Yeah you must continue man, i bought several packs of popcorn for these capacity test episodes xD Perhaps its a B-grade EVE battery they sent you? Anyhow keep up the work í love your channel. Best regards from Sweden.
Just running a set of test cycles on EVE 280's. 3rd run through and now using a heavier C-Rate (75A) charge per cell, doing individual cell charging (actually pretty quick) has indeed made a difference at the top of the voltage curve. Compared to setting cells in parallel and charging the "lot" which I did, this method of 1 cell @ higher C-Rate is better. * Note using CC-CV with bench Powersupply. Allowing to drop to 1A per cell, then setting them in parallel for final topping with charger attached.
@@OffGridGarageAustralia Is this a tried and true statement? Does the cell actually get better over a few cycles of tests? For all cells tested multiple times? Just curious to know. I did encounter this with my 32650 cells, tried to test two a second time. So I am still not exactly sure if this statement is a fact. Thanks for answering. Great videos. Going through them one at a time
Just an idea. You may want to connect your two testers in series to measure Ah and see how their readings differ (or match). Just connect the one with the shunt to the cell and as its load connect the one with the fan. Same current will flow through them so you can see if they read the same amps and Ahs (or how different).
I think you should test the tester. You know voltage reading is not accurate so amps might be erroneous too...? And thank you for the hugely informative content, as you say we're all learning... 👍👌👊👏
Seems like you are getting 98% of the rated capacity, I would be very very happy if my batteries did that well...and also that tester is not super accurate (I have one) and you have a tiny bit of loss in the wires and circuitry of the tester.
Thank you. Why is this not the top comment? Given the price he paid and the frequency of exaggerated claims on alibaba, I'd be ecstatic with those results. I'm really curious to see how well these cells hold up longterm.
There is a fundamental law with electronics and related fields: "The number of answers you get is directly proportional to the number of instruments you have to measure with." I have five different ways to test battery capacity etc. and I get 5 different answers. Most of them are close but the measurement from my chargery BMS (the most expensive tool I have to measure capacity) is the one that gives the worst answer, about 16% off. I have spent an endless amount of time charging and discharging a handful of my 64 LiFePo4 batteries over and over again to the point that I am now designing my own charges, dischargers and testers (I have a EE degree so that helps) and I have learned enough to say that designing an accurate current measuring system that covers a broad range of currents from mill-amps to 100s of amp is actually not a trivial exercise. To measure such currents with a shunt based system requires a shunt of such low resistance (so as to minimize the power dissipation requirements and voltage loss requirements when 10s or 100s of amps are flowing through it) that you have such small voltages across the shunt when measuring only milliamps or low amps that noise from other electrical sources etc. becomes a problem. And hull effect based systems tend to be even less accurate in my experience. Just take your clamp meter and "clamp" it to you one of you power lines and move it around to see the amps measured change right before you eyes...convenient but not good. Bottom line is "be happy" as your batteries are doing much better than most. I might add there are many on youtube you rant at the battery manufacturers when they don't get 100% or more from the capacity tests. It is true that their are rip-offs for sure but more often the folks doing the testing really don't understand the tolerance levels they should expect or all the variables involved. I was one of those people until I did a lot of investigation and found out that there are a great many variables involved and that the equipment we use to test and our techniques and lack of understanding are more often the culprit than the batteries. By the way, you have undoubtedly noticed that your battery voltage stays fairly constant during these tests ( until the end that is) and your load current is equally consistent (provided you have a stable constant load). It is a simple matter to check the accuracy of your instruments. Wait until you are into a test for an hour or so (therefore in the linear range for the battery if you have sufficient loads - you do for your tests based on your setup you videoed) are read how many amps are flowing. Then wait another hour or more and read again. The current will not have changed if you started with full batteries with the loads you have in your videos. Then simply take the time period and convert to amp hours. So, if you read 18 amps on your meters and you took your measurements one hour apart you will have used 18 amp hours. Compare to what your meter says. If it does not agree than the meter is not accurate. Do this over a several hour period (staying in the battery linear range) and you will have a good indicator of your meters error percentage. You can do the same test during charging provided you have a good constant current charging source. Even if you do not it will probably be fine in the battery linear region as the IR and voltage are fairly constant) In my experience on all my instruments they are quite close on the amps (not ah) measurement. However, my BMS gave a very low amp hour (not amps) measurement compared to what it should have calculated. This was particularly strange because its amp measurement was similar to the other instruments. I suspect they out smarted themselves when making this, otherwise simple, calculation. I will also offer that although the amp hour capacity varies on my different instruments the total watt hour calculations are all similar. Some variation of around 5 percent but usually fairly close. Finally, the DROK multifunction shunt meter you used in your second test is actually my most accurate meter (it seems anyway) despite its relatively low cost. I also have a hull effect meter and its accuracy is not great. By the way, the discrepancy in the values of your measurements really isn't much to get excited about in my opinion.
I did get one package delivered of the 320 amp hour batteries from the Samben store and only got 310 capacity. But am just happy the batteries where delivered.
Hi, I recently found your videos. You are making me a big job, now I have to watch them all from the beginning of video one. I think those both testers actually read quite accurately the same. As you charge and discharge the battery couple of times, the capacity might increase a bit. It is nice to know that those cheap testers can get you at least to the ball park when testing old batteries, are they still good or not. Br, Eeli
Excelent work! I am very happy that you are able to test these cells with differnt equipment. These tests should provide a good base line to compare the average capacity. Thanks again for the great video!
I checked yesterday and the new ones seem to be shipping with a sticker that says 272AH now. Same company you used. The sticker also says 3.23 volts and IT is 0.13mOhms. Wish I could show you the picture they sent me.
You have to continue testing because if you find any lower cells than that one your overal battery capacity will be even lower theirfore you will have a greater argument for replacement cells.keep up the good work!
I would test a few more, just to see what the average is. In the end, it doesn't really matter if you are getting 3% less power than speced, when the batteries are 30% cheaper. I'm getting ready to purchase 4 of these cells from your link. Even 200AH batteries for this price is very cheap.
Be aware that PayPal pay only $30.00 dollars to ship it back and it cost several hundreds dollars to send it back to china if you want your money back for these bad quality cells. Cheapest price to send 16 cells 280ah is $2016.00 dollars or $3888.00
I paid $3465.60 for brand new class A which weren't new or class A. It is a scam. If you buy a 12 eggs box because it has 30% off and when you open it has only six eggs Do you say that is fine because it has 30% discount?
I have 8 of these coming and I will test each one, but that is just me. I would be okay with the 271AH but I would much prefer 280AH+... Thanks for your videos and tests! I would love to see how you hook them up to your charge controller and your load.
Decisions, 🤔Decisions, Thanks Again, I enjoy your in depth troubleshooting information, we are all learning about this new technology, Keep up the Good Work!👏
I personally like what you're doing based on your recommendation I order set to 4 cells and I can wait to see that box in front of my door so I can do the test on my battery anyway you doing a great job and I thank you for sharing your test keep going God bless
hi, you should to measure the accuracy of your capacity testers (both may a bit off).. also always measure each capacity of your cells because the less capacity cell (the worst one) become the max capacity of the pack in a serial configuration.. in parallel+serial, me, i match the worst one with the better one (and so on) in my pack and that give a better equalized capacity of cells.. in my case i have around +10% to -10% of the average and if i was putted 2 cells at -10% in parallel, my total capacity was dropped to -20%.. love your car bulbs load which don’t do noise.. happy to see your experiments!!
