I've made quite a few packs, and learned some technique the hard way. I strongly recommend adding more structural support. Add rigid plastic, and have the wires go back over the cells instead of out of them. Rigid plastic helps in a crash. Wires going back over the cells gives an anchor point other than the soldering connection. Look at the donor cell and copy.
You're welcome! I spoke to a few people who DIY their packs (and have tried different methods) and they were clear that solder was the way to go. Spot welded nickel strips have way more resistance.
@@ChrisRosserI've only soldered my own Packs so far. Makes me wonder if a thicker nickle strip would reduce the resistance or if it's a contact surface area issue as well with the spot welding. Soldering is dangerous, as we all know. I've seen a cell pop in person from getting too hot. It would be nice to find a way to improve spot welding.
@@ChrisRosseroh no. nickel strip DC resistance of 0.2x10mm is about 1mohm per cell connection, mostly much less. compared to minimum 25mohm DC resistance of each cell, it is negligible. safety &performance first. you can do this kind of lol soldering on positive, but negative side heating is directly damaging electrolyte & separator.
For 21700 cells use AWG 18 wires to connect. Much easier than those strips. The isolation on the wire helps to prevent shorting the cells via the plus pole on top. Before making packs you should give the cells an extra shrink wrap. If the cells have play to one another and manage to rub the isolation off , your pack will short circuit. Please when DIY LI Ion packs, give extra isolation between the cells and make sure they are sticking well to one another so that they cant rub the isolation off. For the XT60 power cable AWG 16 wire would have been enough. The maximum amp draw is rated 45A anyway. Much lighter and more easy to solder Excelent choice on the p45b cells. Best you can get.
If we're being picky, lion cells shouldn't be soldered to. They should be resistance welded with a Kweld or a Malestrics spot welder. Also, skip the extra shrink wrap on the battery, and replace it with 21700 or 18650 (whatever size you want) insulation gaskets. If I were to build a pack like this, I would use 10mm x .3mm pure nickel stripping. The nickel stripping in the video is likely less than .2mm thick.
That was an awful long time with the iron on the cell. Heat transfer must have been pretty immense. Bigger hotter tip for cell work is key. It's almost guaranteed those cells were overheated during assembly.
I have built two packs before watching this video and I recommend Wojteks “Jet Edf Rc” channel /technique instead 👍🏼 big 150W iron works great in 1-2 seconds
I find it a ton easier to do the soldering by switching from my normal iron tip (BC2) to a larger tip (D4). The bigger tip carries more heat so even with large wires / braid it bonds solder much faster and there's less risk of overheating the cells. Your pack seems to test great though so it doesn't seem necessary, but it does make it easier to build.
THANK YOU for confirming, I've been arguing these points for a long time! I have always soldered my Li-ion packs and I push them incredibly hard, (often well beyond their rated values), but when I land my packs are always just barely warm. Meanwhile folks with "retail li-ion packs" (which are spot welded) often complain about extremely hot packs, those burn marks, & horrible voltage sag. I have never found those to be issues with my DIY packs and have always argued the use thin high resistance nickel strips is the likely cause... Cheers!
Rosser's so fraudulent, that I bet he didn't actually test the capacity of his pack. The manufacturer would say that he spent about 10X too long soldering. Are they just making stuff up? Do you "dwell" that long with your iron when soldering the terminals?
I want to mention why Chris chose to solder instead of spot weld since the comments seem to be negating what he said at 17:25 , though I also want to clarify that there are better practices for spot welding than the 'Gold Line' packs use. This soldered braid will have a lower resistance and allow for a greater current potential (higher amps) than the single strip of what looks like 8mm wide (prob 1.2mm) nickel strip. It's unfortunate that Auline isn't using a thicker strip or at least doubling up the strips for a 2.4mm thick strip, which would likely keep them from charing their fish paper insulator (lmao). As for the heat applied to the cell when soldering the negative side, it would be totally fine if flux and a 100w iron with a larger tip was used. Overall still a great video, Chris. Good work brother 🤙
Bad welding is not an excuse for overheating the lithium cell. This is why it should be welded - to preserve lithium accumulator degradation from overheat.
Soldered braid is capable of far more current than your usual nickel tabs spot welded on. Especially with those molicells the welded tabs will be a current restriction.
With properly scuffed pads, good flux and high heat you should be in and out of there with the iron in 2-3 seconds MAX from a room temperature cell. You're applying heat for way too long. This is exactly why people keep whining about soldering being bad for LiIon packs. High heat and short heat times will get the job done without harming the cells and provide a much better connection than spot welding. Work on tinning one cell pad at a time, giving each cell time to cool before coming back to the opposite side and then again to make the actual wire connections. Your cells wont even get warm if you do it right, you'll have better connections than spot welding and you'll have better current flow than the typical thin nickel strips.
I agree that I could have been faster if I had a bigger iron and better flux. I think the test results demonstrate that I didn't damage the cells. I got full rated capacity and great burst performance.
The 6 welding points on the nickel strips doesn’t seem to cause problems, the strips are too thin for the current, just put more layers. The copper you use is better to get the power thru, but that can not be good to keep 400C for so much time. I suggest to also tin the copper, keep it hot until it touches the cell, and keep something ready to remove the heat, like copper bread from the frezzer. Did you know that tin solder has about 6 times the resistance of copper? So, the solder surface in contact with the battery terminal must be 6 time the section of the copper. For 10mm^2 copper = 60mm^2 solder Nickel strip, or nickel coated steel strips are not the best conductors either they must be oversized to pass the current without getting hot. But there goes your energy density, more copper, nickel, tin, lead, steel, less density. The conductivity of alumin(i)um is almost the same as copper, but much lighter, there could be varying results to solder it :-) Aluminium oxyde is the problem, to tin the aluminium it must be done without oxygen. If the surface is covert by common engine oil, oxydation doesn’t occur, scrach the surface with 80 grid under oil, while tinning keep under oil. Once tinned, degrease and solder. Using flux, there was no trouble for me to solder 16mm2 copper clad aluminium from starter cables into Anderson 50Amp connectors. Maybe worth to try, Well all that could make good fire, so be ready for it, don’t count on plastic to protect against short circuits, when things get hot or cold, a little hard landing, and flames ... :-D Cheers
To make everything easier and also give a much better connection, this is the right project where you should use external soldering flux! You first put soldering flux on both ends sides of the copper braids and then presolder the ends of the braids. After that step, you do the same with the cells like you did, but the soldering tin will make a much smoother connection to the cells. Now that you have presoldered all parts you solder all parts together and the soldering tin, which has soaked deep into the copper braids thanks to use of the external flux, will make a connection with as much surface as possible. Ah: And don't forget to preheat every part to solder before finally soldering the two parts together.
I regularly make packs with the P45B/P28B, 4S/6S-1P/2P, great cells! my first attempt at soldering was a fail and destroyed a cell, now I use a copper/nickel sandwich (0.15mm cu + 0.1mm ni) and spotweld. The strips are also really easy to solder leads to. Great video Chris!
