Pingouin Posted June 3, 2016 Share Posted June 3, 2016 Hi, I require your help. I have a Firewheel that has about 2000km, 1 year and a half, it worked perfectly until yesterday. The problem is that I finished charging my unicycle (99% battery), went for a ride, but about 200m further, it shut down and won't start again (just the red light of the ON/OFF button that lights up for a fraction of a second). I went back home, and used the plugged the charger, it started then shut down again a few seconds later. After lots of attemps, if finally accepted to work correctly, I did a 1 hour and a half (18km) ride with no issue and came home. 1 hour after, I tried it again, it still worked fine. I charged it during the night, and now the same problem occured, I shuts down immediatly. It seems that recharging the battery may cause some sort of over tension and maybe the mainboard shuts it down for security, I'm not sure, but I can't start it unless I plug in the charger, but it doesn't last very long. What do you think about it ? Have you guys ever had an issue like this one ? Thanks alot ! Link to comment Share on other sites More sharing options...
dmethvin Posted June 3, 2016 Share Posted June 3, 2016 Was the first 200m of your trip downhill? Maybe the battery is being overcharged from the regen braking? If plugging in the charger resets it, then it sounds the the BMS may be shutting down. Is your BMS shunted? Link to comment Share on other sites More sharing options...
Pingouin Posted June 3, 2016 Author Share Posted June 3, 2016 Hi, No I was going on flat, in fact the first time it occured just after lifting it to descend the pavement. However today it wasn't the case, it didn't start after fully charging it. After trying to use the battery a little (I still think it has something to do with over voltage) it finally started like yesterday, and worked flawlessly for 35km. It's after the charge, and it seems that when the battery has been used a little, it doesn't shutdown anymore.. What do you mean by BMS "shunted" ? I have a V3 F528 What do you think ? Link to comment Share on other sites More sharing options...
HEC Posted June 3, 2016 Share Posted June 3, 2016 For Shunting read here: It might be some loose contact / solder point which will "reconnect" once the unit warms up a bit - you might need to have it checked / opened looking for that. Link to comment Share on other sites More sharing options...
OliverH Posted June 3, 2016 Share Posted June 3, 2016 Firewheel has some kind of self diagnostic. Does the main board boot and can you here "welcome..." and an error message? Link to comment Share on other sites More sharing options...
Pingouin Posted June 3, 2016 Author Share Posted June 3, 2016 Hi, The firewheel does say welcome, but sometimes it tries to say it put shuts down before the sentence is spoke out? No error message is shown on the display. I'm a bit confused how a loose contact/solder point may cause the unicycle to fail when fully charged but not when half charged (if I try to use it and the battery hasn't been recharged, it works). Link to comment Share on other sites More sharing options...
dmethvin Posted June 4, 2016 Share Posted June 4, 2016 To me it seems more likely there is some problem with the battery pack that is causing the BMS to shut off. You would need to open up the pack and test the BMS and/or cells to figure out what is wrong. Link to comment Share on other sites More sharing options...
OliverH Posted June 4, 2016 Share Posted June 4, 2016 1 hour ago, dmethvin said: To me it seems more likely there is some problem with the battery pack that is causing the BMS to shut off. You would need to open up the pack and test the BMS and/or cells to figure out what is wrong. Could be true. Maybe on battery pack is weak. Link to comment Share on other sites More sharing options...
Pingouin Posted June 4, 2016 Author Share Posted June 4, 2016 I first thought about a weak battery pack, but I don't understand why then it causes the BMS to shut off only when the battery has been fully charged, but when left at 50% of its capacity, it works fine. Plus I get a good range with it (at least 50km), I thought it could be an issue with the balance between battery cells, but that would be the chargers fault. Link to comment Share on other sites More sharing options...
dmethvin Posted June 4, 2016 Share Posted June 4, 2016 @Pingouin a balance problem seems like it would be the fault of the BMS, not the charger. Balancing doesn't start until the charging is almost done and can take an hour or two after the light goes green. There are a bunch of threads here about the process including some graphs. Link to comment Share on other sites More sharing options...
Pingouin Posted June 4, 2016 Author Share Posted June 4, 2016 When the charger is balancing the battery, it blinks right ? Thanks for your help (to all) btw Link to comment Share on other sites More sharing options...
esaj Posted June 4, 2016 Share Posted June 4, 2016 27 minutes ago, Pingouin said: When the charger is balancing the battery, it blinks right ? Thanks for your help (to all) btw The balancing occurs through the BMS, if the charger were to handle the balancing, you'd have a separate connector with 17 leads goint the pack... at least I think it would be 17 (one ground for the negative of the last cell + 16 different "pluses"). I recently bought a 3S 5500mAh LiPo pack (for other purposes than EUCs), and it has a balance-connector with 4 pins. As for why the BMS would suddenly start to cut power with overcharge, I have no idea, but the problem could lay either in the mainboard or BMS. I know that the original BMS of my Firewheel would allow the batteries to be overcharged through the discharge-side (during regenerative braking). And my older Firewheel mainboard started to sometimes not power the motor after startup some time last summer, ie. it would turn on, play the "welcome"-message, but wouldn't start balancing, the motor would just "coach" when moving the whee back and forth (but after one or two restarts, it would engage, and cause no trouble during riding). Link to comment Share on other sites More sharing options...