Build the battery, do some full cycles and after the last low voltage cut off of the bms pick the cells with the lowest and with the highest voltage and do all the tests.
Honestly, I think you should connect the cells together and use a BMS. Then run your test on the pack. When the BMS cuts the output, measure the cell voltages. I am not sure you should expect the same result every time you test a cell. There are too many variables and unknowns. The cells are like living things.
I just ordered 8 of those cells I have the newer model all in one test I think just a different heatsink on it but I am planning to test every cell of mine Then I will try to match each parallel set for capacity I have a 12v system
0:39 shows it was pulling almost 1A so it may not have been fully charged. Also please replace the battery in your voltmeter. drives me nuts to see that flashing icon indicating a low battery. :)
Actually, he has already significantly OVERCHARGED the cell at that point. Lifepo4 has a typical charge termination current of 5%, and 5% of 280ah is 14 amps. Hes just wasting time and slowly killing the battery, unfortunately.:-(
@@ArthurDentZaphodBeeb 5% of cell capacity. Could also sometimes be written as C/20. If you have a 100ah cell, you would terminate the charge when the current falls to 5 amps. For these huge 280ah cells, you would stop at 14 amps.
The deviation between all the cells is just as important as the absolute capacity. To check both just charge all cells (once) in parallel to 3.65v, link all cells in series, then discharge (once) until the lowest cell is 2.50v. The voltage of the remaining cells and your previous tests will indicate the capacities remaining.
A lot of "280ah" batteries are now selling as 272ah... which is what you got. So likely that your cell is 272ah battery (esp with loss over wires from battery to tester)
That is the Truth, I contacted Alibaba fist and two representative's kept saying 272ah and 280ah know difference, I said, well I want 280ah and again they said, "Know Real Difference, Same Battery."
If I had to guess, I would say that these are grade B cells. Cells that didn't make the 280 Ah cut. I bought the same 280 Ah EVE cells but they were considerably more expensive because they were guaranteed matched grade A cells with a measured capacity from 289 to 290 Ah.
Thank you for sharing and have a great 2021 with more nice videos! I would suggest that you test an other from the Carlotta 8 batch - if it shows a similar range (265-270Ah), then test one from the other batches - then you can figure if it's a "batch problem"...
Hi Andy, hope you can answer, I need a inexpensive tester, the shunt looks ok for use as a comparator for 8 battery's , buts what are the specs for buying one and what load did you use or what is suitable. many thanks Gary
I would like to see a capacity test of all 4 batteries individually along with your opinion on how they will work together based on the results. If I understand correctly, battery packs work best when the batteries are closely matched in capacity and internal resistance.
I agree the internal resistance increases with the higher current draw causing the difference in Ahr. The problem is the fact that the battery gets warm to touch proves nothing. The heat created at 1C is occurring over 1 hour whereas at .2C its occurring over 5 hours. Of course the battery gets warmer dissipating even the same amount of energy 5 times faster. To prove it you would need to take a calorimeter approach something like immerse battery as possible in well insulated liquid filled container and measure the rise in temp of liquid etc and account for heat loss of insulation etc. Was too complicated and too much trouble for the return so I am not suggesting you do it. Also it depends highly on the ambient temperature you do the capacity test at. Cooler temp may actually make a higher C more efficient to a degree (no pun intended) if the heat at higher C warms the battery to a more efficient temperature rather than raising it to a too warm temperature.
Your handheld meter showed 2.50 volts when the amp hour device showed 2.48. The device is reading at 99.2% of what your hand held volt meter indicates. 99.2% of 280 amp hours is 277. If the device current reading is also off by 0.8% because of an error in measurement, then your results are effectively 280 amp hours. if you want a reasonable estimate of all of the batteries behavior you need to test five more batteries, find the average reading and the standard deviation and then you can estimate what the rest of the batteries would do. But I think you should just put together the 48 volt battery and see if it meets your expectations.
@@OffGridGarageAustralia I should have just said that results are close enough,. Instead of trying to make the case for them being within the error of measurement without making a good case. I will wait and see what you decide, but hope we get to see a 14+ kWh battery. I suppose you would want to capacity test the finished product so you will know what 1 C is.
What are the capacity tolerances in datasheet? If it is too warm battery will perform less optimally and degrade faster. Could check the battery serial number. They could have been sitting for a while I wear houses and who knows at what pemperature.
Hello, I think it depends on the tester. I have a better tester that measures the voltage with a seperate cable on the battery direct to caculate right. Your tester does not measure (calculate) the Wh that get lost over the cable.
I've done the test with such a tester just before this video. The voltage is not critical when measuring Ah. If you want Wh, yes, I use the tester where it probes directly at the terminals. It's about 7mV drop on each of these cables including connections.
Hello. Why don't you put much thicker cable, with good connectors, mirror polished contact surfaces fully covering the battery posts? Sure the wires you use are thick enough for 20 Ampères, from certain points of views, I mean security, cost efficiency, but if we want the best results, if the battery post is 12 mm diameter, should the cable not be 12 mm also? well if the battery post is aluminium and the cable copper, the copper could be about 1.6 time thinner in surface, 70 square mm instead of 113 square mm. Or 9.5 mm diameter. Also to spare the threads in the aluminium posts, I use studs intead of screws. I wish to find alu studs, for now the best I found are brass, I saw somewere that stainless steel will eat aluminium in certain conditions. Cheers.
@@OffGridGarageAustralia Yes that‘s right. Maybe the Tester measures the Amps just a little inacurate. By testing this long time a inacurency from 0,05 A can make the difference. Can you do a calibration to the tester with a good quality measure equipment? Soryy for my english, I‘m german (you too?)
@@michaelb.1192 Your English is good but we could do German too (guck mal auf meinem deutschen Kanal 'Living Down Under'). The tester cannot be calibrated, bit I compared the current with my multimeters and it is accurate. The voltage is off though...
8:41 I have been following your videos, I want to clarify something. I don't think measured Amp Hrs matter even if there are loses on the cables, so the voltage sense won't be of much help. The current sensor should measure the entire current passing through the system, so AH doesn't need an accurate voltage sensor. The WH will matter but AH, I don't think. Please correct me if I'm wrong. Thanks.
Maybe somebody else said this but doesn't the graph show that you get less total WATTS (power) if you're sinking close to 1C? Or am I wrong? It seems like you get less volts even though you get about the same amount of amps. So watts being the combination of the two it comes out a little lower..?
The batteries have internal resistance and the BMS and other circuits use some power. I did not see a reference or inclusion of these parameters. (Sorry, I commented before the end of the vid) But new LiFePO4 batteries should exceed the AH rating. 96% efficiency is not bad. The question is are these new or used?
I think the spec sheet says they aren't very efficient. Because if the high IR. I'll stick to the "old fashioned" LiPo flat packs. 98% approx for my solar backup. 24 volt system. The only plus I see for LiFe is 4 cells make a good 12v battery and the cycle life is real high. I'd close the book on this.
Hast du bei der elektronischen Last mal geschaut, ob die Ampereanzeige auch genau geht? Nicht dass die Ampereanzeige ein wenig ungenau geht und somit deine Ergenisse nicht stimmen? Vielleicht auch mal ein normales Multimeter dazu in Reihe schalten mit 10A z.b. mal belasten und testen was die Anzeige macht.
I would stop stressing over it and just be happy that a great price for that capacity. Within 5% each one will test a little differently not sure it's something to worry about. Bummer that they rated it so close to the actual I like when they rate the battery lower than the actual makes me feel like I got a better battery.
I think you should do a "real scenario" test where all the batteries are used together to provide power to a realistic load current/power request. Like you mention discharge rate and temperature are key factors on battery performance.
