Testing L91 and L92 batteries on ZTS MBT-1

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ecallahan

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I received one of the newest model MBT-1's today, I say newest because it has the same screen as the newest model shown on ZTS website. I have had a mini for quite a few years.

I purchased the MBT-1 mostly to test my L91 and L92 batteries. I am familiar with testing cr123 primaries, I test them about 5 or 6 or six times in succession until I get 3 readings that are the same.

When I test my L91 and L92 batteries I am getting readings that go something like: 100 - 80 - 60 - 40 - 40 - 40 - 20. I first tested a few batteries I had in my lights. Then I tested new L91 and L92 batteries with expiration dates of 2027. Even though I had never used them, I am getting similar declining capacity readings.

I am waiting about 3 or 4 seconds in between tests.

What is the best way to test these batteries on the ZTS to get the most accurate reading?

Thank you,
 
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magellan

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Are the AA batteries in the ZTS new? I've noticed the occasional odd reading but putting in new batteries seems to fix most problems.
 
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ecallahan

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Are the AA batteries in the ZTS new? I've noticed the occasional odd reading but putting in new batteries seems to fix most problems.

Yes. I just put them in. I used brand new Energizer Ultimate Lithium's - so I don't open the cover up 3 years from now and find a bunch of corrosion.
 
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BillSWPA

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Making sure you have good contact between the button on top of the battery and the positive terminal on the tester makes all the difference. I tend to have the most issues testing Li-Ion cells.
 
SilverFox

SilverFox

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Hello Ecallahan,

The ZTS tester work by applying a pulsed load to the cell being tested and measuring the voltage under load. This voltage is compared to a look up table that ZTS developed by testing a variety of cells of different ages and brands.

It is well known that CR123A cells develop a passivation layer that acts as additional resistance within the cell. Once that layer is burned off you get a "true" reading of the voltage. This is why multiple readings are needed when testing these cells. I don't know if the L91 and L92 battery chemistry behaves the same way but it looks like that is what is going on.

One thing you can try is to put the cell in a single cell light and turn it on for something like 30 seconds. This should burn the passivation layer off and then see if it tests more "normally."

Tom
 
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ecallahan

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I actually did put one of the batteries in and powered on for that exact reason (passivation layer) but it did not make a difference in the readings. FWIW I would not have known about a passivation layer or anything else dealing with batteries without what I learned on this forum. I've never said thanks to you all before and I've been reading these forums for years.

I also have an inquiry into ZTS. I will let you know what they have to say.
 
ElectronGuru

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You sound experienced so it probably doesn't apply, but...

I've noticed funky readings when holding the cell or wire loosely or at a weird angle. I find holding the same cell with solid pressure for the duration of the scan, to fix it.
 
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ecallahan

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I called ZTS, wow where they helpful and took the time to try and explain it to me. They said on the newest testers they are testing the L91 and L92 at ½ amp load, and the test is longer (than a CR123 for example).So if you test the battery multiple times the battery can’t keep up with the load. They said that newer L91 and L92’s will actually start a little lower capacity reading, then go up, then curve back down – he said it is not actually passivation just the characteristics of the battery chemistry. Since it is a longer test, his recommendation was to keep firm connection (as mentioned previously in this thread). I was told it is not as easy to test these batteries as other lithium chemistry (CR123). He recommended making 1 or 2 tests only. For example if your two tests show 80 then 60 – you would be around 80% or 70% on the battery. I hope I’ve done justice to the response by ZTS, I’m sure if one of you call you would be able to ask better questions and get more technical information.
 
Last edited:
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cave dave

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Thanks for the information. Like you I also had a small ZTS and like it so much I bought the big one a couple years back to test Lithium AA, AAA', CR123s and LiIon and have been disappointed. The results on L91, L92 were always inconclusive and displayed results like you found and for LiIon I found i was better off with a volt meter.

I also found that the lithium AAA were much harder to read than the AA, I guess because they sagged more from the load.

Anyway I can highly recommend the small tester for alkaline and Nimh and would say not to bother with the more expensive large tester.
 

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