Li-Ion Capacity Test || DIY constant current load
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- เผยแพร่เมื่อ 8 มิ.ย. 2024
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1x Vero board: s.click.aliexpress.com/e/_dVy...
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1x IRLZ44N N-channel MOSFET: s.click.aliexpress.com/e/_dWh...
1x 500k potentiometer: s.click.aliexpress.com/e/_dX8...
In this video I will show you how to measure the true capacity of Li-Ion batteries. I will also explain how a simple constant current load works and how to build one from very simple parts.
Music:
2011 Lookalike by Bartlebeats - วิทยาศาสตร์และเทคโนโลยี
UltraFire: Not the best name for a Lithium battery.
heyhococo ha
the ultrafire flashlight and batteries I got have protection ic's (batteries) and yes the flashlight (9000lum) can get over 100c under max brightness but the cheap ass batteries have an internal resistance that limits the light from going thermonuclear and even mid quality batteries do exactly the same fire may never happen but I was so worried it would I added arctic mx-5 between the led pcb and the case edge and it smoked a bit before it dried a little and I do like it as it is a great short term spotlight/worklight and seems to pull a stable 3.8a from a pack of 4 18650's
😂😂😂😂😂😂
Lol... True
Like 99% of those are fake with up to 9000mah ratings. That's how you can get free batteries from ebay if you tell the seller that the capacitance doesn't even close to stated one (and risk to burn your house with those).
The highest capacity 18650 cell ever made (afaik) is 3600 mah from Panasonic. But you cannot find these anymore. So currently the highest capacity is 3400 mah again from Panasonic. With the current chemistry its not possible to squeeze more energy into a 18650 cell. Anything above that is automatically a lie, unless it's from one of the top manufacturers, its genuine and a new chemistry has been used.
I believe you probably knew all these and I understand this video is for educational purpose. My comment too.
Mandragoras thank you :)
Vláďula Vaverka :) You're welcome.
Mandragoras Good news. LG is now selling a cell with new chemistry and 3500mah capacity.
goo.gl/ElR7jA
+Mandragoras Thanks for the info. I was looking for a battery for use with arduino and this info as really helpful.
Tomas Schertel
You are welcome. My comment is a little bit old and now there can easily be found new 3500mah cells, available from reputable manufacturers.
i'm gonna use this circuit to test all my liion batteries, thanks
This is the best explanation video out there in the internet about constant current for battery discharge test. Thanks GreatScott!
19% performance - That's pretty good for some Chinese knock off equipment!
finally a guy that knows what he is doing. Very good. There is ao much shit around this subject. Thanks a lot. Peter from Denmark
You're welcome ;-)
Hello Peter
@@I_killed_that_beard_guy Hello. How do you do ?
@@petermatthiesen8288 Hii I am fine :D
@@I_killed_that_beard_guy I am really happy to hear that.
Should read 4800 China-amphours
lol
Bob Brown: "China-amp/hours"!!!!
Reminds me of the Hp ratings of Chinese motors.
There are those little bitty Chinese horses and then
there are those big, strong American horses.............
DD_Ranch Texas most US HP claims are BS. In Japan they under-rated their engines for a while (they started focusing on handling instead of an HP battle, which gave them much faster cars in real life, so they put an upper limit rating of like 275 HP or something even if the engines were 300-400 HP). In the US, we were rating older cars with stupid high HP which is easily disproven, we claimed crap like 1980’s cars with 300 HP that took 18 seconds or more to hit 60 mph... and they were cars, not literal battleships... and the new ratings are also BS, my dads Dodge Dart claims a higher HP rating than his old 1987 Mercedes (which is not even running right), and yet the Mercedes outruns it (and that car has like 200 pound electric seats, I felt like I was breaking my back trying to remove them from another car at the junkyard...). We still claim BS on most of the engines, and of course it’s BS rated on top of not using wheel power (somehow every car has the worlds most inefficient transmission ever produced right? That must be why 240 HP dropping to 170 seems reasonable...)
There are a few US cars that are actually rated correctly (typically dyno tested crate engines), and even a few that are under-rated. But then you also have BS like Dodges Hellcat engine bragging 777 HP or whatever, but then require a “race key” (in red obviously), to “unlock” that power (which is what you paid for already...), basically DLC from video games in real life... What a scam to advertise it as such and then lock it to 500 HP! So that’s beyond stupid.