I bought 8 280Ah cells from aliexpress. The worst one tested at 280Ah. The others tested from 283 to 287. I would want to make sure the test load is truly accurate before making conclusions. I'm using an EBD-A20H to test my cells.
@@Mike_Neukam Hi sorry to bug you can you copy the link in and just delete the com from it ? And how much did you pay per cell of you don't mind me asking ?
Nice vid good info and view points. I would random test 25% of each delivery. If you see deviations test more from that batch. Find a bigger tester to discharge 0.5 c wil safe you alot of time. A nice inverter to make use of f the power instead of turning the power to useles heat ;-)
Does the description say anything like +/-3%?? I would expect 280-285ah from a battery rated at 280ah, the other tester with the lights, the current drops with voltage, the constant current load is constant, it can change the results, I used a buck converter with load, to test, it actually pulls more current with lowering voltage, I would test them all to atleast 3.2v and compare, if they are close use them, you could always add a 5-6 ah cell to the lower cells to make them equal, but I would tell the manufacturer about the test!
Batteries don't hold the same capacity every cycle either. Some batteries increase capacity over the first few cycles and then decline. Temperature is important with capacity testing. A hot battery can give over 100% capacity. And cold will lose 10s of %.
Honestly these batteries should have their minimum rated capacity listed, not the max to be expected, so if it's under it's reasonable to expect more, and I'd ask them about it, certainly. In your setup I can't think of anything wrong that would make that big a difference, small wire size might, but it'd get noticibly warm. The low voltage reading on the meter would make a difference, but you've tried it with the other capacity meter and got a similar result.
Ich habe nicht alle deine Videos komplett gesehen - vielleicht hast du ja eine Genauigkeitsprüfung gemacht. Bei solchen Tests überprüfe ich zunächst die Ah-Meter mit einem genauen Multimeter. Mein Multimeter hat eine angegebene Genauigkeit im 10A DC-Bereich von +/-(0,2%+2). Bei höheren Strömen verwende ich einen Shunt Kl.0,5 oder besser und messe den Spannungsabfall mit dem obigen Multimeter, das im mV-DC-Bereich mit +/-(0,1%+1) angegeben ist. Dein UT 210D ist mit +/-(2,0%+3) angegeben. Die Genauigkeits-Angaben von der 180W Last sind unglaubwürdig oder es ist die Auflösung gemeint. Bei einigen Prozent Ungenauigkeit in der Messung sind dann schnell die Ah-Ergebnisse unbefriedigend. Zum Beispiel: 280Ah -3% = 272Ah
I've done these tests on 16 cells I've gotten, and 2 are around 15-20ah short; the rest are all within 4ah of target or hit target. My Customer Service person doesn't seem very interested in helping tho :/
It will drive you crazy if you worry about it to much I have purchased 4 sets of cells in the last year and a half, only the 16, 150ah from BLS on aliexpress made full capacity. The 90ah and 100 ah where both 3 to 7 % less then rated but the cost was a lot less/ah. Been using everyday off grid and they have been performing well. Just my two cents.
The capacity of a battery must be measured in wh not in Ah. 280Ah x 3.2v nominal should give us 896Wh. Check more on the whs the battery is capable of providing. 846Wh = 264Ah. 0,09v x 22,2A x 12h = 24Wh. 846Wh + 24Wh = 870 Wh. 870 / 3.2v = 272 Ah 🤔 👍 Saludos desde España.
Take 280AH Gross. Subtract 10% for 5% top & bottom margin, gives you 252AH. Remember that between 3.450 to 3.650 is a Steep Curve up (minimal AH) and below 3.00V is a cliff fall . This is ALL LFP cells. $80 for a 280AH cell or call it 250AH is still an outstanding deal when you crunch the numbers . Now go out and get a price quotation for properly Matched & Binned LFP cells (be seated before you see the numbers). What is more important is, are they consistent throughout their operational range of 3.450-3.000. Do you have any Runners which will reach HVD before other cells or Lazies which will hit LVD before the others ? THOSE two types of problematic cells are that limit's the battery assembly capacity/functionality. Impedance & Resistance are player factors in this, one conveniently gets forgotten in discussions.
I haven't studied the spec sheets. Do they specify a range (e.g. "280Ah +1%/-5%" or something like that)? Were the cells they shipped to you matched by batch? Also, you have loss in the leads between battery and tester. How much?
On the Video "3rd Capacity Test with expected result....... Where did you Ge the tester you used to check the load , Ah ,Voltage Tester I would like to get the same Tester you Have described in the video. m just a Novice...Please send me info Thankyou From CANADA. BTW I subcribed and Your Very Very good in your Videos. Thanks AGAIN
“Does get a lot less exciting after three times” LOL :-) Ha! NOW test every cell Andy! If the tester’s voltage is slightly out- which your separate clamp/ volt meter confirms, then the Ah figure is also incorrect. There may well be enough difference to get to 280Ah. At the end of the day though, the sad fact is that you have basically zero chance of refunds or replacements, except maybe for a totally failed cell. However even that would likely be very difficult, not to mention very expensive, with very slow shipping. Maybe you’ll just have to live with what you have and not lose sleep over it. My five year old Winston cells have never been very accurately capacity tested, but do continue to perform very well indeed. They could be slightly over OR under capacity and I wouldn’t really know, (or even care very much). Cheers
No, Dave. The voltage is not taken into account when measuring the Ah. It's the amperes over time, A*h. The voltage is totally irrelevant. And current is absolutely accurate as I have shown in the last two tests. So Ah should be good.
Although they seem they don't perform as expected, there are some differences in voltage on the capacity tester and the multimeter. Isn't that a difference big enough to generate the deviation you are getting? I have recently seen some of these 280 ah cells, appear as 272 ah on Aliexpress. They look exactly the same... Nevertheless, until you get an accurate tester, you will never be sure. For that amount invested in cells I would definitely step it up with a beefier, and better tester. Nevertheless, I would charge them all, get them running with a BMS, and monitor wich ones are at lowest voltage. I would say that the readings you are getting are still pretty good 271 ah. I would worry if they were much lower than that. It all comes down to the price per usable KW/h. After a few cycles it may settle a bit. Still a great value for money, and dealing with chinese companies is not easy. A man with one watch, always knows the time... A man with two watches is never sure... (Two testers)... Great, great content Andy. Love your channel. Keep up the good work.
The voltage is not relevant when measuring Ah. It measures the current over time. The voltage is included in the Energy (Wh) though. Yes, you're right. I have to setup the full system first and go from there to identify weak cells. Otherwise, too many watches... ;)
@@OffGridGarageAustralia thanks for coming back at me. I am learning a lot with your videos. I am learning all I can, so can set up my own system later next year. Thank you again from Madrid Spain.
