Lithium Button Batteries

[Stilllearning]

The tv remote control, (or one of them, don’t get me started) was ‘saying’ it’s batteries were flat, so I took them out, checked them on my multimeter, and both showed 3.04 volts, and they are rated at 3 volts.

Having other batteries of the same size (3025) laying around the place, I checked them, and found two that showed 3.24 volts on the meter. Problem solved, the remote works again, but this prompts a couple of questions: why doesn’t a 3.04 volts battery do the job, and are all lithium batteries actually higher power than it says on the back of them?

[Alan de Enfield]

Just compare it to a FLA battery :

 

You have a "12v" battery that is actually only 40% SoC at 12v, and ~12.8v is 'fully charged'

[MtB]

10 minutes ago, Stilllearning said:

why doesn’t a 3.04 volts battery do the job, and are all lithium batteries actually higher power than it says on the back of them?

 

You are measuring the open circuit, no load voltage. I expect if you measured the voltage with the old cells inserted into the remote and a button pressed down, it would fall away to just a volt or two. 

 

With the new cells in place they would hold up around the nominal 3 volts. 

[Ronaldo47]

Although I do have several multimeters, including some that have battery-checking options that check performance under load, I still mostly use my late father's pre-war battery tester.  The brightness of the bulb gives a good enough indication of discharge state. 

Edited January 12, 2022 by Ronaldo47
typos

[Stilllearning]

On 12/01/2022 at 11:54, MtB said:

 

You are measuring the open circuit, no load voltage. I expect if you measured the voltage with the old cells inserted into the remote and a button pressed down, it would fall away to just a volt or two. 

 

With the new cells in place they would hold up around the nominal 3 volts. 

Thank you, of course, now I understand!

19 hours ago, Ronaldo47 said:

Although I do have several multimeters, including some that have battery-checking options that check performance under load, I still mostly use my late father's pre-war battery tester.  The brightness of the bulb gives a good enough indication of discharge state. 

What a fantastic piece of equipment.

[MtB]

31 minutes ago, Stilllearning said:

Thank you, of course, now I understand!

What a fantastic piece of equipment.

 

Isn't it just! 

 

From the days when I was a brat and I remember one could figure out how things worked by looking at them or taking them to pieces. 

 

 

[Slim]

19 hours ago, Ronaldo47 said:

Although I do have several multimeters, including some that have battery-checking options that check performance under load, I still mostly use my late father's pre-war battery tester.  The brightness of the bulb gives a good enough indication of discharge state. 

Now, that's technology I appreciate, cheap, simple and long lasting. Can you still get the bulbs?

Note the Made in England stamp. Don't see that very often 😞

Edited January 13, 2022 by Slim
additional info

[Tony Brooks]

In fact many "high resistance" faults are made complicated for people who insist on using a voltmeter rather than a test light with (say) a 21 watt bulb. Unless you are aware of the limitations of voltmeter in finding high resistance faults you would be find diagnosis far easier with a test lamp.

That goes for very discharged batteries but that is not such a problem on boat  systems.

Edited January 13, 2022 by Tony Brooks

[Ronaldo47]

Electronics suppliers such as  Farnell/CPC  and RS still stock this sort of torch bulb. Maplin used to stock them. A 2.5V bulb is fine for ordinary 1.5V cells and 3V coin cells. I use a 3.5V bulb for 4.5V flat batteries  and a 12V bulb for the 12V ones  used in some remote controls.  

[TheBiscuits]

3 hours ago, Stilllearning said:

What a fantastic piece of equipment.

 

More exciting on 600V circuits though  

[Jess--]

16 hours ago, TheBiscuits said:

 

More exciting on 600V circuits though  

at least on a 600v circuit you won't need to see if the bulb lights up