How to solder 18650 Li-ion batteries to make a custom-made battery pack (Ebike)

[keithosterkamp]

I watched several other people try to explain how to do this and I felt uneasy after each one. Then I watched your video and it was the most well explained process, answered all my questions, and put in mind that I can do this successfully. A Very well done video!

[FelipeElLocito]

This is one of the most articulate, information-rich instructional videos of any that I've seen on YouTube. Many thanks!

[Valhorde]

'' You dont want to inhale this.. i dont want to inhale this !'' Great Video ! very well explains, using clear explanations and shooting angle.. thanks a lot.

[momentsPY]

Good tip, but it's easier and safer for the batteries if you apply solder to your connecting strip as well and then place it facing the battery cap so when you apply heat, both solder covered points melt very rapidly and so it takes a very little amount of time.

[ddistrbd]

absolutely the clearest explanation, thank you for taking the time to make this video.

[himax]

I needed to solder batteries together for my R.C. helicopter. Used your method and it worked great. Thank you so much for sharing. Norman.

[Ra-zor]

Drill a small hole through the connecting strip at each solder point about 5mm, tin the strip at the hole (just filling the hole) and tin the battery with a small amount of solder, then connect the strip by soldering through the hole in the strip to the battery and adding a small amount of solder if needed, being fast as the strip will retain heat. The solder will flow between the strip and the battery creating the perfect joint.

[cabbott]

extremely clear and explaining how the + and - will be different

[tomstdenis]

pro-tip: use magnets to hold tab wire down. I use an insulated screw driver in my other hand to hold the tab down as I solder so it cools in place (makes a good joint). The problem I find is if you lift the soldering iron without pressure on the tab the tab could lift with the iron.

[rachirachies]

I have been going through lot of videos aka battery building, but yours is pretty different you're amazing, with your teaching I'm probably going to build my electric battery

[juliusabraham]

Its a great lesson I just learnt... Pls I need more tutorials more on Li-ion cells management
..

[sparty]

this is very helpful for a project i'm in the middle of. these 18650 cells are tricky to solder.

[alanlybus]

Saves money instead of buying a spot welder. Thank you sir!

[recepgunoglu]

This helped me a lot. Thanks for the video. Now i have a 21 volts 6 ah battery that i made for less than half the price.

[EduardRitok]

Sir, you highly exceeded the heating time of negative casing of those cells.. I use old 50w russian solderingg iron with big tip ( a bit bigger than yours) to ensure high enough thermal mass .. In combination with alpha solder, my pre-soldering ( applying sokder to the metal casing) usually takes 1, maximum 3 seconds, no.more .. If i need to apply more solder, I wait until the cell cools.down, but usually I apply enough right away. Also I need to point out absence of insulating rings on positive dide in your case. . . While soldering the strio, you are taking chances of shorting those cells .. If I don't use insulating rings, I usually lift the strip away from the cells a bit, and let it dip down only in places, where strip makes contact with the cell. . negstive casing around positive terminal has only a thin plastic foil as an insulator and it can melt and make you sad very quickly . .. good.luck with your projects 🙏💪

[eltoro]

Awesome video and very easy to understand. Thanks a lot. I would appreciate more content from you.

[TheGeekzoid]

Your one of my best YouTuber and make great videos.

[eugenenalpin]

You make it look easy 😂

Gonna give it a shot, have a battrty pack repair project in mind & looking for info on doing it the right way. Very detailed explanations & demonstrations, tysm for the video 👍

[tracegentis]

While building my last ebike battery pack the spot welder quit working right near the end of the build, so I had solder the last 12 cells into the pack. One step that improves solder adhesion is to rough up the new cell metal surface with sandpaper before tinning the cells. Solder adheres to the rougher surface more effectively than a smooth surface.

Even after taking all precautions to tin every surface and solder the cells quickly, when I equalize charge the pack (where you can see every cell voltage at once) it's quite obvious that the brand new cells that were soldered into the pack have many tenths of volts lower resting voltage than the rest of the same brand new cells (that were spot welded into) the pack.

So, sadly, no matter how carefully cells are soldered, damage still happens. A person will never see the result of the damage unless you are able to use a balance charger frequently which shows all the cells voltages on a display in the pack at one time and watch the equalization process every time. Most people (those relying on the BMS) will never see the difference in cell voltage so clearly, and if you are soldering the whole pack, the damage will be distributed equally accross all the cells in the pack, so you'll never be able to perceive the damage because all the cells will be damaged equally.

This was a lesson I learned only because I equalize balance my packs.

I ordered a K-Weld spot welder even though they are a bit spendy so this will not happen again. The K-Weld unit was most highly recomended if you are ok with using a car battery for the power supply.

Great video though concerning the soldering process if you are forced to do it.
Thanks

[MikeHewitt]

scuffing the cell with a scotch bright pad or fine sandpaper just prior to applying the flux will help your solder flow out much nicer