How to Properly Test New and Used Li-Ion Batteries (Including Cool Testers)

[@McTroyd]

Thanks for the tip about inserting and removing from the negative end of the battery to avoid a short. Really simple thing, yet I never thought about that. 👍

[@AndreasSpiess]

You are welcome!

[@phasemargin]

Thanks for the sample devices to do charge / discharge look testing. Looks like I will avoid a lot of shopping risk simply by starting with the ones you already bought and evaluated. Battery selection and proper usage in designs remains a critical design element, thanks for your usual thorough treatment.

[@AndreasSpiess]

I agree, testing and creating a dispute is a good way to put the risk on the supplier...

[@rsa1032]

The guy with the Swiss accent just keeps on delivering! Muito obrigado, vielen Dank Andeas und Glück auf!

[@AndreasSpiess]

Danke!

[@MikeKranidis]

Great and helpful video as always. Thanks Mr. Spiess !

[@AndreasSpiess]

My pleasure!

[@ClementsProjects]

Great presentation as always, thanks, Andreas! One thing good to know: the 18650 Tester needs a 5.1k resistor on the USB-C port to work with every USB-C charger that complies with USB-C standards; otherwise, this tester won't work with all USB chargers. I modified my tester and now, works like a charm!

[@veryboringname.]

In a pinch, a USB A to C cable will work too.

[@sofronio.]

Yes. Get two 5.1k resistors on cc1 to gnd and cc2 to gnd. Not only the charger, but also converting other devices for c-c useage like directly connect a typc-c microphone to android phone.

[@Goodmanperson55]

This problem is so typical for a lot of devices that decide to cut corners on the USB-C port. It's been over a decade since this problem has been identified and yet some chinese factory out there is still churning out that bad design.

[@AndreasSpiess]

I agree: This problem is well-known and still not taken care of. This is why I still have many USBA to USBC cables in my lab...

[@robert574]

One of my flashlights has a scalloped face so I can see light if I leave it on and stand it on its face. My best one, like yours, is flat and if you tap it against the counter when you set it down, it will turn on sometimes and you can't see it. I always set it on a thin plastic box so the light is visible. I'm curious about the fire because I reuse cells out of my old laptop batteries, and I don't think they are protected.

[@AndreasSpiess]

Only one started to explode, so you might be lucky. But it was impressive for me...

[@mkk4044]

Thanks for your great video as always😊, Could you please explain how the passivation layer in some battries affects series resistance measurements and how to overcome this effect?

[@AndreasSpiess]

Batteries are "black boxes" for me. So you have to ask a specialist (probably a Chemist).

[@nrdesign1991]

Swollen pouch cells are swollen because of the pressure that has built up inside. Sometimes a cell swells locally because there is a leak on the outer layer, letting moisture inside. The insides of a Lithium battery can react with the air and moisture of its environment and lead to further damage, which can in time - or while charging - lead to catastrophic failure. A swollen battery pack is a reminder to get rid of it, no exceptions.

[@TD-er]

Maybe the "NO Exceptions" in your statement should be made more clear as it really is dangerous. Such warnings cannot be stressed enough. The last repaircafe I attended, someone brought in one of those hoverwheel 'toys' which had its battery nearly bursting. I did measure the unconnected voltage and it was more than 4.3V per cell. Really glad they brought it in and didn't leave it connected to the charger. Who knows what would have happened if they did.

[@andreasbentz6106]

@@TD-er Well I am 99.9% sure what would have happened: Whooooof. If kept indoors a good chance of burned down house syndrome. Had such an experience with that infamous production series of DELL Notebook batteries. Within two days over the weekend, the battery pack inflated so much, that the keyboard nearly popped out. I opened the notebook body immerdiately and took out the pouch pack. Unfortunately the edge of a shielding already cut the foil of the pouch and most likely manipulating the Notebook to unscrew the bottom did the rest. I barely managed to separate the connector before the light-show startet. I was smart enough, to do that operation outside, so no damage done. Since that event I have a metal bucket with a lid in my garden. Filled with dry sand, where I bury suspicious pouch cells until I dispose them properly.

