esaj Posted January 24, 2016 Share Posted January 24, 2016 0.7V sounds a bit weird, are the packs connected together (ie. is it the voltage difference between the packs, voltage of one pack on one side of the fuse and voltage of the other on the other side)? Otherwise it would mean there's a 0.7V voltage drop ACROSS the fuse, which would mean it's still conducting and that it's actually passing at least some current. But as you say that there's resistance between the fuse leads, it must be broken (probably there'd be a little bit of resistance even if it's ok, but I mean really little, like 1/10ths or 1/100ths of ohm). One thing (that might be slightly hazardous) I can think of to try would be taking a smaller rated, something like 1A, fuse (similar sized car fuse) and holding it with ONE HAND, touch the fuse leads to the leads in the BMS (where the current fuse is), of course taking care not to accidentally poke it so that it short circuits the traces in the PCB. If the fuse blows, there's something seriously wrong (ie. large current starts moving the second there's a connection, I believe your batteries should not be discharging to anywhere right now?). Link to comment Share on other sites More sharing options...
Cloud Posted January 24, 2016 Author Share Posted January 24, 2016 3 minutes ago, esaj said: 0.7V sounds a bit weird, are the packs connected together (ie. is it the voltage difference between the packs, voltage of one pack on one side of the fuse and voltage of the other on the other side)? Otherwise it would mean there's a 0.7V voltage drop ACROSS the fuse, which would mean it's still conducting and that it's actually passing at least some current. But as you say that there's resistance between the fuse leads, it must be broken (probably there'd be a little bit of resistance even if it's ok, but I mean really little, like 1/100ths or 1/1000ths of ohm). One thing (that might be slightly hazardous) I can think of to try would be taking a small, something like 1A, fuse (similar sized car fuse) and holding it with ONE HAND, touch the fuse leads to the leads in the BMS (where the current fuse is), of course taking care not to accidentally poke it so that it short circuits the traces in the PCB. If the fuse blows, there's something seriously wrong (ie. current starts moving the second there's a connection, I believe your batteries should not be discharging to anywhere right now?). Right niw the batteries are disconnected from everything, and i am checking one pack at a time. What did you mean by saying one pack and the other pack? Did you mean several assemblies of cells within one pack/ blue shrink wrap? i dont have a 1 a fuse but i coukd run a thin wire across and plug in the charger to see if the battery starts charging? I already connected the two contacts of the fuse with no load and nothing happened. Is it still dangerous to connect them under the load of the charger? Link to comment Share on other sites More sharing options...
esaj Posted January 24, 2016 Share Posted January 24, 2016 1 minute ago, Cloud said: Right niw the batteries are disconnected from everything, and i am checking one pack at a time. What did you mean by saying one pack and the other pack? Did you mean several assemblies of cells within one pack/ blue shrink wrap? I was thinking that maybe you had two or more packs in parallel, just trying to figure out where that 0.7V value comes from. It would also closely match a typical diode forward voltage drop... if there's absolutely no connection between the "sides" of the fuse (ie. no common ground or other pathway), you shouldn't see any voltage, AFAIK. 1 minute ago, Cloud said: i dont have a 1 a fuse but i coukd run a thin wire across and plug in the charger to see if the battery starts charging? A single strand of wire would probably burn fairly easily with low current, so maybe that could be somewhat safe, on the other hand, if it burns through, you cannot really tell how much current was involved (ie was it excessive or was the wire just too thin for charging current). Of course again if it burns through before you're actually charging or discharging the pack, there's something really wrong. A real fuse would be a safer option. Link to comment Share on other sites More sharing options...
Cloud Posted January 24, 2016 Author Share Posted January 24, 2016 Ok im gonna go for it.. I will use several strands of wire to hold the two contacts together and will plug in the charger. Now this i understand could be dangerous so if you dont hear back from me in a few minutes it probably means something has happened.. Ok. Over and out...will report in a few if i am able. Link to comment Share on other sites More sharing options...
esaj Posted January 24, 2016 Share Posted January 24, 2016 3 minutes ago, Cloud said: Ok im gonna go for it.. I will use several strands of wire to hold the two contacts together and will plug in the charger. Now this i understand could be dangerous so if you dont hear back from me in a few minutes it probably means something has happened.. Ok. Over and out...will report in a few if i am able. Wait, how are you going to hold the wires in place? Do not use your hands... If you use both your hands, at least some of the current would pass through your hands and through your heart, not a good thing. Link to comment Share on other sites More sharing options...