What spot welder setup do you use for this? I've mostly soldered because I was under the impression that you'd likely be in it for >350USD for a spot welder that can swing the copper/nickel sandwich.
man to much time with the iron touching the cell. I think it´s a big mistake, just user a bigger iron with more termal inertia to solder the cells. With mine in less than a second I can solder 1mm copper strips.
If you wanted to keep doing this I recommend looking into kWeld and getting strips of nickel and copper. You need to use much higher welding capabilities than anything on Amazon can supply (something around 1000-1500 amps for copper-nickel). I build mine with 0.15mm nickel and 0.15mm copper strips (nickel being the top that is used to weld the copper) with the same batteries you used. Much cleaner than soldering and slightly easier IMO to make. I can easily push the battery more without overheating risks associated with just nickel strips.
The less time the iron is touching the cell, the better. But not at the cost of a bad joint: The iron tip should be much larger than what was used here, as Chris noted. This will make sure the heat is transferred quicker, so you can spend less time with the iron on the cell. If you're spending too much time on the cell, you can stop, and let the cell cool down. With a powerful soldering station, and a big, fat iron tip (the one I use is a flat wedge, about 0.25inch wide, shaped kind of like a flat-head screwdriver), careful prepping: sanding the contact areas of each cell to be soldered, pre-tin every part, add flux to areas to be soldered, my iron is never on the cell for more than about 5~7seconds at most. My welds are solid.
Very cool. From a lot of these comments it seems like we could use a video comparing the nickel strips to the braid -- maybe a before and after of upgrading the auline pack? Nice work, as usual very informative.
I'm just now looking into these. They are more than double the price of the 2800mah but I guess that's how it goes when you are the leader of the pack you can charge what you want.
@@djSpinegeyou can but the problem is you need one of the more expensive welders, if you have one of the cheaper welders you can double up the strips or solder copper double decker style on top of the strips
This video is comparing apple to orange. The latest Molicel P45B VS other older Li-Ion cell at different MAH. Better to compare DIY P45B VS manufatured P45B at the same cell count (4S, 6S, etc)
You can also use welding and copper in conjunction, welding for the speed and not overheating the cells and the nickel stips are easy to solder the copper to either braid or wire to increase current capacity.
I had not thought of that before. So, I can solder braided copper to a nickel strip, and then spot-weld the nickel strip, with its braid, to the cell. My only question would be, how does the resistance between cells that are spot-welded, with copper braid piggy-backed, compare with cells that are copper braid welded, without nickel strips? If I understand correctly, the current is only flowing, either through the spot-welds, or through the solder joint?
What thickness is that nichel strip? I was also thinking of using cooper braid, but 0.2mm pure nichel strip might also do the job. I’m planing on doing a test to determine exactly where is the sweet spot for a safe long range LiIon pack.
Thank you so much.I am just curious is there any way to charge this battery setting without parallel cabling ? And if there is , how should I set the charger?
He should have mentioned that the cells all need to be balanced before you start. Also showing a safe way to remove leads from the donor pack would be helpful because it’s easy for people to cause problems. Also a discussion of how hot you can get each cell during soldering would be wise.
Thanks for making this video. I liked the comparison of the braid vs the nickle strip with respect to resistance. It would be interesting to see what happens if you change the nickle strips to braid...
Thanks Chris, looking forward to making my own li-ion packs now 😎 Oh Chris i can only find Molicell P42A's locally instead of the 42B's, would the 42A's still be ok?
Hello Chris, First of all thanks for making the fpv hobby next level! I have a question about molicells/voltage sack/and use for edf models. i build myself of a crashed L-39 Freewing plane a F22 Foamy for fun light and no nonense flying. specs: 80mm 6s100a 2150KV Edf. i fly over 1 year with selfmade 4s lion (molicell p45B ) great cells for cruising drone and al normal rc planes for long flight. I have used them as 2 pakkaged 4s 2p config for this motor i was thinking for a 1500 gram plane would be fine and long flight time... it works... but just enough ... flight time is there btw. i like to try something and i now... more voltage means more rpm and heat but what i want to try (probably gonne lose the edf): Specs 8s esc 100a Cont. 8s molicell 1p and throttle down about 70% maybe dynamic throttle as second step or an alarm for the first minute or so. Is there any way to make this happen or would it be better to make a 6s 2p config and don't worry about it . the problem is also weight 8cells or 12 cells(would be too heavy for this consept).
UpgradeEnergy uses these Molicell 21700's in their DarkLithium long range packs. They have a robot spot welder and decades experience building batteries! I used them to make my Stay High Fueld Charging Pack that's 6S 15Ah (6S3P 21700) Copper bars FTW 💪
My friend is making his own Li-Ion packs from these 21700 cells for his long-range drone all the time. But he uses a contact welder to weld the metal strips to the cells. Good thing about it is that you can choose the best cells for the pack and also you can customize the pack shape and size exactly according to your needs and the drone...Also you can make 2P, 4P packs if you want, scale it as you wish...
Hello Chris, what I see is that the join between the strips cause a problem not the welding on the batteries? My I be wrong but could you think about it? I think that soldering with to less heat and heating iron with to less thermalcapitiy couldt cause bigger problems than welding?
It seems to wet just fine using regular flux; with acid flux unless your cleaning is impeccable (and it's pretty hard to get under the positive tab to clean any spillovers) it could corrode later..
My main mx chaser rig I use 4s 21700 molicel and get a good 12-18mins from my 4" apex builds . And there plenty of current to get 140km/h and even can freestyle it fairly hard too . Been the best performing setup for this application
Hey, My analog FPV setup has decent range, but sometimes the video in my googles starts to randomly drift to the right and gets black/white sometimes. After a few seconds my Skyzone Sky04X beep once and the video signal is perfectly finde again. This happens super randomly, completley independent on how far the drone is away from me... Also don´t think its a overheating issue... Any tips on what to do? I need the video signal to be reliable, since i´ll use it for a fpv-job!
You can't spot weld copper (it's too conductive). Nickel strips have too much resistance for a high performance pack. Copper is nearly 5x the conductivity. I've spoken to quite a few serious Li-Ion pilots who've spot welded and soldered. There is good evidence that soldering gives a better performing pack.
The P50B does have a factory 60A non-continuous current rating (limited to 80°C) but you cannot run it at 50A continuously. It will get hot enough to boil water and the cell will be damaged.
@@kerrymillar4981 I got the 60A rating from the P50B datasheet. Where did you see a 50A temp-limited rating? Wait…you didn’t quote the rating Evva gave it, did you? Without confirming it was correct before saying either I’m wrong or Moli is lying? Hmm… I don’t say these are true continuous current ratings because they require the discharge to end early to stay below the temp limit. A true continuous current rating allows you to compare cells directly as it’s a single discharge down to the cutoff (typically 2.5V). Yes, you can argue that it’s continuous for a while but that’s no different than saying it’s a burst/pulse rating, a rating that has the cell stop discharging before it reaches its low voltage cutoff rating. But this is semantics. 🙂 What’s important is what the number actually is and the P50B datasheet only has one rating, 60A (implicitly limited to 80°C as that’s the max cell surface temp rating).
