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Anyone know of a capacity tester that will discharge a 52v battery at around 500w?

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    Anyone know of a capacity tester that will discharge a 52v battery at around 500w?

    I'm looking to end the fraudulent eBike battery amp hour listings on ebay, and need an accurate and dependable capacity tester in order to do so. Somewhat obviously I'd like to get one that's reasonably priced if possible.

    So far in my endeavor to put an end to this fraud I've already gotten a free supposed 52v, 20AH (which is actually closer to 15 or 16AH) hailong style battery out of the deal from a Chinese seller via ebay's money back guarantee policy for not-as-described listings, but as nice as that may be, that's not my goal. My goal is to end this rampant fraud altogether, or at least greatly reduce it, as a huge number of people are getting scammed by these sellers.

    Just as a note, this same type of a scam is being conducted with lights and lumen ratings as well. I'll eventually purchase a lumen tester and move on to them next, but for now I want to focus on these battery packs.

    Thanks

    #2
    Same here.
    Received a 48v 20Ah battery that will only come close to that at a discharge rate of 2Amps, which will never occur in actual use on an ebike. It'll be more like 10A - 20A draw.
    The capacity at those draw rates will probably be half that.

    I ordered a 48v inverter to do higher load tests with mine. I'm into solar power so I can use it other ways.

    I do not know of a ready made product to discharge at rates above 10Amps that isn't prohibitively expensive.
    The popular DL24P 180watt dummy load tester will only go to about 140watts which is only 2.6Amps at 48volts.

    A few suggestions I received was using automotive headlamps or the older circular style coil stove top burners as a load and measuring the amp draw and timing the discharge time manually.

    Will decide on returning the battery I received after running some heavier load tests with the inverter and a PZEM-15 shunt battery monitor device.

    Comment


      #3
      There are RC watt-hour/amp-hour meters that can be had very inexpensively however they likely aren't terribly accurate. I've got a batt-man that supports calibrating and have a nice calibrated bench meter that I used to calibrate it so it's good. I use a skillet that pulls about 5A for a load: https://electricbike.com/forum/forum...discharge-load. It is very inexpensive and if I really wanted I could parallel up a couple.

      One big issue is that amp-hour is different depending on the load so ideally you'd want a variable constant-current load too. E.g. the amp-hour will be different for a 0.1C load vs. a 1C load and watt-hours even more so. With a constant-current load you could just time it too, wouldn't need a meter aside from just ensuring the current draw was accurate. Such loads are available commercially but not inexpensive for the voltages and currents we're talking about. I've built them in the past and that's actually pretty easy but you need monster heat sinks.

      Also when they "rate" capacity they're talking the best case cell capacity at the best case load and running it from 100% to flat - something most BMS's won't do... so the usable capacity is going to be less than the actual maximum battery capacity - think of it like a fuel tank that's rated for "C" but since there will always be some unusable fuel you can't get to (call it "U") you'll only have C-U usable fuel. Is the fuel tank manufacturer lying when they say it's C and you can only use C-U? Tell you what, there's not a fuel tank maker that doesn't advertise C. Likewise with batteries... I.e. while the true battery capacity when the battery is new at some ideal load is C, the actual usable amount is C-U and that again is only a a load that is constant and may not reflect real-world use but the manufacturer is always going to advertise C, just like the fuel tank guys do since that's the "true" capacity even if you can't get to it all.


      Regardless, if you want to measure it and get close you can just get the cheap RC meters and run a skillet or some other load and get a good idea. Batt-man will be more accurate which is what I've done. I installed a connector between the harness and motor last time I removed the motor to make motor removal easier so it's pretty trivial for me to hook a load up instead of the motor. I don't have a constant-current load however, just the skillet but it's plenty good for me as far as looking at battery condition and to compare them to one another...

      YMMV

      Comment


        #4
        Originally posted by Steve-- View Post
        I'm looking to end the fraudulent eBike battery amp hour listings on ebay, and need an accurate and dependable capacity tester in order to do so. Somewhat obviously I'd like to get one that's reasonably priced if possible.