Cloud Posted January 24, 2016 Author Share Posted January 24, 2016 I will just hold the wire by the insulated portion and will make the naked portion touch both contacts while charger is connected Link to comment Share on other sites More sharing options...
esaj Posted January 24, 2016 Share Posted January 24, 2016 2 minutes ago, Cloud said: I will just hold the wire by the insulated portion and will make the naked portion touch both contacts while charger is connected It will likely spark a bit... also be careful, the the wires might weld into the contacts due to sparking/high currents. Link to comment Share on other sites More sharing options...
Cloud Posted January 24, 2016 Author Share Posted January 24, 2016 Ok good news. Im still alive. The wires werent working so well, so i used my car key to connect the contacts and the charger went red and its fan has kicked in!!!! Link to comment Share on other sites More sharing options...
Cloud Posted January 24, 2016 Author Share Posted January 24, 2016 Ok now that i know its the fuse, i have a few more questions: 1. Can i use the regular soldering iron to disconnect the fuse and solder the new one in? What kind of iron shoukd i use for connection, anything specific or whatever they sell in 99 cents store will work? 2 once i am done, what do i seal the contacts with? There was this white goey stuff i have to clean off to get to the fuse. What can i use instead? 3 on one of the packs, i removed the shrink wrap from one side completely. I can buy similar size roll of shrink wrap but ive never wrapped it around a battery. Do i need special skills to do that? Dies it matter how many layers to wrap around? How do i secure the ends of the wrap on the battery pack? thanks!! Link to comment Share on other sites More sharing options...
esaj Posted January 25, 2016 Share Posted January 25, 2016 2 minutes ago, Cloud said: Ok now that i know its the fuse, i have a few more questions: 1. Can i use the regular soldering iron to disconnect the fuse and solder the new one in? What kind of iron shoukd i use for connection, anything specific or whatever they sell in 99 cents store will work? 2 once i am done, what do i seal the contacts with? There was this white goey stuff i have to clean off to get to the fuse. What can i use instead? 3 on one of the packs, i removed the shrink wrap from one side completely. I can buy similar size roll of shrink wrap but ive never wrapped it around a battery. Do i need special skills to do that? Dies it matter how many layers to wrap around? How do i secure the ends of the wrap on the battery pack? thanks!! 1. AFAIK, pretty much any soldering iron should do, it's not precision work, just be careful not to overheat anything in the vicinity (especially the cells!) in the process, and don't let the solder get in "wrong" places (like shorting other contacts or such). Also get some solder wick and/or a solder pump to remove the old solder: A basic pump like that probably costs something like couple of bucks at most. 2. I don't know if they actually need any sealing, was the gooey stuff some sort of glue or heat paste? 3. Of course I didn't find a good image right now, so this will have to do: If you look at close near the wires, there's actually two layers of wrap that are placed 90 degrees apart. So first you would slip one wrap so that the "top" and "bottom" of the pack are open, then shrink that, then slip another wraps "sideways", so that the to and bottom get covered. Take wires out the corner. Shrink. Btw, I've never done this myself When shrinking, again be careful not to heat the pack too much! Link to comment Share on other sites More sharing options...