I made my own battery’s years ago and still running strong , I was told soldering was bad but a big iron fast heat has always worked maybe not for a first prodject. But even on the demo the battery can take a lot , but as said there are lots of off the shelf items as a option.
I wish he would have measured the thickness of the nickel stripping. It's probably something like .15mm thick, which would limit it's ampacity to roughly 14 ampere. 10mm x .3mm would do almost double that. Nickel stripping can also be doubled though it's not ideal. What is ideal, is copper stripping but it takes specialized welding equipment. The kapton tape is a good alternative to ring gaskets but if you have a choice, ring gaskets are ideal.
I'd recommend using some extra flux and a larger iron. I also pre-tin the batteries. My large soldering tip almost tins the batteries immediately without putting too much heat in the cells. I use a cheap 80w iron with a huge copper tip. I think its meant for soldering pipes and stuff. Works like a charm and it cost me 15 bucks at the hardware store.
I managed to WELD the tips of my metal tweezers together when I was building my Li-Ion packs. I wasn’t being careful enough and must have created a short circuit. Learn from my stupid mistake! Also, don’t use fully charged packs during the build.
Wow really keeping the soldering ion on that for quite a long time think I would just use some silicone wire to join if soldering less chance of a short and possibly some flux would speed things up.
A bigger iron and flux would certainly make the job go quicker! Given my results and what I've learnt opening up quite a few of these cells is that risk of damage with decent soldering technique is minimal.
The transfer of heat into the cell is minimal when done quickly. 5 seconds of heat will not blow up a battery. spot welder is better obv, but for a single pack its not worth the investment.
Ok so cells werent damaged 😅.. For 1P i def use P45B for a 2P or more id prob switch to 50S. I have a 4P 18650 i want try 4P 21700 if drone can fly the pack U were running 20aH & 22.5aH draw 5C. Damn no wonder when i run 6S1P on the 8" the pack gets warm and i try to stay light on throttle 15aH average i think
Whoever decides to build this; please read this. Hey Chris, I like you and your videos for you being a fellow engineer and standing for what a good engineer should be. You know the theory, you know the practice. I build a lot of packs for drones, bikes, electric racecars etc… Thus I hope you don’t take this personal. This video is nothing short of hazardous. There are a few concerning safety issues with it that need to be adressed. - The soldering: It is a bad idea for various reasons. Firstly the cells get damaged. You see for yourself how long you have to heat up the cell with the soldering iron. You definitely cooked some electrolyte, degrading the cell by a good amount… so far that’s just not smart but not really dangerousl. What I s dangerous is that you easily could drip solder in between the positive terminal and the negative can. This will short circuit and most likely make the cell burst into flames. NEVER solder a cell. It’s a fight against windmills because people will keep doing it. It is not smart. Usable spotwelders on Amazon are 20€… Second of all: The thing that literally schocked me was you showing that you reuse the LiPo lead but don’t loose a word about NOT cutting both leads off at the same time since this will short the LiPo. And these things at 4S are MEAN! Hundreds of amps of current will create a HUGE arc flash. You just skipped the part where you cut it… wouldn’t do that. Third: you need to address that while connecting the cells there will be the danger of short circuiting when connecting the wrong terminals on the opposite side. Please include these safety notes. That is not how it’s done.
Holy cow, was that a full 60 sec of direct contact between soldering iron and cell?! Isn't it pretty well established that even 5-10 sec will likely increase cell internal resistance and reduce capacity? I'm not gonna say soldering can't be done effectively, but nowadays you can buy a $15 spot welding module for up to 0.2mm pure nickel (for reference, 0.2mm x 8mm strip = 16AWG copper wire)!
Thanks a bunch for the tutorial, Chris! 😊 I've made a few of those... But I definitely going to get a spot welder for it. Sequr has a pretty cheap one. Anyway, stay safe there with your family! 🖖😊
all my packs are soldered no issue. that said Ive made p42a, p45B, 40T and more... the 45B isnt worth the cost for an extra 300mah compared to the 42B and similar discharge curve unless Chris has tested both and found any major discharge discrencies. if you are gonna solder i have vids on my channel BUT fatter tip, max that iron at 450c (or more) and I use 12ga silicone wire and all is good in the world!
Only issue is we need to unpack and unsolder the whole thing every time to charge those 21700! Just kidding. How do you charge them? Just started learning about building batteries
You should be using super flux m8. Can't remember exactly which acid it is, but it essentially binds INSTANTLY with the mating surface. No warm up time. Its crazy. Just gotta remember to wipe any excess off when youre done. I was using the rustoleum rust remover last time I did it, just what I had on hand. You can make your own as well. Look into it.
Was this meant to rage bait?? For someone who “sticks to the science” in FPV this is piss pour work… not trying to hate but damn. Do I need to make a video on how to do this better and safer?
just when everybody seems to settle on spot welding because of possible heat damage to the cells, here comes one and sends them back to the roots - to soldering. Dang...
Under the Goldline battery wrap, it should have the MFG of the cells printed right on them. I'm willing to bet they just re-wrapped a Lishen or Molicel would be my guess.
i know everyone doesnt like soldering to liion cells, but its really not that bad, personally i pop them in and out of the freezer while working on them so it doesnt get them nearly as hot overall, its also important to note that once connected in series, you have "cans" that are positivly charged and you really should have used flux, like proper flux, also also, the 18650 molicells actually have more energy density if you do the math based on specs, id love to see you test the 2 molicell 18650's
@@dieselphiend when connecting cells in series you don't need to worry about the voltage matching perfectly, and I only put them in the freezer for long enough to cool the heated cell I don't leave it in there for long enough to freeze the cells, it's literally like 30 seconds at a time just to remove the heat from soldering as fast as possible and a little bit of a pre chill before the initial solder so the internals don't get so hot
@@christhorney A 1p pack (one in parallel) with a balance output will be balanced by the internal battery management system inside of the correct charger. Beyond 1p, you absolutely have to worry about cell matching.
@@dieselphiend brother, you asked me if I worry about putting them in the freezer, I only do that during construction while making series connections, I even specifically said in my reply when making series connections that the voltage doesn't matter, ofc parellel connection it matters but that's not what I was doing nor was it what I was talking about anywhere, once I build my pack with series connections I charge it on my balance charger then I use a 2into1 connector to parellel 2 packs together for 1 of my planes, when making parellel connections voltage is important and capacity does not matter, and opposite of that when making series connections the voltage does not matter but the capacity is very important. Regardless, no I don't worry about using the freezer during construction of a series pack and yes I know basics of battery management as to not parellel connect packs with wildly different voltages
@@christhorney Man, I wouldn't care about any of this if I didn't know people will read it. I think it's important to be highly technical when explaining these things. I would consider the BMS the last line of defense. Sometimes they go bad. Often times they are miscalibrated from the factory. It's just best practice to use perfectly balanced, brand new cells.
