„Not elegant work xD“, you where lucky that the loose nickel strips didnt short circuit other series connections. A tip, weld more nickel strip layers instead of the copper soldering crap. If you solder direct on the welds, the welds get softer an can peel off.
awesome Andy, I soldered on some lipo packs yesterday that had some faulty cells. It always gives me an adrenaline rush. The way these batteries can vaporize almost anything if you short them out will never get old.
Spot welding is always boring but the 1st rule is to press down as hard as possible with the electrodes when welding.A good flux and thinning the wires also helps.Nice little video...the fit looks perfect..a bit of sponge under the pack wouldnt go a miss either....what connector did you finally use XT90??
It almost looks like it shorted out between the positive and negative of that middle cell. If it got hot enough it could have burned/melted through the isolator rings and shorted that cell
It's worth buying some "50ml Soldering Acid/flux for difficult to solder surfaces especially for Nickel" it's a game-changer when soldering. You can find it on Ebay
Good work andy, i prefear thick copper with solder in my packs, and yes another cut haha! you inspired me to modify my ebikes controller, i beefed the pcb weith 2.5mm2 copper wire everywhere across tracks, with some shunt modification too
Congrats for you great video ,it show me enough but ,do you still recomend this battery today 2022 or you recomend another one ,this Samsung have good durability ?,regards .
Another good DIY video Andy I know you have a big soldering iron but the ts100 soldering iron at 24 volts with an angled flat tip outperforms anything else I've ever used but before you solder always wipe your batteries with acetone then I use a little paint brush dipped in rosenflux perfect sauders every time catch you on the next video.
Good fix I built a battery the other day with the 21700 40t cells 72v 16ah You could have used some more nickel over the tops or the copper to make sure the connections stay together. This was what I did
@@alireza071 ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-YAch05Or27A.html This is it. Best bms used and tbh it’s only gonna use 60A max atm. It’s been used on a 3k motor and a 60a controller
That looks a lot better now must have been a weak joint like you said for it to heat up like that I guess high current will always show up weak areas. That's the good thing about your BMS monitoring system or you wouldn't have even known you had a problem until it was too late. Great job done thanks for sharing and stay safe.
Question. I want to put two hub motors, two controllers, and two batteries that I can isolate from using the front wheel or back wheel separately or together. Will I need two cycle analysts and two shunts. Thank you
You made me to build something similar! Frame will be self made from scrap (cutting costs...) wheels axles etc cheap from ebay, engine 1500W but controller and battery will be the same :) Thanks for knowlidge!
Just been doing it a long time mate. I ran a lithium polymer battery company many moons ago. We used to make electric powertrains for model aircraft so this is like the same but bigger 😁
At 2:15 on the far sided copper wire/solder on the bank just left of the removed bank (I hope u can follow that jumbled description) looks as if it was burnt as well.
Thanks for the video - useful to see your approach to a typical in-life challenge ! Always difficult, fiddling with a built-battery to remove dead cells. With the nickel strips on the positive cell ends, I would have trimmed the ends round to minimise overlap to the negative case, nickel in this area serves no useful purpose. I didn't see a flux pen in your video and I have found these to help a lot even when using the inevitable flux-cored solder. Lastly, I don't know why your thick wire block to block connections were fitted above the cell tops, I should have thought it better to locate these at the interconnect point between the cells so that less heat has to bleed into the cell. Just my 2cents
Hi, it's a 72V battery. Run time is about an hour of mixed riding. Or you could probably drain the pack in about 30 minutes if you went hard! My BMS has registered maximum power of 10KW... see the last video.
@@andykirby ok so 10k. is a burst or peek ... a 30min run time means you've pulled on ave. 18amps.. ?here is how you may work it out..ok.. ?amps. x 60. div.by ( run time in mins...or amps if you know. ) if div by amps will give TIME.. BUTT IF DIV BY TIME WILL GIVE AMPS.. OK i use my bike on 48v 20a back pack. doing?? mph this is my third pack. fist was lipo. ?? oops did dog impressions. second was 15a re cyc worked for 4 years now on 20a 48v ... i do have the li ion 48v 20a cell pack but it Herts my back. sharp corners .. lolol
Did the paper protection on top get cut, the scorch marks seemed to be at the edge? Also maybe consider separating the series connections too, to avoid the plastic wrap getting scratched and catching fire. Last thing you want is a full current short on a pack like that.
I've been watching your videos for years now and recently purchased a load of cells ect to build a 26s 8p pack. I've been doing the research for a while but it still looks scary. Soon as I make a spot welder I'll start the challenge 😕.
