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LiitoKala Voltage reading wrong by -0.30V
#1
Did anyone have the same experience? I was testing 4 18650s and just an hour after plugging it in charger displayed NULL, which was weird because it takes way more than that. When I plugged the batteries in they couldn't be recognized. I used my MM and I found out that it overcharged the batteries I was testing to 4.55 volts. I tried putting a 4.15v battery and it was reading it at 3.90v, an hour later I tried again the reading was 4.02v, severly under the MM reading. My Opus BC3100 was only had a 0.03v discrepancy from my MM. 


Very weird that the Voltage reading is below under by 0.30v but it can't recognize the ones it overcharged to 4.55v.
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#2
Sounds like its ready for the trash bin... those testers dont last forever, I have lost a couple to heavy use. Once they start acting up I retire the unit.
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#3
(07-18-2019, 12:03 AM)Crimp Daddy Wrote: Sounds like its ready for the trash bin...  those testers dont last forever, I have lost a couple to heavy use.  Once they start acting up I retire the unit.

Oh boy, it's only 8 months old and have tested less than 200 cells.
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#4
(07-18-2019, 11:47 AM)barns Wrote:
(07-18-2019, 12:03 AM)Crimp Daddy Wrote: Sounds like its ready for the trash bin...  those testers dont last forever, I have lost a couple to heavy use.  Once they start acting up I retire the unit.

Oh boy, it's only 8 months old and have tested less than 200 cells.

I find what ended up killing mine are heaters... some cells get so damn hot when testing I think it ends up damaging the tester.

Maybe you just got a bad one... I have not experienced a significant voltage reading issue with mine.
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#5
(07-17-2019, 10:58 PM)barns Wrote: I used my MM

What multimeter do you use?
LiFePO4: QB26650 2500mAh 50A vs A123 ANR26650M1B: https://youtu.be/GOSkte11lRc

Yinlong LTO Lithium Titanate safety tests: https://youtu.be/eAUYbSDEy6I
Toshiba SCiB LTO Lithium Titanate safety tests: https://youtu.be/XsrRDZxEFQE

XTAR DRAGON 4-slot battery tester review: https://youtu.be/S6yVMsIuauE
Miboxer C4-12 4 slot x 3.0A charger review: https://youtu.be/X-ww1YALjvU
Miboxer C2-4000 smart battery tester review: https://youtu.be/jrbJceNXv1g

Samsung 33J for TESLA: https://youtu.be/7FMxgMmPeh4
Samsung 40T - a high drain 35A 21700 cellhttps://youtu.be/lxgKWiQ9580
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#6
(07-18-2019, 08:56 PM)thunderheart Wrote:
(07-17-2019, 10:58 PM)barns Wrote: I used my MM

What multimeter do you use?

Cheapest DMM I can find on my local hardware. I also have an Opus and a discharge tester bk586 and all three are within +-0.03 volts. The Lii 500 is not only reading low by 0.3v, it is also inconsistent and unable to detect the batteries it overcharged.


(07-18-2019, 06:05 PM)Crimp Daddy Wrote:
(07-18-2019, 11:47 AM)barns Wrote:
(07-18-2019, 12:03 AM)Crimp Daddy Wrote: Sounds like its ready for the trash bin...  those testers dont last forever, I have lost a couple to heavy use.  Once they start acting up I retire the unit.

Oh boy, it's only 8 months old and have tested less than 200 cells.

I find what ended up killing mine are heaters... some cells get so damn hot when testing I think it ends up damaging the tester.

Maybe you just got a bad one... I have not experienced a significant voltage reading issue with mine.
Heaters are unlikely. I never leave cells unchecked. I do an IR thermometer reading hourly so no little chance of heaters.
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#7
I agree with you, I think there is something wrong with the charger.  Perhaps you just got a bad one, and I would personally retire it at this point.  Im glad you are cross comparing with other devices, but the only advise I can give is invest in a decent DMM.  I've used the spectrum over many years and if there is one bit of wisdom I can pass on is that the level of confidence and trust in a reading goes a long way.  The count and resolution is really nice to have, but accuracy matters as well depending no what you are doing.  

With a high resolution / high count meter, you can “watch grass grow”.  The activity is generally pretty boring until you can see it move.  The UT61E delivers a lot of that at a budget, 22,000 count meter.  Great for what we are doing, monitoring charge/discharge and other activities.

You don't need to spend a lot, but here are my two recommendations.  

~$50-$100 price points

UNI-T UT61E

Import market Fluke 17B
https://www.aliexpress.com/item/32802251073.html?spm=a2g0s.9042311.0.0.27424c4dtaoJZM
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#8
Check your multimeter battery, and leads. A flat battery can make your multimeter do all kinds of funny things. Really cheap multimeters are usually best avoid.
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#9
I appreciate the MM concerns but that's not the issue.
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#10
(07-19-2019, 12:31 PM)barns Wrote: I appreciate the MM concerns but that's not the issue.

There are reasons why most would jump to the conclusion of your MM. I'm not certain, but I don't really think an 18650 could even hold 4.55v. I sure wouldn't even like to test it. I imagine somewhere around 4.3-4.4v it would just start burning off the charge as heat. The cell most assuredly would be hot when removed from the charger. It would most likely trigger the CID.

If you were sure that a cell actually hit 4.55v, I would discharge and bin it. The useful life has most likely been cooked out of it. I would definitely handle with care, as it most likely will have some pressure built up inside.
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