Comparing Battery Testers on LF280K & LF304 EVE, ZKE EBC-A40L, Heater w/Fan and our Findings

[@CollinBaillie]

So, to capacity test cells, look at the watt hours as tested. Makes sense. Lots of batteries sold with a watt hour rating. Then you use your chosen nominal voltage and divide Wh measured by nominal voltage, giving you the tested Ah. Important take away, you need to know the advertised nominal voltage and watt hour rating to be able to verify if your tested capacity matches the advertised capacity. Thanks for going through it for us. Great video.

[@awengirr]

Thanks for the video. I think you should calibrate the ZKETECH first. It is not calibrated by default from factory. You will get accurate measures.

[@gemrough]

There is no replacement for quality equipment! You can’t compare a harbor freight multimeter to a fluke… although I see “KZbin Gurus” do it all the time! Kudos to you for spending the $ for quality!!

[@CollinBaillie]

I believe the common use of Ah is all about the rating of the battery to safely provide a give current rate to a load, and the safe charging rate is related to that. I agree that Wh is a very common rating to see on a battery/cell. The key rating. Ah seems to be related to charge/discharge rate and nominal voltage to be a ballpark figure to be used in calculating supplied voltage level when designing equipment or applying power to equipment. There's a tolerance in a nominal figure. Equipment usually has a safe operating voltage range, and in that range is the nominal or usual or safe target voltage.

[@rilosvideos877]

How much is your electronic load, the HP8182? I guess its 5000 USD+ - maybe more?

[@JawadAhmadsahibzada]

2:52 coz you taking readings on cells and discharger measuring after adding wires resistance.

[@ForgottenGamesAndMods]

Higher nominal translates into lower value of current at discharge test.

[@jacopo.scarpellini]

how can it overstate the Ah if voltage is underreporting? Ah are A *h, hence not affected by voltage

[@fldutch]

Even if i still do not like the normalisation thing, i might agree. Anyway if you look at the actual measured Wh and compare them to the nominal Wh or to the factory measured normalised Wh that is totally fine in my view. Just do not normalise measured Ah with 3.2v nominal voltage. On the 5 cycles: the EVE datasheets says to reach the specs there are more tries allowed - so that should be fine. Maybe for the chemistry of a cell that stayed between 30-50% SoC for storage some months it needs some activity to reach full specs. Oh and thanks for the preview of that hp8182 software - looks promising. Would have thought there was ready to rumble software coming with it ;). I am curios how those tests will compare to the EBC-40l.

[@CollinBaillie]

Your labels say 3.3v. Might be worth rectifying that, for the uninitiated.

[@sfkenergy]

We will fix this, in our latest version of the label it will say 3.2v

[@calvinflager4457]

You keep calling the load tester a charger. Doesn't inspire much confidence in what you're doing. As well, you only tried one volt meter. Doesn't every know that there may be quite a significance in the readings from different volt meters?

[@adon8672]

Interesting. What I understand from this video as it relates to the results of Ray's test is if at all there is any errors, those errors lie with the cell and the tester and not with him. The challenge here is that he used the same tester and same methods for all his tests. As I suggested in my comments on one of your previous videos, you might want to consider making more conservative claims about your cells. If a cell will yield the stated amp hours only after 5 tests then state that clearly on the cell. The stickers you put on those cells are unusually large and should have enough space for detailed information if written appropriately.

[@sfkenergy]

Mr. Ray always has tested grade B cells whose voltage under load is below 3.2V during the tests so for him work without having to normalize. However, since he had claimed he had tested Luyuan cells before we assumed he had been doing the voltage normalization, if not its not possible to for the Luyuan cells (same as ours) to test a 284 X 3.25v = 923 WH, all LF280K cells settle to around 896-904 WH very quickly, this is by design. So I think he never actually tested Luyuan Grade A cells before which is why our results were so screwed up; honestly if we had known this we would never sent out kit / cells...We tried to explain but got no where... Anyway: THE CHEMISTRY OF The LF280K IS DIFFERENT THAN LF304. The 304 Chemistry follows the label closely, I do not think you can use the same method of grading on this High Cycle life capacity type prismatic cell. Thus AH test is not a good way to determine Grade A or Grade B on the LF280K. Lastly we do not make this data on this label, it is supplied by EVE the manufacturer.

[@fldutch]

@@sfkenergy As i commented in another video: normalizing by 3.2v does not have any effect if you get relative numbers compared to nominal capacity (% of nominal capacity is the same for Ah and normalised Wh). Simple math 🤷🏻.