        So far in my endeavor to put an end to this fraud I've already gotten a free supposed 52v, 20AH (which is actually closer to 15 or 16AH) hailong style battery out of the deal from a Chinese seller via ebay's money back guarantee policy for not-as-described listings, but as nice as that may be, that's not my goal. My goal is to end this rampant fraud altogether, or at least greatly reduce it, as a huge number of people are getting scammed by these sellers.

        Just as a note, this same type of a scam is being conducted with lights and lumen ratings as well. I'll eventually purchase a lumen tester and move on to them next, but for now I want to focus on these battery packs.

        Thanks
        Just curious.....

        You say you need a way to check the capacity of the battery.....but stated it had only 15 or 16Ah capacity.

        How did you determine the capacity was only 15 or 16Ah ?

        What were the discharge parameters you used to determine that?
        Last edited by MemberOfDistinction; 06-16-2021, 05:23 PM.

        Comment


          #5
          Originally posted by Mike_V
          Well, did you start testing yet or waiting for a precise instrument?
          How about:
          Connect up a 500W+? heat lamp bulb and see when it goes dark ?

          I did my test at 16A because I figured that's closer to the amp draw around mid current on a 750 - 100watt motor. I have a 48v battery pack.

          He should try to go with 700watts on that battery to get to at least 14Amps

          Then again, he hasn't been back so who knows ?

          Comment


            #6
            Originally posted by MemberOfDistinction View Post

            Just curious.....

            You say you need a way to check the capacity of the battery.....but stated it had only 15 or 16Ah capacity.

            How did you determine the capacity was only 15 or 16Ah ?

            What were the discharge parameters you used to determine that?
            The 15-16Ah figure I gave was based off a real-world test I did with it against another 48v battery that I have, which I know is 20 Ah. Coincidentally, at my weight and with my current setup, at about 15mph I get almost EXACTLY 1 mile per amp hour on fairly level ground, with minimal to no wind resistance. I set my display to maintain a constant speed and ran each battery to depletion on the same identical path two times (two times for each battery). My battery that I know is 20Ah's moved me almost 22 miles along that predetermined path both times, and both times the new battery from ebay took me about a little over 16 miles. Since the new battery is 52v, and my original known Ah battery is 48v, the 52v battery should have theoretically taken me slightly farther than the 48v battery due to more total Wh's.

            So there was certainly a little guesswork in the 15-16Ah figure I gave, but that's far outside the margin of error, and absolutely a falsely advertised battery.

            I've now ordered a cc cv cr cp smart capacity tester, with a constant discharge load capability of 400w, and will be testing it against a local ebike shop's professional capacity tester to determine accuracy. I've also ordered 3 more of the supposed 52v, 20Ah batteries from 3 different Chinese sellers on ebay, and I suspect I will be getting them all for free as well, because they're all constructed with 71 x 18650 cells, and at that number of cells it would take the very best cells available on the market to achieve 20Ah with a 52v battery, and at $250 that's just not possible. It would cost well over twice that much just for the loose cells alone, even at an EXTREMELY reduced wholesale bulk discount.

            So... There's not a chance any of these batteries are going to be the advertised 20Ah's, and therefore ebay's money back guarantee policy will be applicable. I'll either get to keep the batteries for free, will get them at a great discount, or the Chinese suppliers will be sending me an additional $100 each to ship them back, and after probably spending close to that to send them over here, I HIGHLY doubt they're going to be doing that, especially when they'll be receiving a returned items in unknown physical and functional condition.

            I've been telling other people to do this as well. I wonder how many of these they'll have to eat before they quit their false advertising?

            And again, the free batteries are only a bonus, and are not my motivation for doing this. Even if they just keep giving me the approx. $100 to send them back and I get nothing out of the deal, I'm going to just keep on buying them and returning them until the deception ends. I may even start ordering 20 - 30 of them at a time.
            Last edited by Steve--; 07-20-2021, 06:45 AM.

