OT: Alkaline Battery Testing With Multimeter

[Wade Garrett]

After 11 years of use, my trusty Home Depot Commercial Electric battery tester has gone screwy-- needle swinging back and forth during testing.

I was going to just go buy another one but remembered that I recently picked up a good quality digital multi-meter that of course has a volt setting. I'd be testing the voltage with no load on the 1.5 volt batteries (AAA, AA, C, D).

I wonder if these no-load readings- assuming they'd be something less than 1.5v- would be a reliable indicator of whether the battery should be tossed or maybe downgraded to some non-critical device, or was still good.

What about the square 9 volt batteries also?

[Tekkie©]

On Wed, 15 Sep 2021 16:53:14 -0400, Wade Garrett posted for all of us to digest...

There is some u tube vids on this. Sorry gotta run.

[hubops]

That's all I've used for years - a multimeter. AA AAA 9 V. and the little ones. A co-worker always used a little battery tester to check store-returns - either he or the tester were often off .. Actual full battery voltage can differ from nominal for different types of battery. and some devices can work OK on low batteries - other devices are more fussy. When the lcd finally failed on my old Fluke I just bought a cheap-ish Klein with the ammeter jaw - OK for homeowner use.. John T.

[Pat]

Or a tester that would tell us when the batteries are about to leak and destroy the battery compartment.

[rbowman]

You do need a load. The input impedance on a digital voltmeter is usually over 1 megaohm. Great for not loading the circuit under test, not so great for testing batteries. I'd put a resistor across the battery, 470 ohms or maybe a little lower. Whatever I came to first in the junk box.

In that MacGyver'd lashup, the coil is also the load.

[rbowman]

Schroedinger's Cat. Observing the battery means it will leak 30 second after you put it back in the device.

[gfretwell]

Standard AA and AAA will show about 1.6v new and if they get much below 1.3 or 1.4 chuck them. You are just asking for them to go flat and leak shortly after you forget they are still in there. I have got to the point that I never store anything that I am not using regularly with the batteries in it. The strange thing is those no name chinese batteries you get in flashlights and such seem to be less problem than a name brand like Duracell.

[Ralph Mowery]

Batteries need to be tested under some load. If no load and the meters shows less than the rated voltage the battery is bad, toss it. If it shows the same or sometimes slightly more with no load the battery may or may not be good.

[Wade Garrett]

OK, thanks for all the suggestions.

I think I'll pop for a new cheapie battery tester- $8.97 at the Home Depot.

[Tekkie©]

On Wed, 15 Sep 2021 20:25:02 -0400, Pat posted for all of us to digest...

I have had bad luck with Duracell's leaking

Be advised that some co's have a warranty that if it leaks you send the item back to them and they will repair or replace the item. I jot a check for several hundred bux once.

The local electric supply likes ray o vac but I think they are not up to snuff in the longevity with Dura & Eveready.

I know the co's have different *levels* or chemistry they are now touting.

Maybe John T can tell us his method. What is usable or not.

Let us know your results.

[Tekkie©]

On Wed, 15 Sep 2021 23:08:28 -0400, [e-mail] posted for all of us to digest...

I have also noticed that! Puzzling... I guess the manufacturer of the device doesn't want any leaks so the buy the batteries from their uncle who puts a thick case and no juice inside to leak.

[hubops]

Depends what you're using it in. I've taken 2 year old 9v. from a neglected smoke detector and measured ~ 9 v. and put it in the clock-radio where it lasted another few years. In both devices the battery is basically idle 98 % of the time.

The NiMH in the TV clickers will work OK down to ~ 1 v. but not true in the beard trimmer. John T.

[gfretwell]

I have thought about trying to buy those brands but I imagine you need to buy 10,000 at a time from Alibaba. Maybe Ebay has someone breaking down that wholesale package. That seems to be how electronic components are sold there. You may just have to wait 3 weeks if the unbundling is not happening in a bay in California near Long Beach. I know that stuff is dirt cheap. I bought some 6500 joule MOVs for about a dime each. That is what is in a $50 dollar surge protector.

[rbowman]

I test the 9V batteries with my tongue...

[Mark Lloyd]

I've tested a lot that way, and know what a good battery testes like.

9v is a good voltage for that. 1.5v is too weak to be sure of and 12v is getting too strong.

[micky]

YOu got that right. I put fresh batteries in my TV remote control and it still barely did anything on my beard.