[@martehoudesheldt5885]

why does the tag say 3.3 volt?? normalize to 3.2v? or normalize to 3.1 ??

[@sfkenergy]

In our next batch the label will say 3.2v on the cell label. This was an error on our part. Please see how to match label capacity to learn more about normalize voltage readings to 3.2

[@matija3791]

I bought 16 cells 280K from an alibaba distributor and three of the 16 cells tested above 920Wh. So you are saying that those are not 280K cells :)?

[@sfkenergy]

That would be quite interesting, please provide us a link to your test data and results. We would also like to know if these were grade A cells (with the manufacturer test report) or grade B cells. Alternatively you can email it, visit our site for our email (posting emails on youtube will get the reply flagged/spam checked).

[@matija3791]

@@sfkenergy tried to post a link, but the comment instantly got deleted...

[@sfkenergy]

@@matija3791 send an email to cs(at)sunfunkits.com

[@DyslexicDancer]

So here’s the thing, the whole “normalizing” thing you are trying to do doesn’t make any sense nor does it make any sense to try and figure out a batteries true capacity by measuring watt hours Watts is a measurement of “Power” and watt hours is a measurement of power produced over time, but in order to calculate watt hours you need to multiply Amp Hours by Voltage, and the voltage on a battery cycle test varies over the time of that test. What does not vary is the current. These tests are preformed using a constant current, so it’s very easy to calculate Amp hours. If your battery is fully charged, and if you pull 40 amps for exactly 8 hours before the battery is empty, you have battery capacity of 320 Amp hours. You can use the measured 320 Amp hours from that test to find out how much “power” your battery delivered by multiplying the Amp Hours by the nominal voltage of 3.2V (for LiFePO4) but the measurement you get in Watt hours by preforming this multiplication will only be a close estimate to the actual amount of “power” (as calculated in watt hours) produced because the voltage of the battery will have varied over time. It a very close estimate, but the nominal voltage of batteries using the same chemistry will always vary a little due to many things including impurities in the cathode/anode and density of the electrolyte in the cell. It may only be a small difference , but it’s a difference nonetheless I understand the desire to try and measure the capacity of a battery in watt hours because it’s an easier concept to understand for most people, but a watt hours calculation is not the “Capacity” of the battery, it’s the calculated “Power” that the battery produced over a given time by multiplying Amp Hours and nominal voltage. The “Capacity” of the battery is measured in Amp Hours. This is why every single battery manufacturer does their capacity tests in Amp Hours, one only need look at the battery datasheets to see the testing methods and battery specifications, you will not find watt hours listed under battery capacity in any of the EVE datasheets, rather you will find Amp Hours listed both in the specification and testing portions of the datasheet

[@sfkenergy]

Please look at your actual cell you will see a WH rating not Amp Hour its on the QR code. Amp Hour without voltage is meaningless. Looks like it will take a few years to clear up this Mess because 1 youtuber decided AH ignoring voltage is the way to measure batteries and everyone else has just hopped on board. Next time you look at cars, laptops, even cell phones they will always be rated in WH not in AH.

[@DyslexicDancer]

@@sfkenergy this has nothing to do with any youtuber, I honestly don't even know who you're referring to. Can I ask you a serious question, why are you so opposed to measuring a cell's capacity in Amp Hours? Using Amp hours is literally the industry standard for capacity measurements of any battery cell, doesn't matter if it's a LiFePO4 battery or a Trojan T105 Lead Acid battery, capacity is always measured in Amp hours, You can't directly measure the watt hours of a battery, because watt hours isn't actually a measurement, it's a calculation of power that is derived from the Amp hours (which you can directly measure) and the Voltage, (Which you can also directly measure) Resistance is another property that can be directly measured, but no need to go there for this conversation. Please do me a favor, because I can't post a link here, go to EVE's website and download the datasheet for the LF280K it lists the Nominal Capacity as "280.0 Ah" nowhere in the datasheet does it mention Watt Hours, then look at the testing conditions, again, it does not mention Watt Hours anywhere all it's lists are Amp hours. Then do the same thing for CATL, download the datasheet for their 302 AH cell and look at how the cell capacity is measured, again it's in Amp Hours You mentioned the QR code on the batteries, download the "LiFePoQR battery QR Scanner" from the app store, scan a QR code on one of your battery cells, and report back how the capacity is listed from decoding the QR code......spoiler alert........ it's in Amp Hours Cars, laptops, and cellphones all have battery cell capacities listed in Amp Hours, they may additionally list watt hours so that it's easier for most consumers to understand the total power they can expect from the battery, but the battery cells themselves are indeed measured in Amp Hours for their cell capacity, look at any 18650, 2170, CR123, doesn't really matter, all have capacities list in mAh, which is to say their capacity is measured in Amp Hours. let's take a look at Tesla, While they list the KW/h of the entire battery pack, that's just to avoid confusion for a general public who has no idea what the pack voltage is, so using KW/H is just easier for them to list so consumers can compare the total power available of the battery pack, again watt hours are a measurement of Power, not capacity. If you look at the individual battery cells that make up the Tesla battery pack you'll find that Tesla lists capacity of the individual cells in Amp Hours . For Example that their newer 4680-type battery cell. Tesla lists the estimated total capacity as 26.136 Ah, and they list the total estimated energy as at 96-99 Wh I guess I don't understand your reluctance to measure capacity in amp hours, but hey, it's your channel and this is a free country, so keep doing things your way, just don't be surprised when you get pushback on your idea that watt hours is somehow a measurable quality of a battery cell, because it's simply a calculation of power derived from the cell capacity as measured in AH and the nominal voltage of the battery