            Comment


            • Steve--
              Steve-- commented
              Editing a comment
              Yeah, that's a good point too. I also carry around a lot of extra weight (In addition to the extra weight I carry around on my body :D ). It' a heavy, cheaper full suspension bike to begin with, plus I have two racks on it. One mounted on the front of the bike with a detachable pouch that's stuffed full, and the other a seat post mounted rack with my main battery secured to it, and with one of the larger, wide rectangular milk crates attached sideways to the top of that. And not only is it usually stuffed full crap as well (a great deal of it unnecessary, but since the space is there I tend to utilize it lol), but being sideways it also creates more wind resistance. Plus like you, I also carry a heavy lock, a second battery and a lot of liquid. I also have a handlebar extender with a phone holder and 4 Tesecu 1,300 lumen headlights mounted to it.

              No one thing in itself weighs that much, but cumulatively everything adds up. Plus I might add, I've always been a big gadget guy, so I tend to carry a lot of things on my person as well. This has all got me curious now as to what my typical total weight is. I'll have to weigh the total package, including myself one of these days. But now just guessing, I bet it's an easy 400lbs, maybe even more. That's a hell of a lot of weight really, when considering the relatively small size of the BBSHD and the typical ebike battery. And with that much weight, even just a super slight incline will increase the load on the system tremendously.

            • AZguy
              AZguy commented
              Editing a comment
              Another thing that works against me is that I'm running really aggressive knobby 26x4.8" tires usually at just 10-12psi so rolling resistance is on the higher side of things...

            • Steve--
              Steve-- commented
              Editing a comment
              Yeah, I don't have that problem yet, but I plan on putting that type of tire on mine too, so I soon will. We'll see how much further that reduces my range.

              And just another fyi/update. I just received 2 of the 3 new batteries I ordered. I'm still waiting on the 400w tester to arrive, but in the meantime I might take them each out for a few more real-world comparison tests like I did with the first one. As I mentioned previously though, I know there's no way they'll perform as advertised based on the relationship of cost and current day battery technology... There's just no way.

              Edit: P.S. Plus I already dealt with the first one that didn't measure up, and these ones appear to be identical, each from different vendors, but all from the same manufacturer.
              Last edited by Steve--; 07-21-2021, 03:28 PM.

            #7
            Steve--

            You might want to consider an RC meter that measures amp-hours / watt-hours, etc. and a load like that skillet I referred to

            In my experience the RC meters aren't super accurate or all that durable but it would give you some reasonable numbers at least to compare the different batteries you have if nothing else - an example is this: https://www.amazon.com/dp/B01LVTST80...xpY2s9dHJ1ZQ==

            I have no idea at all about that specific model but I think they're all pretty similar and all around the same price point

            The link to the skillet load is here: https://electricbike.com/forum/forum...discharge-load

            The skillet load may not be the load the batteries are characterized at but it will discharge them in just a few hours so at least useful and again, at least good for comparing the different batteries

            Comment


              #8
              Wouldn't a cycle analyst do the job in real world use? Battery capacity in wh is an average so if you compare that to average watts used then that should give a real world capacity.

              Comment


              • AZguy
                AZguy commented
                Editing a comment
                A cycle-analyst or similar does a pretty good job (I've got a calibrated batt-man - love it) and the RC meters are used similarly by some riders. It's reasonably repeatable when riding but there's definitely a difference when riding really hard vs. really gentle and if you are trying to do a repeatable [more lab-style] measurement it's best to do it in a steady load. Plus it's just plain easier. The OP was looking for a way to get a "true" capacity measurement and while the batt-man/cycle analyst approach will work if you are really trying to get from 100% to very low while riding you are almost certainly going to kiss up against the controller low-voltage cutoff too and how soon you do that will depend a *lot* on how hard you are riding when it's getting low.

                I've got an XT90 between the motor and batt-man/batteries that I put in a long time ago to make it easier to remove the motor and have plugged in the skillet load at that point to measure some of my own batteries using the batt-man.

