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Real difference between LR44 and SR44 button cells? Info please

I bought a card full of approx forty assorted LR button cells marked "silver oxide" for a pound (not even two US dollars).

I didn't expect much but to my sheer total astonishment they seemed to work quite well! So far.

Then I got to thinking that maybe they will leak horribly when exhausted. So I figured I should see what the designation "LR" means. As you can see below, I am not much wiser!

Can someone offer some real facts on the difference between LR and SR button cells.

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I have found lots of contradictory info on the web about the difference between LR44 and SR44 button cells. Or just LR and SR cells.

(1) Some say that the LR44 is ALKALINE, others say it is SILVER OXIDE. Some same it is both!

(2) Another says LR44 and SR44 are designations used by DIFFERENT MANUFACTURERS. For example:

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(3) Some say that a silver oxide cell has greater CAPACITY than the equivalent alkaline.

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(4) Others say that the silver oxide SELF-DISCHARGES quickly other say slowly.

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(5) Some refer to RATE OF DRAIN and say the silver oxide can take a heavy load. Others say the alkaline can deliver more.

(6) One says that some SR44s are EQUIVALENT to type 357 but that some different SR44s are equivalent to type 303. Weird. See

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(7) Most seem to say that the silver oxides deliver a constant voltage until they pack up whereas the alkalines deliver a declining voltage.

All that truly confuses me now. Oh dear! What of the above is true?

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Reply to
Jax
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As I recall, LR44 is alkaline and SR44 is silver oxide. Silver oxide gives a more constant voltage.

357 is like SR44 but with lower internal resistance. Some Olympus cameras are much happier with 357 than with SR44.
Reply to
mc

It is alkaline. A lot of people are confused nowadays.

No, they are the same mfr., alkaline and silver oxide respectively. At least that was the case when I was researching camera batteries about 5 years ago.

Depends on the load current, probably.

Slowly.

Hard to say unless quantified. Also depends on whether you are willing for the voltage to drop as the battery gets used up. Alkaline drops a lot more than silver oxide.

When I looked into it, 357 was an SR44 with lower internal resistance than an MS76, which is also supposedly equivalent to SR44. Olympus cameras tend to prefer 357 to MS76. (OM-2S and OM-4T SLRs, that is.)

Right.

Reply to
mc

MC:

Do you have a source for your information? I was very happy to learn that what I had guessed was apparently correct, but would like to read/learn more.

H. R.(Bob) Hofmann

Reply to
hrhofmann

On 16 Jan 2006 15:31:38 -0800, snipped-for-privacy@att.net put finger to keyboard and composed:

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- Franc Zabkar

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Please remove one 'i' from my address when replying by email.
Reply to
Franc Zabkar

Omron do some 4mm dia. domes (B3D-4112). ITT Cannon do a side-actuated one with a 1.66x3.5mm profile x 5.5mm wide - if you could find a way to stack these maybe they would be worth a look. KSS221G

Also look at people like ALPS, but obtaining small qtys may be tricky. Perhaps investigate dead digital cameras/mobile phones....

Reply to
Mike Harrison

If your stylus happens to be metal, a simple copper grid might suffice. A pair of interleaving comb patterns, with trace/space small enough so that the stylus will touch both adjacent traces without the tip radius bottoming out in the gap. Add an 0402 cap to debounce.

Reply to
DJ Delorie

It's all the extra parts for ESD protection that I'd be worried about. The debounce wouldn be best done in firmware. Perhaps a stylus could be made with a softish* conductive rubber button at the end, but insulated from a plastic shaft. Maybe a zebra strip surgically modified-- cut to size and sliced horizontally to expose a conductive strip, then glued to squared-off end of an insulating rod.

*whatever durometer that turns out to be

Best regards, Spehro Pefhany

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Reply to
Spehro Pefhany

I don't believe that answers relating to major/reputable brands would be of much relevance to the '40-ish for a pound' Chinese ones from market-stalls, etc. I've used them for some years, from cards with various obscure makers' names and a motley collection of sizes and type-designations, but have always taken the word 'silver' (or an SR or AG prefix) 'with a pinch of salt'.

That said, they're certainly good value for money: occasional cells 'dead on arrival' (and with external corrosion) apart, they've lasted pretty well and have never later leaked. Certainly, IMO, fine for anything but an expensive analogue watch which one doesn't wish to take the back off more frequently than essential (risk of dust/dirt) ...

--
Peter Duck
Reply to
Peter Duck

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