Cleaning 18650 cell ends and quick Internal resistance test

[@WereCatf]

The tip about the CID and possible holes when removing the strips was a good one, I hadn't even thought about it.

[@sreekumarUSA]

Appreciate the idea of removing the positive side nickel strip, they way you do. I do too, the similar way. This is because the positive terminal metal is stronger. So far so good. BUT... the Negative end of the Battery is very thin and if you use force (the way you do/did) 99% times you tend to pull the parent metal also, thus creating a HOLE. Result.. battery leak, (spewing the Electrolytes) rendering the Battery useless and dangerous. This is because of the strong spot weld on thin parent metal. Please be aware of this. You may try nipping the nickel strip close to the Negative end and the balance protrusion can, either be smoothed out by appropriate attachment to Dremel and carefully grind (the spot weld) the metal piece, or file it a smooth file. Thanks for the video. Cheers.

[@jasonmiddleton5491]

Do not file or scratch the cell terminals, it invites rust which weakens the cell and can cause fire

[@pointedspider]

I like to leave a piece of original strip on both sides. It's way easier to solder to that way

[@maxheadrom3088]

Hi! Can I sand the surfaces? I would use a very high grain count sand paper over a flat granite stone to do it. Thanks!

[@TomlinsTE]

Wow, you covered exactly what I was looking for. When I removed the bottom tabs one of the batteries got a tiny hole in the bottom. That battery still has s charge and seems normal, but I believe you said I should discard it because the protection is compromised. Thanks for the great information.

[@simon7030]

Great Information it has helped me as person who already strips cells.I normally spot weld but your tip for soldering to a bit left on the top and bottom is good to help solder take.

[@Captain_Kdawg]

On some of these testers I’ve noticed that the IR is different like a big difference when the cells are charged or discharged. When is the ideal voltage on 18650 batteries to take the internal resistance??

[@DIYTechRepairs]

You need a 4wire tester that do ac based testing and then you Will get more even Numbers :)

[@Captain_Kdawg]

@@DIYTechRepairs could you possibly post a link of one of them testers?

[@DIYTechRepairs]

@@Captain_Kdawg ​ @kevin black Here is a good one: rover.ebay.com/rover/1/711-53200-19255-0/1?ff3=4&toolid=11800&pub=5575290868&campid=5338074051&mpre=https%3A%2F%2Fwww.ebay.com%2Fitm%2FYR1035-Lithium-Battery-Internal-Resistance-Tester-KIT-Range-0-100V-0-200-os12%2F124250416615%3Fhash%3Ditem1cede6e5e7%3Ag%3AdhAAAOSwOopfu2jD And this one is a bit cheaper. rover.ebay.com/rover/1/711-53200-19255-0/1?ff3=4&toolid=11800&pub=5575290868&campid=5338074051&mpre=https%3A%2F%2Fwww.ebay.com%2Fitm%2FYR1030-Battery-Internal-Resistance-Meter-Tester-Lead-acid-Lithium-Cadmium-Ni%2F113750079601%3Fhash%3Ditem1a7c087871%3Ag%3A1zkAAOSwbudc-JIc

[@Captain_Kdawg]

@@DIYTechRepairs thank for the info man I got the littcalla 500 charger (how ever you spell it) and it seems to be very different on the internal resistance from charged 4.2 volts to nominal voltage 3.6-3.7 volts

[@DIYTechRepairs]

@@Captain_Kdawg Lii among the others can diff 100% between tests just by applying different pressure

[@jeffgorkisch4489]

Thank you for the information. What would be considered too high of internal resistance to be used in a powerwall setup?

[@DIYTechRepairs]

Depends on the power draw. This one is something i have seen float around that should work out pretty well for current below 1A per cell: Milli-Ohm Battery Voltage Ranking 75-150mOhm 3.6V Excellent 150-250mOhm 3.6V Good 250-350mOhm 3.6V Marginal 350-500mOhm 3.6V Poor Above 500mOhm DUMP

[@welshnutterz]

DIY Tech & Repairs would these maximum figures be roughly the same for fully charged cells? 4.2v

[@mikeh6286]

Great video! I see you are using opus c3100 chargers. I'm looking for a "storage" function for my leftover cells to put them at 3.7-3.85v 50-60%. Do you know any charger that can measure IR/capacity and with storage function? Thank you very much.

[@DIYTechRepairs]

Most RC chargers can do that. I suggest the Icharger DUO series that can send lefover energy to the 2nd port or the source port directly and make it faster. It also is better in terms of IR than any of the cheap ones out there.

[@jasonmiddleton2375]

Hi, I have slot of used cells that are rusted on the negitive terminal, I'm not bothered about using the cells I'm more interested in making them safe for the rubbish bin

[@DIYTechRepairs]

I just stack them in that bin and go to the recycler. Most of my cells are discharged anyways. If yours arent then just discharge them. Put them into a tray hooked up to a light or resistor for a day or 3 so they are empty

[@jasonmiddleton2375]

@@DIYTechRepairs so discharged cells are safer?

