Best Procedure for Testing CR123s?

[awyeah]

I have a ZTS Mini-MBT (thanks to recommendations from CPF!) that I use to test my CR123s. I have noticed that I sometimes get different readings on the same cell after I put it in a light and run it for 15 seconds.

Additionally, I like to take several readings, 10-15 seconds apart, until I get a few in a row that match.

My question is: What is considered the best procedure for testing these on the mini-MBT to get the most accurate results? And what is it about this chemistry that causes the results to differ (sometimes by a lot) in different tests on the same cell?

Thanks!

 

[Viking]

I have the same problems as you on my ZTS Mini-MBT.
Both when I test CR123s and eneloop's , I very often get very different results.
I haven't tested other battery types than the 2 types above.

I have tried to wait a minut between the readings , but that did't helped.

 

[ElectronGuru]

I've noticed variances when I press to lightly. Firm pressure each time and throughout the reading, makes my results more consistent.

 

[Gregozedobe]

I agree with EG, if you press too lightly (or even worse. lift off slightly while the tester is doing its thing) then you will get a falsely low reading.

I've noticed some odd readings from my ZTS-1with 1.7v and 3.0v lithiums, particularly "new" batteries that haven't been used for a while.

They seem to start off low (eg 40%), then each time I re-test the % charge increases, sometimes up to 80%, sometimes up to 100% and these batteries seem OK. Others get worse with re-testing and I discard them as "duds".

I have a vague idea I have read something (probably on here) about the chemistry of lithium primary batteries causing them to under-read at first, and that using them on high in a light for 30 seconds or so can wake them up properly (I'm sure it was expressed much more technically accurately than that, but that was the gist of the message that I took away).

I have read that ZTS testing eneloops is often quite inaccurate, because these testers base their results on voltage drop, and eneloops have very little volatge drop until they are nearly discharged (which is why they are such a useful battery).

 

[RBWNY]

My experiences with the ZTS are the same. I've read that although it IS a reliable unit, taking power measurements with NiMH cells in particular is often not "exact" but rather a rough estimate. With CR123's, I'll often get a second opinion with my older (non-digital) radio shack battery tester. I always used to rely on that one for all my AA's, 123's, etc., before getting into rechargeables and buying the ZTS.

 

[SilverFox]

Hello Awyeah,

The ZTS tester is sensitive to contact resistance. Make sure you have good contact when using it.

Lithium primary cells can develop a passivation layer that will give you a lower voltage reading under load. By using the cell for a few seconds, that layer is burned off and you get a better reading.

When testing CR123 cells I keep testing until I get 3 readings in a row that are the same. This gives a closer approximation to the remaining capacity.

Different brands of cells behave differently as far as passivation goes. I believe the ZTS calibration data was done with Duracell, Energizer, and Panasonic cells and will be most accurate with them. Other brands behave somewhat similarly, but there may be a little wider scatter. The real problem comes with cheap cells. They can vary all over the place and if used in multi cell applications can end up with explosive results.

One problem with the ZTS and testing cheap CR123 cells is that it doesn't apply enough load to burn off the passivation layer. You end up with different results every time you test. After running 20 - 30 tests you begin to scratch your head wondering what is going on. Pop the cell in to a light and run it for 15 - 20 seconds, then test it and you end up with better results.

Tom

 

[awyeah]

I'm actually using SureFire cells, so theoretically I should get fairly accurate results - those are the same as the Panasonics, Duracells and Energizers right? However, these cells are a few years old (most in the box are dated 2018).

About how long does it take for the passivation layer to develop after use? Specifically, how long after it's under load will I have before I should load the cell again?