Battery Test Function on VOM - Why Not?

[EPAIII]

There are battery testers. Yes, I know that. And they are inexpensive. Perhaps too inexpensive as they often don't work from the get-go or have a limited life, both due to cheap construction.

But what would it take to add an under load, battery check function to a VOM, either analog or digital? I am not talking about car, truck, or even motorcycle batteries, just household coin cells, AAA, AA, C, D, 9V batteries.  A simple group of load resistors and some push button switches to place them across the Voltage test leads is all that would be needed. Possibly a fuse or circuit breaker of current limiting circuit to prevent damage. Oh, and some labeling. A Chinese OEM could do it for pennies.

I did a quick internet search and found zero VOMs with this feature. Many instructions on how to use a VOM to test batteries, but none with that as a feature. NONE! OK, I did find one:

https://ennologic.com/product/digital-multimeter-em530s/

So, why does almost no one do it? With everything digital today, perhaps the difficulty of a good-bad indication with a digital display? But those displays can say Volts, Ohms, Amps, etc. so why not Good or Bad or Questionable?

I am thinking about making a simple plug in PCB with two banana plugs and some battery sockets. But that would be an add-on.

Why does almost no VOM maker have under load, battery check as a built-in feature.

[EPAIII]

And if it is a great idea, I INVENTED IT and want millions!

[Kim Christensen]

There are battery testers. Yes, I know that. And they are inexpensive.

I think that's the main reason. The other reason is that the battery load test is a very rough and vague test. That's why most of those cheap testers have those Go-No-Go indicators on them. No need for an accurate digital readout. Plus there's just so many capacities and chemistries. ie: A NiMH AA cell is going to look half dead on a tester designed for an alkaline AA. A D-cell is going to need a bigger load than a AAAA cell even if the chemistry is the same, etc.
Plus people who buy multimeters would consider a battery load test function one of the last feature on the list of must haves. I know I would.

[schmitt trigger]

I have got an analog Sanwa YX361 meter which does have that function.

As long as you measure AA or AAA alkaline batteries, it does the job.

[Veteran68]

There are DMMs with a battery test feature. It's not exactly common but not unheard of either. I don't have specific examples off the top of my head, but I've run across them. I'm sure when I have a minute I could name a few.

There are battery testers. Yes, I know that. And they are inexpensive.

I think that's the main reason. The other reason is that the battery load test is a very rough and vague test. That's why most of those cheap testers have those Go-No-Go indicators on them. No need for an accurate digital readout. Plus there's just so many capacities and chemistries. ie: A NiMH AA cell is going to look half dead on a tester designed for an alkaline AA. A D-cell is going to need a bigger load than a AAAA cell even if the chemistry is the same, etc.
Plus people who buy multimeters would consider a battery load test function one of the last feature on the list of must haves. I know I would.

There are cheap battery testers that have exact voltage readouts, not just green/yellow/red indicators. I've had this one for some time and it works quite well. Just as an anecdotal example, I got a new FLIR DM64 meter last week, and it shipped with 2x Energizer AAA's with fresh dates (2026). As soon as I put them in the meter I thought the display was a bit dim, and the low battery indicator appeared immediately. After a couple minutes, the meter shutoff and wouldn't turn back on. I popped the batteries out and measured them in this little Aneng tester and then with the FLIR meter after I replaced the batteries. Both measured 300mv on one of the AAA batteries, so it was dead from the factory.

It's also easier and quicker to deploy than a DMM which would usually require me to unwrap leads and awkwardly probe a battery.

[Fungus]

And if it is a great idea, I INVENTED IT and want millions!

Lots of Chinese meters have battery test functions.

eg.

https://lygte-info.dk/review/DMMAnengV8%20UK.html

https://lygte-info.dk/review/DMMAnengV7%20UK.html

[Nusa]

The ultra-cheap Harbor Freight Centech meter has a battery test feature for 1.5V and 9V. So there's an example of existence.

Decent meters have to decide what features are worth the space on the dial, and battery test doesn't make the cut. After all, anyone with a brain can check the battery voltage on the normal voltage range. That's all you need to know in 99% of cases.

[Fungus]

Decent meters have to decide what features are worth the space on the dial, and battery test doesn't make the cut. After all, anyone with a brain can check the battery voltage on the normal voltage range. That's all you need to know in 99% of cases.

It's much easier if the meter puts a small load on the battery.

[mwb1100]

After all, anyone with a brain can check the battery voltage on the normal voltage range. That's all you need to know in 99% of cases.

Except sometimes that check lies.

