Curious longlived battery

snipped-for-privacy@at.BioStrategist.dot.dot.com wrote in news:japfqp$goa$ snipped-for-privacy@reader1.panix.com:

probably a lithium coin cell. some can run for 10 years or more.

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Jim Yanik
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15 years from a 7 year battery is quite impressive. I would guess(tm) silver oxide battery. Lithium batteries can do almost as well, but unless your dive watch is huge and can fit a coin cell, Lithium is normally not used in watches.

I'm fairly sure you can disassemble the watch with the proper tools, instructions, and main force.

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Jeff Liebermann     jeffl@cruzio.com
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"Normal" is a matter of opinion. I've owned watches that use coin cells.

Yes, but were they lithium or silver oxide coin cells? One or two cells in your watch?

These daze, you can get either chemistry in almost every size coin cell. However, as my foggy memory vaguely recalls, 15 years ago, the smaller cells tended to be silver oxide, while the larger cells were lithium.

Of course, the real difference can be measured. Single cell silver oxide cells have a nominal voltage of 1.55V. Lithium is about 3.1V. If your watch had 2 batteries, they were probably silver oxide. If one battery, probably lithium manganese dioxide. If the OP would kindly disclose the maker and model, perhaps the correct battery could be identified.

There's also a small chance it might have been a mercury battery. They were banned in the USA in 1996, but may have been available in 1995 for the dive watch.

Drivel: I gave up using a watch years ago and currently perfer the clock and calendar on my cell phone or iPhone PDA.

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Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

They were lithium. Single cells. To be honest, I've never seen a silver-oxide coin cell -- only button cells.

The buttons on my jacket look more like coins.

A bit of Googling showed that you're correct. Lithium cells are usually called coin cells, while silver oxide are the somewhat smaller diameter and fatter button cells. I also couldn't find any thin silver oxide coin cells, but I did find plenty of lithium batteries in both configurations. I stand corrected.

Note the first paragraph, which also trys to make the distinction:

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Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Bought and early Casio lithium powered digital watch circa 1980 labelled '5 year life'. Buttons stuck quite quickly making it impossible to operate light or change settings so it was put to one side. Came across it earlier this year and it was still going after 30 years - probably because the light had never been used.

Don't know whether there are any records for this but this must be near the upper limit.

Chris K

I couldn't find any statistics for digital watches.

Incidentally, Smart Meters require similar long battery life. 10 to

20 years specified battery life is typical. Here's one product that's been going for 25 years:

They use lithium thionyl chloride chemistry.

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

I've got a Casio [248] W-750 ALARM CHRONOGRAPH wristwatch I've been using since the mid '80s. Its on its 5th or 6th replacement lithium coin cell. Can't remember whether its CR2032 or CR2025 - the latter I think as I keep the former in stock for motherboards. Still working reasonably well, though the time setting gets glitchy with a fresh battery.

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Ian Malcolm.   London, ENGLAND.  (NEWSGROUP REPLY PREFERRED)
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A, fifteen years is not so impressive...how about a number of sets of AA batteries from 1980 that were found in factory original equipment and these still have a charge of 1.2VDC each (this was opened on Saturday at out shop - sealed since 1980 - that's 31 years in circuit holding a charge!)? They were the battery backup for 5101 CMOS RAM memory in a video game called Robotron by Williams Industries.

Not the first time for us either, both Rayovac and Duracels have (in some cases) retained a charge all these years in these old New Old Stock video and pinball games.

Unfortunately this game (Robotron mini/cabaret) was our last NOS game from that time (we had about twenty pinballs and videos sealed from

1980, that were sold and then opened in the past ten years)...but I've kept some of the batteries.

John :-#)#

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At the end of 2007 I replaced a Toshiba AAA battery (alkaline manganese) in a desktop clock-calendar (12.5 mm LCD display), which was given to me in

1983. It was not new then, as it had already been working for at least 12 - 18 months.

Just before I removed it, I measured its on-load voltage (if you can call 1 microamp a load!) as 0.956 volts. For comparison, the current with a new replacement battery was 1.9 microamps.

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Jeff