For a 0.1C discharge, you're not drawing enough current (at least as indicated). Before you complain about cell capacity, you need to test EVERY cell in the same manner and do it with test equipment of KNOWN accuracy. Would you use a $10 Harbor Freight digital multimeter to do this testing? Some of those have a calibration pot for the voltmeter section and those can be set for decent accuracy over a small range but they're don't compare to a Fluke for accuracy when purchased. What is the RATED accuracy of each test instrument you are using? I know from experience that the EPSolar/EPEver solar charge controllers have more accurate metering than the MakeSkyBlue charge controllers and the inexpensive (and some not-so-inexpensive) voltmeters and ammeters from China can be all over the place. How accurate is the A measurement (in %) and the H measurement (in %) of all-in-one device you are using? Does it measure 20.000 amps accurately or does it show 20.1xx or 19.9xx? Does it measure 12 hours exactly or is it off by a few minutes one way or the other? First you test the test equipment, then you test the battery if you want high accuracy. Voltage measuring I can do accurately by using an AD584L voltage reference (factory trimmed to +/- 0.005volt on the 10.0 volt output, which is better than 1%, and similar accuracy on the 2.5 and 5.0 volt outputs which are useful to this discussion and the calbration chart with the device will have 4 or 5 digits of precision) to calibrate the voltmeter(s) being used. How accurate is your voltmeter at 2.5 and 3.65 volts? Having your meter off by 0.1 volt (0.4% at 2.5 volts) could make a major difference in the apparent battery capacity. Charging to 3.55v and discharging to 2.4v is not the specified range of the cell. Current measurements need to be equally accurate for AH. On the other hand, what is the battery manufacturer's RATED capacity accuracy? Almost everything has some type of specification accuracy (vehicle speedometers in the US are to be -0 to +7%. It's OK if it reads high but not low). I use an AH meter to monitor the discharge and charge of my AGM battery bank. In this case, I know what the voltages are at rest and under load for various states of charge and I can use that and the AH in/out to determine the safe discharge level and the fully recharged state of the battery bank. Whatever the discharge AH may be, the correct charge AH is (discharge AH + 10%). I got 9 years from the previous bank, replacing it when half the batteries dropped below 80% of original capacity. I generally consider +/-5% a good battery in early all-in-one testing unless the manufacturer specifies tighter tolerances, which will require that I use better test equipment.
You are using the electronic load out of it's specs. Max current should be 20 A, this is why the current is flipping around and may give a wrong sum. Set it to 19A, this should be constant 'till the battery is empty. The R of the battery is also wrong, because the battery can deliver way more current, than the load can handle. It simply cannot measure the resistance with only 20A.
@@OffGridGarageAustralia it is true but still some losses in the electronic and still some mesurement errors. And 271 for 280 annunced (3% less than annunced), for a Chinese product that cost 1/3 of non chinese products, it is quite a performance lol. I bought 310 Mah batteries that I am waiting for. If I get 300 I will be happy. A lot of testers found that their 280 Ah chinese batteries deliver about 280 Ah. In general these chinese batteries are a very good deal (75% less expensive for 3% capacity less in the worst case)... if these batteries last 10 to 15 years (the only question is : how long will they really last) ?
@@OffGridGarageAustralia yep I saw that in different forums... many are actually 272ah batteries, but seeing the comments someone managed to get above 270ah out of their batteries, so there may be genuine 280ah out there. All in all for the cost of them it's not bad at all, mine are on their way here, I paid USD $824 shipped and tax included, not bad for 8 units
Capacity is dependant on the discharge current. At, say, 50 Amps, You will get much less. At 5 Amps, You may get a lot more than 280 Ah. This test is performed as CC, the previous test was not. Light bulbs as load is not an accurate way of rating a battery. Now, try this, recharge and do this test once more with this tester, same Amperage, and You may get a couple more Ah.
FYI I recently ordered 16 cells from Shenzen Basen on Alibaba and they told me they are out of stock of the 280ah EVE cells and shipped me 272ah Lishen cells without asking me first. Take that for what you will. There was an ~$80 refund issued.
You should get proper electronic load to do this tests. The cheap Chinese or DIY measurement tools have so much error you can not trust anything you get for the resolution you are trying to measure.
Die Chinesen haben den Etikettenschwindel perfektioniert. Ist ja schön weit weg. Nach 5 Wochen habe ich Batterien und BMS gekriegt und siehe da BMS defekt. Also anderes bestellen und noch mal 5 Wochen warten. Capazitätstester ist gar nicht erst gekommen. I`m frustated!!!
You're slowly killing your cells if you are charging them to 3.6v with a termination current of 1 amp. Lifepo4 has a typical charge termination current of 5%, and 5% of 280ah is 14 amps. If your charger charges at less than 14 amps, you need to stop charging it AS SOON as it reaches 3.6-3.65v. You're just wasting time and slowly killing the battery, unfortunately, by letting the current fall off. :-(
@@OffGridGarageAustralia the longer they stay at 3.65v, the shorter the lifespan. Its no secret lithium cells dont like that. It's why we dont store them fully charged. I'm not sure what the output of your charger is, but a lower end-voltage termination is definitely recommended. If you care about the longevity of the cells
It's just a usual chinese Ah worth less than usual average SI Ah, or simply they lied. Not to mention it should bee more than advertised like +5-10 Ah than less and this is at 0.1C discharge how bad it can be at 1C ... I guess half the advertised. At least not marketed as 9999 Ah
Test all. Show the world that these cells are used or bad quality that don't charge or discharge at same level when in series. It is very disappointing and a scam that aliexpress ebay and PayPal are covering it up and don't want to refund your money.
Yeah you must continue man, i bought several packs of popcorn for these capacity test episodes xD Perhaps its a B-grade EVE battery they sent you? Anyhow keep up the work í love your channel. Best regards from Sweden.
Spec sheet says to repeat 3 times each cell. I had a couple of my 280s come in 280 after being charged and discharged a few times individually.
That's a great trip and exactly what I saw with mine too. The ones I tested got better with every cycle.
Just running a set of test cycles on EVE 280's.
3rd run through and now using a heavier C-Rate (75A) charge per cell, doing individual cell charging (actually pretty quick) has indeed made a difference at the top of the voltage curve. Compared to setting cells in parallel and charging the
"lot" which I did, this method of 1 cell @ higher C-Rate is better.
* Note using CC-CV with bench Powersupply. Allowing to drop to 1A per cell, then setting them in parallel for final topping with charger attached.
@@OffGridGarageAustralia Is this a tried and true statement? Does the cell actually get better over a few cycles of tests? For all cells tested multiple times? Just curious to know. I did encounter this with my 32650 cells, tried to test two a second time. So I am still not exactly sure if this statement is a fact. Thanks for answering. Great videos. Going through them one at a time
Just an idea. You may want to connect your two testers in series to measure Ah and see how their readings differ (or match). Just connect the one with the shunt to the cell and as its load connect the one with the fan. Same current will flow through them so you can see if they read the same amps and Ahs (or how different).
I think you should test the tester. You know voltage reading is not accurate so amps might be erroneous too...? And thank you for the hugely informative content, as you say we're all learning... 👍👌👊👏
I measured the amps in the last two tests and they seem to be accurate. But, yeah, too many testers...
@@OffGridGarageAustralia Of course you did! 🤦♂️🙄😜
Go all the way! 14 more!
I'm too tired 😁
@@OffGridGarageAustralia You may not want to hear it, but you know you need to test them all....
Seems like you are getting 98% of the rated capacity, I would be very very happy if my batteries did that well...and also that tester is not super accurate (I have one) and you have a tiny bit of loss in the wires and circuitry of the tester.
Thank you. Why is this not the top comment?
Given the price he paid and the frequency of exaggerated claims on alibaba, I'd be ecstatic with those results. I'm really curious to see how well these cells hold up longterm.