[@AndreasSpiess]

Thank you for sharing your experience! It is the proof that the housing can damage batteries.

[@TD-er]

@@AndreasSpiess Yep that was exactly the reason why those 1st Note devices could catch fire. The battery had no room to expand and some part of the enclosure then could puncture the battery.

[@ivekuukkeli2156]

Thanks for this excellent presentation. All the relevant values are included. That 2 pin measuring stick is new; sharper tip like in test beds would be even superior.

[@veryboringname.]

I can just imagine someone accidentally poking a pouch cell with it! :)

[@AndreasSpiess]

The pins are not sharp, their front is quite big to get enough surface.

[@ivekuukkeli2156]

@@veryboringname. Test pins are continually used in production. These pins are spring damped.

[@Poult100]

"good enough for the girls I go out with." Priceless! 😂

[@nixxda270]

Made me chuckle! AvE however sais it with much more confidence! Also, I've been told by cirtain individuals that it's wildly unaständig to say!)

[@Poult100]

@nixxda270 yeah! Not politically correct, some would say. Still funny!

[@AmirASD]

😂 😂 I don't think I will be able to stop myself from quoting this from now on. 😅

[@EvgeniX.]

How do I measure the maximum safe current draw for a particular battery that doesn't mention discharge rate? is there a way calculating it from internal resistance?

[@alistercarmichael4990]

Nice to see that it is not only me that suffers from low battery in the calipers. I keep mine in the case and the reliable way to prevent them activating when not in use is to open them slightly and then tighten the slide lock. Environmental effects will not move them like this and they remain "off" At the very least avoid leaving them fully closed.

[@andreasbentz6106]

You are correct with your measures against "unassisted activation". However my experience - and also from some KZbinrs - is, that the battery drain does not only come from activation. Unfortunately the electronics inside draw a significant residual current when the caliper is switched off. The only counter measure here is taking out the battery when not using the caliper (my way, but very tedous) or adding a hardware switch (tricky). In one video I saw a guy replacing the battery with a super cap and building a charger, that keeps the cap charged as long as the caliper sits on the charger. The charge was enough to keep the caliper on for a couple of minutes - enough for some measurements. I'm still not sure if this is a good idea, because you are limited to places with power supply. Cheers Another Andreas

[@alistercarmichael4990]

@andreasbentz6106 both good ideas. I need them too often though to be placing the battery back in each time I need them. This sounds like an opportunity to get them on the bench and check the standby draw provided my meter has the resolution. A better solution may be a deep sleep power switch.

[@AndreasSpiess]

I use cheap batteries and replace them from time to time. They still work for a long time even when they blink.

[@heinrichmaske5367]

The car battery tester does not work with higher currents than the yr1030+. The measuring principle is the same. It applies a 1kHz small voltage signal and reads the current. This is pretty neat for fast signal changes. It calulates the fast resistance. BUT when it comes to long term/steady current draw, the internal resistance of a battery rises or in other words: the voltage drop increases. The 1kHz measurement is indeed nice, but useless if you want to know steady current draw resistance. I figured out in practical use just double the value of the reading and you are fine.

[@AndreasSpiess]

Thanks for the additional info. For me, these measurements are just relative. Bad batteries usually produce very different readings also with this method. But the "real thing" is always to hit the starter button. I know this from my 1700cc Harley ;-)

[@Alexander-ri1bp]

As far as I know, the battery capacity is given with constant current discharge metod (IEC). The china testers just put a resistor in and log current and voltage for mWh calculation. Not the same. I got one of those china testers and was a bit disapointed when I saw the design. So you can not really compare datasheet values with data given from a non-constant current tester.

