Battery Meter/Tester

[RPC]

I have done a lot of searching & reading here on battery safety, testing, etc. and have not found a succinct answer to my question:

I recently got into lights and like CR123 driven ones. Can I get recommendations on a good, basic battery meter/tester so I can test and match 123s in multi-cell lights? I plan to exclusively use SureFire brand 123s.

Thanks in advance.

 

[MarNav1]

ZTS.com

 

[Derek Dean]

Howdy RPC and welcome to CPF,
I'm glad to hear that you've been reading up on battery safety, good for you. For what you're talking about, measuring CR123 cells, pretty much any decent multimeter should work, and you can find those for $10 and up. However, a lot of folks tend to expand their interests once they've been here for a while, so it never hurts to buy a quality meter with more capabilities than you think you might need at the moment.

Be sure and check out the "Flashlight Electronics, Batteries Included" section of CPF:
http://www.candlepowerforums.com/vb/forumdisplay.php?9-Flashlight-Electronics-Batteries-Included

They talk about, and review, many meters on that forum. You can also use the little search box located at the top left of most CPF pages. Leave it checked for "CPF Only" and it will limit it's search to CPF. Try something like "battery testers".

Good luck with your search.

By the way, it's http://www.ztsinc.com/

 

[RPC]

Thanks Derek.

Can someone give me the Idiot's Guide version of the difference between a DMM & a battery tester? Why do I see so many people insisting both are necessary?

I want to:
- Test new SF 123s and match like voltages for use
- Test "dead" 123s for later use with other used cells of like voltage
- Potential future use with rechargeables (if I get in that deep :-) )
- Use in lieu of my cheap RadioShack battery tester for other household battery types

Mods- Feel free to move his thread if there's a better place for it.

 

[archimedes]

Sure ... very simplified info follows ;)

A voltmeter (one of the many functions of a multimeter) will tell you a battery's voltage.

For certain battery chemistries, such as lithium ion (ICR, IMR) rechargeables, the open-circuit (unloaded) voltage correlates fairly well with the state-of-charge (SoC).

For other battery chemistries (such as lithium primary, alkaline primary, or nickel metal hydride rechargeable), it does not. For these chemistries, a better estimate of SoC is based on voltage drop under a current load.

A battery tester is an automated and simplified way of testing this voltage drop under load, and comparing it to (pre-measured and calculated) standardized values.

Both are useful, especially if you use a variety of battery types and chemistries.

Hope that helps ! :)

 

[RPC]

Thanks Archimedes! Your statement of a test under load being a better method for certain battery types- is that what folks are duplicating when using a DMM + a resistor?

I am surprised by all the hype I see around ZTS testers given the seemingly limited information supplied. They simply indicate, "X% battery life(?) left at Y% resistance", right? If load = resistance, are battery testers variable? Wouldn't electronic devices each pull a different load, thusly requiring variable levels of resistance to truly measure X% battery life(?) left at Y% resistance?

 

[archimedes]

Yes .... Your perceptive questions clearly indicate that you have now graduated from "Batteries 101" ( and in just one post! ) , congratulations :D

For "Batteries 201", you may want to enroll at batteryuniversity.com ....

Battery capacity (in mAh, not SoC) does indeed significantly depend on the current draw.

 

[SilverFox]

Hello RPC,

Welcome to CPF.

The ZTS tester initially found popularity in photography shops. People could check the batteries in their cameras and flash units to see where they stand. The military found the test method useful and ordered some of the ZTS testers for their use. At CPF we got interested in the ZTS when problems came up using multiple CR123 batteries in series. While the information from the ZTS is limited, that limited information can be very useful.

The advantage of the ZTS is its design. It pulses the load and compares the voltage under load to a table derived by testing most of the name brand batteries. The loads vary for the various test stations and were picked by checking "typical" loads involved with consumer devices that are most common. As with all general indicators, if your specific device varies from the general your data will be off.

The advantage of the pulsed load is that it doesn't reduce the capacity of the battery you are testing by very much. Holding a resistor in place while you are waiting for the voltage to stabilize so you can take a reading uses much more capacity from the battery you are testing.

It works very well when used to match primary cells in a multi cell application. It works reasonably well with newer secondary cells, but as these cell age their voltage profile changes and that alters the response from the ZTS test.

In general as a general indicator it works well. When looking at a specific brand of battery or a specific application there are differences between what the ZTS indicates and what you actually experience. However, after using it awhile you can generally factor in an adjustment factor to cover your specific needs.

It's not perfect or precise, but in general it works well.

Tom

 

[RPC]

Arc/Tom- you guys are awesome.

 

[archimedes]

Although the ZTS "manual" mentions this somewhere, if I recall correctly, it may be worth noting here that the first couple of ZTS tests on a cell may occasionally read low (especially for older primaries that have sat unused for some time).

I believe this can be due to the passivation effect. I generally test at least a couple of times in quick succession, until I see the results plateau.

 

[SilverFox]

Hello Archimedes,

I believe that applies mostly to primary CR123 cells. When testing "other than major brands" of those cells you can frequently get low readings especially if the cells have been stored for a longer period of time. This seems to be caused by a passivisation layer forming on the electrodes inside the cell. Normally you would use the cell for a very short period of time to burn this layer off but the ZTS uses so little current that it takes several tests to do the same thing.

I have not noticed this being a problem with other chemistries. Just to be sure I usually test until I get 3 similar readings.

Tom

 

[archimedes]

Thanks for confirming ....

I have not noticed this to any significant degree with ICR cells, either, but then I rarely ZTS test Li-Ion chemistry cells (since simple open-circuit voltage provides a reasonable estimate of their SoC) :)