Author Topic: DMM and battery life - battery choices ..  (Read 8215 times)

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Offline Kiriakos-GR

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DMM and battery life - battery choices ..
« on: May 16, 2010, 11:50:42 am »
Usually most DMM's  use an 9V battery .

If you favor any brand or type more than the others , just share your opinion with the forum.

I live in one country with stable weather and temperatures  from 12 - 37 Celsius ..
So I can not compare  the Batteries by their behavior in cold climates.

About my choices in Batteries , I prefer most Sony and Varta Alkaline's (high energy).
They usually run well even for 2 years ...

But now with Fluke 87 at hand , I think that I will become more cautious ,
about the selection of batteries,  as it looks more hungry than my other DMM's    
 

Offline EEVblog

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Re: DMM and battery life - battery choices ..
« Reply #1 on: May 16, 2010, 12:49:21 pm »
If you are concerned with battery life, use an expensive 9V Lithium.

Most big brand name Alkalines are pretty similar in performance and capacity.

Dave.
 

Offline switcher

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Re: DMM and battery life - battery choices ..
« Reply #2 on: May 16, 2010, 01:28:29 pm »
I've put Lithiums into my Fluke 85 and Fluke 77.
We'll see how long they last.
I don't think the 9V lithiums will fit into some meters as they are physically slightly larger than yer average PP3.
 

Offline personalinformatics

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Re: DMM and battery life - battery choices ..
« Reply #3 on: May 16, 2010, 01:33:34 pm »
Alkaline Battery Shoot Out
Testing 9 Volt Batteries



Alkaline: 600mAh @25mA discharge, ~$2.50
Lithium: 750mAh @25mA discharge, ~$10.00
 

alm

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Re: DMM and battery life - battery choices ..
« Reply #4 on: May 16, 2010, 02:45:12 pm »
I can't find anything about lithium 9V batteries in both links. The CPF link is only about AAA, AA and D, the lithium batteries were much better (more than twice the capacity of alkalines). I would be surprised if 9V batteries would show a completely result. The other link is only about alkaline and carbon-zinc.

Both tests were done at much higher currents than your average DMM will ever draw, so it's not completely representative.
 

Offline personalinformatics

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Re: DMM and battery life - battery choices ..
« Reply #5 on: May 16, 2010, 06:31:21 pm »
The two websites I linked were primarily of conventional batteries. (Most people are not going to pay $10.00 for a 9V battery.) I got mAh numbers from the Energizer website.
 

Offline Kiriakos-GR

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Re: DMM and battery life - battery choices ..
« Reply #6 on: May 16, 2010, 06:56:00 pm »
I will not get involved about criticizing those two web links about , how correct they did the tests ..

Specially the second , speaks about termination voltage as 0.1 Volt .. thats an even ridicules as idea ..

Any 9V battery if it drops one Volt , starts to be rejected from devices like the DMM's  !!
So, we do not care  about anything else other than  useful " mAh " as amount ,
stored in one 9V Block ..

Even me, I am not aware  the true  " mAh "  of the Varta Alkaline's (high energy),
that I got as balk of 20 pieces.

Thats why I started this thread , so to compare the batteries , by our experiences .

The first link , has an interesting measurement  alkaline VS Lithium , pointing out that at the same battery dimensions  ( AA )  the lithium one managed to have stored the triple  amount of  " Ah " .
http://img.photobucket.com/albums/v482/SilverFoxCPF/AALiAlkComparison05A.jpg

But from my point of view , because I own an  ANSMANN battery station , capable to charge 9V NiMH ,
I am thinking , if it worths to get 9V NiMH , and just recharge .

I am aware that the 9V NiMH have less power in comparison with the Alkaline's  .
But I am not going to make my mind today about it ..
I have lot of New Alkaline's next to me ...  and this buying me time, so to get in the future an better 9V NiMH if they make any, or find out the truth about the Lithium ones ,  that as far as I am aware of , they fall at the 75%  of their capacity in just two years from the production , as they have very active chemistry.
And die at the third to fourth year  , again from their active chemistry.  

  

    
 

alm

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Re: DMM and battery life - battery choices ..
« Reply #7 on: May 16, 2010, 07:17:44 pm »
Lithium batteries usually have a shelf life of about ten years, so they're not likely to die within four years. Lithium batteries are often used for functions like memory backup (before EEPROM and similar technologies came along), and can last many years (with a very tiny current draw). The self discharge is also very low.