There is a fundamental law with electronics and related fields: "The number of answers you get is directly proportional to the number of instruments you have to measure with." I have five different ways to test battery capacity etc. and I get 5 different answers. Most of them are close but the measurement from my chargery BMS (the most expensive tool I have to measure capacity) is the one that gives the worst answer, about 16% off. I have spent an endless amount of time charging and discharging a handful of my 64 LiFePo4 batteries over and over again to the point that I am now designing my own charges, dischargers and testers (I have a EE degree so that helps) and I have learned enough to say that designing an accurate current measuring system that covers a broad range of currents from mill-amps to 100s of amp is actually not a trivial exercise. To measure such currents with a shunt based system requires a shunt of such low resistance (so as to minimize the power dissipation requirements and voltage loss requirements when 10s or 100s of amps are flowing through it) that you have such small voltages across the shunt when measuring only milliamps or low amps that noise from other electrical sources etc. becomes a problem. And hull effect based systems tend to be even less accurate in my experience. Just take your clamp meter and "clamp" it to you one of you power lines and move it around to see the amps measured change right before you eyes...convenient but not good. Bottom line is "be happy" as your batteries are doing much better than most. I might add there are many on youtube you rant at the battery manufacturers when they don't get 100% or more from the capacity tests. It is true that their are rip-offs for sure but more often the folks doing the testing really don't understand the tolerance levels they should expect or all the variables involved. I was one of those people until I did a lot of investigation and found out that there are a great many variables involved and that the equipment we use to test and our techniques and lack of understanding are more often the culprit than the batteries. By the way, you have undoubtedly noticed that your battery voltage stays fairly constant during these tests ( until the end that is) and your load current is equally consistent (provided you have a stable constant load). It is a simple matter to check the accuracy of your instruments. Wait until you are into a test for an hour or so (therefore in the linear range for the battery if you have sufficient loads - you do for your tests based on your setup you videoed) are read how many amps are flowing. Then wait another hour or more and read again. The current will not have changed if you started with full batteries with the loads you have in your videos. Then simply take the time period and convert to amp hours. So, if you read 18 amps on your meters and you took your measurements one hour apart you will have used 18 amp hours. Compare to what your meter says. If it does not agree than the meter is not accurate. Do this over a several hour period (staying in the battery linear range) and you will have a good indicator of your meters error percentage. You can do the same test during charging provided you have a good constant current charging source. Even if you do not it will probably be fine in the battery linear region as the IR and voltage are fairly constant) In my experience on all my instruments they are quite close on the amps (not ah) measurement. However, my BMS gave a very low amp hour (not amps) measurement compared to what it should have calculated. This was particularly strange because its amp measurement was similar to the other instruments. I suspect they out smarted themselves when making this, otherwise simple, calculation. I will also offer that although the amp hour capacity varies on my different instruments the total watt hour calculations are all similar. Some variation of around 5 percent but usually fairly close. Finally, the DROK multifunction shunt meter you used in your second test is actually my most accurate meter (it seems anyway) despite its relatively low cost. I also have a hull effect meter and its accuracy is not great. By the way, the discrepancy in the values of your measurements really isn't much to get excited about in my opinion.
I did get one package delivered of the 320 amp hour batteries from the Samben store and only got 310 capacity. But am just happy the batteries where delivered.
As long as you're happy, that's the main thing.
Hi, I recently found your videos. You are making me a big job, now I have to watch them all from the beginning of video one. I think those both testers actually read quite accurately the same. As you charge and discharge the battery couple of times, the capacity might increase a bit. It is nice to know that those cheap testers can get you at least to the ball park when testing old batteries, are they still good or not. Br, Eeli
Excelent work! I am very happy that you are able to test these cells with differnt equipment. These tests should provide a good base line to compare the average capacity. Thanks again for the great video!
Try pressing the first cell thogeter with some pressure and capacity test it again!😅
I checked yesterday and the new ones seem to be shipping with a sticker that says 272AH now. Same company you used. The sticker also says 3.23 volts and IT is 0.13mOhms. Wish I could show you the picture they sent me.
You have to continue testing because if you find any lower cells than that one your overal battery capacity will be even lower theirfore you will have a greater argument for replacement cells.keep up the good work!
I probably build the full battery first and watch the BMS if it identifies any week cells over time.
A quick measure of each individual IR should be enough for that purpose
thank you for sharing your findings! you are appreciated!
I would test a few more, just to see what the average is. In the end, it doesn't really matter if you are getting 3% less power than speced, when the batteries are 30% cheaper. I'm getting ready to purchase 4 of these cells from your link. Even 200AH batteries for this price is very cheap.
Be aware that PayPal pay only $30.00 dollars to ship it back and it cost several hundreds dollars to send it back to china if you want your money back for these bad quality cells. Cheapest price to send 16 cells 280ah is $2016.00 dollars or $3888.00
I paid $3465.60 for brand new class A which weren't new or class A. It is a scam. If you buy a 12 eggs box because it has 30% off and when you open it has only six eggs Do you say that is fine because it has 30% discount?
@DIY Projects Sorry for the cheap math, more like 50% cheaper. I was quoted $473 for 4 cells delivered, $118 each USD.
I have 8 of these coming and I will test each one, but that is just me. I would be okay with the 271AH but I would much prefer 280AH+... Thanks for your videos and tests! I would love to see how you hook them up to your charge controller and your load.
Thanks Peter. These videos will come soon...
Decisions, 🤔Decisions, Thanks Again, I enjoy your in depth troubleshooting information, we are all learning about this new technology, Keep up the Good Work!👏
I personally like what you're doing based on your recommendation I order set to 4 cells and I can wait to see that box in front of my door so I can do the test on my battery anyway you doing a great job and I thank you for sharing your test keep going God bless
hi, you should to measure the accuracy of your capacity testers (both may a bit off).. also always measure each capacity of your cells because the less capacity cell (the worst one) become the max capacity of the pack in a serial configuration.. in parallel+serial, me, i match the worst one with the better one (and so on) in my pack and that give a better equalized capacity of cells.. in my case i have around +10% to -10% of the average and if i was putted 2 cells at -10% in parallel, my total capacity was dropped to -20%.. love your car bulbs load which don’t do noise.. happy to see your experiments!!
Build the battery, do some full cycles and after the last low voltage cut off of the bms pick the cells with the lowest and with the highest voltage and do all the tests.
Yes, that's what I'm going to do now. Easiest and fastest way. Thanks.
Honestly, I think you should connect the cells together and use a BMS. Then run your test on the pack. When the BMS cuts the output, measure the cell voltages.
I am not sure you should expect the same result every time you test a cell. There are too many variables and unknowns. The cells are like living things.
I just ordered 8 of those cells I have the newer model all in one test I think just a different heatsink on it but I am planning to test every cell of mine
Then I will try to match each parallel set for capacity I have a 12v system
0:39 shows it was pulling almost 1A so it may not have been fully charged. Also please replace the battery in your voltmeter. drives me nuts to see that flashing icon indicating a low battery. :)
The amount that it might possibly have been undercharged would be absolutely minuscule. You might gain perhaps something like one extra Ah.
Actually, he has already significantly OVERCHARGED the cell at that point. Lifepo4 has a typical charge termination current of 5%, and 5% of 280ah is 14 amps. Hes just wasting time and slowly killing the battery, unfortunately.:-(
@@blackz06 could you explain what charge termination of 5% means? How is it determined? How is it applied?
@@ArthurDentZaphodBeeb 5% of cell capacity. Could also sometimes be written as C/20. If you have a 100ah cell, you would terminate the charge when the current falls to 5 amps. For these huge 280ah cells, you would stop at 14 amps.
The deviation between all the cells is just as important as the absolute capacity. To check both just charge all cells (once) in parallel to 3.65v, link all cells in series, then discharge (once) until the lowest cell is 2.50v.
The voltage of the remaining cells and your previous tests will indicate the capacities remaining.
