of solder. If you look closely there's like a crater around the legs. Typically, lack of a solder fillet on the part's leg is caused by not enough flux during soldering or 'dirty' part leads. The joint's aren't ideal and if one was concerned, a quick reflow (with ample flux added) and cleaning with isopropyl to remove the flux residue should make them ship shape. I wouldn't be terribly concerned short term with the caveat that once I know something isn't as right as it should be and that I can fix it, leaving it unfixed would bug me. But that's mostly a personal problem. 1 Quote Link to comment Share on other sites More sharing options...
Cerbera Posted July 6, 2022 Author Share Posted July 6, 2022 On 7/5/2022 at 2:06 AM, alcatraz said: Do you see that? Yeah, I kind of do, now you mention it ! Uh-oh ! 13 hours ago, Arbolest said: Nothing to worry about. Those older style boards actually had two very-close-together holes for one leg of each of the caps, probably to accommodate two different capacitor types/styles/brands based on whichever was required/available at the time. That's why one of the solder joints on each cap looks a bit funky. Phew... 11 hours ago, alcatraz said: Interesting, but I was referring to the lack of solder. If you look closely there's like a crater around the legs. Uh-oh ! Yes I do notice that. It'll be interesting to see if it bugs me enough to fix it given the wheel appears to be working fine now, and that new one is (hopefully) weeks away... 13 hours ago, Arbolest said: That is good news! I hope the ride and the many I'm sure will come after it will set your mind at ease a bit. Build your confidence in the machine back up over the next few rides and get back to enjoying it! After looking at the pics of your board and your testimony, I'm still not entirely sure what caused the accident, but it's sounding/looking more like a one-time fluke or possibly just a temporarily overtaxed battery. I don't personally believe you will need to worry much about the repair if you ride normally until your new wheel arrives, so I think you can relax on that front. Just remember to listen to your wheel when it tells you something! Good luck! Thank you ! All good advice ! CBR Quote Link to comment Share on other sites More sharing options...
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