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General => General Technical Chat => Topic started by: Boris_yo on September 18, 2022, 04:12:06 am

Title: Why Battery Voltage Varies Between Different Testers?
Post by: Boris_yo on September 18, 2022, 04:12:06 am
Hi. Tested new alkaline battery 1.5v and here are the readings I got:

1. Chinese battery tester: 1.27v
2. Aneng brand Chinese battery tester: 1.50v
3. Chinese multimeter: 1.53v

Used lithium AA single-use battery:

1. Chinese battery tester: 1.23v
2. Aneng brand Chinese battery tester: 1.48v

Tested Sanyo 2500mAh barely charged AA battery:

1. Chinese battery tester: 1.03v
2. Aneng brand Chinese battery tester: 1.11v

Tested 9v alkaline rectangular battery:

1. Chinese battery tester: 8.85v
2. Aneng brand Chinese battery tester: 9.12v

It seems that while multimeter puts on zero load, the battery testers put a tad bit. Though why readings between both battery testers vary?
Title: Re: Why Battery Voltage Varies Between Different Testers?
Post by: Ed.Kloonk on September 18, 2022, 04:30:35 am
Are these 'testers' analog meter variety? The cheaper the meter component the more inaccurate they are.

A analog meter is supposed to considered *most accurate at FSD (full scale deflection). Connect them to a good variable power supply and set the output to what the maximum range the meter should read. If that is anywhere near accurate, then check the meter at 1/4, 1/2, 3/4 range to see how good it is.


edit: most
Title: Re: Why Battery Voltage Varies Between Different Testers?
Post by: WattsThat on September 18, 2022, 04:32:22 am
Yes, battery testers load the battery, a multimeter/DMM does not.
Title: Re: Why Battery Voltage Varies Between Different Testers?
Post by: Ed.Kloonk on September 18, 2022, 04:36:17 am
Yes, battery testers load the battery, a multimeter/DMM does not.

I see now the question asked. Disregard my answer. Sorry.
Title: Re: Why Battery Voltage Varies Between Different Testers?
Post by: tooki on September 18, 2022, 04:33:24 pm
Hi. Tested new alkaline battery 1.5v and here are the readings I got:

::snip::

It seems that while multimeter puts on zero load, the battery testers put a tad bit. Though why readings between both battery testers vary?
Yes, a multimeter places essentially no load, while a tester places a load. As for the differences — well, think about it for a moment: what would cause a difference in measured voltage? Give us your hypothesis and we’ll let you know if it’s right.
Title: Re: Why Battery Voltage Varies Between Different Testers?
Post by: bdunham7 on September 18, 2022, 05:01:13 pm
I think your generic or unnamed "Chinese battery tester" is the one getting the job done here...
Title: Re: Why Battery Voltage Varies Between Different Testers?
Post by: ledtester on September 18, 2022, 05:05:51 pm
Which one is your Aneng tester? Does it look like this:

[attach=1]
Title: Re: Why Battery Voltage Varies Between Different Testers?
Post by: BeBuLamar on September 18, 2022, 09:07:37 pm
Connect a power supply set for 1.5V with rather hefty current capacity (at least 2A) and see what the #1 tester reads and how much current does it draw from the power supply.
Title: Re: Why Battery Voltage Varies Between Different Testers?
Post by: unknownparticle on September 19, 2022, 05:57:51 pm
Some DMM's have a dedicated range for 1.5 and 9 volt batteries, which place a load across the cell. This gives a more realistic idea of the cell capacity.
Title: Re: Why Battery Voltage Varies Between Different Testers?
Post by: Boris_yo on October 04, 2022, 08:46:32 am
As for the differences — well, think about it for a moment: what would cause a difference in measured voltage? Give us your hypothesis and we’ll let you know if it’s right.

Impaired conductivity of battery tester? I used electronics contact spray on the one giving lowest reading and it still does. Probably has some kind of internal resistance or crappy components.

Quote from: ledtester
Which one is your Aneng tester? Does it look like this:

That's the one. Also here's the multimeter face. For voltage reading I set on 2 under V-
Title: Re: Why Battery Voltage Varies Between Different Testers?
Post by: Nominal Animal on October 04, 2022, 11:48:15 am
Impaired conductivity of battery tester?
No.  A battery is not a perfect voltage or current source, it has real world characteristics.  Consider what those characteristics are.
Title: Re: Why Battery Voltage Varies Between Different Testers?
Post by: SmallCog on October 06, 2022, 01:53:49 am
I suggest you probe the battery with the meter whilst it's being tested by the battery tester.

Theoretically you'll see more similar readings between the meter and tester as the meter will be reading the loaded battery
Title: Re: Why Battery Voltage Varies Between Different Testers?
Post by: Kasper on October 06, 2022, 05:10:01 am
Measure the battery current during the battery test to check for differences between testers.
Title: Re: Why Battery Voltage Varies Between Different Testers?
Post by: tooki on October 06, 2022, 06:21:22 am
As for the differences — well, think about it for a moment: what would cause a difference in measured voltage? Give us your hypothesis and we’ll let you know if it’s right.

Impaired conductivity of battery tester? I used electronics contact spray on the one giving lowest reading and it still does.
No, it’s not that.

Probably has some kind of internal resistance or crappy components.
Earlier, you mentioned the battery tester applying a load. That is correct. Now, what poses a higher load (= more current flow): a smaller resistance or a larger one?
Title: Re: Why Battery Voltage Varies Between Different Testers?
Post by: Boris_yo on October 10, 2022, 06:40:04 am
Quote from: tooki
Probably has some kind of internal resistance or crappy components.
Earlier, you mentioned the battery tester applying a load. That is correct. Now, what poses a higher load (= more current flow): a smaller resistance or a larger one?

Are you talking about resistance of battery or impedance of battery tester?
Title: Re: Why Battery Voltage Varies Between Different Testers?
Post by: tooki on October 10, 2022, 01:30:55 pm
It’s a general question to see if you understand Ohm’s law.