                I couldn't agree with you more that batt-man/cycle analyst is going to be better than the cheap RC meters, I don't think they are very accurate or at best, hit or miss with some closer than others just due to tolerance issues. However the skillet load is easier (can be done in the shop) and much more repeatable.

                The skillet is far from perfect though. When characterizing batteries they usually use a constant-current (CC) load and I'll bet to get the best numbers, they load them at pretty low currents (~0.1C?). The skillet being essentially a resistor changes how much it's drawing as the battery discharges and the voltage drops so not as good as a CC load and obviously it's not adjustable like most all the CC loads. One of these days I may go buy another $20 skillet so I can hook them up in series or in parallel in addition to just using one so get three levels of discharge. Half skillet (1/4 power), one skillet and 2x skillet (4x power)... or cook breakfast =]

              #9
              Originally posted by AZguy View Post
              Steve--

              You might want to consider an RC meter that measures amp-hours / watt-hours, etc. and a load like that skillet I referred to

              In my experience the RC meters aren't super accurate or all that durable but it would give you some reasonable numbers at least to compare the different batteries you have if nothing else - an example is this: https://www.amazon.com/dp/B01LVTST80...xpY2s9dHJ1ZQ==

              I have no idea at all about that specific model but I think they're all pretty similar and all around the same price point

              The link to the skillet load is here: https://electricbike.com/forum/forum...discharge-load

              The skillet load may not be the load the batteries are characterized at but it will discharge them in just a few hours so at least useful and again, at least good for comparing the different batteries
              I actually just received that capacity tester I ordered. Here is it:

              https://www.aliexpress.com/item/4000...35804c4d4GhqDD

              I'm running a test on one of them right now, and it seems to be doing it's job, although I won't really know for sure until I test it against some type of control, either a known reliable tester, or against another battery that has a trustable AH rating. Like I was saying before though, I'm taking at least one of them to a local ebike shop to have it tested just for that purpose. Assuming that this machine is accurate though, it's not looking good for this battery (As I expeted). It has only racked up 9.4 Ah so far, and it's already down to 44.75v, and it's a 52v battery, so the cut off is at 42v. I have it discharging at 7 amps by the way, just in case you were interested. And just on the fly here as I'm typing, I just noticed it automatically drop the discharge amps to about 2. It must just do that for the last 3v - 4v or so to reduce that temporary voltage dip that occurs when a battery is under load, so as to avoid hitting the cutoff voltage prematurely and ending the test.

              Comment


                #10
                If its a steady load I'm not sure why it would drop near the end. It doesn't seem like there are too many use cases that would act like that so seems like kinda a dumb way to test unless the goal is to come up with numbers that no one would ever get in real use. I would think even in a steady load state the rate would even go up as the voltage drops since lower voltage would mean less work being done so presumably what is regulating things would increase the speed to compensate.

                Comment


                • AZguy
                  AZguy commented
                  Editing a comment
                  It's the standard for how cells/batteries are characterized - it's not real world, but it's how the industry does it and it's highly repeatable (i.e. "scientific")

                  The drop at the end is normal for Li-ion and frankly most cell chemistries

                • AZguy
                  AZguy commented
                  Editing a comment
                  You are talking about constant power mode measuring the batteries energy capacity and while that does a much better job at emulating real-world (except most electric bikes control the battery current, not the power), it's just not how the industry does it - industry goal is to characterize coulomb capacity (amp-hour) vs. energy capacity (watt-hours) and that's done at constant-current. One reason is just like you stated, the current will go up at lower voltages if constant-power load.

                  His meter will do constant power so maybe he'll run some of those tests too with his new toy!