As an engineer, I’d call it a faulty reject if it doesn’t hit the spec, if I buy a car and it’s out of tolerance, it should go in the scrap bin. The US marketing teams are about like the Chinese (which is super frustrating, I don’t pick a parts spec out of thin air, if that electronics piece smokes itself or melts at half the power, then why put that rating sticker on it?!?). Anyways, US drag racing is also flawed, it doesn’t measure time until the front wheel has already passed the laser, which means it takes off like 1/10 of a second or more (and yet posting crap in the thousandths of a second like it’s accurate or something...), so you could by their standard hit 60 mph in 0.000 seconds! Unfortunately you can’t get a negative time to 60 mph, but obviously if another car hit it 80 mph it wouldn’t have a lower 0-60 time). I guess it makes tanks with really long tracks look super good or something, it’s pointless, they are purposely measuring it wrong, just have a second laser, but oh no that would screw up marketing!
Fuck China
Is like PMPO Watts.
Got the same result using my charger that tells how much mA was charged. Thanks for this test. Now i know I can trust my charger
Just found your channel today, and after watching few vids, subbed. Keep 'em coming!
I am following your channel from Iraq and I found the videos very useful, educational and practical for hobbies and professional engineers, keep it up, many thanks.
good job man! nice usefull project, the interaction between mosfet and opamp was simple and great at same time.
The way you used to speak 4 years ago 😀 it's really great how you progress in many ways
Don't forget to report the idiots that sell these counterfeit products on Ebay.
+TransfixedBunnies There is literally dozen of them popping up everyday on eBay, nothing will happen if you report them, in fact I've seen some of the better sellers will say it's not genuine, but what do you expect for $1 dollar? Most people will buy the battery pop it in the flash light and it will run for an hour and they will be satisfied. Your other option is to spend $11 bucks and buy something like Keeppower with Japanese protected cell so you get what you pay for.
Dima Prok My problem is not that you get what you pay for, that part is a property of the market economy. My problem is that you do not get what you pay for, or to be more precise, what you are promised. There is no gray area or matter of opinion in scientific matters. 9000mAh is 9000mAh, not 1000mAh + imaginary saved cash flow.
Sadly I have to at least partially share your pessimism about the end result of reporting fakery in ebay. That is just ebay for ya.
What do you expect of Chinese sellers? I once read a question on Quora, I don't remember exact wording but it was something about why do Chinese copy (steal) and sell cloned technology. And the answer was by Chinese guy is that for them it's a way of life and they don't consider this wrong. So I think this exact same mentality applies to grossly exaggerating specs, it's just part of marketing, how they do business. But you know this is not the worst, I was shopping for Power Supply just few days ago, and I see a big seller with 98% feedback and I am concerned about this seller's reputation, so I started reading complains and there was literally over a hundred complains in the last 6 months. #1 was seller was listing that he was located in CA while the items were shipped from China, then there were up to 10 day delays in shipping stuff out, there were people who never received stuff and didn't get refund, there were people who got wrong /broken / used items and it made me wonder how is this guy still in business? Well I guess if you sell 20 little junk items that people won't complain and then screw someone over a bigger item the feedback looks fine and ebay doesn't care because they get their piece of pie.
+Dima Prok Forgot to mention, I try to look for 99.5% or better feedback with big sellers. With small sellers I look how many negative feedback there was in 6-12 months and what kind it is. If the item arrived damaged, then most likely it's shipping company fault but most people will blame seller.
+Dima Prok you make good points. Having read entrepreneur blog and talked to people who have worked in China I gather contracts are much more abstract and flexible (as in not trustworthy in same degree) than in Western countries.
and I will see you next time... love the thought
Greatscott you change way I previously think about electronic. Thanks bro .......😃😃
Fantastic! This is exactly what I was looking for. I tried making a constant current load with an LM317 to test battery capacity, but the voltage was too low resulting in the whole thing falling out of regulation. I think I have most of these parts lying around. Thank you so much, I can't wait to try it out!