[@sfkenergy]

@@DyslexicDancer I see you are quite dedicated to your Beliefs,. but the industry standard has always been watt hours: Watt hours = amp hours x nominal voltage. If you are going to use amp-hours you must also include the nominal voltage. OR you must normalize the amp-hours to the nominal voltage of the chemistry you are referring to. Please see this video: kzbin.info/www/bejne/aaXRl4SVfd99ps0 in regards to the scanning app, it would seem quite silly to do that when the QR code already states the WH on the cell itself.

[@diconustra]

RE: Watt-hours - when I put a battery into service with real-world loads, I care about the amount of work that I can perform using the batteries capacity. The work performed is measured in units of energy (watt-hours, kilowatt-hours, Joules, BTU, etc.). For a given amount of work (running a 12V refrigerator for a given amount of time, for example) I will consume a given amount of energy. The energy I need cannot be measure in Ah, simply because the Ah I use will be dependent on the voltage at the instant that the current is drawn from the battery - as the voltage drops, the currents draw in amps will rise, but power measured in appropriate units of energy will remain constant. Ah would only be useful if voltage were constant - which of course it is not. Even though Ah are commonly used to express battery capacity, the unit that matters is watt-hours, simply because that's the unit that actually measures the amount of energy that I will be able to draw from the battery before it goes dead. Unfortunately it's common practice to use Ah instead and strange constructs such as 'nominal voltage' to market batteries. There is a reason my electric company charges me by the kWh, not by the Ah. If they billed me by Ah I'd be contacting the Utility Regulators and complaining. :)

[@DyslexicDancer]

@@diconustra I have no issue with anything you are saying. Knowing the calculated Watt Hours of a battery is a useful bit of information to have. My point is that you cannot directly measure the capacity of a battery in watt hours and attempting to "normalize" the Amp Hour rating of the battery makes no sense. To calculate the Watt Hours of a battery you have to first measure the capacity of the battery in Amp Hours and then multiply the AH by the nominal voltage of the cell. You can't directly measure the Watt Hours of a battery because it is a calculation of power derived from Amp Hours and Voltage.

[@typxxilps]

I do not know what you are doing but the key figure is missing: the ambient temperature EVE has mentioned in their spec sheet 25°C and the EVE LF280K shows the graphs and impact of temperature on the capacity you can get out of it. 10°C less would result in 4% capacity missing - rule of thumb in the range from 25 to 10°C below the 10°C that will increase to 9% loss. 4% means roughly 11 Ah missing due to too low ambient temperature This is based on the assumption that the missing graphs for 25° and 45°C (you can see them in the legend but not the graph) are overlaying the 35°C curve and therefore have been eleminated by EVE cause they usually are damn close to each other from 25 to 45°C. I wonder how long all these youtube channels will show the capacity tests without mentioning the ambient temperature of the cells and how long they had been stored there cause it does not make sense to bring a cell out from the cold into the warm test room just before the test starts. Yes, they do heat up a bit during charging period but it is a different thing , a total different thing all should now from their EV usage. EV The battery heats up during use but the range will not come back cause it heats up slowly and not totally. As long this will not happen you can not judge any battery regarding capacity and also it needs a proof when and how the device has been calibrated last time cause in case of changing temperatures this can also have an impact as we have seen before with this particular ZKE EBC-A40L tester at least those from 2021 and 2022.

[@sfkenergy]

Ok from now on we will include the temperature but it is RTP during our tests.