Cloud Posted January 25, 2016 Author Share Posted January 25, 2016 2 minutes ago, esaj said: 1. AFAIK, pretty much any soldering iron should do, it's not precision work, just be careful not to overheat anything in the vicinity (especially the cells!) in the process, and don't let the solder get in "wrong" places (like shorting other contacts or such). Also get some solder wick and/or a solder pump to remove the old solder: A basic pump like that probably costs something like couple of bucks at most. 2. I don't know if they actually need any sealing, was the gooey stuff some sort of glue or heat paste? 3. Of course I didn't find a good image right now, so this will have to do: If you look at close near the wires, there's actually two layers of wrap that are placed 90 degrees apart. So first you would slip one wrap so that the "top" and "bottom" of the pack are open, then shrink that, then slip another wraps "sideways", so that the to and bottom get covered. Take wires out the corner. Shrink. Btw, I've never done this myself When shrinking, again be careful not to heat the pack too much! Thanks! The white goey stuff is probably heat paste, i dont thinkits glue. Ok, this probably sounds stupid but how do you shrink the shrink wrap? Do you have to heat it up at the edge so it melts into the other edge and becomes one? I have no idea... Thanks Link to comment Share on other sites More sharing options...
esaj Posted January 25, 2016 Share Posted January 25, 2016 2 minutes ago, Cloud said: Thanks! The white goey stuff is probably heat paste, i dont thinkits glue. I don't think a fuse would need heat paste for anything, maybe it has spread from some other part (like the protection mosfets). 2 minutes ago, Cloud said: Ok, this probably sounds stupid but how do you shrink the shrink wrap? Do you have to heat it up at the edge so it melts into the other edge and becomes one? I have no idea... Thanks It just shrinks when heated, doesn't actually melt. For that large object, a hot air blower would probably work good. You'd want something that heats it up fast, but doesn't overheat the battery, trying to heat it slowly would probably also cause the cells to heat up. You could blow some hot air on the wrap, let it shrink a bit, then let it cool (so the cells don't start to warm up), then repeat. But I'm mostly guessing, like said, I've never shrink wrapped batteries, just some wires and such. @Cranium could probably give you more useful advice, he just shrink-wrapped his Ninebot batteries. Also, do you have any idea why the fuse burned? You might have said earlier in this thread, but I was lazy and didn't check through Link to comment Share on other sites More sharing options...
Cloud Posted January 25, 2016 Author Share Posted January 25, 2016 I dont know except that i braked shafp and maybe the high current burnt it? I was going forward pretty slow, wanted to do the pendulum thing and when i hit the brakes to go back it happened.. But it was weird how it broke - read my first post in this thread with a more detailed description of what happened. Right now ive installed the new control board on y to find out that the batteries dont power the wheel and cant be charged. Now i know whats wrong with the batteries. I am praying that the motor is not broken, if it is i will probably give up. Link to comment Share on other sites More sharing options...
esaj Posted January 25, 2016 Share Posted January 25, 2016 7 minutes ago, Cloud said: I dont know except that i braked shafp and maybe the high current burnt it? I was going forward pretty slow, wanted to do the pendulum thing and when i hit the brakes to go back it happened.. But it was weird how it broke - read my first post in this thread with a more detailed description of what happened. Right now ive installed the new control board on y to find out that the batteries dont power the wheel and cant be charged. Now i know whats wrong with the batteries. I am praying that the motor is not broken, if it is i will probably give up. Oh right, now I remember which thread this was I read through all messages that come to the boards, so after over a month of this thing starting, I didn't even remember it anymore... Let's hope that it was just the faulty mainboard that blew the fuses (or accidental short circuit when installing the new board), and there's nothing wrong with the packs themselves. Link to comment Share on other sites More sharing options...
Cloud Posted January 25, 2016 Author Share Posted January 25, 2016 2 minutes ago, esaj said: Oh right, now I remember which thread this was I read through all messages that come to the boards, so after over a month of this thing starting, I didn't even remember it anymore... Let's hope that it was just the faulty mainboard that blew the fuses (or accidental short circuit when installing the new board), and there's nothing wrong with the packs themselves. There was also loud thids in the motor so i am hoping the motor is not damaged, also, i still dont understand about shrink wrap. When i look at the battery i see that the wrap has no edge. Its like a sleever the batteries are in. When i buy shrink wrap i will have to cut a piece out and when i wrap it around what do i do with the edge? Link to comment Share on other sites More sharing options...