Why don't you use a tp4056 charging and discharging module. It will automatically cuttoff you battery connection with your lm317 tester when it discharge alot....
I know I'm little bit late here,😅
Love your work.. I wouldn't mind seeing the same test being done on a highly regarded battery brand, such as Duracell or for those people in the RC hobbies maybe turnigy.. Thanks for your informative video keep them rolling.
Thank You, Greatscott, for all your constant output vids!Robert Murray-Smith has a large vid library devoted to DIY paper/carbon megacapacitors for use in motive apps. The voltage drop on a megacap is like a rock slide. I dunno if homebrew (raw materials start-point) development is your idea of fun, but I propose that megacaps constructed of low-ESR kilocaps would be the solution to this competent alternative to li-Ion, if efficient solid-state power-switching can be done to sequentially boost volts at the expense of amps as discharge progresses. RMS ( a phD chemist) is trying to compete with his professor-brother for the kiddie-crowd and sticking to paper bacitors. I further propose that nickel foil and PET film starting materials would guarantee low ESR and high cycle efficiencies. If you know anybody who wants to wow 'em with high-power motive demos (electric motorbikes, etc) this approach looks ripe-- but I dunno electronics, so maybe you could comment on the utility of the above switching scheme. Yours is the most awesome DIY electronics channel I've found in many years of YT searches. Thanks again, for being so cool!
Thank you for your effort on saying the reality! Much appreciated. Some advices about good baterries?
Good video GS..!
Just a few small points to add for all......
1. The constant load circuit is simple and neat but there are alternatives which will eliminate the ripple. This is relevant if we wish to to test capacity precisely.
2. The relationship between discharge current and capacity is non-linear. The lower the current, the greater the measured capacity.
3. I suspect you will find the Ultrafire is rated for a discharge current less than your 0.5A, which means you will generate a pessimistic result.
4. Low voltage cut-off at 2.5V will not damage the battery. All one can say is that life measured in discharge cycles will be lower compared to 3V cut-off.
Keep up the good work..!
Awesome video yet again!
Two thumbs up. A great demo.
As usuall a great video, thank you!
Great to see another lefty ;)
Leaving a portuguese message for this vídeo:
foi bom pra caramba!
Ai Caramba!
Jung was hast du denn gelernt?
Einfach Klasse was du da immer hinzauberst xD
Fantastic Experiment.
I also made the same circuit to test a couple of fake lithium ion batteries that I had.
The actual capacity of those batteries proves out to be only 418mAh.
And not 2500mAh as mentioned on them.
Thank you very much for letting me know this capacity test experiment.
900mah Capacity at 2.5V discharged is even worse than the average 3.0V/2.9V most smart dischargers use. But those batteries are known for this. 900mah is actually higher than you see when other test the same batteries. I actually purchased 6 once and the capacity said 3000mah, but they actually tested 2200mah at 3.0V(I was floored). But the basic wear and tear(charge and discharging) cause it to lose Mah quickly. After 3 or 4, the MAH dropped to around 1100. I just put them in my recycled 18650 bin and called it a day! Great Video Great Scott!!
I would like to have seen a direct comparison of a correctly marked battery with this example. To show how a proper battery should hold up.
*takes exact same ultrafire cell and writes "500mAh" on it* :D
yeah ... not very scientific
When I tested my li-on battery for power tool, I just measured voltage over the resistor load at different times. For example I measured (18v at t=0, 17v at t=30min and 16.5v at t=1h) then I just do polynomial interpolate u(t) in matlab and integrate the function (p = u(t)^2/R) over the test time. This should give you stupendously accurate results since u(t) is changing slowly monothonically over time :)
Btw it is easier to measure voltage accurately than current
very useful video, thank you!
Best channel i ever seen about electronics...
Pls sir can you make a video about IR proximity sensor using LM358. And can you show how to make it??????
Very usable research! Thanks!
Great vid man !
All good people are left hand writers Great video very interesting Thank you
Very well explained.
Great video! Could you modify this circuit to use the current for charging an empty battery? Basically, run a battery discharge test while charging an empty battery. Might be a great idea for future video!
When it comes to 18650 Li-Ion battery, the valid ranges are from 2,000 to 3,500 mAh depends on its drain characteristics.
Avoid the batteries claiming anything below or above this range.