A couple photos showing a 9V battery measuring 9.6+V on a couple meters (Fluke 179 and an el cheapo Mastfuyi FY77 that Amazon often sells for around $10).  The FY77 has some battery test ranges that put a load on the battery, about 900 Ohm on the 9V test range.  That photo shows the battery only putting out 5V when loaded.  The battery was in a meter and couldn't keep the thing on for more than 10 seconds or so.  Believe the simple voltage reading and you might think something other than the battery is the problem - at least until you put another battery in the meter.

I imagine that pro meters don't generally have a battery test because they don't want it taking up selector real estate and it's probably not in high demand among people who use meters for electronic or electrical work.

By the way, I kind of like the FY77 for $10. Seems accurate enough and it auto ranges unlike the HF cheapo/freebie.  However there's no capacitance range. The continuity test is actually good - as long as you ditch the included leads for something better (which will probably cost you more than the meter itself).

The pics:

[Kleinstein]

The battery test under load is not as easy as it may look at first. With a high external voltage there is quite some power loss at the load and a high voltage capable switch adds to the size.

With alkaline cells there is no need to measure under load. The no / low load case is OK to see how good the battery still is. A measurement under load is mainly a thing for old dry cells and CR2030 or similar li based primary batteries.

[floobydust]

Why do we reinvent the wheel?
https://www.eevblog.com/forum/projects/alkaline-battery-tester/msg1774790/#msg1774790 at least 40 years old and does great.

[BeBuLamar]

Let see!
If I want to check the AA alkaline battery what kind of load should it be and which range of voltage reading should it be considered good? And then for each type of batteries?

[floobydust]

Yes.

[Nusa]

After all, anyone with a brain can check the battery voltage on the normal voltage range. That's all you need to know in 99% of cases.

Except sometimes that check lies.

A couple photos showing a 9V battery measuring 9.6+V on a couple meters (Fluke 179 and an el cheapo Mastfuyi FY77 that Amazon often sells for around $10).  The FY77 has some battery test ranges that put a load on the battery, about 900 Ohm on the 9V test range.  That photo shows the battery only putting out 5V when loaded.  The battery was in a meter and couldn't keep the thing on for more than 10 seconds or so.  Believe the simple voltage reading and you might think something other than the battery is the problem - at least until you put another battery in the meter.

I imagine that pro meters don't generally have a battery test because they don't want it taking up selector real estate and it's probably not in high demand among people who use meters for electronic or electrical work.

By the way, I kind of like the FY77 for $10. Seems accurate enough and it auto ranges unlike the HF cheapo/freebie.  However there's no capacitance range. The continuity test is actually good - as long as you ditch the included leads for something better (which will probably cost you more than the meter itself).

The pics:

I recognize that battery. Labeled "heavy duty" (means carbon-zinc chemistry) and "not for retail sale" under your label, cheapest battery the manufacturer could buy to send with the device. Naturally it's not going to last as long or behave like the standard alkaline battery that people use 99% of the time. You found the 1% case.

[mwb1100]

I recognize that battery. Labeled "heavy duty" (means carbon-zinc chemistry) and "not for retail sale" under your label, cheapest battery the manufacturer could buy to send with the device. Naturally it's not going to last as long or behave like the standard alkaline battery that people use 99% of the time. You found the 1% case.

Yeah, it was a battery that came with some multimeter.  I didn't expect that it was going to be a long lasting battery (in fact, it was already dead/near dead when I first tried out the device).  I also understand that most of the time getting an open circuit voltage reading from a multimeter gives a fine indication of the state of the battery.  But this wasn't the first time I've come across a battery that had a reasonable open circuit voltage but badly failed a loaded test.

Are you saying that alkalines don't exhibit that kind of behavior?  Is it only a characteristic of carbon-zinc?  (these are honest questions - I really don't know)

[ozcar]

The ultra-cheap Harbor Freight Centech meter has a battery test feature for 1.5V and 9V. So there's an example of existence.
...

Certainly such meters are not uncommon. From time to time Aldi sell multimeters (not always the same), and quite often those have had battery test ranges. In fact, they will have one for sale this Saturday here in Oz (or at least in NSW where I am).

I'm not sure about the one they have coming up now, but ones that they sold before did not have a go/nogo indicator, it was up to the user to make that judgement based on the voltage reading. Given the sort of people who buy these meters maybe that does not work out. I know of somebody who bought one of the previous Aldi meters. He tested a few batteries with it, and his judgement was that the meter was defective, because the readings were different to those on another meter he had, which did not have battery test ranges! He ended up returning it to Aldi.

[BeBuLamar]

I haven't seen a good battery tester yet and thus if a mulitmeter that has that feature I woudn't want it.

[BILLPOD]

I am a believer that batteries should be tested under the load of the device they will be used in.  So for me a tester should have an adjustable load.