                #11
                Originally posted by Steve-- View Post
                I actually just received that capacity tester I ordered. Here is it:

                https://www.aliexpress.com/item/4000...35804c4d4GhqDD

                I'm running a test on one of them right now, and it seems to be doing it's job, although I won't really know for sure until I test it against some type of control, either a known reliable tester, or against another battery that has a trustable AH rating. Like I was saying before though, I'm taking at least one of them to a local ebike shop to have it tested just for that purpose. Assuming that this machine is accurate though, it's not looking good for this battery (As I expeted). It has only racked up 9.4 Ah so far, and it's already down to 44.75v, and it's a 52v battery, so the cut off is at 42v. I have it discharging at 7 amps by the way, just in case you were interested. And just on the fly here as I'm typing, I just noticed it automatically drop the discharge amps to about 2. It must just do that for the last 3v - 4v or so to reduce that temporary voltage dip that occurs when a battery is under load, so as to avoid hitting the cutoff voltage prematurely and ending the test.
                Nice! Proper tool for the job although it might be nice to compare it with a well-calibrated meter... beats the skillet by a long way except it won't cook - it'll heat the room tho =]

                I'm guessing that they characterize these at lower currents than what you are pulling - maybe 0.1C? E.g. if your battery is 14Ah use a 1.4A constant-current load for a 10hr discharge target. 42V is reasonable for 52V but when they characterize the cells they do take them down further than 3V/cell - not that it's a good idea and doubt you would even see 10% more past that anyway. If your battery is 14Ah, then 7A is 0.5C.

                I'd be really interested in the difference in Ah capacity at different discharge rates. Maybe 0.05C, 0.1C, 0.2C, 0.5C, 1C, 2C... 1C would push the limits of that load for a >14Ah though...

                Comment


                  #12
                  Originally posted by 73Eldo View Post
                  If its a steady load I'm not sure why it would drop near the end. It doesn't seem like there are too many use cases that would act like that so seems like kinda a dumb way to test unless the goal is to come up with numbers that no one would ever get in real use. I would think even in a steady load state the rate would even go up as the voltage drops since lower voltage would mean less work being done so presumably what is regulating things would increase the speed to compensate.
                  Because That's how all li-ion batteries are rated. I'm trying to test the validity/accuracy of the advertised Ah rating of the batteries I purchased, and for me to test them according to a different standard, and/or by a different method would be useless for what I'm trying to accomplish. Li-ion batteries are rated in Ah, therefore it requires a CC (Constant Current) discharge test to determine that.

                  The unit I bought is also capable of doing a CP (Constant Power) discharge test as well, and I will probably eventually do that too for my own curiosity, but that's not the proper test for what I'm trying to accomplish right now

                  And regarding the voltage drop off, that's the physical nature of batteries. Any time you apply a load to any battery there will be a temporary voltage drop that will remain as so long as the load is applied. Once you release the load, the voltage will rise back up to it's normal level. So if you're running your ebike motor at full power towards the tail end of it's charge, it's going to cause the BMS to break the circuit sooner than would occur if you were to apply a lesser load.

                  But yeah, your general thought on this is correct though. I constant power test would definitely be the most accurate and appropriate way to test any batteries true capacity. Though again, unfortunately that's not how the industry rates them. I'm guessing the reason for that is that back when they first started testing batteries for capacity, it either wasn't convenient, or else wasn't possible to accurately maintain a constant power discharge, and once a standard like that has been established for so long, it's difficult to change it. That's why the U.S. still hasn't switched over to the obviously far superior metric system.

                  Comment


                    #13
                    Originally posted by AZguy View Post

                    Nice! Proper tool for the job although it might be nice to compare it with a well-calibrated meter... beats the skillet by a long way except it won't cook - it'll heat the room tho =]

                    I'm guessing that they characterize these at lower currents than what you are pulling - maybe 0.1C? E.g. if your battery is 14Ah use a 1.4A constant-current load for a 10hr discharge target. 42V is reasonable for 52V but when they characterize the cells they do take them down further than 3V/cell - not that it's a good idea and doubt you would even see 10% more past that anyway. If your battery is 14Ah, then 7A is 0.5C.

                    I'd be really interested in the difference in Ah capacity at different discharge rates. Maybe 0.05C, 0.1C, 0.2C, 0.5C, 1C, 2C... 1C would push the limits of that load for a >14Ah though...
                    Sorry for being so long winded again... I can't seem to help it, lol.