Btw, higher the drain current(>30A), the smaller the capacity (close to 2,000 mAh), and of course, lower the drain current(
2:18 "this guy will get really hot...literally."
Excellent explaination. Very thorough, you make precise and easy to understand videos. Cheers
Great video!
Great job,.. Sir 😁
Great :-) . I´ve checked an 9800 mAh LiIon Cell for a friend, it has had exactly the same: 900 mAh. And thanks for the circuit idea. Ich finde es übrigens auch gut dass die Videos - für alle - in englisch sind, und nicht nur in deutsch. So haben mehr Leute etwas davon :-) .
Hello :) which wires are you using for PCB ?
Your video are amazing !
Nice job!
perfect timing. just got somthing in with some rather shady battery that had some pretty interesting warnings on the side. i need battery's, whats the best brand name for Li-Ion?
good job!
I once bought a pair of Ultrafire 14500's rated at 1200mAh, and yeah, real capacity was about 300mAh.
Such a genius u r....!!!!!!!!!!!
Great video !!!
Its surprise to see it only works 900mAH
GreatScott. I watch and like your every video. Plz make 18650 4X or 8X discharged capacity tester using Arduino, I would really really appreciate that.
(I'm not a natural english speaker so if theres ugly errors about right writing , please do not account . Im still learning) So than , to the real comment. I just spent like a hole day watching your videos. Excellent channel and videos !! If you can , please make some video about using ir reciever with raspberry pi ( using php , or the languages that you use as well .. they are beeing very usefull to me , to learn some things and , get some ideas for my own project) .
Thanks , and again awesome channel !
João Eduardo Saad Thanks ;-) I will put your idea on my to-do list.
This is another excellent video. Your productions are clear and you get right to the point, even if it's over my head! Would you consider creating a project that would measure many recycled 18650s at once? Although many people buy a fake battery or two for their vaping, others of us have 100 or more cells from eBay we are trying to recover. I have been scouring the internet for ways to test many cells at once in order to create balanced packs out of these kinds of cells. Thanks. I will keep watching!!!
Very informative.
Yes a very good video from someone who is far more technical than me. I am not anywhere near as technical as this guy but he certainly knows what he is talking about.
I know a better way though.
Don't buy cheap Chinese batteries.
I buy only the Panasonic enelop rechargeables or the Optimum Power 18650's from Japan. These have never let me down and I have had them for years and still going strong.
Hi GreatScott,
I have used this schematic, slightly changed and made PCB to test the 18650's. But i have a doubt, when you discharge the cell with 1ohm load and 5ohm load separately with same discharge current. Then for both the scenarios is the battery capacity calculation same or do we also have to take into load resistance value into consideration? Thank you
This circuit also works very well as an LED driver.
you make great vedios
Hello GreatScott! I have made this dummy load several years ago, all by your instructions. It really works great and I have found it to be more than suited for my use for many DIY projects. Still, I would have 1 question please. What is the max voltage that I can apply to the dummy load input? So far it worked for me with 25V, but I dont know if I can go any higher. Also, what is the max current that you would suggest - I try to avoid anything above 1A (I do have a large heat sink, so heat is not an issue). Many thanks for all your videos and for a possible reply. Dont forget to make more of those easy projects for us dummies ;)
Kind regards from Slovenia
The max current would be the continuous current limit of the Mosfet. The max voltage will be the op amps limit, if it is lower than the Mosfet's drain to source voltage limit. Also, consider the resistor and mosfet's power limit or you'll have some interesting smoke. You can use a beefy heatsink with fan for the mosfet if it does get toasty.
Just a simple and dumb question, but only for being sure, in the constant curent load diagram, you use the logic level z44n, but i have the normal irfz44n, if i supply it with anyting between 10 to 12 v i suppose it will work as well, the only question is if the potentiometer to regulate the current pat has to change a lot or it can be the same 500k.
Thanks.
jotasgasco Potentiometer value stays the same. But you may need to increase the supply voltage for the LM358 and potentiometer. From 5V to 12V should do the trick.