Molicel batteries are hard to beat,been using them in vapes for years and still going strong, Fogstar is the best place to buy them if you're in the UK 👍
Those cells look like they test great, thanks for those results Chris! If anyone is looking to spot weld nickel strips to make a pack and is looking for clarity on the size of strip and how to arrange them I found this video useful. ua-cam.com/video/wdZ_Ca_sAZE/v-deo.htmlsi=HRH6x8kpTCWSnT1B
Chris, please do not solder the cells.. this will damage the internal separator between the electrodes inside the cell. The separator melts at around 130C, specially a problem on the anode. Spot welding!!! I am sure you'll not hear the end of it...
Come on man, buy some 21mm (or 18mm if using 18650's) isolator rings at least if youre going to make a video. Also, standard silicon insulated wire is much easier to use... soldering is fine if its done quickly but its taking you way too long with that braided cable.
I expected much better from this video... the construction of that pack is far from ideal/safe. good isolation is lacking, and soldering introduces a lot of heat causing potential damage and a shorter lifespan/performance from the pack. If there were a note saying that "this pack was made for the purposes of testing, please do research on good pack building methods/practice before making your own" I wouldn't mind it but a lot of people look up to you for your knowledge, and going straight into the wrong ways of making a well performing and safe pack shows some oversight (not trying to praise the pre made batteries either, they have their fair share of shortcomings)
@@ChrisRosser Do you need all that conductivity? What is this burst test you are talking about? That amount of heat you put one the cell when soldering can damage the cell.
oh man. so much contention over soldering the cells. Lithium cells are ALWAYS DANGEROUS. nickel or copper with solder, both are not without issues. Use nickel if you are most people because it is most common and well documented, I prefer copper and solder for many reasons, but higher fail rates using nickel has always been my experience.
I recommend always, to discharge all the individual cells before making packs. Than I use a dremel with a wheel and shortly clean the cell top's before soldering, than use a C4soldering Tip or even bigger and quickly Pre-Tin all the cells, (5 seconds solder time). Then you can solder the wires,or I use copper strips. (also 5 seconds) during soldering add some additional tin. (normally no need for extra flux) (5 seconds max) . the soldered PACKS have lower IR than the spot welded packs and are better suited for high current applications.
Good video, but I think the nickel stripes a better solution. Obviously those are charred cause they are either too too thin or their width is not enough. There are bigger, thicker nickel stripes that can support 45A. I even made some of my batteries with two nickel stripes one on top of each other. Anyway - their big advantage is that they add a significant structural rigidity of the pack. This can't be done with flexible braided stripes. The cables are flexible, the tape in between is soft... everything is flexible. Whilst the nickel stripes make the pack solid.
Agreed I double up my strips, to hold everything in place on my first pack, I hot glued the cells together. For the next one I 3d printed some "holders" like those end cap once you see but they slide down so not covering the ends and just use kapton tape ever everything, then heat shrink.
I think it depends on your priorities. With Nickel you will always be fighting physics. Copper is nearly 5x as conductive. The reason Nickel welds so well is it's relatively high resistivity. I guess multiple strips will improve things but it's difficult to imagine anyone welding several mm thickness of Nickel strips to match 10x1mm of copper braid. If someone is paying good money for decent high drain cells to get the best performance then it seems a shame to throw a bunch of burst performance away.
![Lp. Сердце Вселенной #60 РОЖДЕНИЕ ЛОЛОЛОШКИ [Финал] • Майнкрафт](http://i.ytimg.com/vi/YoR0pAV9FVQ/mqdefault.jpg)
I've made quite a few packs, and learned some technique the hard way. I strongly recommend adding more structural support. Add rigid plastic, and have the wires go back over the cells instead of out of them. Rigid plastic helps in a crash. Wires going back over the cells gives an anchor point other than the soldering connection. Look at the donor cell and copy.
Takes a lot of courage to post a soldering video in a community full of know it all's lol Thanks for the test.
You're welcome! I spoke to a few people who DIY their packs (and have tried different methods) and they were clear that solder was the way to go. Spot welded nickel strips have way more resistance.
@@ChrisRosserI've only soldered my own Packs so far. Makes me wonder if a thicker nickle strip would reduce the resistance or if it's a contact surface area issue as well with the spot welding.
Soldering is dangerous, as we all know. I've seen a cell pop in person from getting too hot. It would be nice to find a way to improve spot welding.
@@ChrisRosseroh no. nickel strip DC resistance of 0.2x10mm is about 1mohm per cell connection, mostly much less. compared to minimum 25mohm DC resistance of each cell, it is negligible. safety &performance first. you can do this kind of lol soldering on positive, but negative side heating is directly damaging electrolyte & separator.
For 21700 cells use AWG 18 wires to connect. Much easier than those strips. The isolation on the wire helps to prevent shorting the cells via the plus pole on top.
Before making packs you should give the cells an extra shrink wrap. If the cells have play to one another and manage to rub the isolation off , your pack will short circuit.
Please when DIY LI Ion packs, give extra isolation between the cells and make sure they are sticking well to one another so that they cant rub the isolation off.
For the XT60 power cable AWG 16 wire would have been enough. The maximum amp draw is rated 45A anyway. Much lighter and more easy to solder
Excelent choice on the p45b cells. Best you can get.
👍🏻 this
Much better idea
If we're being picky, lion cells shouldn't be soldered to. They should be resistance welded with a Kweld or a Malestrics spot welder. Also, skip the extra shrink wrap on the battery, and replace it with 21700 or 18650 (whatever size you want) insulation gaskets. If I were to build a pack like this, I would use 10mm x .3mm pure nickel stripping. The nickel stripping in the video is likely less than .2mm thick.
Even better, use the proper thicc insulator paper
That was an awful long time with the iron on the cell. Heat transfer must have been pretty immense. Bigger hotter tip for cell work is key. It's almost guaranteed those cells were overheated during assembly.
But yet they outperformed the other cells still
Yeah but is not necessary if you have a bigger tip and use some flux, plus pre tining
I was thinking exactly the same thing. Not sure I would have used braided wire using a soldering iron. Spot welder would keep the heat down.
I have built two packs before watching this video and I recommend Wojteks “Jet Edf Rc” channel /technique instead 👍🏼 big 150W iron works great in 1-2 seconds
I find it a ton easier to do the soldering by switching from my normal iron tip (BC2) to a larger tip (D4). The bigger tip carries more heat so even with large wires / braid it bonds solder much faster and there's less risk of overheating the cells. Your pack seems to test great though so it doesn't seem necessary, but it does make it easier to build.
5:30 how long can you keep the iron on the cell before they start loosing performance ?
5-10 sec max.
@@olafschermann1592 too long, the iron needs to be off the cell asap. tin wires before introduced to cell and use flux to ensure super fast soldering
THANK YOU for confirming, I've been arguing these points for a long time! I have always soldered my Li-ion packs and I push them incredibly hard, (often well beyond their rated values), but when I land my packs are always just barely warm. Meanwhile folks with "retail li-ion packs" (which are spot welded) often complain about extremely hot packs, those burn marks, & horrible voltage sag. I have never found those to be issues with my DIY packs and have always argued the use thin high resistance nickel strips is the likely cause... Cheers!