It looks like the shunt meter is only good for rough monitoring. Thanks for testing them out! 😇🙏
A lot of "280ah" batteries are now selling as 272ah... which is what you got. So likely that your cell is 272ah battery (esp with loss over wires from battery to tester)
That is the Truth, I contacted Alibaba fist and two representative's kept saying 272ah and 280ah know difference, I said, well I want 280ah and again they said, "Know Real Difference, Same Battery."
Depends where you buy them on Alibaba. There are 272Ah and 280Ah cells available.
The place I'm talking to is also trying to sell me $272 amp hour batteries
280 ah under ideal temperature conditions. Those units with shunts must be calibrated, I've yet to find one that was in specs.
If I had to guess, I would say that these are grade B cells. Cells that didn't make the 280 Ah cut. I bought the same 280 Ah EVE cells but they were considerably more expensive because they were guaranteed matched grade A cells with a measured capacity from 289 to 290 Ah.
Thank you for sharing and have a great 2021 with more nice videos!
I would suggest that you test an other from the Carlotta 8 batch - if it shows a similar range (265-270Ah), then test one from the other batches - then you can figure if it's a "batch problem"...
Hi Andy, hope you can answer, I need a inexpensive tester, the shunt looks ok for use as a comparator for 8 battery's , buts what are the specs for buying one and what load did you use or what is suitable. many thanks Gary
does the 1 hour recovery period include a temperature spec? I'd throw that bad boy in with the Spatz to be calibrated properly... ;-)
Thank you for sharing your tests. Greetings from Bavaria Germany
12 hours at 22 Amp/h is amazing for me, that's means around of 12 Amp/h at 220 volts in my country Spain good job, congratulations.
May the force be with you. SMILEY FACE
I would like to see a capacity test of all 4 batteries individually along with your opinion on how they will work together based on the results.
If I understand correctly, battery packs work best when the batteries are closely matched in capacity and internal resistance.
What's your home insurance policy? Did you notify them of DIY system? If a panel or battery fires up accidentally are u covered?
I agree the internal resistance increases with the higher current draw causing the difference in Ahr. The problem is the fact that the battery gets warm to touch proves nothing. The heat created at 1C is occurring over 1 hour whereas at .2C its occurring over 5 hours. Of course the battery gets warmer dissipating even the same amount of energy 5 times faster.
To prove it you would need to take a calorimeter approach something like immerse battery as possible in well insulated liquid filled container and measure the rise in temp of liquid etc and account for heat loss of insulation etc. Was too complicated and too much trouble for the return so I am not suggesting you do it. Also it depends highly on the ambient temperature you do the capacity test at. Cooler temp may actually make a higher C more efficient to a degree (no pun intended) if the heat at higher C warms the battery to a more efficient temperature rather than raising it to a too warm temperature.
What was the ambient temperature during testing?
Your handheld meter showed 2.50 volts when the amp hour device showed 2.48. The device is reading at 99.2% of what your hand held volt meter indicates. 99.2% of 280 amp hours is 277. If the device current reading is also off by 0.8% because of an error in measurement, then your results are effectively 280 amp hours. if you want a reasonable estimate of all of the batteries behavior you need to test five more batteries, find the average reading and the standard deviation and then you can estimate what the rest of the batteries would do. But I think you should just put together the 48 volt battery and see if it meets your expectations.
The voltage is not important when measuring Ah (it's A * h). Only when measuring Wh, you need accurate voltage.
@@OffGridGarageAustralia I should have just said that results are close enough,. Instead of trying to make the case for them being within the error of measurement without making a good case. I will wait and see what you decide, but hope we get to see a 14+ kWh battery. I suppose you would want to capacity test the finished product so you will know what 1 C is.
Hello.
To measure the ampères, you measure the tiny voltage drop in the shunt, it's written on the side of the shunt.
Cheers.
As far as I know only the catl cells are 280 ah. Those from the ohter manufacturers are slighly below.
What are the capacity tolerances in datasheet? If it is too warm battery will perform less optimally and degrade faster.
Could check the battery serial number. They could have been sitting for a while I wear houses and who knows at what pemperature.
Hello, I think it depends on the tester. I have a better tester that measures the voltage with a seperate cable on the battery direct to caculate right. Your tester does not measure (calculate) the Wh that get lost over the cable.
I've done the test with such a tester just before this video. The voltage is not critical when measuring Ah. If you want Wh, yes, I use the tester where it probes directly at the terminals. It's about 7mV drop on each of these cables including connections.
Hello.
Why don't you put much thicker cable, with good connectors, mirror polished contact surfaces fully covering the battery posts? Sure the wires you use are thick enough for 20 Ampères, from certain points of views, I mean security, cost efficiency, but if we want the best results, if the battery post is 12 mm diameter, should the cable not be 12 mm also? well if the battery post is aluminium and the cable copper, the copper could be about 1.6 time thinner in surface, 70 square mm instead of 113 square mm. Or 9.5 mm diameter.
Also to spare the threads in the aluminium posts, I use studs intead of screws. I wish to find alu studs, for now the best I found are brass, I saw somewere that stainless steel will eat aluminium in certain conditions.
Cheers.
@@OffGridGarageAustralia Yes that‘s right. Maybe the Tester measures the Amps just a little inacurate. By testing this long time a inacurency from 0,05 A can make the difference. Can you do a calibration to the tester with a good quality measure equipment? Soryy for my english, I‘m german (you too?)
@@michaelb.1192 Your English is good but we could do German too (guck mal auf meinem deutschen Kanal 'Living Down Under').
The tester cannot be calibrated, bit I compared the current with my multimeters and it is accurate. The voltage is off though...
Which tester do you recommend Andy?
8:41 I have been following your videos, I want to clarify something. I don't think measured Amp Hrs matter even if there are loses on the cables, so the voltage sense won't be of much help. The current sensor should measure the entire current passing through the system, so AH doesn't need an accurate voltage sensor. The WH will matter but AH, I don't think. Please correct me if I'm wrong. Thanks.
+1 We are measuring Ah of the batteries.
Which is discharge hours ratings of this battery?
10hours?
Maybe somebody else said this but doesn't the graph show that you get less total WATTS (power) if you're sinking close to 1C? Or am I wrong? It seems like you get less volts even though you get about the same amount of amps. So watts being the combination of the two it comes out a little lower..?
The batteries have internal resistance and the BMS and other circuits use some power.
I did not see a reference or inclusion of these parameters.
(Sorry, I commented before the end of the vid)
But new LiFePO4 batteries should exceed the AH rating.
96% efficiency is not bad.
The question is are these new or used?
I think the spec sheet says they aren't very efficient. Because if the high IR. I'll stick to the "old fashioned" LiPo flat packs. 98% approx for my solar backup. 24 volt system. The only plus I see for LiFe is 4 cells make a good 12v battery and the cycle life is real high. I'd close the book on this.
Hast du bei der elektronischen Last mal geschaut, ob die Ampereanzeige auch genau geht? Nicht dass die Ampereanzeige ein wenig ungenau geht und somit deine Ergenisse nicht stimmen? Vielleicht auch mal ein normales Multimeter dazu in Reihe schalten mit 10A z.b. mal belasten und testen was die Anzeige macht.
I would stop stressing over it and just be happy that a great price for that capacity. Within 5% each one will test a little differently not sure it's something to worry about. Bummer that they rated it so close to the actual I like when they rate the battery lower than the actual makes me feel like I got a better battery.
Yes, you're right 👍
To honest with you, I'd balance the batteries and charge them.
Checking the other 14 batteries would take nearly a month.