GreatScott! BIG Thanks! that did the trick for me, here in Taiwan i only can get the IRFZ44V and the C358C, with 5V i was getting only 200mA max load. With 12V i can increase the load to 1A or even higher, but 0.5A is enough for testing LiIo's... i finally have a constant current load i always wanted, now i just need to dig out the arduino + gnuplot thingy i made a while ago to make real accurate testings. Besten Dank und.... Ohren steif halten und weiter machen!
tt
Thank you.
Is the heat energy, from the c-mos calculated for ;)
Would it work to reduce the swing by adding a negative feedback capacitor to the opamp, to produce an analog gate voltage and change on resistance
Can you make a video to do with Cell Broadcasting?
I am wondering if the amount of current that you continuously withdraw can affect the measurements i.e., if withdrawing 250 mAh will last for 3.6 hours
Are you sure your clamp is off by 15mA? I have seem some videos and the UT210 is pretty precise, supposing you did the correct zeroing procedure. Anyway, with this kind of circuit, it would be better to use an inline current measurement, no?
I know that this video is more than 4 years old, but I just bought 9800mah UltraFire Li-Ion cells. They were really cheap when purchased in a lot of 50. I have a bicycle headlight that the 8.4v 3000mah battery pack was not powering the headlight more than 20 minutes when 3 years ago lasted as much as 1 hour. So I assembled 2 rows of 6 cells of these UltraFire with a BMS expecting this battery pack to last more than 2 hours. I charged it and it lasted about 35 minutes on the headlight.
I charged one of the 9800mah cells using a Li-Ion battery charger and then discharged it using the same charger/discharger and only got 1300mah. You can bet I was disappointed. But when purchased in a lot of 50, they were much cheaper than other 3000mah cells. I guess you get what you pay for.
Hey Great Scott! I would like to know, why You disregard the transistor consumption power? You said that it's really getting hot... Hot means energy... I think that You don't need constant current, but constant power. I would choose buck-boost for constant voltage on the resistor. Constant voltage on resistor means constant current means constant power consuming minus buck boost efficiency.
Isn't the current used by the heating process? That's where what you are measuring goes if I understand correctly.
gooooood job
Love it!
So can I discharge my 2.1V cell from this setup in constant current 1A, and how can I add a display for voltage drop.
good video
nice video
Is there any way to do this test quicker? Or to estimate the time it would take to reach 2,5V (dead) at a constant 500mA load?
Nice trick to check battery capacity
Another possibility was to use a microcontroller circuit that monitor and saves the current in a SD card. Then, use some computer program to plot the current x time and do the integral.
What can we add to this to make it better ? it doesn't seem very practical in this form with the requirement of using external measuring stuff, how can we add something which is going to show when the circuit is operating properly and also when the battery is drained ? comparator linked to an LED ?
Great video, shows how a lot of sellers on eBay are liars!!!! :)
wow you are so owsome thanks for video
Can you eliminate the oscillation in the op amp circuit by adding a capacitor in the feedback path?
Maybe by lowering the gain of the OP. Was surprised that he had no feedback loop.
Isn't the oscillation the point? It's effectively making a PWM load instead of literally constant current, isn't it?
@@reubenkriegel7639 No the oscillation is not the point, and it's a linear circuit (a non-inverting buffer), not PWM.
@@gamingSlasher It has 100% negative feedback already, so you can't lower the closed loop gain any further. It's a non-inverting buffer with the mosfet simply adding extra current capability (which it happens to draw from a separate supply - the battery under test).
To eliminate the oscillation, I'm pretty sure the solution is just to decouple the supply properly. Add a 100nF ceramic capacitor between pins 4 and 8 of the opamp, as close as possible to it. It wouldn't hurt to put a 10μF electrolytic capacitor across the incoming 5V supply, especially if you have long supply leads.
Could you explain how clamp meters work? Specifically when measuring amps? Thank you!
A clamp meter or clamp tester is a DMM with an in built current transformer. The CT can measure an ac current without having to connect the terminals of the meter or without having to cut open the cable whose current flow needs to be measured.
A CT (current transformer) is a device that measures a large current with an instrument having restricted range of about 5 Amps.
Thanks for doing and sharing that. It's very useful and important stuff. Given your test to highlight the dodgy batteries out there, which brands can you recommend? Many thanks.
Kevin Hannan Stick with the big brands.