Rosser's so fraudulent, that I bet he didn't actually test the capacity of his pack. The manufacturer would say that he spent about 10X too long soldering. Are they just making stuff up? Do you "dwell" that long with your iron when soldering the terminals?
Thanks Chris! Your videos are an incredible resource for the hobby. I've been wanting to try this myself
Awesome Chris thanks for this!
I want to mention why Chris chose to solder instead of spot weld since the comments seem to be negating what he said at 17:25 , though I also want to clarify that there are better practices for spot welding than the 'Gold Line' packs use. This soldered braid will have a lower resistance and allow for a greater current potential (higher amps) than the single strip of what looks like 8mm wide (prob 1.2mm) nickel strip. It's unfortunate that Auline isn't using a thicker strip or at least doubling up the strips for a 2.4mm thick strip, which would likely keep them from charing their fish paper insulator (lmao). As for the heat applied to the cell when soldering the negative side, it would be totally fine if flux and a 100w iron with a larger tip was used.
Overall still a great video, Chris. Good work brother 🤙
Bad welding is not an excuse for overheating the lithium cell. This is why it should be welded - to preserve lithium accumulator degradation from overheat.
effectively delivered as always Chris, thanks for the demo.
effective damaging cells, thanks, not for me.
It's cool and very useful that you showed a burned isolation layer after some load tests on another battery pack.
Thanks
You really should spot-weld those cells, because of the danger of overheating them by soldering.
I second this. I picked up a rechargeable spot welder for pretty cheap and it has changed the way I build packs. Faster, safer, and better
Or soldered much more quickly. I was cringing.
Soldered braid is capable of far more current than your usual nickel tabs spot welded on. Especially with those molicells the welded tabs will be a current restriction.
Yea, you should be quick. But soldering works just fine. I've soldered many Li-ion battery packs. No problem.
the braid cable would be insanely hard to spot-weld
Brilliant test Chris. Thanks for another interesting, informative, entertaining video. Happy flying amigo. Cheers 🍻.
brilliant forbidden soldering to cells. and sheeps hail. omg.
With properly scuffed pads, good flux and high heat you should be in and out of there with the iron in 2-3 seconds MAX from a room temperature cell. You're applying heat for way too long. This is exactly why people keep whining about soldering being bad for LiIon packs.
High heat and short heat times will get the job done without harming the cells and provide a much better connection than spot welding. Work on tinning one cell pad at a time, giving each cell time to cool before coming back to the opposite side and then again to make the actual wire connections. Your cells wont even get warm if you do it right, you'll have better connections than spot welding and you'll have better current flow than the typical thin nickel strips.
I agree that I could have been faster if I had a bigger iron and better flux. I think the test results demonstrate that I didn't damage the cells. I got full rated capacity and great burst performance.
The 6 welding points on the nickel strips doesn’t seem to cause problems, the strips are too thin for the current, just put more layers.
The copper you use is better to get the power thru, but that can not be good to keep 400C for so much time.
I suggest to also tin the copper, keep it hot until it touches the cell, and keep something ready to remove the heat, like copper bread from the frezzer.
Did you know that tin solder has about 6 times the resistance of copper?
So, the solder surface in contact with the battery terminal must be 6 time the section of the copper. For 10mm^2 copper = 60mm^2 solder
Nickel strip, or nickel coated steel strips are not the best conductors either they must be oversized to pass the current without getting hot.
But there goes your energy density, more copper, nickel, tin, lead, steel, less density.
The conductivity of alumin(i)um is almost the same as copper, but much lighter, there could be varying results to solder it :-)
Aluminium oxyde is the problem, to tin the aluminium it must be done without oxygen.
If the surface is covert by common engine oil, oxydation doesn’t occur, scrach the surface with 80 grid under oil, while tinning keep under oil.
Once tinned, degrease and solder.
Using flux, there was no trouble for me to solder 16mm2 copper clad aluminium from starter cables into Anderson 50Amp connectors.
Maybe worth to try,
Well all that could make good fire, so be ready for it, don’t count on plastic to protect against short circuits, when things get hot or cold, a little hard landing, and flames ...
:-D
Cheers
To make everything easier and also give a much better connection, this is the right project where you should use external soldering flux!
You first put soldering flux on both ends sides of the copper braids and then presolder the ends of the braids.
After that step, you do the same with the cells like you did, but the soldering tin will make a much smoother connection to the cells.
Now that you have presoldered all parts you solder all parts together and the soldering tin, which has soaked deep into the copper braids thanks to use of the external flux, will make a connection with as much surface as possible.
Ah: And don't forget to preheat every part to solder before finally soldering the two parts together.
I would like to see a revisit of this pack to show handmade packs age comparably to bought ones too. In 6 months to a year?
I regularly make packs with the P45B/P28B, 4S/6S-1P/2P, great cells! my first attempt at soldering was a fail and destroyed a cell, now I use a copper/nickel sandwich (0.15mm cu + 0.1mm ni) and spotweld. The strips are also really easy to solder leads to. Great video Chris!
This is the best compromise for safety/speed/performance/ease
What spot welder setup do you use for this? I've mostly soldered because I was under the impression that you'd likely be in it for >350USD for a spot welder that can swing the copper/nickel sandwich.
Thanks for the info.
For a 6S pack should I use the P45B ? Which brand are you using?
@@PatientZiro molicel are the best out right now
@@CesiumSalamispot welders are about 50 bucks on amazon
man to much time with the iron touching the cell. I think it´s a big mistake, just user a bigger iron with more termal inertia to solder the cells. With mine in less than a second I can solder 1mm copper strips.
If you wanted to keep doing this I recommend looking into kWeld and getting strips of nickel and copper. You need to use much higher welding capabilities than anything on Amazon can supply (something around 1000-1500 amps for copper-nickel). I build mine with 0.15mm nickel and 0.15mm copper strips (nickel being the top that is used to weld the copper) with the same batteries you used. Much cleaner than soldering and slightly easier IMO to make. I can easily push the battery more without overheating risks associated with just nickel strips.
I always thought long periods of heat was a complete no no with these cells?. Please tell me if I'm wrong
The less time the iron is touching the cell, the better. But not at the cost of a bad joint:
The iron tip should be much larger than what was used here, as Chris noted. This will make sure the heat is transferred quicker, so you can spend less time with the iron on the cell. If you're spending too much time on the cell, you can stop, and let the cell cool down. With a powerful soldering station, and a big, fat iron tip (the one I use is a flat wedge, about 0.25inch wide, shaped kind of like a flat-head screwdriver), careful prepping: sanding the contact areas of each cell to be soldered, pre-tin every part, add flux to areas to be soldered, my iron is never on the cell for more than about 5~7seconds at most. My welds are solid.
Was thinking about this but wasn't sure how it would go. great video thanks for showing.
One more case for testing ESR of the cells and total pack, specially if you compare packs. But its like beating a dead horse.
Very cool. From a lot of these comments it seems like we could use a video comparing the nickel strips to the braid -- maybe a before and after of upgrading the auline pack? Nice work, as usual very informative.