I think you should do a "real scenario" test where all the batteries are used together to provide power to a realistic load current/power request. Like you mention discharge rate and temperature are key factors on battery performance.
I bought 8 280Ah cells from aliexpress. The worst one tested at 280Ah. The others tested from 283 to 287. I would want to make sure the test load is truly accurate before making conclusions. I'm using an EBD-A20H to test my cells.
Thanks for sharing and your comment. I think the cells are fine and will put the battery together now and see how it performs.
Hi Mike could you link your cells from AliExpress looking to get Grade A new cells and don't want to get ripped off from shaddy sellers.
@@liv04soccer apparently I can't post a link here. My cells are branded VariCore
@@Mike_Neukam Hi sorry to bug you can you copy the link in and just delete the com from it ? And how much did you pay per cell of you don't mind me asking ?
Nice vid good info and view points. I would random test 25% of each delivery. If you see deviations test more from that batch. Find a bigger tester to discharge 0.5 c wil safe you alot of time. A nice inverter to make use of f the power instead of turning the power to useles heat ;-)
Hy Andy, i whish you and your family a happy new year walter
You should test that battery the same way you tested the first. Do not wait for the hour and then you can compare the results.
Another great video. How long did it take you to charge up that battery back up again using your small power supply?
Does the description say anything like +/-3%?? I would expect 280-285ah from a battery rated at 280ah, the other tester with the lights, the current drops with voltage, the constant current load is constant, it can change the results, I used a buck converter with load, to test, it actually pulls more current with lowering voltage, I would test them all to atleast 3.2v and compare, if they are close use them, you could always add a 5-6 ah cell to the lower cells to make them equal, but I would tell the manufacturer about the test!
what kind of bms are you using?
Batteries don't hold the same capacity every cycle either. Some batteries increase capacity over the first few cycles and then decline. Temperature is important with capacity testing. A hot battery can give over 100% capacity. And cold will lose 10s of %.
Honestly these batteries should have their minimum rated capacity listed, not the max to be expected, so if it's under it's reasonable to expect more, and I'd ask them about it, certainly.
In your setup I can't think of anything wrong that would make that big a difference, small wire size might, but it'd get noticibly warm. The low voltage reading on the meter would make a difference, but you've tried it with the other capacity meter and got a similar result.
Are these batteries good for car audio?.
My 100ah cells specs say maximum low discharge is 2.3v?
Different cell, different chemistry inside. If it says this in the specs, you can discharge down to 2.3V safely.
Ich habe nicht alle deine Videos komplett gesehen - vielleicht hast du ja eine Genauigkeitsprüfung gemacht. Bei solchen Tests überprüfe ich zunächst die Ah-Meter mit einem genauen Multimeter. Mein Multimeter hat eine angegebene Genauigkeit im 10A DC-Bereich von +/-(0,2%+2). Bei höheren Strömen verwende ich einen Shunt Kl.0,5 oder besser und messe den Spannungsabfall mit dem obigen Multimeter, das im mV-DC-Bereich mit +/-(0,1%+1) angegeben ist. Dein UT 210D ist mit +/-(2,0%+3) angegeben. Die Genauigkeits-Angaben von der 180W Last sind unglaubwürdig oder es ist die Auflösung gemeint. Bei einigen Prozent Ungenauigkeit in der Messung sind dann schnell die Ah-Ergebnisse unbefriedigend. Zum Beispiel: 280Ah -3% = 272Ah
I've done these tests on 16 cells I've gotten, and 2 are around 15-20ah short; the rest are all within 4ah of target or hit target. My Customer Service person doesn't seem very interested in helping tho :/
That's not good. I would make videos about this and sent them the link everytime hundreds of people watched it too. Keep pushing!
I'd say test one more from that same lot
It will drive you crazy if you worry about it to much I have purchased 4 sets of cells in the last year and a half, only the 16, 150ah from BLS on aliexpress made full capacity. The 90ah and 100 ah where both 3 to 7 % less then rated but the cost was a lot less/ah. Been using everyday off grid and they have been performing well. Just my two cents.
Yeah... Do another one 🙂 💡💡💡💡💡💡💡💡💡
The capacity of a battery must be measured in wh not in Ah. 280Ah x 3.2v nominal should give us 896Wh. Check more on the whs the battery is capable of providing. 846Wh = 264Ah. 0,09v x 22,2A x 12h = 24Wh. 846Wh + 24Wh = 870 Wh. 870 / 3.2v = 272 Ah 🤔
👍 Saludos desde España.
Take 280AH Gross. Subtract 10% for 5% top & bottom margin, gives you 252AH.
Remember that between 3.450 to 3.650 is a Steep Curve up (minimal AH) and below 3.00V is a cliff fall . This is ALL LFP cells.
$80 for a 280AH cell or call it 250AH is still an outstanding deal when you crunch the numbers . Now go out and get a price quotation for properly Matched & Binned LFP cells (be seated before you see the numbers).
What is more important is, are they consistent throughout their operational range of 3.450-3.000. Do you have any Runners which will reach HVD before other cells or Lazies which will hit LVD before the others ? THOSE two types of problematic cells are that limit's the battery assembly capacity/functionality. Impedance & Resistance are player factors in this, one conveniently gets forgotten in discussions.
I haven't studied the spec sheets. Do they specify a range (e.g. "280Ah +1%/-5%" or something like that)? Were the cells they shipped to you matched by batch?
Also, you have loss in the leads between battery and tester. How much?
On the Video "3rd Capacity Test with expected result....... Where did you Ge the tester you used to check the load , Ah ,Voltage Tester I would like to get the same Tester you Have described in the video. m just a Novice...Please send me info Thankyou
From CANADA. BTW I subcribed and Your Very Very good in your Videos. Thanks AGAIN
Hey, thanks, have a look at the description under the video or here on my website: off-grid-garage.com/measurement-tools-and-analisers/
“Does get a lot less exciting after three times” LOL :-)
Ha! NOW test every cell Andy!
If the tester’s voltage is slightly out- which your separate clamp/ volt meter confirms, then the Ah figure is also incorrect. There may well be enough difference to get to 280Ah.
At the end of the day though, the sad fact is that you have basically zero chance of refunds or replacements, except maybe for a totally failed cell. However even that would likely be very difficult, not to mention very expensive, with very slow shipping.
Maybe you’ll just have to live with what you have and not lose sleep over it.
My five year old Winston cells have never been very accurately capacity tested, but do continue to perform very well indeed. They could be slightly over OR under capacity and I wouldn’t really know, (or even care very much).
Cheers
No, Dave. The voltage is not taken into account when measuring the Ah. It's the amperes over time, A*h. The voltage is totally irrelevant. And current is absolutely accurate as I have shown in the last two tests. So Ah should be good.
@@OffGridGarageAustralia Of course, didn’t think that one through did I - was thinking watt hours not amp hours, stupid me 😂
Although they seem they don't perform as expected, there are some differences in voltage on the capacity tester and the multimeter. Isn't that a difference big enough to generate the deviation you are getting?
I have recently seen some of these 280 ah cells, appear as 272 ah on Aliexpress. They look exactly the same...
Nevertheless, until you get an accurate tester, you will never be sure. For that amount invested in cells I would definitely step it up with a beefier, and better tester.
Nevertheless, I would charge them all, get them running with a BMS, and monitor wich ones are at lowest voltage. I would say that the readings you are getting are still pretty good 271 ah. I would worry if they were much lower than that. It all comes down to the price per usable KW/h. After a few cycles it may settle a bit. Still a great value for money, and dealing with chinese companies is not easy.
