33 years old AA battery, still in good health

[mcinque]

I found an old sharp calculator in a friend's house. He had never used it basically.

I asked him if he had ever changed the battery on it, since leaks are the first thing I think of in battery-powered devices.

He told me that he "didn't even know it had a battery" (how did you think it worked?).

I opened it up and found an AA battery that is apparently dated 1989 and has been there without leaks ever since that year. The calculator still turns on, the battery is at 10 percent.

Sure the calculator is still alive just because the battery is not a modern alkaline, but 33 years sitting there seems like a great accomplishment!

[amyk]

It probably has thicker terminal seals and casing than those today, because the materials were relatively cheaper back then.

[Sal Ammoniac]

He told me that he "didn't even know it had a battery" (how did you think it worked?).

Many calculators in that era used solar cells for power and didn't use batteries.

[Stray Electron]

   That calculator obviously used a battery. 

     I have had Japanese made Sanyo NiCad batteries that lasted over 30 years. And I have some of the old big 6 volt lantern batteries made by Rayovac that are about 45 years old (1976 date codes) that still have voltage but I don't know if they will carry a load. I bought an old camping lantern a couple of years ago and there were four of them in it. One has slight signs of leakage and had some slight corrosion on the battery but not in the lantern, but the other three are fine and all four measured about 6 volts OC. One of these days I should put a load on them and see how they read.

[mcinque]

He told me that he "didn't even know it had a battery" (how did you think it worked?).

Many calculators in that era used solar cells for power and didn't use batteries.

Well, yes. But the solar cells are clearly visible. I can understand not everyone can recognize it, but

[unknownparticle]

My Mums gas fire needed repair, I found a D cell, zinc chloride type in the igniter unit that was dated  1996, it still had capacity, not much but some and no sign of leakage!  In some respects, actually many it seems, technology is going backwards these days!

[mcinque]

technology is going backwards these days!

I think the fault lies in the attempt to have more and more energy density than competitors, better shelf life and the consequent use of new materials and chemicals.

Carbon-zinc batteries leak too, but they leak ammonium chloride that it's mildly acid, while potassium hydroxide (alkaline) is a strong base. But alkalines have a longer shelf life and a greater energy density: carbon-zinc cannot last in "modern" devices with high current demand.

[mcinque]

He told me that he "didn't even know it had a battery" (how did you think it worked?).

Many calculators in that era used solar cells for power and didn't use batteries.

well that's true, but they usually had the cells exposed and a visible "solar cells/powered" label.

[joeqsmith]

I was given an old analog meter that I suspect had the original batteries.  These leaked but they had a thick plastic seal that prevented an external leak.   

https://www.eevblog.com/forum/testgear/history-of-tachikawa-(tmk)/msg1321927/#msg1321927

[RoGeorge]

Why did you peel off the battery?

I've noticed many electronics from back then, when the remote controls and pocket calculators used to be a PCB black blob instead of a chip with soldered terminals, they tend to preserve very well the batteries.

I have a few thermometers, a remote control from a former AC kept because of it's very good accuracy as a clock+thermometer, a pocket calculator, the clock inside an old Samsung boom-box, all have a PCB black blob IC, and they run for 5-10 years, maybe more, with the same battery.

I wonder if such PCB-blob chips somehow acts as an energy harvester from the surrounding EM fields (unintended, only as a side effect of that technology), so they recharge the battery.  So far I have had at least two batteries that lasted longer inside the clock of a digital radio than the other two batteries from the same package that were sited as NOS on a shelf.  It's a mystery. 

Anybody knows what technology was that, during the 70s-90s, when the IC used to be a black blob on the PCB for many consumer devices like clocks/thermometers/pocket calculators?  It was CMOS, or something else, and what size?

[tooki]

Black blobs are unrelated to the IC technology and are still routinely used in remote controls and calculators.

[AndyBeez]

The arrival of the LCD display was a quantum leap in power consumption. My first Texas calculator with its miniature red LED bubble display, needed new batteries every month; it was converted to 'power brick' operation just to save money. Then, my first LCD Casio needed new AAs when the display had faded out - which was once in whenever.

I have a battery&solar calculator c1987 that never did have the button cell replaced. A moot point as under artifical light, the postage stamp sized solar panel provides enough micro-watts to power the logic and display. I eventually removed the slightly tarnished cell after 30 years and it works perfectly in the light off the computer monitor. I suspect these calculators were only meant to last three years, before you bought a new one.

Given how few micro-watts - or less? - an LCD calculator consumes, having an AA cell still functioning decades later is no real surprise. The only surprise is the electrolyte played nice for that long. Your friend's calculator sure has its place in Silicon Heaven.

[mcinque]

Why did you peel off the battery?

I did it to see how the cell was sealed

I've noticed many electronics from back then, when the remote controls and pocket calculators used to be a PCB black blob instead of a chip with soldered terminals, they tend to preserve very well the batteries.

chip on board it's done only because it's cheaper. the reason the battery last years is probably just that those devices draw few microamps.

I wonder if such PCB-blob chips somehow acts as an energy harvester from the surrounding EM fields (unintended, only as a side effect of that technology), so they recharge the battery.

definitely not, you can exclude it.