The Molicel P30B 18650 are also great for smaller drones such as the 4" Flywoo long range.
I'm just now looking into these. They are more than double the price of the 2800mah but I guess that's how it goes when you are the leader of the pack you can charge what you want.
Maybe we can double spot weld another set of strips on top of original nickel strips to improve the current flow? What do you think?
I'm pretty sure you could buy a thicker strip. I've never done spot welding so I'm not sure why people don't go thicker.
Yes, you can use multiple layers of the strips if a single one is not enough.
You can also solder copper mesh or wire to the nickel strips for more current capacity
@@djSpinegeyou can but the problem is you need one of the more expensive welders, if you have one of the cheaper welders you can double up the strips or solder copper double decker style on top of the strips
@@ugpfpv361 The best cheap one is the Malestrics spot welder.
This video is comparing apple to orange. The latest Molicel P45B VS other older Li-Ion cell at different MAH. Better to compare DIY P45B VS manufatured P45B at the same cell count (4S, 6S, etc)
You can also use welding and copper in conjunction, welding for the speed and not overheating the cells and the nickel stips are easy to solder the copper to either braid or wire to increase current capacity.
I had not thought of that before. So, I can solder braided copper to a nickel strip, and then spot-weld the nickel strip, with its braid, to the cell. My only question would be, how does the resistance between cells that are spot-welded, with copper braid piggy-backed, compare with cells that are copper braid welded, without nickel strips? If I understand correctly, the current is only flowing, either through the spot-welds, or through the solder joint?
What thickness is that nichel strip? I was also thinking of using cooper braid, but 0.2mm pure nichel strip might also do the job. I’m planing on doing a test to determine exactly where is the sweet spot for a safe long range LiIon pack.
Thank you so much.I am just curious is there any way to charge this battery setting without parallel cabling ? And if there is , how should I set the charger?
Hello Chris, Is it useful to use bms, or is it not necessary? Thanks.
He should have mentioned that the cells all need to be balanced before you start. Also showing a safe way to remove leads from the donor pack would be helpful because it’s easy for people to cause problems. Also a discussion of how hot you can get each cell during soldering would be wise.
they dont have to be when doing 6s1p
Thanks for making this video. I liked the comparison of the braid vs the nickle strip with respect to resistance. It would be interesting to see what happens if you change the nickle strips to braid...
The other thing you can do is weld the nickel strips with soldered copper on them so you get more current capabilities then the strips alone
@@ugpfpv361I suppose, tho, I have a feeling those strips don't like to be soldered.
@@marcfruchtman9473much easier to solder to them than the battery terminals.
@@marcfruchtman9473 actually pretty easy to solder to
Definitely a reasonable option. You need to do a lot of welds though to make sure you don't get a heap of resistance across the spot weld.
Great video Chris, thank you
Can i do the same with a 14500 cell or can you recommend me something that is smaller if i want to make a small 3s battery for a sub250 plane?
Thanks Chris, looking forward to making my own li-ion packs now 😎
Oh Chris i can only find Molicell P42A's locally instead of the 42B's, would the 42A's still be ok?
Hello Chris, First of all thanks for making the fpv hobby next level! I have a question about molicells/voltage sack/and use for edf models. i build myself of a crashed L-39 Freewing plane a F22 Foamy for fun light and no nonense flying. specs: 80mm 6s100a 2150KV Edf. i fly over 1 year with selfmade 4s lion (molicell p45B ) great cells for cruising drone and al normal rc planes for long flight. I have used them as 2 pakkaged 4s 2p config for this motor i was thinking for a 1500 gram plane would be fine and long flight time... it works... but just enough ... flight time is there btw. i like to try something and i now... more voltage means more rpm and heat but what i want to try (probably gonne lose the edf): Specs 8s esc 100a Cont. 8s molicell 1p and throttle down about 70% maybe dynamic throttle as second step or an alarm for the first minute or so. Is there any way to make this happen or would it be better to make a 6s 2p config and don't worry about it . the problem is also weight 8cells or 12 cells(would be too heavy for this consept).
UpgradeEnergy uses these Molicell 21700's in their DarkLithium long range packs. They have a robot spot welder and decades experience building batteries! I used them to make my Stay High Fueld Charging Pack that's 6S 15Ah (6S3P 21700) Copper bars FTW 💪
My friend is making his own Li-Ion packs from these 21700 cells for his long-range drone all the time. But he uses a contact welder to weld the metal strips to the cells. Good thing about it is that you can choose the best cells for the pack and also you can customize the pack shape and size exactly according to your needs and the drone...Also you can make 2P, 4P packs if you want, scale it as you wish...
Hello Chris, what I see is that the join between the strips cause a problem not the welding on the batteries? My I be wrong but could you think about it? I think that soldering with to less heat and heating iron with to less thermalcapitiy couldt cause bigger problems than welding?
I really appreciate your content.
Is this video just in a lower frame rate or is something wrong on my end?
Nice work 😊
I use solder AG soldering acid. You can solder lots quicker with it.
It seems to wet just fine using regular flux; with acid flux unless your cleaning is impeccable (and it's pretty hard to get under the positive tab to clean any spillovers) it could corrode later..
@@jiatan_fpv that's the downside. I usually tin then wash off with DI water.
Why not sony vtc6 ?
The 21700 VTC6A is only 4100 mah the P45B is better.
aaaa yeah, these P45Bs are actually really good the more I look at them@@thirtythreeeyes8624
My main mx chaser rig I use 4s 21700 molicel and get a good 12-18mins from my 4" apex builds . And there plenty of current to get 140km/h and even can freestyle it fairly hard too . Been the best performing setup for this application
Hey,
My analog FPV setup has decent range, but sometimes the video in my googles starts to randomly drift to the right and gets black/white sometimes. After a few seconds my Skyzone Sky04X beep once and the video signal is perfectly finde again.
This happens super randomly, completley independent on how far the drone is away from me... Also don´t think its a overheating issue...
Any tips on what to do? I need the video signal to be reliable, since i´ll use it for a fpv-job!
These are sold out everywhere... is this normal?
why didnt you spot weld the cells?
You can't spot weld copper (it's too conductive). Nickel strips have too much resistance for a high performance pack. Copper is nearly 5x the conductivity. I've spoken to quite a few serious Li-Ion pilots who've spot welded and soldered. There is good evidence that soldering gives a better performing pack.
I think the answer to that was the main point of the video.
Also Maxamps makes custom 21700 packs. I want to try a 6S4P 21700 20aH pack. Big jump in maH vs the weight jump
Molicell p50b is out soon its 5000mah 50amp continuous discharge 60amp burst
Awesome
Great
The P50B does have a factory 60A non-continuous current rating (limited to 80°C) but you cannot run it at 50A continuously. It will get hot enough to boil water and the cell will be damaged.