Each parallel group of cells should be wrapped in fish paper so they can't wear through the shrink wrap and short between the parallel group next to it.
you need to solder the cells with solar bus bar (5x0.2mm tinned copper strip). it has far lower resistance than nickel and you get huge contact surface on the terminals. you need to tin the terminals with a flat blunt end soldering iron using a minute amount of stainless steel flux (it all has to be consumed during soldering, any excess will cause corrosion). depending on the current, you can just stack up as many bus bar strips as you want. I do it on the batteries I build and I have no issue whatsoever with high resistance in connectors. and it's really fast, much faster than spot welding. I built a 13S3P 21700 pack from start to finish including fitting in a Reention case with Smart Bluetooth BMS in less than 2h30min ! here's a picture of a battery pack I built a while ago. the cells are crap, but you get the idea of how to use solar bus bar for cell connections scontent.fqls1-1.fna.fbcdn.net/v/t1.0-9/127184848_102057098411828_3100370901208885422_o.jpg?_nc_cat=107&ccb=3&_nc_sid=e3f864&_nc_ohc=lsVGsDa3Bx0AX8YC5S4&_nc_ht=scontent.fqls1-1.fna&oh=d306c113e9585497a388e941dbf07d09&oe=605238DC
Hi mate, please do some research on battery making before you make any more packs. Have a look at the esk8 forums and check out Lee Wrights battery builds. I'm not hating but there are a few things that you need to change on this pack to make it safer.
Hiya. I have the same issue with one of my single cells. But I don't know the mah capacity of each of the cells. So I was A. Gonna put a 3000mah spare vape battery in there or B. Removing the whole bank so its still 60v but less than the 30ah it is maki g battery smaller! Im struggling to find someone i can use to repair the battery for me :(
hmm my comment got deleted? strange - anyway - why dont you use complete copper strips rather than nickel with copper wires? Does it not like to spot weld
Hi Andy, I think that I saw all your ebike videos, they're great, I've learned a lot. I would like your opinion to make my ebike battery, will make a 20" fat bike. I'm gonna use a 3000W hub motor, controller: 50A peak current and 25A constant, using a 72V battery. For the I'm trying to decide between a: --- 20S6P with LG INR18650-MJ1 3500mAh-10A - will make a 21Ah, 60A, these batteries hardly handle 10A each - 120 batteries price will be 406€ --- 20S5P with Molicel INR21700-P42A 4000mAh - 45A - will make a 20Ah, 225A peak - 100 batteries price will be 455€ --- 20S6P with Samsung INR21700-30T 3000mAh - 35A - will make 18Ah, 210A peak - 100 batteries price will be 450€ In terms of amperage they are similar between 18-21Ah, but the current is very different, only 60A with the MJ1 and 210-225A woth the molicel and samsung batteries, despite only have a 50A peak controller; 1 - the 21700's will work like a 1\4 of the amperage capabilitty, do I have any advantage on that? 2 - does the 60A from MJ1, are more than enough? But I can never upgrade the controller to a powerful one. 3 - In range and acceleration any difference? 4 - I would like a 35-40km of range, just using throttle, do you think the 20Ah is enough? What would you choose? the price difference isn't big between batteries. Thank a lot, sorry for the big comment.
Damn... That was sketchy, that could have gone very badly but it looks like you caught it in time. I was really expecting a ride at the end because of the music..... 😩 Next time I guess.
What happens if a cell dies, I had this battery for one day….when I first got it….it charged fine and worked good, after it went to %75 I decided to charge it after it charged I plugged it In and heard a pop sound….then a pop pop pop and now the battery reads 1% And changes to %23 if you try to throttle it it will move a little than shuts off….I put the battery on charge and it says it’s fully charged, I decided to reset the controller. Back to factory settings and was able to finish the hall sensor test and it passed so after all the parameters being sat I hooked the battery to the charger and it charged for 1 min and was done.
I watch you all the time. I don't have an Ebike but a friend does. It is a fairly new bike his second. When you plug the battery in it gives a 7 code. Well we're dumber than a box of rocks so he gets a new battery. same thing ! Can anyone offer any info? Thanks!
Omg, super cringe. Welding on top of cells will heat up the internals to more than 60C where the thin battery wire connect to the poles of the battery. Better to solder copper in the gaps between the cells. Also better to use wider nickel straps instead of stacking nickel layers. Check out 25mm nickel tape!
Spot welding is a super quick blast of current on a focused point, the cells don't heat up at all. Soldering heats them up more... but both methods are fine really, rarely damages the cells.