[@renxula]

I think the mWh capacity of any individual battery should come out pretty much constant with both methods, but you're right, converting it to mAh isn't fully trivial. I'm usually more interested in the total mWh. Which value is more useful, depends on the device being powered. Assuming a constant power draw in the device, linear regulators draw constant current, but buck/boost regulators draw increasingly more current as the battery voltage drops.

[@michaels3003]

​@@renxula, batteries are much more complex than a voltage source plus a resistor. The constant current method should be used like he stated.

[@renxula]

@michaels3003 they are a bit more complex, but I don't think it matters much in hobby use. Like, will the measurements be 1%, 5%, 10% more accurate? If I want to know the capacity in order to estimate how long the battery will last in some device, then I'll leave a much bigger margin for error anyway.

[@michaels3003]

@renxula , a "bit more complex" is not correct. They are very nonlinear devices. He briefly "touched" on this subject when discussing the so-called internal resistance. Batteries also age. Knowing that the batteries have overstated specifications (this should be expected at the very low prices), just buy somewhat "bigger" batterylies than you really need.

[@lohikarhu734]

Grüße Andreas... I just went through the first "slide", and I am so tired! You set a very high bar to accomplish in 15 minutes!

[@AndreasSpiess]

Unfortunately, I do not get your point :-(

[@huggekarlsson]

Andreas! You need to try out the new rd-03d mmwave sensor!

[@AndreasSpiess]

Why do you think?

[@patrickcardon1643]

The 18650 tester is apparently not available in all locations (not for France anyway) ... would you have a reference so we can look for another supplier? Cheers!

[@AndreasSpiess]

Strange. Maybe you find it on ebay. Or another supplier on Aliexpress

[@StarsAtNight1]

I bought a toy boat from china that contained a 3s 2000mha battery that was bloated. To my surprise it when back to normal size with a few very low current charge/discharge cycles. I don't really understand how this could work. Also have a few chhl batteries that are bloated (by high amperage draw) but can't fix it with slow charge/discharge cycles. I opened these up and have salvaged a few cells that way that I use in low current devices.

[@AndreasSpiess]

Maybe the first had a pressure valve that let the pressure out over time. BTW: I never open LiIon batteries because they love air and can explode. So you were lucky!

[@StarsAtNight1]

@@AndreasSpiess With opened up I meant that I disconnected the series connection (3S) and use the individual healthy cells separate. Also to my knowledge the battery that was bloated and is fixed is still air tight. I would never open up any lithium cell. I don't want to burn my house down.

[@abdelhakimallal3753]

Big thanks, this is so helpful

[@AndreasSpiess]

My pleasure!

[@petittoto7433]

I just bought a DL24 with the accessories for 24.- CHF (Ali) It is great, and very easy to check capacity according to the current. Will see how long it last...

[@AndreasSpiess]

Somebody wrote that the FET goes sour after 5 years...

[@madcow3417]

I must have missed video 197. That device looks cool, watching that one next. 160 after that. Your numbering system is quite handy.

[@AndreasSpiess]

The numbering is also handy for me ;-)

[@dougbas3980]

A friend burned his house down charging Li-ion battery pack he made for himself. His knowledge of the battery properties was very limited and he paid a big price. He lost all their family photos for instance.

[@AndreasSpiess]

That is bad luck! I hope it will never happen to me. One advantage we have here is: We do not use a lot of wood for our houses. So I hope that only one or two rooms would burn out.

[@sarahdaviscc]

What a nightmare!

[@NathanCroucher]

did you burn down his house......

[@Luke-san]

That is why I never ever leave my place when charging batteries, and also not only charging Li-Ion but also NiMh ones. I had 2 AA cells burn a hole in a cheap charger and almost start a fire. Seems the heat protection didn't work and the plastic melted. The smell was still in my house a week later. For Li-Ion etc, I always charge outside away from direct sunlight and away from anything that can catch fire. During the very cold wintertime on tiles in an iron (empty) cookiebox but I will not leave the house. As for your friend, that is a nightmare! One word of advice that a guy from an insurance company gave me and which I highly advice was the following. In case something like this happens and your place burns down you will have a hard time remembering what furniture you had, tech model types, serial numbers etc etc etc. Take 20 minutes time to film and take pictures of everything and upload it in the cloud. Your personal belongings will still be gone but it should be a lot easier to get some money back from the insurance company.