@batterymoooch factory rating is 50a continuously limited to 80 degrees, so either your wrong or they are lying
@@kerrymillar4981 I got the 60A rating from the P50B datasheet. Where did you see a 50A temp-limited rating? Wait…you didn’t quote the rating Evva gave it, did you? Without confirming it was correct before saying either I’m wrong or Moli is lying? Hmm…
I don’t say these are true continuous current ratings because they require the discharge to end early to stay below the temp limit. A true continuous current rating allows you to compare cells directly as it’s a single discharge down to the cutoff (typically 2.5V). Yes, you can argue that it’s continuous for a while but that’s no different than saying it’s a burst/pulse rating, a rating that has the cell stop discharging before it reaches its low voltage cutoff rating.
But this is semantics. 🙂 What’s important is what the number actually is and the P50B datasheet only has one rating, 60A (implicitly limited to 80°C as that’s the max cell surface temp rating).
this is fine! 🔥
🙃😉😂
I made my own battery’s years ago and still running strong , I was told soldering was bad but a big iron fast heat has always worked maybe not for a first prodject. But even on the demo the battery can take a lot , but as said there are lots of off the shelf items as a option.
With the P45B in a 4s pack, I'm getting 18' flight time easily with my 6''.
Yea I think P45B best cells right now. Anything over 10aH draw it beats 50S in capacity
I wish he would have measured the thickness of the nickel stripping. It's probably something like .15mm thick, which would limit it's ampacity to roughly 14 ampere. 10mm x .3mm would do almost double that. Nickel stripping can also be doubled though it's not ideal. What is ideal, is copper stripping but it takes specialized welding equipment. The kapton tape is a good alternative to ring gaskets but if you have a choice, ring gaskets are ideal.
I'd recommend using some extra flux and a larger iron. I also pre-tin the batteries. My large soldering tip almost tins the batteries immediately without putting too much heat in the cells.
I use a cheap 80w iron with a huge copper tip. I think its meant for soldering pipes and stuff. Works like a charm and it cost me 15 bucks at the hardware store.
I managed to WELD the tips of my metal tweezers together when I was building my Li-Ion packs. I wasn’t being careful enough and must have created a short circuit. Learn from my stupid mistake! Also, don’t use fully charged packs during the build.
Kapton tape is the way! Make sure to fully cover around the positive terminals of all the cells
Wow really keeping the soldering ion on that for quite a long time think I would just use some silicone wire to join if soldering less chance of a short and possibly some flux would speed things up.
A bigger iron and flux would certainly make the job go quicker! Given my results and what I've learnt opening up quite a few of these cells is that risk of damage with decent soldering technique is minimal.
I don't like you soldering the cells. It is a big safety risk and no one should imitate that.
The transfer of heat into the cell is minimal when done quickly. 5 seconds of heat will not blow up a battery. spot welder is better obv, but for a single pack its not worth the investment.
Yeah it only takes a few seconds with a good iron. He's taking a tad to long.
Agreed. I got a spot welder on banggood for £7 and it works like a champ. No need to risk cell damage.
It is very safe lipo cells are hard to set on fire iff your aremt an idiot
1up for spot welding. Lots of folks have made videos about the effects of high temps on Li-ion cells
Ok so cells werent damaged 😅..
For 1P i def use P45B for a 2P or more id prob switch to 50S. I have a 4P 18650 i want try 4P 21700 if drone can fly the pack
U were running 20aH & 22.5aH draw 5C. Damn no wonder when i run 6S1P on the 8" the pack gets warm and i try to stay light on throttle 15aH average i think
Whoever decides to build this; please read this.
Hey Chris, I like you and your videos for you being a fellow engineer and standing for what a good engineer should be. You know the theory, you know the practice. I build a lot of packs for drones, bikes, electric racecars etc…
Thus I hope you don’t take this personal. This video is nothing short of hazardous.
There are a few concerning safety issues with it that need to be adressed.
- The soldering: It is a bad idea for various reasons. Firstly the cells get damaged. You see for yourself how long you have to heat up the cell with the soldering iron. You definitely cooked some electrolyte, degrading the cell by a good amount… so far that’s just not smart but not really dangerousl.
What I s dangerous is that you easily could drip solder in between the positive terminal and the negative can. This will short circuit and most likely make the cell burst into flames. NEVER solder a cell. It’s a fight against windmills because people will keep doing it. It is not smart. Usable spotwelders on Amazon are 20€…
Second of all: The thing that literally schocked me was you showing that you reuse the LiPo lead but don’t loose a word about NOT cutting both leads off at the same time since this will short the LiPo. And these things at 4S are MEAN! Hundreds of amps of current will create a HUGE arc flash. You just skipped the part where you cut it… wouldn’t do that.
Third: you need to address that while connecting the cells there will be the danger of short circuiting when connecting the wrong terminals on the opposite side.
Please include these safety notes. That is not how it’s done.
I did it with molicell's too, 4S got me like 15min's of flight
5" drone
Holy cow, was that a full 60 sec of direct contact between soldering iron and cell?! Isn't it pretty well established that even 5-10 sec will likely increase cell internal resistance and reduce capacity? I'm not gonna say soldering can't be done effectively, but nowadays you can buy a $15 spot welding module for up to 0.2mm pure nickel (for reference, 0.2mm x 8mm strip = 16AWG copper wire)!
I've been harvesting the lion cells from disposable vapes. 550mah, 1500mah, tested with high volt charge. They're pukka.
What’s going on with the shutter speed on this vid? This hurts my brain.
Thanks a bunch for the tutorial, Chris! 😊
I've made a few of those... But I definitely going to get a spot welder for it. Sequr has a pretty cheap one.
Anyway, stay safe there with your family! 🖖😊
Great video, but:
Bigger tip, hotter tip, flux, pre-tinning and you’ll get a better result holding the solder there for 2 seconds
nice!!
all my packs are soldered no issue. that said Ive made p42a, p45B, 40T and more... the 45B isnt worth the cost for an extra 300mah compared to the 42B and similar discharge curve unless Chris has tested both and found any major discharge discrencies.
if you are gonna solder i have vids on my channel BUT fatter tip, max that iron at 450c (or more) and I use 12ga silicone wire and all is good in the world!
That braid was so wide it nearly bridged the top of the positive cells
Only issue is we need to unpack and unsolder the whole thing every time to charge those 21700! Just kidding. How do you charge them? Just started learning about building batteries
You can use a standard LiPo charger for drone packs. That's what the balance lead is needed for, otherwise you'd have to unsolder them as you say!
You should be using super flux m8. Can't remember exactly which acid it is, but it essentially binds INSTANTLY with the mating surface. No warm up time. Its crazy. Just gotta remember to wipe any excess off when youre done. I was using the rustoleum rust remover last time I did it, just what I had on hand. You can make your own as well. Look into it.
You can buy stick on insulator rings, better than kapton tape I reckon
Was this meant to rage bait?? For someone who “sticks to the science” in FPV this is piss pour work… not trying to hate but damn. Do I need to make a video on how to do this better and safer?
just when everybody seems to settle on spot welding because of possible heat damage to the cells, here comes one and sends them back to the roots - to soldering. Dang...
Under the Goldline battery wrap, it should have the MFG of the cells printed right on them. I'm willing to bet they just re-wrapped a Lishen or Molicel would be my guess.