Pingouin Posted June 4, 2016 Author Share Posted June 4, 2016 I orderd a new charger, if it doesn't solve the issue, then I'll probably have to open the unicycle, cut I'm not very keen in these sort of things. And you are perfectly right, most lithium batteries have a charge/discharge connector and a balance plug, but the unicycle charger only has one plug so it must be the BMS that balances the elements. Link to comment Share on other sites More sharing options...
esaj Posted June 4, 2016 Share Posted June 4, 2016 4 hours ago, Pingouin said: I orderd a new charger, if it doesn't solve the issue, then I'll probably have to open the unicycle, cut I'm not very keen in these sort of things. And you are perfectly right, most lithium batteries have a charge/discharge connector and a balance plug, but the unicycle charger only has one plug so it must be the BMS that balances the elements. If you have a multimeter, and know how to do it, you could try to measure the voltage of your charger to see that it isn't putting out too high voltage for some reason. There might be a trimmer-potentiometer or such inside the charger to adjust the voltage, but I've never opened up mine. Link to comment Share on other sites More sharing options...
Pingouin Posted June 4, 2016 Author Share Posted June 4, 2016 I have one, but it won't accept anything above 48V....I might burn it by testing it, but I'll try to ask a friend. If the new charger solves the pb, then it can only be the charger that overcharges the battery, if not, it must be the BMS like you guys said. Link to comment Share on other sites More sharing options...
Pingouin Posted June 6, 2016 Author Share Posted June 6, 2016 Hi, some uptdate. While waiting for the new charger, I charged the battery with the old charger, but stopped the charge before the light turns green (it shortens the charge of about 30minutes), unicycle display shows 99%. However, doing this makes the unicycle work with no issue. So either the BMS or the charger must overcharge the battery. Link to comment Share on other sites More sharing options...
Pingouin Posted June 9, 2016 Author Share Posted June 9, 2016 Hi ! I received my new charger, and the problem is solved !!! It must be the old charger that overcharged the battery, so if you have a problem like mine, check yours Link to comment Share on other sites More sharing options...
Pingouin Posted June 12, 2016 Author Share Posted June 12, 2016 Hi, So, the problem is there again, but this time it's not a matter of what percentage of charge is left, it shuts down in 20 to 30s after turning it on, and the charger is the only ay to restart it, btw if I let the charger plugged in the unicycle, it stays on. I've noticed something strange during the charge, every 20-30s, the red light turns green for a sec then goes back to red... I've opened the firewheel, and found these two cables that seem cut off, I think it's normal but what do you think ? Link to comment Share on other sites More sharing options...
HEC Posted June 12, 2016 Share Posted June 12, 2016 Those are most likely used for calibration of the board and during normal usage should be cut like this. Link to comment Share on other sites More sharing options...
esaj Posted June 12, 2016 Share Posted June 12, 2016 If those white wires are running between the battery packs, they're likely balancing wires, and should not be cut. Here's a couple of pictures from my original F260 (264Wh, 2 * 8S2P -packs in series): For F520 (528Wh) and F779 (696Wh), I've heard the configuration is even weirder: 4 * 4S4P in series Link to comment Share on other sites More sharing options...
Pingouin Posted June 12, 2016 Author Share Posted June 12, 2016 I have another red wire that is cut, however they seem they have been cut and didn't just brake... My unicycle seems dead, now it immediatly shuts off as soon as I unplug the charger Link to comment Share on other sites More sharing options...
Hunka Hunka Burning Love Posted June 12, 2016 Share Posted June 12, 2016 If you look closer at the photo there are two short broken wires under the blue plastic wrap. I wonder if they are supposed to connect onto there but what polarity if any? Either that or do you have a jealous girlfriend or wife who is mad at you and who knows about that big life insurance policy you have locked away in your safe? Dun dun dun sabotage! Link to comment Share on other sites More sharing options...
esaj Posted June 12, 2016 Share Posted June 12, 2016 10 minutes ago, Pingouin said: I have another red wire that is cut, however they seem they have been cut and didn't just brake... My unicycle seems dead, now it immediatly shuts off as soon as I unplug the charger I had problems with the sharp edges of the shell halves scraping/cutting sheathing on wires if they got pinched when closing it up. Could that be the cause? The wheel might get power through the BMS from the charger when it's plugged on, so the battery problem only manifests without the charger... not sure though, would need to see more pictures on the cut wires and then take wild guesses what wires they are? Link to comment Share on other sites More sharing options...
Pingouin Posted June 12, 2016 Author Share Posted June 12, 2016 Yes I've noticed those, but I'm preety sure that they were cut on purpose and not broken (the wire is cut too clean..) Here is the red cut wire, but I've looked closly there isn't anything it might have been wired to... I'm preety sure it's the BMS that doesn't receive power by the batteries, but I can't figure out why.. Link to comment Share on other sites More sharing options...
Hunka Hunka Burning Love Posted June 12, 2016 Share Posted June 12, 2016 Dun dun dun! Sleep with one eye open! On a serious note - couldn't they at least use some rainbow coloured wiring? Geez Louise look at all those white wires... I don't think they are cut on purpose as electronics people don't leave open wire ends like that dangling or hanging around. Usually. Take a real close look at the insulation and wire breakage pattern to see which wire end might join up with the other. It can be like a mini jigsaw puzzle, but it might be enough to figure out which wire connects to which. Link to comment Share on other sites More sharing options...
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