[@VolkanTaninmis]

​@@Luke-sansolid advice!

[@KennyWan-s9x]

Very informative 👍

[@AndreasSpiess]

Thank you!

[@devluz]

Have you ever tried the new 6.4V / 12.8V LiFePo batteries that come in a package similar to sealed lead-acid batteries for cars / boats? They often appear to have a BMS and undervoltage / overcharge protection. I wonder if they are better for beginners than dealing directly with Li-Ion batteries

[@AndreasSpiess]

Indeed, they have to have a BMS because they use more than one cell in series. I built one myself (24V LiFePo4, 7.5kWh). These batteries have very different applications than the ones I covered here. As you write: Because they have protections, they are much easier to use.

[@johndevires5911]

Thank you for another great lecture, and the AliX links. The links for the batteries don't work for the UK. :(

[@AndreasSpiess]

Moving batteries these days is quite complicated. We get them through Amsterdam, no more direct. Maybe they do not have a way to the UK...

[@vevenaneathna]

very good video. some suggestions, using an ir camera when charging several batteries in parrelel, checking charged batteries voltage against eachother some time later to see if there is excessive self discharge. using a label printer is a really good idea to quickly mark down weight, delivered voltage, capacity after testing, and to serialize battery cells so you dont loose track of the questionable ones. inspecting for damage is a very important step ive learned the hard way when receiving 280ah lifepo4 cells (~1kwh!). had one burst and leak out all of its electrolyte. i know theyre safer chemistry but holy cow that could have ended badly (it was in my car serving as a car battery lol, i know i know).

[@AndreasSpiess]

You are very professional with your batteries! But the trick with the label printer is much better than my very bad handwriting!

[@vevenaneathna]

@@AndreasSpiess i got one of those blutooth app label printers called nimbot. small enough to keep in my backpack. it was like 12 usd, i think the labels were around 3$/roll of 100?

[@seabassvn]

“Good enough for the girls I go out with “ hahaha! There’s always a gem in your vid!

[@AndreasSpiess]

It is borrowed from famous AvE ;-)

[@PhG1961]

Great overview!

[@AndreasSpiess]

Thank you!

[@bfs007a]

Great stuff!!

[@AndreasSpiess]

Thank you!

[@jmespejmespe7245]

thanks for that vid ! I was wondering about the "pouch batteries" : are there better ? significantly lighter ? yes they can inflate BUT if the 18650 cannot, what about the chemical inside ? I suspect inflate is just a visible corruption while the 18650 does not allow that visiblility but allow the corruption (collapse of the capacity) regards ....

[@_DSch]

The 18650 would just vent through the top cap, triggering the CID and making it dead forever if everything goes right.

[@primonda56]

Commonly, pouch cells (li-poly) has better electrical characteristics than most cylindrical (li-ion) cells. It usually have bit higher density (capacity) and lower internal resistance which permits higher charging/draining rate and possibly lowering it's self-discharge rate too. Another advantage is because they are commonly flat-shaped, heat dissipations are slightly better depending of it's dimension. However, the trade-offs are pouch cells can be a little more dangerous, more fragile and have lower tolerance to abuses. It is really important to handle and use them with extra care.

[@AndreasSpiess]

The biggest differences for me are the form factor. Often, flat rectangular fits better in my case. And second, they usually come with protection built-in. I never compared capacity per weight/volume.

[@notofinterest]

Andreas, can you give your viewers few expert tipps to kickstart a drained battery a regular charger won’t accept anymore? tried this a few times, but was to anxious to had success.