Kevin Hannan Lithium batteries? Panasonic, Samsung, LG, Sony or Sanyo if you can still find them.
Nice and simple circuit. I made it work, but mine is quite inaccurate. I suspect the voltage drop in the traces between the mosfet and the shunt resistor is the reason.
Ok with this tips i think many people will stop to buy Chinese battery, you must create a tutorial to make our own 4800 mA battery ^^ Great job :)
Can i ask why are you choose 2.5V threshold?
Dear Scott, can this constant current load be used for testing Lead acid battery, let's say a car battery of 70Ah?
Yes, but it will take quite a while. If you don't feel like timing it yourself, add a simple voltage cutoff comparator with an SR Latch. You begin the discharge process, the clock gets power, it starts ticking and after some time the voltage drops, the comparator notices, resets the SR Latch which stops the discharging process and the clock as well. Now, you got a number like 23 hours. At 3A, that would be 69 Ah. This will work, but very slowly.
Who here is happy that they got all this information?
was suggested this video, your accent has improved so much since 2015, you don't even sound that German anymore
Good tutorial as always. 1 question: Can i use lm393? :)
In this circuit, the opamp is not working as a comparator since a comparator operates without negative feedback. The opamp used in the circuit does not require any of the features of a comparator, such as its large allowable input differential range, so an LM393 seems to be a bit of a waste when an LM358 would do the job.
In this circuit, there would be little difference between them as long as you remember to include a resistor around 10K for output pullup on the LM393.
Quick question: 3:40...WHY is I=Vin/R ? Would like to know how you found that formula. I mean I know how ohm's law works, but how does the op-amp affect it ?
Opamps with negative feedback always change their output to keep their inputs at the same voltage. The opamp and mosfet together are working as a simple non-inverting buffer that fixes the voltage at the source of the mosfet to the same voltage as is supplied from the wiper of the potentiometer. That constant voltage provides a constant voltage across R1, which gives a constant current through R1 and therefore draws a constant current from the supply to the mosfet's drain, i.e. the battery under test.
GreatScott, thank you. If I need to get 2 A current, do I need to replace R1 resistor to 0.5 Ohm?
yas
Yes and add a decent sized heatsink to the IRLZ44.
Hi! Thank you for the video! I want to build it but only have a TLC272CN op-amp and IRFZ44N, IRF540, IRF740 and IRF1404 mosfets. Which one to choose and what to change to make it work? I don't want big loads but only measure some big car hifi capacitors; ~1F.
If you're working with a 10V supply, any of the mosfets will be fine. For 5V supplies, you really should use "logic-level" mosfets like the IRLZ44 or IRL540, etc. The TLC272CN works with supplies from 3V to 16V, so is fine with any supply in that range. You don't need to make any changes.
Tell me one thing the lm358 does negative side switching so how does this n channel mosfet run with the negative switching
UltraFire batteries are interesting. I bought a set of "4000mAh" red UltraFire's a few years back, and have been getting a fairly consistent capacity of around 2000mAh out of them when charging from around 3.2v to 4.2v which is very surprising considering.
Despite my fairly good results with a set of UltraFire, I still wouldn't recommend them for anything of importance as I doubt they will handle much of a load and despite being labelled as protected mine do not have protection circuits in them. Also I think I was extremely lucky with the set that I bought as 2000mAh is very high compared to what others seem to get. UltraFire is comparable to playing the lottery :D
hi, it is possible to make power supply with this curcuit and Lm317 for control amps and volts?
will this work for 21700 cells im gonna bying 48 for a project and wanna check if they are really samsungs cells
I did the same test a while ago, but i used a diy usb powerbank where you can insert your own 18650 (1€ from ebay), an adjustable load (3€ from ebay) and a usb charger tester (same price) and tested some vander batteries with it. The promised 6.000 mAh cells only took about 1.2 Ah..
it works like a modul for charging a Li-Ion baterry?
Firstly thanks for your videos. I am learning a lot. A question:
Did you measure the current as 500 mA till the voltage dropped to 2.5 volts?
I was wondering, why he stop the proces at this voltage level?
2.5 is the max discharge voltage in li-ion cells
@@DrkTrx below 3v it will drop dramatically
Thanks