[@Kolin4556]

You're not testing correctly. First of all, measure the stability of the current consumed by the load. All Zketeech loads have very high thermal current instability ~ -20%, due to poor circuitry and shunting. Because of this, the battery capacity will be ~ + 10-20%. So a large measured capacitance means nothing. Calibration will not help, it will allow you to adjust the current in cold mode, after operation and warming up the current will drop (or maybe increase) even by 20% and the measured capacity will be very inaccurate. The Atorch DL24 more accurately holds the load current out of the box and the measured capacitance is more accurate.

[@jbuszkie]

I'm not buying this normalization thing. Ah are Ah... if a battery is rated for 280Ah.. It should provide 280Ah. Now Wh may have some fudge factor in. To get the true Wh.. You have to integrate across the whole test. Folks just use 3.2V for LFP because that's the average V across it's range. These batteries are, correct me if I'm wrong, sold by their Ah rating not the Wh rating. So there is no normalization that should happen... Your own test showed 276Ah!

[@sfkenergy]

Batteries are always rated in WH. Please look at any Electric car like a Tesla, or Ford they will always state the size of the battery in WH never in AH. You can not have a result that matches the WH but also fails the AH. They must both pass or both fail, which is why nominal voltage is important. Our tests showed 276 AH x 3.25V = 896 WH which is exactly what is on the Cell it self if you look at the QR code on your cell you see it is rated in WH. You can display the result as 280 x 3.2 = 896 WH which is the nominal voltage of LFP batteries.

[@jbuszkie]

@@sfkenergy This is not an EV tesla battery.. These are individual cells. hell 280 is in the name! All these individual cells are rated in Ah. Your own website list your complete batteries as Ah, not Wh... Everyone else that tests these are benchmarking them against they Ah... Not Wh..

[@sfkenergy]

@@jbuszkie Unfortunately you have been brainwashed by reviewers who keep looking at the AH without the voltage. You can look at Laptop Batteries, you will see they are rated in Watt Hours. Please do some research on this subject. Amp hours without voltage is meaningless, if you are using it causally then its fine, but if you are wanting to perform capacity test you must Have amp-hours with nominal voltage.

[@jbuszkie]

And the car makers have to do this because most of the public doesn't understand Ah. And How many car owners know what the voltage of their battery is? The general public understands Wh and kWh.. If the car folks said in Ah, they wouldn't be able to compare one car from the other.. It's Wh that are probably normalized..

[@jbuszkie]

@@sfkenergy Again these are packs. They voltage is varied from laptop pack to laptop pack. So they have to rate in Wh. People building these packs buy their cells based on Ah. How are all these 18650's sold? By Wh?? no by Ah..

[@PowerPaulAu]

You guys are so inconsistent! You talk about the cells actually being rated at the Wh rating, so stop giving an Ah rating on them. You need to standardise how you discuss this, because all you're doing is confusing everyone and making a mess of the ratings, and making it very difficult for people like Ray to get to the truth. Then you also talk about the LF280K being rated at 3.2v, yet YOUR label says 3.3v... Make up you mind! If you actually provide a 3.2v Ah rating, and quote 3.3v on your label, then it's misleading (AKA a lie). If you rate the cell at 3.3v, then give the 3.3v Ah rating. When you measured the voltage of the electronic load, you measured the voltage at the battery, not at the load... That was a mistake that you have done before (Andy has pointed that out), yet you did it again. Before you go saying others are wrong, you need to get things right yourselves.

[@sfkenergy]

You have valid points, in the future our next batch of labels will state 3.2V. The Tested capacity comes from the manufacturers' test report its not something we create, there capacity is based on 3.2V nominal. Our tests have v-sense on them we also agreed with Andy and fixed this issue. In regards to issues with other tests, if you are looking at AH without nominal voltage the conclusions you would make it from it are incorrect, that particular review did not take this into account.

[@PowerPaulAu]

@@sfkenergy I wasn't referring to any particular review. I'm referring to the massive confusion you create with all the different numbers mentioned. All the things you mention, leave a lot to interpretation and that leads to confusion and likely misunderstandings about capacity results. If you want to rate your cells in Wh, then rate them in Wh. Don't rate them in Ah with ambiguous different nominal voltages like 3.2, 3.25 and 3.3v that don't appear to have any solid foundation. Wh, Ah and nominal Voltage should ALL calculate correctly, and your labels don't seem to do that. Also if you put a label in a battery, the numbers should be from YOUR test results, not the manufacturers results. When I see a battery with a label on it, I expect that data to be produced by the producer of the label, to confirm the manufacturer results. Or just leave the label off and provide the customer with the manufacturer data. Perhaps you should clearly state that the testing is NOT from SFK.