[@AndreasSpiess]

If there is no protection board, you can do it with a lab power supply with a few mA current. If it has a protection, you usually have to remove it before. But as I said: My experience with re-charging a LiIon battery was not good. It started to burn :-(

[@notofinterest]

@ unprotected; did it with 300mA for cpl hrs (permanently monitored of course), never worked. Anyway, tnx for answer.

[@AndreasSpiess]

@@notofinterest Strange. Then, the defect was severe...

[@kokopelli314]

Once I purchased a 36 V 10s 2p 18650 pack. it was seriously under delivering capacity so I disassembled it and tested the cells individually. Half of the cells, one out of every two in parallel was reading 0 V, so I cut the dead cells open and found that they were filled with dirt.

[@AndreasSpiess]

Incredible! That is why I always test batteries when they come and start a dispute. I got a few times my money back. But I never opened a battery to test if they contain dirt.

[@boussaoudfarid8297]

2:14 Both equations are wrong. You have to add a factor of 1000 to the calculation. 1Ah = 1000mAh.

[@AndreasSpiess]

You are right! Nobody saw my mistake before!

[@TMS5100]

Which tester do you recommend for those of us in the first row?

[@AndreasSpiess]

You decide. I mentioned my favorite for 3.7V cells. If you have other voltages to test, you have to use a different one.

[@karlbesser1696]

Angenommen, man schaltet 2 LiIons in Reihe und möchte sie perfekt balanzieren. Reicht es aus, die Zellen auf dieselbe Leerlaufspannung zu bringen oder sollte bei Aufladung an beiden Zellen dieselbe Spannung abfallen?

[@dasgibmekker768]

Würde nie eine Serienschaltung ohne einen Balancer bauen. Aber wenn, dann nur Identische aus derselben Charge. Beide parallel voll laden und dann in Serie schalten.

[@AndreasSpiess]

Wenn man zwei ähnliche Batterien in Serie schaltet reicht es, sie ab- und zu maximal aufzuladen. Das heisst: Jede Zelle muss einzeln überwacht werden dass ihre Spannung nicht über 4.2V geht. Der Ladestrom wird dann an ihr vorbei zur 2. Zelle geleitet bis die ebenfalls voll ist. Wie @dasgibmekker768 schreibt machen das normalerweise Balancer. Zwei unterschiedliche Batterien sollte man nicht in Serie schalten.

[@joeshmoe7899]

I was just looking for a battery tester/electronic load, and you make this. What are the odds?

[@AndreasSpiess]

So you can decide which one is right for you ;-)

[@AJB2K3]

I have that 4 set unit and its a good basic tester.

[@AndreasSpiess]

Very good!

[@copernicofelinis]

08:05 ah, the "German notation" for voltage. I have been looking for a screenshot like this to put as an example of use by notable KZbinrs, but I have been through a lot of your videos and couldn't find it (despite remembering seeing it multiple times!). Now that I have published the video, I find it!!! Do you happen to know if this notation has a name? I know it follows the definition of voltage given by the IEC (which is in Switzerland, btw) and is used in Switzerland, Germany, at least part of Belgium and Serbia, while France, Italy, Spain and the UK use the opposite notation. The US on the other hand doesn't like to use arrows, just signs.

[@AndreasSpiess]

I learned it this way when I was young (at the Swiss ETH) and never looked at the roots. I assume, most people can live with it.

[@gosdeCarrer]

But, for measuring the capacity with an ammeter, you should use a constant current circuit, right? otherwise with a fix resistor as the voltage goes down, the current also varies. And it is not linear.

[@renxula]

Yes, or with a fixed resistor you could log the voltage over time and use software to calculate the total Watt-hours (which should be close to constant current results). But instead of anything custom like that, it's probably wiser to buy a battery tester :)

[@AndreasSpiess]

Most loads also behave like resistors, so testing with a resistor usually is good enough for mAh. For mWh you anyway have to measure the voltage and do the calculation.

[@dg9bfc]

another option is to use a combined power meter that sums up the wh I bought a meter that measures volts, amps, multiplies that to show actual power in watts... and sums that up over time to show watthours ... routed inline a charger or a load shows you all details after a few charge discharge cycles (I use in on my Ebike)

[@carlosbah4623]

¡Gracias por compartir!