About using rechargeable batteries for DMM's, beware that the self-discharge rate of regular NiMH batteries is quite high, possibly higher than the average current draw of the DMM (depending on the amount of use and how often you use the backlight). An NiMH battery will have lost a significant part of its charge within a month (30%?), and are basically flat after a year (without any current being drawn). So they aren't a great fit for equipment that draws very little power. Low self-discharge NiMH batteries (Sanyo Eneloop is the most well known) fix this problem, but 9V LSD batteries aren't very common, especially not from the reputable manufacturers.
 

Offline Kiriakos-GR

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Re: DMM and battery life - battery choices ..
« Reply #8 on: May 16, 2010, 07:34:01 pm »
Lithium batteries usually have a shelf life of about ten years

Do not compare the button cells,  with high energy batteries for laptops.
The second ones , have active chemistry .
The second ones can form possibly the 9V block version.  



About using rechargeable batteries ........ Low self-discharge NiMH batteries (Sanyo Eneloop is the most well known) fix this problem
The fix  causes lower true  usable Ah .. this is not a fix but sacrifice .
I own (Sanyo) Eneloop 2000mA(Min 1900)    - Ansmann 2800mA - Sanyo 2700mA AA , are the only brands that I trust.
But I got the Eneloop just to test them , and nothing more..

 
« Last Edit: May 16, 2010, 07:42:40 pm by Kiriakos-GR »
 

alm

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Re: DMM and battery life - battery choices ..
« Reply #9 on: May 16, 2010, 07:50:51 pm »
The laptop batteries are lithium-ion, they are rechargeable, and usually have a voltage of about 4V (eg. 3.7V), not a very good match for a 9V battery. All 9V lithium batteries that I've seen are primary batteries (non-rechargeable), and have a chemistry similar to the button cells.
 

Offline Kiriakos-GR

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Re: DMM and battery life - battery choices ..
« Reply #10 on: May 16, 2010, 09:26:01 pm »
Any way, if Dave had a link about the ones that he likes to use , we will have one comparison point,
about the 9 V blocks .

Personally until today  I am not aware of any 9V Lithium. (non-rechargeable) or (rechargeable).
 

Offline EEVblog

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Re: DMM and battery life - battery choices ..
« Reply #11 on: May 16, 2010, 09:58:34 pm »
Energizer sell 9V primary lithiums:
http://data.energizer.com/PDFs/la522.pdf

I recommended people use them in the battery hogging Agilent OLED meter for example, budget permitting.

I don't bother, I just use regular Enegizer or Duracell 9V Alkalines.

Dave.
 

Offline Kiriakos-GR

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Re: DMM and battery life - battery choices ..
« Reply #12 on: May 16, 2010, 10:36:45 pm »
Well it looks by the specs that it has as 25 hours of service with 25mAh .. (8 volts )

The Fluke 87-5  by the review , looks to have 1.1mAh ( no back light)

So by my own quick calculation , we have  about 25times the 25 hours = 625 Hours of service,
compared to the about 400 Hours of service ( Fluke words Alkaline )  = 50% more hours,
or just another 200 +/_  hours of service ..


So... if I am guessing or calculating,  correctly,  if the Lithium costs more that two Alkaline's ,
its not worth it at all .    



By the way , with what brand of batteries the New Fluke DMM comes with ? 
« Last Edit: May 16, 2010, 10:56:11 pm by Kiriakos-GR »
 

Offline Pyr0Beast

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Re: DMM and battery life - battery choices ..
« Reply #13 on: May 16, 2010, 11:09:20 pm »
I have seen our Duracell batteries we get here in Slovenia perform really poor, quite different from what is sold in Austria. Even some cheap chinese alkalines outperform them. Varta ones are better and for a start, they don't leak after they go dead.
(I've had bad experience with a 'high quality' battery which burned main transformer in heating regulation due to developed short from its leaking 'acid' (which is lye actually) - only Zinc-Carbon to go in there from now on)


9V lithiums are better due to the fact they only have half the cells of ordinary 9V alkalines.
With 9V rechargeable batteries, be sure to charge them the moment your DMM shows you 'dead battery' sign and every 3 months to keep them in service for a long time to come.
 


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