Testing Batteries e.g. 1.5, 6 and 9V

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alisam

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#176991 18-Jul-2015 10:51

I have 7 smoke alarms and when the alarm begins to beep I usually wait the for weekend and then attempt to find out which one is dying. This time I was too late.
Fortunately I borrowed a multimeter from a work colleague and found the dead battery. His multimeter is an old Disk Smith one which requires a battery to power it. I have read that these should be avoided if possible.

I am now thinking that I need a device to test any sort of battery. I can only imagine myself using it for testing batteries and I figure it should last for a long time (or at least until AA, AAA batteries are obsolete).

Can anyone recommend a battery tester. I have seen cheap ones for $5 and multimeters start at say $30-$40.

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Jase2985

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#1346655 18-Jul-2015 11:03

any decent multimeter has a battery in it.

my advice to you is change the battery when it first starts to beep :)

gregmcc

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#1346656 18-Jul-2015 11:09

Think about it, if it's an analogue meter (with a needle) no battery is actually required to read voltage, although to do an ohms reading the battery would be required

No a digital meter.....battery is required to do any tests.....

Sideface

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#1346727 18-Jul-2015 14:14

alisam: I have 7 smoke alarms and when the alarm begins to beep I usually wait the for weekend and then attempt to find out which one is dying. ...

If one of them starts to bleep replace ALL of the batteries immediately - you should be doing this at least once a year anyway.

Battery testing is almost irrelevant - if one battery has died, they will all die soon.

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alisam

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#1346734 18-Jul-2015 14:31

I don't need to change all the batteries at once, because they are not all of the same age.

My post is for a recommendation for a device to test batteries.

Jase2985

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#1346792 18-Jul-2015 15:24

your method is very illogical

but here:
http://www.jaycar.co.nz/Test-%26-Measurement/Multimeters/Digital/Cat-III-Multimeter-with-Temperature/p/QM1323
http://www.jaycar.co.nz/Test-%26-Measurement/Multimeters/Digital/Low-Cost-Digital-Multimeter-%28DMM%29/p/QM1500

ive made one of the bottom ones before and seemed to work ok, the top one is what some students at uni use and seems to be ok

gregmcc

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#1346823 18-Jul-2015 15:57

the charged and flat voltages will also vary with battery chemistry, it is certainly an awful lot of effort to figure out when a battery may be flat

Jase2985

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#1346877 18-Jul-2015 17:17

gregmcc: the charged and flat voltages will also vary with battery chemistry, it is certainly an awful lot of effort to figure out when a battery may be flat

yep especially when you can get them for less than $1 each on TM, once a year go and spend $7 on batteries and change them all at once

you are potentially playing with peoples lives over a few $$

do it the logical and recommended way

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Rikkitic

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#1346890 18-Jul-2015 17:40

I don't know how reliable battery testers are, especially cheap ones. I prefer to use an analogue multi-meter because digital meters are too sensitive and may show a battery at full voltage when it is actually dead. Analogue meters load the battery a little, giving a more reliable reading. Even better is to put a proper resistive load across the battery and then measure it. If there is no voltage dip you know the battery is good.

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Niel

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#1347328 19-Jul-2015 20:06

Analogue and digital meters are both good. It is only when the battery of a cheap digital meter gets low then the reading goes all over the place (found with the $12 one from Jaycar linked above).

Smoke alarms can run with a very low battery voltage, there is a fair grace period between starting to beep and stopping to beep. However, that only applies when you use alkaline batteries. But you should anyway never ever use "heavy duty" or "super" batteries for anything, which are carbon zinc and functions by corrosion and eventually corrodes the canister causing acid leaks. Alkaline have a 7 year shelf life, carbon zinc has about 6 months.

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1101

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#1347504 20-Jul-2015 09:56

Rikkitic: Analogue meters load the battery a little, giving a more reliable reading. Even better is to put a proper resistive load across the battery and then measure it. If there is no voltage dip you know the battery is good.

Analogue meters actually put b8gger all load on it ,so little load its irrelevant here, look at the meter specs .(ohms per volt).
:-)
Good point about putting a real load on it, though its easier to just replace batts regardless .

FIFO

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#1347763 20-Jul-2015 13:33

I just have a few cheap torchlights in the cupboard which use single batteries of different sizes. I pop in the battery and check how bright it lights up.