[@AndreasSpiess]

De nada

[@brianfritz575]

Cells which are swelling are typically because the electrolyte is breaking down. Even if the voltage the pack sees over its life is correct, individual areas in the cell can see overvoltage which can lead to this electrolyte decomposition. This is a bad sign. Such cells should not be used. The other big reason is delamination of the layers of the cell. This will lead to swelling, which leads to further delamination, which then leads to electrolyte decomposition. The electrolyte used in the cells is flammable, so I highly suggest disposing of such cells as soon as swelling is noticed. I've always noted swelling in bagged cells before they undergo catastrophic rapid disassembly! (ie: They explode)

[@AndreasSpiess]

Thank you for your clear words!

[@peter.stimpel]

Nice summary, Andreas. Seems, battery health is a science on its own meanwhile. Times are long gone where "battery" referred to a AAA or even D20 or 4.5 V batteries, and you only took care if it is empty or not ...

[@AndreasSpiess]

Thank you! Indeed, batteries became an important factor for modern societies. With mobility, cables are no more the best solution, I assume.

[@michaels3003]

Yes, the "AAA" cell was not actually a battery in the "classical" meaning of the word (it required multiple things to be used at the same time).

[@michaels3003]

​@@AndreasSpiess, thank you Alessandro Volta, 1800, for this invention. At least he got a physical unit named after him.

[@Thingstest-rl8xu]

⚠ Aluminum case Power Resistors Watts Rating are only when mounted on a heat sink. When used in free air Watts rating is 1/2 or less then label. Mounted on other cases to vehicle frames then can be in between printed and free air. Go look at Vishay and other real datasheats for metal case power resistors. Common Example is 6 ohm 50 watts Al case unit for vehicles that "upgraded" Tungsten to LED but burns itself and more because resistor is not mounted properly if mounted at all...

[@AndreasSpiess]

You are right. Thus my warning about becoming hot.

[@Thingstest-rl8xu]

@@AndreasSpiess Why the added ⚠? 1. Seen that but warning is buried and little info. 2. Most readers very likely won't understand watt ratings for power resistors. Al cases like shown need proper mounting or can easily be "Red hot" and burn everything even if gets a lot of air VS. Ceramic and other types want a lot of Free Air or Forced Air to flow on the entire part. If a ceramic is mounted then must allow free air flow not mounted on any surface and no heat sink is used. Another Example: Majority of Vehicles use hidden > 1 ohm High Watt Power Resistors and Forced Air to cool to control Radiator and Heater fans and when garbage covers them often starts a fire even after OEM started putting thermal fuses and guards on the resistor assembles.

[@_DSch]

Sidenote to that tester: it seems like the firmware is still buggy even on version 5.4 Something that has just happened to me was that I could enable discharge mode on discharged (2.5v) cells, which has triggered a bug where the voltage gets too low and then it tries to do internal resistance measurment (so shorting the cell)... in a loop! that is really bad. Also the internal resistance measurement should happen when the cell is full... that charger only does it while it/the battery gets plugged in which is SO stupid. I have to make an openocd (jtag) debug probe for that 8051 mcu and patch the firmware, didn't get around to do that. A better Idea i had was to make little battery modules with some configurable battery charger ic, protection and a coulomb counter - exposing their i2c bus over usb-c CC pins. That would allow to use higher Voltages (the TI chip I looked at supported like 5-12v VBUS), have it modular and usable for battery powered projects (5v OTG)! The charging&discharging part would only need female usb connectors, i2c multiplexer, ch341a for pc comm. and a big discharge resistor, add a simple ac/dc IR meter for good measure ;)

[@AkosLukacs42]

Which tester?

[@_DSch]

@@AkosLukacs42 that 4 channel thing, it works fine but has annoying issues

[@AndreasSpiess]

Thanks for sharing your experience. So far, I did not discover firmware bugs because I use it in auto mode down to 3.0V...