Just checked. Nothing printed on the metal can at all.
@@ChrisRosser wow. Kinda surprised about that.
Samsung have a 50S cell tat is more capacity, but slightly less discharge rate.
Over 10aH it actually less capacity than P45B. But if ur using a 4s2P ud be good
i know everyone doesnt like soldering to liion cells, but its really not that bad, personally i pop them in and out of the freezer while working on them so it doesnt get them nearly as hot overall, its also important to note that once connected in series, you have "cans" that are positivly charged and you really should have used flux, like proper flux, also also, the 18650 molicells actually have more energy density if you do the math based on specs, id love to see you test the 2 molicell 18650's
Don't you worry that putting them in the freezer might cause some to lose more of their charge than others?
@@dieselphiend when connecting cells in series you don't need to worry about the voltage matching perfectly, and I only put them in the freezer for long enough to cool the heated cell I don't leave it in there for long enough to freeze the cells, it's literally like 30 seconds at a time just to remove the heat from soldering as fast as possible and a little bit of a pre chill before the initial solder so the internals don't get so hot
@@christhorney A 1p pack (one in parallel) with a balance output will be balanced by the internal battery management system inside of the correct charger. Beyond 1p, you absolutely have to worry about cell matching.
@@dieselphiend brother, you asked me if I worry about putting them in the freezer, I only do that during construction while making series connections, I even specifically said in my reply when making series connections that the voltage doesn't matter, ofc parellel connection it matters but that's not what I was doing nor was it what I was talking about anywhere, once I build my pack with series connections I charge it on my balance charger then I use a 2into1 connector to parellel 2 packs together for 1 of my planes, when making parellel connections voltage is important and capacity does not matter, and opposite of that when making series connections the voltage does not matter but the capacity is very important. Regardless, no I don't worry about using the freezer during construction of a series pack and yes I know basics of battery management as to not parellel connect packs with wildly different voltages
@@christhorney Man, I wouldn't care about any of this if I didn't know people will read it. I think it's important to be highly technical when explaining these things. I would consider the BMS the last line of defense. Sometimes they go bad. Often times they are miscalibrated from the factory. It's just best practice to use perfectly balanced, brand new cells.
Let the liquid lead drop on the contact surface of the battery, no direct hot iron on the battery terminals
Molicel batteries are hard to beat,been using them in vapes for years and still going strong, Fogstar is the best place to buy them if you're in the UK 👍
Those cells look like they test great, thanks for those results Chris! If anyone is looking to spot weld nickel strips to make a pack and is looking for clarity on the size of strip and how to arrange them I found this video useful. ua-cam.com/video/wdZ_Ca_sAZE/v-deo.htmlsi=HRH6x8kpTCWSnT1B
Chris, please do not solder the cells.. this will damage the internal separator between the electrodes inside the cell.
The separator melts at around 130C, specially a problem on the anode.
Spot welding!!!
I am sure you'll not hear the end of it...
Come on man, buy some 21mm (or 18mm if using 18650's) isolator rings at least if youre going to make a video.
Also, standard silicon insulated wire is much easier to use... soldering is fine if its done quickly but its taking you way too long with that braided cable.
I was wondering why typical wire wasn't used as well.
My trick to dont suffer from bad batteries anymore worked the best. I quit fpv.
Please wear safety googles during soldering of LiPos. Better safe than sorry ! ✌
All the people complaining about soldering the cells have been watching to much UA-cam
Why not use typical wire? Is this really lower resistance?
Normal wire is fine too. Flat braid gives a nice shape to the finished pack.
@@ChrisRosser thanks. That makes sense. I though maybe increased conductivity or cooling.
Chris com on bruh you are cooking this cell's ...
COMPARE WITH UPGRADE ENERGY DARK LITHIUM V2 MOLICEL 21700 😮
I expected much better from this video... the construction of that pack is far from ideal/safe. good isolation is lacking, and soldering introduces a lot of heat causing potential damage and a shorter lifespan/performance from the pack.
If there were a note saying that "this pack was made for the purposes of testing, please do research on good pack building methods/practice before making your own" I wouldn't mind it but a lot of people look up to you for your knowledge, and going straight into the wrong ways of making a well performing and safe pack shows some oversight
(not trying to praise the pre made batteries either, they have their fair share of shortcomings)
Are these cells the same as Sony VTC5D?
no lol they are molicel
@@christhorney thanks. I was confusing it with Murata/Sony.
@@GR8SCOTT ah true, yeah nah the sony cells are decent but the molicel cells make much better flight packs
Just use thicker and wider nickel and spot weld that.
Copper is around 5x the conductivity of Nickel so you need to use a lot of strips and do a lot of spot welding to match the performance.
@@ChrisRosser Do you need all that conductivity? What is this burst test you are talking about? That amount of heat you put one the cell when soldering can damage the cell.
oh man. so much contention over soldering the cells. Lithium cells are ALWAYS DANGEROUS. nickel or copper with solder, both are not without issues. Use nickel if you are most people because it is most common and well documented, I prefer copper and solder for many reasons, but higher fail rates using nickel has always been my experience.
Aluminium tabs ? Soldering?
Cats, flying plane, squirrel...
I recommend always, to discharge all the individual cells before making packs. Than I use a dremel with a wheel and shortly clean the cell top's before soldering, than use a C4soldering Tip or even bigger and quickly Pre-Tin all the cells, (5 seconds solder time). Then you can solder the wires,or I use copper strips. (also 5 seconds) during soldering add some additional tin. (normally no need for extra flux) (5 seconds max) . the soldered PACKS have lower IR than the spot welded packs and are better suited for high current applications.
Heating up that battery for 20+ seconds is a very bad idea. Then you have to heat it up again for the wires...
Good video, but I think the nickel stripes a better solution. Obviously those are charred cause they are either too too thin or their width is not enough. There are bigger, thicker nickel stripes that can support 45A. I even made some of my batteries with two nickel stripes one on top of each other. Anyway - their big advantage is that they add a significant structural rigidity of the pack. This can't be done with flexible braided stripes. The cables are flexible, the tape in between is soft... everything is flexible. Whilst the nickel stripes make the pack solid.
Agreed I double up my strips, to hold everything in place on my first pack, I hot glued the cells together. For the next one I 3d printed some "holders" like those end cap once you see but they slide down so not covering the ends and just use kapton tape ever everything, then heat shrink.
I think it depends on your priorities. With Nickel you will always be fighting physics. Copper is nearly 5x as conductive. The reason Nickel welds so well is it's relatively high resistivity. I guess multiple strips will improve things but it's difficult to imagine anyone welding several mm thickness of Nickel strips to match 10x1mm of copper braid. If someone is paying good money for decent high drain cells to get the best performance then it seems a shame to throw a bunch of burst performance away.
lol - nice tape job - don't you know they make specific "stickies" that protect the positive terminal??
Bro at leastuse alot of flux and it will be much easier and much faster on binding to the cell, also less damage on the cell
thats for when you accidentaly ordered too many battries.