esaj Posted January 25, 2016 Share Posted January 25, 2016 2 minutes ago, Cloud said: There was also loud thids in the motor so i am hoping the motor is not damaged, also, i still dont understand about shrink wrap. When i look at the battery i see that the wrap has no edge. Its like a sleever the batteries are in. When i buy shrink wrap i will have to cut a piece out and when i wrap it around what do i do with the edge? You need shrink tubing, not "normal" shrink wrap. That's what I meant when I said you slip two layers of it with 90 degrees apart... I'll see if I can find any better images. "Shrink tubing" or "shrink sleeve" are typical search words to use when looking for this stuff. Not sure on the size you need, you'll have to measure your battery pack and take into account that the tubing will shrink something like 30-50% in the process (I think, check the percentages also). Small diameter tubing: Larger tubing slipped partially over a bunch of LiPo-packs: Three cells with one layer of tubing, the other layer would be slipped from "top" to "bottom" to cover those open sides: Link to comment Share on other sites More sharing options...
Cloud Posted January 25, 2016 Author Share Posted January 25, 2016 I do see that the batteries are wrapped with layers oriented at 90 degrees but they are still sleeves. What ive seen for sale was a roll of flat material. I havent seen any tubing / sleeves of the right size to wrap a pack of batteries....pictures of the material or link of it for sale would be great. Thanks Link to comment Share on other sites More sharing options...
trya Posted January 25, 2016 Share Posted January 25, 2016 @Cloud something like this, I guess:http://www.aliexpress.com/item/AA-18650-Battery-66MM-PVC-Heat-Shrink-Tubing-5M-Black/32224087815.html Link to comment Share on other sites More sharing options...
esaj Posted January 25, 2016 Share Posted January 25, 2016 4 minutes ago, Cloud said: I do see that the batteries are wrapped with layers oriented at 90 degrees but they are still sleeves. What ive seen for sale was a roll of flat material. I havent seen any tubing / sleeves of the right size to wrap a pack of batteries....pictures of the material or link of it for sale would be great. Thanks Search for "shrink tubing" or "shrink sleeve" or "battery shrink tubing" etc. combinations in Aliexpress or eBay or Amazon or something... Here's an example: http://www.aliexpress.com/item/160mm-diameter-102mm-PVC-Heat-Shrink-Tubing-Battery-Wrap-Mould-Parts-ROHS-1-Meter/32557425505.html It's 160mm diameter, not sure if it's the right size... you'll have to do some measurements and calculations. Getting a bit too big isn't that bad, as it can shrink quite a lot (even up to 50% maybe?), but getting too small you can't get it around the batteries. Link to comment Share on other sites More sharing options...
Cloud Posted January 25, 2016 Author Share Posted January 25, 2016 Thank you. I didnt realize it was a flattened tube, i thought they were selling sheets of shrink wrap. Id get i need about 200mm wide, i will look. Thank you for all your help guys! Link to comment Share on other sites More sharing options...
Cranium Posted January 25, 2016 Share Posted January 25, 2016 1 hour ago, Cloud said: Thanks! The white goey stuff is probably heat paste, i dont thinkits glue. Ok, this probably sounds stupid but how do you shrink the shrink wrap? Do you have to heat it up at the edge so it melts into the other edge and becomes one? I have no idea... Thanks The method I used is very easy. I got a piece of string (or wire or cable) and wrap it around the battery pack. I measured the length and this gave me the circumference I needed. The heat shrink typically tells you what the measurement across is flat and what the diameter would be if you made a circle. The easiest thing is using the first one because if you buy 200mm shrink wrap (127mm diameter), you know that the circumference is twice that of it laying flat so 400mm. You want the shrinkwrap to be around 20% larger than your measurement (give or take 10%). So to summarize and simplify the paragraph, I measured 350mm around my battery, added 20% to get 420mm. Divided by 2 and to get 210mm for the shrink wrap measurement to look for when laid flat. I went with 200mm as being close enough (15% bigger). I bought a 1 meter strip that you just cut off what you need to size with scissors. This will be enough to do 2-4 batteries depending on the size. http://www.aliexpress.com/item/200mm-diameter-127mm-PVC-Heat-Shrink-Tubing-Battery-Wrap-Mould-Parts-ROHS-1-Meter/32557485097.html To shrink it, I used a heat gun that