                    I actually did test them both twice, once at a 7.1A discharge, and the second at a 2A discharge. Surprisingly though, it made very little difference in the results. I didn't record the results of the first test on each of the two batteries (The unit will connect to a computer and log all that, but I haven't set it up yet), so I don't remember EXACTLY what the numbers were, but there wasn't any more than about 1/3 of one Ah difference between the high and low load tests. All four tests, low and high load, on each battery, all ranged from about within 10.3Ah's to 10.6Ah's

                    Now that's pretty shitty for battery packs there were advertised at 20Ah's, don't ya think? lol, almost exactly half of their advertised rating. You'll see them all over ebay if you look. Here's one for sale from one of many sellers of the same battery. https://www.ebay.com/itm/38417924574...0AAOSwWKhgqJmE

                    Some additional information you might be interested in, I tested a few other batteries while I was at it as well, just to gather more data. I tested two 18V, 4Ah Ryobi tool batteries. A 40v (36v), 7.5Ah Ryobi electric lawnmower battery, and a LawnMaster, 24, 2Ah battery, and it seems like at least with these, actual capacity tends to be right around between 80% - 90% of advertised capacity ratings. Like I said though, I'll take at least one of these 52 volters to an ebike shop and have them tested on another machine to see how my machine measures up. However, the reviews I've read on it have been good so far though. It also has many other functions too beyond just capacity testing. It actually seems like a pretty nice little machine for the money, especially compared to similar machines by different manufacturers (around $600 or more).
                    Last edited by Steve--; 07-25-2021, 09:35 PM.

                    Comment


                      #14
                      Originally posted by Steve-- View Post

                      ...Now that's pretty shitty for battery packs there were advertised at 20Ah's, don't ya think? lol, almost exactly half of their advertised rating. You'll see them all over ebay if you look. Here's one for sale from one of many sellers of the same battery. https://www.ebay.com/itm/38417924574...0AAOSwWKhgqJmE....
                      At that price I would have been very suspicious right off the bat... you may not generally get what you pay for but you almost always have to pay for what you get and I wouldn't ever expect to find a legit new 52V/20Ah under ~$600... not to mention those cases only hold 52-56 18650 cells so impossible to get 20Ah at 48/52V - they're only 4p packs! Best cells on the market that are typically used in electric bikes are ~3.5Ah so best case would be <14Ah in that package - I've got one of those I bought new (US supplier) in the $500-$600 range

                      Measuring with the batt-man nearly all my batteries give about 10-15% less than what they "advertise" riding them on the bike but I expect that since I don't run them all the way down (LVCO in the bike is set higher than that) and also expect that the advertised capacity to be optimal conditions from full charge to discharge when brand new - I get shy of 12Ah on the one that advertised 13.5Ah.

                      I guess if you are getting 10Ah that's not bad for a battery at that size and especially that price... I think I'd look at it that way... I have batteries I get 10Ah from that cost a lot more than that! OTOH I got a brand new battery advertised at 48V/11.5Ah for $250 but that's from a fellow that bought it at twice that not realizing it wasn't compatible with his bike - he could document that it was new and when it came it was still in original packing so I got a great deal - it is one that does about 10Ah. I got lucky taking chances on a asian supplier selling out of the US with an 11.5Ah advertised for >$300 and it also clocks in at just under 10Ah on the bike

                      The best "deal" I got was a monster 14s8p pack - you need 7-8p with the typical 18650 cells used in bike batteries to get more than 20Ah - it was gifted to me by a very cool guy getting out of bikes... and it does better than 20Ah real world on the bike but it weighs twice what the battery in the ebay ad does and is quite a bit larger....


