DMM battery question

[Russ]

Hello

   Why are so many people opposed to meters that use the little 9v battery?

Thanks
Russ

[saturation]

AA and AAA are more widespread, so others feel 9V are no longer necessary.  There are many power management circuits that can easily take the lower 1.5V of an AA, or multiples of them, and boost them to whatever is necessary. Alkaline AAA typically 1Ah and AA 2Ah capacity, which will reduce the need to change batteries and overall, reduce waste production.

That said, AA/AAA alkaline manufacture has become so poor, they are likely to leak and damage the internals particularly with the reduced need to change them frequently. 

9V alkaline very rarely leak, because they are double housed but they are typically only 0.20.50Ah  [my error, 0.250Ah is NiMH 9v as another posted] , and also cost more, and may require changing more often.

AA, AAA, and 9v exist in Lithium primary and secondary chemistry, as well as secondary NiMH, these cells rarely if not ever leak and all have much great Ah for longer life and should be your go-to chemistry to replace alkaline in whichever DMM you choose. 

[rdl]

9 volt batteries are ridiculously expensive for the tiny amount of power they contain. I always tried to avoid buying anything that used them. Then about six months ago I bought some 9 volt NiMH and Lithium ion batteries and a charger. Now I don't mind them so much.

[HKJ]

9V primary batteries are about 600mAh: http://lygte-info.dk/review/batteries9V/Common9Vcomparator.php
But AAA batteries are about 1000mA and two or 3 of them are much cheaper.
Most multimeters  need 2 to 3V and will use a linear regulator to drop a 9V batter down to that range.

In multimeters I use for logging I prefer AA batteries (2800mAh), but for more occasionally use I do not really care. My current go to meter uses a 9V battery (Keysight U1252B).

[David Hess]

Energy density for AAs and AAAs is better than for a 9 volt battery even after switching regulator losses are taken into account (1) and they have a better energy/cost ratio.  Very good inexpensive low discharge AA and AAA NiMH cells are available while rechargeable 9 volt batteries are expensive and of questionable quality.

A 9 volt battery with a linear regulator has an advantage with noise but with careful design, this is not a problem for a switching regulator and 1.5 volt cells.

But all of my handheld multimeters use 9 volt batteries and I have no complaints about that aspect of their operation.

(1) Linear Technology used to have a trade magazine advertisement about "how to suck a 9 volt battery dry" which compared 9 volt and 2 x AA cell performance with different voltage regulator configurations.

[HKJ]

Some comparable values:

9V Alkaline: 4.8Wh, but because DMM's often use linear regulators they waste maybe half the energy.
AAA Alkaline: 1.1Wh
AA Alkaline: 3Wh

Value will vary with load and battery quality, the above values are with a low load (Like a multimeter).

[Electro Detective]

Regardless of the power math, AA and AAA batteries are more likely to leak, regardless of price or brand BS.   

I have lost 2 good meters because of that, and a few leakers I managed to save just in time before the crud got into the electronics and switch selector tracks.

I have NEVER had a leak issue with 9 volt batteries (cheap or Duracell) in any meter, be it a cheapie or Fluke 87x etc

Suggest to check all equipment with AA and AAA batteries every 3 to 6 months, especially in hot/humid climate

[HKJ]

Duracell is very bad a leaking in my experience, other brands, even cheap ones, are not that bad.

[rdl]

If you're concerned about leaks then don't use alkaline batteries. I've heard rumors that NiMH can leak, but I've never seen it happen. I've seen dozens of leaking alkalines though. I only have four alkaline batteries left. They're in remote controls. They will be replaced with NiMH when the time comes.

[Russ]

Thanks for the replies. I have been using rechargeable Eneloop AA & AAA batteries for quite some time now. I? have never had one leak. Duracell alkalines have been a nightmare. 😬

[David Hess]

NiCd and NiMH cells can leak but the result is a lot less destructive because the volume of electrolyte is low.  Typically the only sign is that the positive terminal looks "fuzzy" from potassium hydroxide crystals.

[Russ]

Duracell is very bad a leaking in my experience, other brands, even cheap ones, are not that bad.

    I agree. They are known to leak.

[nes999]

I get AAs, AAAs for free from work. So is rather not buy over priced 9v batteries. I agree with others Duracells seem to leak often. I personally only use Rayovac.

[Electro Detective]

Nowadays I use any battery brand that's cheap, appears well made with decent packaging and quality/power claims, and used previously with no problems.