[@un2mensch]

It's not true that a higher "factor" means a better battery. It is true that cells with higher specific density require better quality engineering to manufacture, but this is also the problem! Because high quality engineering means tighter manufacturing tolerances, which - at least for chemical / battery cells - usually means there's more ways for things to go wrong, and more chance for failure. It's the usual triangle of compromise: (a) capacity, (b) reliability, (c) lightness -- choose 2. (And don't worry about cost right now, I didn't want to make a triangle with 4 corners, it's too early in the morning for that kind of geometrical sacrilege). But I think even more importantly, the more *power* you require from your Lithium cell (ie, very high charge-C and discharge-C), the heavier it will be for the same capacity.

[@duhnboa5447]

How about a tetrahedron? 😉

[@AndreasSpiess]

Thank you for the additional info!

[@dfgaJK]

With regards to testing for OCP by shorting the battery, afaik some 18650 have fuses under the positive cap. Doesn't this mean they have protection but shorting the battery to test the OCP would render the battery useless?

[@alistercarmichael4990]

It is normally a self rest device. Not a fuse as such. Depending on the cell or battery it may even be a full protection circuit with FET switching and a BMS.

[@volodumurkalunyak4651]

​@@alistercarmichael4990there are pressure fuses in 18650 cells - those trigger mechanically from internal pressure. Those are named CID - current interrupt device. Electronical protection is external to that.

[@AndreasSpiess]

I do not know of any electrical fuses inside unprotected 18650 batteries. The protected ones stop at a bit over 3A if I remember right.

[@remy44444]

Great video for recycle the vapes batteries of the girls I go out with ;D

[@AndreasSpiess]

:-))

[@joeshmoe7899]

DL24, I hear the mosfet goes bad after 5 years, even with light use.

[@AndreasSpiess]

I never heard about this. But if you know the mistake, it probably can be fixed if it happens.

[@NanobyteOnline]

3:45 Your calipers blink because of low battery in a video about batteries :-D

[@AndreasSpiess]

These calipers work for month blinking. And they are still accurate. So I do not change the battery until it is really dead...

[@NanobyteOnline]

@@AndreasSpiess I do the same, but only because im too lazy to change the battery :-D

[@danjadave]

Thanks, Swiss AvE! …SAvE?! 🧐

[@AndreasSpiess]

:-))

[@pioupiou3935]

I think if a battery package expand it can breaks and lithium + air = fire.

[@AndreasSpiess]

I agree with the air andfire. However, I do not have information when it will break.

[@SabineTob]

Also important: Li-Ion Cells should not be stored fully charged or discharged for a longer period! Best is about 50% charge.

[@AndreasSpiess]

I agree.

[@byronwatkins2565]

Caution: Good ammeter fuses are expensive. If blowing the fuse is the test, then you need not use an ammeter and risk damaging it... just short the battery with the fuse and see whether it blows.

[@AndreasSpiess]

You probably saw how I did it in the video...

[@fazerider9287]

Testing the presence of overcurrent protection by shorting the cell through your meter’s high Ampere circuit is not advisable. A decent meter will have a fuse capable of interrupting enormous currents and these are not cheap.

[@AndreasSpiess]

You are right!

[@gf2e]

I have an 8Ah 18650. Amazingly light - one of my lightest 18650s. I'm a little suspicious of it. It's an "UltraFire" brand. That sounds safe, right? :)

[@nrdesign1991]

8 Chinese Ah

[@volodumurkalunyak4651]

There aren't any 18650 cells with over 4a*h of real capacity as for now (24.11.2024). Any cell that claims higher capacity has to be a fake cell.

[@AndreasSpiess]

Ultrafire is or was famous for selling very strong batteries (on paper).

[@dg9bfc]

​@@AndreasSpiessah yes.. ultra fire and surefire ... 10000mAh in an 18650 😂😂😂😂

[@jamess1787]

"good enough for the girls i go out with". I used this with the wife, she did not approve.