                      Like I say - if you are getting 10Ah from a $230 battery, you got a good deal! Click image for larger version

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                      Comment


                        #15
                        Originally posted by AZguy View Post
                        At that price I would have been very suspicious right off the bat... you may not generally get what you pay for but you almost always have to pay for what you get and I wouldn't ever expect to find a legit new 52V/20Ah under ~$600... not to mention those cases only hold 52-56 18650 cells so impossible to get 20Ah at 48/52V - they're only 4p packs! Best cells on the market that are typically used in electric bikes are ~3.5Ah so best case would be <14Ah in that package - I've got one of those I bought new (US supplier) in the $500-$600 range

                        Measuring with the batt-man nearly all my batteries give about 10-15% less than what they "advertise" riding them on the bike but I expect that since I don't run them all the way down (LVCO in the bike is set higher than that) and also expect that the advertised capacity to be optimal conditions from full charge to discharge when brand new - I get shy of 12Ah on the one that advertised 13.5Ah.

                        I guess if you are getting 10Ah that's not bad for a battery at that size and especially that price... I think I'd look at it that way... I have batteries I get 10Ah from that cost a lot more than that! OTOH I got a brand new battery advertised at 48V/11.5Ah for $250 but that's from a fellow that bought it at twice that not realizing it wasn't compatible with his bike - he could document that it was new and when it came it was still in original packing so I got a great deal - it is one that does about 10Ah. I got lucky taking chances on a asian supplier selling out of the US with an 11.5Ah advertised for >$300 and it also clocks in at just under 10Ah on the bike

                        The best "deal" I got was a monster 14s8p pack - you need 7-8p with the typical 18650 cells used in bike batteries to get more than 20Ah - it was gifted to me by a very cool guy getting out of bikes... and it does better than 20Ah real world on the bike but it weighs twice what the battery in the ebay ad does and is quite a bit larger....


                        Like I say - if you are getting 10Ah from a $230 battery, you got a good deal! Click image for larger version  Name:	nod.gif Views:	0 Size:	990 Bytes ID:	132855
                        Here's a testing update. I told you before that the first 7.1A test I performed on the two batteries I didn't log and couldn't remember the exact results, so I performed that test again on each of them, logging them this time. Here are the final results for for all four testss.


                        For some reason I'm getting slightly lower capacity readings from the low load tests than the high load tests. I don't know if this is a low quality BMS issue in the packs, or if it's due to my testing unit, and won't know until I complete the comparative tests at the ebike store. With the information I have so far though, including the reviews I've seen, I'm kind of assuming the former for now. But again, here they are...

                        (Round 2 is still in progress, but the high load test is complete on Battery B, and I included that to the right of the test A result)

                        ROUND 1

                        BATTERY (A)
                        Test #1. @ 7.1A Draw = 10.96Ah
                        Test #2. @ 2.0A Draw = 10.55Ah

                        BATTERY (B)
                        Test #1. @ 7.1A Draw = 10.76Ah : Rd.-2 = 10.77Ah (You can't get much more consistent than that, huh?)
                        Test #2. @ 2.0A Draw = 10.32Ah


                        At that price I would have been very suspicious right off the bat
                        Oh yeah, you're right on everything you said. That's what I was saying in the beginning. I understand the technology, and KNEW for a fact that these packs wouldn't/couldn't be as advertised for all the same reasons you mentioned. By the way, these are 5p, 70 cell packs, and the cases have a cell capacity of 80, or a little over I believe.

                        And I also agree that these still aren't a bad value, it's just the false advertising issue that has me upset, and the resulting thousands of people they have deceived. I purchased these with the specific intention of testing them, proving they're not as advertised, and then returning them under ebay's "not-as-advertised" money back guarantee policy, which would be resolved in one of two possible ways. Either they would be forced to return my money, plus send me an additional $100 or so beyond that to cover return shipping, or if that wasn't cost effective for them, would result in them having to return all my money, while still allowing me to keep the battery (and this is exactly how it worked out with the first one I purchased a couple months ago). So yeah, I knew exactly what I was getting, and knew that one way or the other it's going to hurt these liars financially and hopefully force a change on ebay so this mass scamming campaign comes to an end.

                        Measuring with the batt-man nearly all my batteries give about 10-15% less than what they "advertise"
                        Well that seems to be pretty consistent with the other more reputable batteries I've tested so far.
                        Last edited by Steve--; 07-26-2021, 12:29 PM.

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