[@jasonmiddleton5491]

@@DIYTechRepairs I should of listened, around 10 cells caught fire yesterday because of the rust, using a dremel on cells is bad news, I converted a gas cylinder into a safety housing for the cells I'm not using so luckily nothing was damaged

[@johncoops6897]

@@jasonmiddleton2375 - old question, but I will answer it... A lithium cell with no charge in it has zero energy inside so there is nothing to "exploded". They are only dangerous because of the energy inside them, not the chemicals or metals. If you release the energy suddenly (either by overloading, or a short circuit internally or externally) then a massive amount of current flows and the battery heats up. When it heats up, the internal reactions causes more heat... and a so-called "thermal runaway" occurs. Sometimes there is enough heat and/or sparks to iginite the gasses that are being created by the overheating. This results in fair, and once it starts it is very difficult to extinguish. So, to prevent accidents, FULLY discharge the cells that are *never* going to be used. For those cells that are tested and deemed OK, but are not being returned to service immediately... charge or discharge them to about 3.8V, write the exact voltage on them, then store. 6-12 months later, check the voltage again and discard any that have dropped below 3.4V or so.

[@delatorrerodrigo]

What happens if you do get a hole in the negative side when removing the strips?

[@DIYTechRepairs]

Rodrigo de la Torre i bin the cell. You have destroyed the cell if you get that and the built in protection wont work

[@_BangDroid_]

Don't literally put the cell in the bin though, unless you have a fire extinguisher nearby

[@jasonmiddleton2375]

@@_BangDroid_ so what should you do with them? I have around 70 cells where the negitive terminal has rusted

[@Lij_MC]

​@@DIYTechRepairscan you just solder it shut?

[@AnkitSingh-bc4rl]

How can i repair my 204 impedance (resitance) 18650 cell

[@DIYTechRepairs]

You cant Give it to the recycler

[@amorton94]

If the negative end bulges out a little when you're removing the tab, is the cell now bad?

[@DIYTechRepairs]

As Long as There Arent any holes in the cell it should be fine.

[@jasonmiddleton5491]

Also do NOT scratch or sand etc... The cell terminals - this invites rust which damages the cell and makes it very very dangerous, I speak from experience - luckily I keep my spare battery's in an old gas cylinder modified to safely allow lithium ion fire and explosion

[@Aussat]

Great information, easy to understand! Thank you for the video.

[@robertbaumer471]

I use a Dremel tool to clean up if the tool does get everything.

[@andrewgrasso9003]

Good insight in the internal resistance test. Thanks.

[@Woodyjims-shack]

Thanks for the video again. You are the first to mention the inbuilt protection that I have seen on youtube. I have bought a few Litokala e 500 chargers (in transit) and I'm considering getting a SM8124 impedance meter to check resistance for my packs as it appears to be reasonably good for 18650 batteries. Do you think its worth it? I hope to at least partly group by impedance when putting my packs together.

[@DIYTechRepairs]

Could be worth it. Im not testing the IR more than in the discharge test... But in ideal world i would say yes to testing IR...

[@Lij_MC]

​​​@@DIYTechRepairsIf I make a hole will cid still work if I solder the hole shut? Also will the battery still work if there is a small hole?

[@rtoebak76]

In your other video you have the SM8124 for testing. I just bought it. And measure all when charged is also good, after that you can discharge for total mah inside. :-)

[@AlfieMakes]

Great video!. Could you make a video about how BMS work? I'm interested on building an OpenSource initiative to help people with small budgets get their powerwalls together.

[@DIYTechRepairs]

There are several out there about bms systems and quite a few datasheets and white papers explaining them :) Though i have had in mind doing a simple BMS guide some day

[@yuriselektro2236]

Good information sir..

[@allcomm]

That ROLL method is danger. You may see little holes in bottom and top electrodes of cells -on place where are spotted.

[@MrSummitville]

What is the better method?

[@jamest.5001]

I leave the tabs on! If they are well attached. So I can solder to the tab insted of the cell. I'm not the best at soldering the cells. And do not want to over heat the cells!! I charge then discharge test the cells. And note the start voltage. Especially if it is a very low voltage. So I can test them first if the pack has issues later! Most of my cells are around .070 Mr I have seen 150 mr but the cells were low capacity. And not used! Great video! And idea of a good cheap bms/ balance board for a 7s liion battery bank? I want to get a baitrium. That will have to wait. I have nearly $1000 on cells only. If I had $400 to spend. I'd likely buy more cells! I'd love to have the capacity to run my home for a week without sun! And have the solar to recharge in a day or two! I do not have alot of power consumption like the average home. Just fridge, microwave, well pump (7amps max) and TV and a few led lights. And most is DC from the bank. For less losses. So its ambitious. Just not as much as you may think. I have gas water heater and stove. And use the generator to run the washer & drier! , sorry I'm rambling again!!!

[@vanmasterflash7153]

Thanks. Very clever discovery.

[@oldtimeengineer26]

Thanks well done

[@Beakerzor]

great video, thanks!

[@mikemiles3068]

Very good video

[@Woodyjims-shack]

Thanks again, yes great little flush cutters for a very low price 👍

[@danjackson2014]

Another great video

[@bostjantrancar9605]

Excellent video.... 👍

[@mhmdsaleh3502]

Exactly like I do 😄 thanks

[@rodneysmith633]

Excellent!

[@bobamericana3099]

i have 48 volts 65 amp battery system and it only cost me 240 dollars... my build weighs 25 pounds but it is more durable than these little wannabe cells

[@TheAlexthemole]

Bob Americana wonderful... If you want to run 48 volts. Not sure my laptop would like it though 😂

[@DIYTechRepairs]

Bob Americana Good for you!