is made for this type of work that I've had for many years (Similar to this one). It gets hotter than a hair dryer with the nozzle being able to reach over 400°F. I'm not sure how well a hair dryer would work for thicker materials so if that is what you have, cut off a piece of heat shrink first and try it out before running into issues with it on the battery. I cut the heat shrink to be a little longer than the battery is wide and slipped it over the battery (In my case 18cm). I started in the center and as it started to shrink worked my way out. The material is very soft and flexible when it is hot so if the edges start to curl up, just redirect them. As it shrinks, it will all fit like a glove! When one side is done, flip it over, do the other side and get the two edges. It will only shrink down to a certain point and is easy to tell when it stops shrinking. Ten cut another sleeve and apply another layer 90° off from the first to seal the battery completely. You won't need to really worry about heat too much. The electronics can handle it. The boards and components have already survived an oven that raised them to a temperature to melt the solder paste to attach the components so some hot air on the heat shrink won't even come close to that. The batteries are more temperature sensitive but for the amount of time it takes to shrink it completely, you won't be raising the battery temperature enough to be concerned about. Just be concerned about everything if your heat shrink starts to actually melt. This is two layers of heat shrink on my pack. I used clear heat shrink for the looks but many colors are available: I haven't sealed the ends with caulk yet but will in the next day or two. Hope this helps Link to comment Share on other sites More sharing options...
Cloud Posted January 25, 2016 Author Share Posted January 25, 2016 Thanks! I will try my best with it! Link to comment Share on other sites More sharing options...
Cloud Posted January 28, 2016 Author Share Posted January 28, 2016 Ok here is un update, i am hoping the experts can help. I cant find a 40a mini fuse, all car stores sell mini fuses uo to 30 a, but .. 1. i assume i can connect 2 20a mini fuses instead of a 40a and it will be the same correct? There are 40a mini fuses online from china but they will take a while to arrive 2 the mini fuses i saw in a store are rated for 32v. The battery is 67v. The fuse installed in the battery looks identical to the ones in the store. I am puzzled. Is it ok to use a 32 v rated fuse?? The 40a mini fuses online seem to be also rated for 32 a... thanks! Link to comment Share on other sites More sharing options...
esaj Posted January 28, 2016 Share Posted January 28, 2016 12 minutes ago, Cloud said: Ok here is un update, i am hoping the experts can help. I cant find a 40a mini fuse, all car stores sell mini fuses uo to 30 a, but .. 1. i assume i can connect 2 20a mini fuses instead of a 40a and it will be the same correct? There are 40a mini fuses online from china but they will take a while to arrive 2 the mini fuses i saw in a store are rated for 32v. The battery is 67v. The fuse installed in the battery looks identical to the ones in the store. I am puzzled. Is it ok to use a 32 v rated fuse?? The 40a mini fuses online seem to be also rated for 32 a... thanks! To be on the safe side, I'd go with a single fuse having high enough voltage rating. Littelfuse is an american company, so I'd expect you'd find their products somewhere, for example the FK3 80V Maxi-series are rated for 80V and have amperages up to 50A: http://www.littelfuse.com/products/fuses/automotive-passenger-car/blade-fuses/fk3-80v.aspx http://www.littelfuse.com/~/media/automotive/datasheets/fuses/automotive-fuses/littelfuse_automotive_blade_fuse_fk3_maxi_80v.pdf Do note the time / current characteristics, these are fairly slow fuses, so better not go overboard with the amp-rating. Time-Current Characteristics % of Rating Opening Time Min / Max (s) 100 360,000 s / – 135 – / 1,800 s 200 2 s / 60 s 350 0.20 s / 7 s 600 0.040 s / 1 s Link to comment Share on other sites More sharing options...
Cloud Posted January 28, 2016 Author Share Posted January 28, 2016 Thanks a lot, @esaj, i will try to find a small one rated properly. I looked at the links you attached, these seem to be a very large size, mine is about 11 mm wide....but i will look with some other suppliers then....funny thing is, i am pretty sure the original one is rated 32v it looks identical to the ones i got from the store Link to comment Share on other sites More sharing options...
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