[@AndreasSpiess]

I can imagine ;-)

[@reversetransistor4129]

You forgot one testing method, the smell. If it smells electrolyte, it's because it's almost dead, those who are swollen, have more probably to have a high resistance.

[@AndreasSpiess]

Good point. I never used this method!

[@aquahoodjd]

They grow crystals and those crystals can puncture the interior membrane.

[@AndreasSpiess]

That is what I read, too. Particularly if they are heavily charged at low temperatures.

[@gmag11]

Why the hell finding a good Li-ion battery is so difficult when not a lottery?

[@michaels3003]

This is the price you pay for very low prices. Pun intended.

[@AndreasSpiess]

I usually go with brands like Samsung or LiitoKala. Or I buy them locally.

[@min32215]

I think, we all want to sit in the first row again, not in the front row anymore...

[@AndreasSpiess]

Maybe I change it in the future ;-)

[@richard_wenner]

One day I will make the first comment! Often using filament bulbs is a good alternative to resistors as a load.

[@AndreasSpiess]

Indeed. And they have a built-in power indicator visible for everybody...

[@lohikarhu734]

Funny thing: So many people refer to, say, a AA "battery", but it's an "AA cell". I think that the word "battery" is properly applied to multiple cells connected in parallel or series to get a desired battery capacity. A 3,7 V Li battery is usually a 3,7 V Li ion cell.

[@inothome]

Correct, most people refer to individual cells as batteries. But it is true in one older common battery type. A 9V battery is an actual battery of individual cells inside to make the 9 Volts. There is no 9V chemistry used in them.

[@SKotekar]

I think the context matters here and its not a singular/plural thing. In everyday usage, only batteries power your device and that battery could be made up of a single cell.

[@renxula]

Exactly, it may have originally been "a battery of voltaic cells" a hundred years ago, but the meaning has changed in practice now that we use batteries as everyday consumer items.

[@AndreasSpiess]

For me, "battery" is a household name and much better than "cell" (cell has other main meanings in medicine, for example)

[@josepalacid]

Before disputing labeled capacity you should take into considertion that in comunist societies, and chinese is rooted on comunism, you are supposed to increase your numbers each year or you will be on risk of being banned from your activity. Agriculture and fishing must increase their numbers even if aren't real. Even if everyone knows they are fake numbers, you have to increase them every year when you publish them or you'll be ceased from your duties.

[@josepalacid]

And that trend is translated to all activities, including your products specifications. That's what you are supposed to do, even if it's a lie, because it's what all other sellers will do and you are not allowed to debunk them in any way.

[@dan-nutu]

Having lived in both communist and capitalist times and countries, I can say with utmost confidence that this happens everywhere

[@josepalacid]

@@dan-nutu Just take a look at fishing captures on China on the last 10 years.

[@dg9bfc]

and when you as a customer buy a 52v25Ah cell pack for your Ebike and think it is 5x5Ah 21700... they put in 5 or 6x18650 with 3.something Ah and your claimed 25Ah pack has 15 to 19Ah (false advertising or in other words a rip-off) .. or even lower capacity... most user will not find that out and just use it.. and the few that moans.. get a refund ... at the end the company makes more money from the higher price as they throw out for refunds

[@Irilia_neko]

To charge the maximum of the LFP battery just use a Jkbms (BMS and some batteries older) and they will always be charged and balanced 😉

[@AndreasSpiess]

Thank you for the info!

[@Irilia_neko]

I avoid li-ion as much as possible, I replace them by LFP as much as possible.

[@AndreasSpiess]

I agree. However, most boards I have are made for 3.7V

[@Irilia_neko]

@AndreasSpiess yes but the li-ion battery are so a gamble, I prefer to avoid them as much as possible, all the life expectancy of a LFP battery is so high compared to the li-ion battery.

[@roberttco1]

For you @Mymatevince :)

[@AndreasSpiess]

??