A man with one watch, always knows the time... A man with two watches is never sure... (Two testers)...
Great, great content Andy. Love your channel. Keep up the good work.
The voltage is not relevant when measuring Ah. It measures the current over time. The voltage is included in the Energy (Wh) though.
Yes, you're right. I have to setup the full system first and go from there to identify weak cells. Otherwise, too many watches... ;)
@@OffGridGarageAustralia thanks for coming back at me. I am learning a lot with your videos. I am learning all I can, so can set up my own system later next year. Thank you again from Madrid Spain.
For a 0.1C discharge, you're not drawing enough current (at least as indicated). Before you complain about cell capacity, you need to test EVERY cell in the same manner and do it with test equipment of KNOWN accuracy. Would you use a $10 Harbor Freight digital multimeter to do this testing? Some of those have a calibration pot for the voltmeter section and those can be set for decent accuracy over a small range but they're don't compare to a Fluke for accuracy when purchased.
What is the RATED accuracy of each test instrument you are using?
I know from experience that the EPSolar/EPEver solar charge controllers have more accurate metering than the MakeSkyBlue charge controllers and the inexpensive (and some not-so-inexpensive) voltmeters and ammeters from China can be all over the place. How accurate is the A measurement (in %) and the H measurement (in %) of all-in-one device you are using? Does it measure 20.000 amps accurately or does it show 20.1xx or 19.9xx? Does it measure 12 hours exactly or is it off by a few minutes one way or the other? First you test the test equipment, then you test the battery if you want high accuracy.
Voltage measuring I can do accurately by using an AD584L voltage reference (factory trimmed to +/- 0.005volt on the 10.0 volt output, which is better than 1%, and similar accuracy on the 2.5 and 5.0 volt outputs which are useful to this discussion and the calbration chart with the device will have 4 or 5 digits of precision) to calibrate the voltmeter(s) being used. How accurate is your voltmeter at 2.5 and 3.65 volts? Having your meter off by 0.1 volt (0.4% at 2.5 volts) could make a major difference in the apparent battery capacity. Charging to 3.55v and discharging to 2.4v is not the specified range of the cell. Current measurements need to be equally accurate for AH.
On the other hand, what is the battery manufacturer's RATED capacity accuracy? Almost everything has some type of specification accuracy (vehicle speedometers in the US are to be -0 to +7%. It's OK if it reads high but not low).
I use an AH meter to monitor the discharge and charge of my AGM battery bank. In this case, I know what the voltages are at rest and under load for various states of charge and I can use that and the AH in/out to determine the safe discharge level and the fully recharged state of the battery bank. Whatever the discharge AH may be, the correct charge AH is (discharge AH + 10%). I got 9 years from the previous bank, replacing it when half the batteries dropped below 80% of original capacity.
I generally consider +/-5% a good battery in early all-in-one testing unless the manufacturer specifies tighter tolerances, which will require that I use better test equipment.
after yesterday, i thought you were done with testing ;)
You are using the electronic load out of it's specs. Max current should be 20 A, this is why the current is flipping around and may give a wrong sum. Set it to 19A, this should be constant 'till the battery is empty. The R of the battery is also wrong, because the battery can deliver way more current, than the load can handle. It simply cannot measure the resistance with only 20A.
A great idea for a vid? Show us how to drive that discharger. It's UI is bloody awful!
Instead of 280 but you forgot all the energy losses in cables and the electronic devices. I think the 280 are here...
Cable losses after not relevant if you measure Ah.
@@OffGridGarageAustralia it is true but still some losses in the electronic and still some mesurement errors. And 271 for 280 annunced (3% less than annunced), for a Chinese product that cost 1/3 of non chinese products, it is quite a performance lol. I bought 310 Mah batteries that I am waiting for. If I get 300 I will be happy. A lot of testers found that their 280 Ah chinese batteries deliver about 280 Ah. In general these chinese batteries are a very good deal (75% less expensive for 3% capacity less in the worst case)... if these batteries last 10 to 15 years (the only question is : how long will they really last) ?
They are advertised as 280, but in reality many are 272ah, it's well know.
Well known?
@@OffGridGarageAustralia yep I saw that in different forums... many are actually 272ah batteries, but seeing the comments someone managed to get above 270ah out of their batteries, so there may be genuine 280ah out there.
All in all for the cost of them it's not bad at all, mine are on their way here, I paid USD $824 shipped and tax included, not bad for 8 units
Testing each battery means another 14 videos... :)
Capacity is dependant on the discharge current. At, say, 50 Amps, You will get much less. At 5 Amps, You may get a lot more than 280 Ah.
This test is performed as CC, the previous test was not. Light bulbs as load is not an accurate way of rating a battery. Now, try this, recharge and do this test once more with this tester, same Amperage, and You may get a couple more Ah.
I believe that you are thinking of lead acid.The lifepo4 chemistry is not so load dependent if you don't exceed 1C in this case 280Ah.
FYI I recently ordered 16 cells from Shenzen Basen on Alibaba and they told me they are out of stock of the 280ah EVE cells and shipped me 272ah Lishen cells without asking me first. Take that for what you will. There was an ~$80 refund issued.
Wow. I just ordered 8 of these cells yesterday. Still waiting for the shipping confirmation. Let's see what they come up with
You should get proper electronic load to do this tests. The cheap Chinese or DIY measurement tools have so much error you can not trust anything you get for the resolution you are trying to measure.
Okay the cells did not reach 280ah,,i have these cells,, im happy coz they dont cost so much,, even if i only get 200ah i will be happy
Buy 15 more if these testers and discharge them at the same time!
Noooooooo 😄
Die Chinesen haben den Etikettenschwindel perfektioniert. Ist ja schön weit weg. Nach 5 Wochen habe ich Batterien und BMS gekriegt und siehe da BMS defekt. Also anderes bestellen und noch mal 5 Wochen warten. Capazitätstester ist gar nicht erst gekommen.
I`m frustated!!!
Schade! Bisher habe ich gute Erfahrungen mit Bestellungen direkt in China gemacht.
Maybe you need their own tester to get 280ah haha
You're slowly killing your cells if you are charging them to 3.6v with a termination current of 1 amp. Lifepo4 has a typical charge termination current of 5%, and 5% of 280ah is 14 amps. If your charger charges at less than 14 amps, you need to stop charging it AS SOON as it reaches 3.6-3.65v. You're just wasting time and slowly killing the battery, unfortunately, by letting the current fall off. :-(
Never heard or read of this before that cells will die if you slow charge or absorb them.
@@OffGridGarageAustralia the longer they stay at 3.65v, the shorter the lifespan. Its no secret lithium cells dont like that. It's why we dont store them fully charged. I'm not sure what the output of your charger is, but a lower end-voltage termination is definitely recommended. If you care about the longevity of the cells
Second!
nitpicky? or are you overreaching for content?
It's just a usual chinese Ah worth less than usual average SI Ah, or simply they lied. Not to mention it should bee more than advertised like +5-10 Ah than less and this is at 0.1C discharge how bad it can be at 1C ... I guess half the advertised. At least not marketed as 9999 Ah
So Nice 💘💘💘💘💘💘
Test all. Show the world that these cells are used or bad quality that don't charge or discharge at same level when in series. It is very disappointing and a scam that aliexpress ebay and PayPal are covering it up and don't want to refund your money.
Any spec less than 10% out is as good as it gets there is no reality it is theoretic spec
You may find specs that say +10% or - 10% and every one of the products sold matches the -10%. That's called marketing. LOL.
Put $18 tester on floor and compress with 300kgf...
Best Comment +1