But I stick with overpriced Duracell 9v in smoke detectors because they appear to be the 'standard'...think 'Insurance Policy' going south if the smoke detector/s failed, the house or business premises are toast,
and the  'bad hair day'  claims investigator spots the 2006 dated, leaking 50 cent  'TooHungLo Pwoer Baterry'  installed.     

When swapped out yearly the used 9v Duracells go into multimeters, so I get the most bang for buck on them.    

[6PTsocket]

Regardless of the power math, AA and AAA batteries are more likely to leak, regardless of price or brand BS.   

I have lost 2 good meters because of that, and a few leakers I managed to save just in time before the crud got into the electronics and switch selector tracks.

I have NEVER had a leak issue with 9 volt batteries (cheap or Duracell) in any meter, be it a cheapie or Fluke 87x etc

Suggest to check all equipment with AA and AAA batteries every 3 to 6 months, especially in hot/humid climate

Just cleaned up after a leaker  yesterday. Plain distilled white vinegar and a Q tip. It often looks worse than it is. Some alkalines seem to leak worse than others Practically every damn one of the Kirklands (Costco house brand) leaked on me in the last batch . I think they are made by Duracell. Better luck with Pannasonic and  Harbor Freight's Chinese house brand AA and AAA.

Sent from my SM-G900V using Tapatalk

[001]

(1) Linear Technology used to have a trade magazine advertisement about "how to suck a 9 volt battery dry" which compared 9 volt and 2 x AA cell performance with different voltage regulator configurations.

it is interesting! how to find this article?

[HKJ]

With data from my website is is fairly easy to compare AAA/AA/9V batteries:

9V: http://lygte-info.dk/review/batteries9V/Common9Vcomparator.php
AA/AAA: http://lygte-info.dk/review/batteries2012/CommonAAcomparator.php
There is also 3 comparators for different sizes LiIon batteries.

You have to select the individual reviews to get Wh curves that can be compared independent of voltage and I do not include any looses to regulators.

[bd139]

Just a point that no one has made. A rare event but worth mentioning. Sometimes 9v batteries explode. I'm not talking about the phoney crap you see on youtube or shorting them on anything, but they do explode spontaneously sometimes. I have seen this first hand twice in 30 years and my sister has seen it as well; she worked for a supermarket distribution company which handled crates of the things. All were major brand in date batteries stored in original packaging. Usually one of the cells explodes and blows the end off. Makes one hell of a bang.

Never heard of that for AA's; they just leak! Apart from GP Ultra; have used thousands of them and they don't seem to leak at all.

One reason I bought a Keysight U1241C was it doesn't take 9v batteries.

[HKJ]

Just a point that no one has made. A rare event but worth mentioning. Sometimes 9v batteries explode.

Most 9V batteries are fairly leaky in construction and cannot explode. You can see how they are build here: http://lygte-info.dk/info/BatteryDisassembly9VAlkaline%20UK.html

[bd139]

It's always the middle cells in the flat packed ones that go bang. They sure can explode!

Incidentally both the ones I had blow up were Duracells.

[David Hess]

(1) Linear Technology used to have a trade magazine advertisement about "how to suck a 9 volt battery dry" which compared 9 volt and 2 x AA cell performance with different voltage regulator configurations.

it is interesting! how to find this article?

If you want to look through old issues of Electronic Design or Electronic Design News, then you can find it.  It was just an advertisement although a humorous one.  Linear Technology design note 63 was based on it.

[rrinker]

 The controllers for my model railroad us 9V batteries, and they don't last very long - one thing I wanted to do was alter them to use 2x AA instead. I think even just replacing the stock regulator with an LDO type would work, as they get erratic at about 8.6V measured across the battery under load.

[Russ]

I prefer to use rechargeable Eneloops. But for almalines, the AC Delco batteries have always worked very well and never leak on me. Plus, they are very cheap on Amazon.

[001]

I prefer to use rechargeable Eneloops.

And what type of rechergeable 9V batts You can reccomend for DMMs like 87V?
NiMH vs Li-Ion?

[HKJ]

I prefer to use rechargeable Eneloops.

And what type of rechergeable 9V batts You can reccomend for DMMs like 87V?
NiMH vs Li-Ion?

For 9V batteries LiIon is the way to go: 3 times capacity of NiMH and very low self discharge.
But you have to use the meter a lot, before there is any reason to use a rechargeable battery in it.