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  #1  
Old 06-11-2000, 10:26 PM
Greg Charles Greg Charles is offline
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OK, here's the situation. My mom's garage door opener stopped working so I helped her change the battery. The whole time I was saying that she must have changed it several times already, because she's lived in her place for 15 years. When I got it open though, I saw the battery was one of those silver Everready types, with the logo of a black cat jumping through a 9. I remember those disappearing shortly after the Energizer was introduced, something like 20 years ago. It still had some juice left in it!

If the old batteries could open garage doors for two decades, why the switch to alkaline? They seem to die after a couple of years in drawer doing nothing.
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Old 06-11-2000, 10:28 PM
argyle87 argyle87 is offline
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Did you ever consider how little power a garage door opener uses?
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Old 06-11-2000, 10:54 PM
astro astro is offline
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I don't think a standard carbon type 9 volt could last 20 years *in use* with any usefulness. Maybe 10+/- years but 20 is *really* stretching thisngs.

The more likely explanation is that the 9 volt may be 15+ years old but was sealed and unused in an ideal environment (back of a drawer maybe) until it was put into use several years ago. A garage door opener control will use less electricity on average over a given span of time than just about any other appliance I can think of.

It's also possible to re-charge carbon batteries to a limited degree. Whether some neighborhood handyman did this for her with a battery he had laying around may be possible though unlikely.
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Old 06-11-2000, 10:59 PM
stuyguy stuyguy is offline
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Not so fast, Greg

I do believe you are mistaken about those silver-foil-clad "general purpose," cat-thru-the-nine batteries being taken off the market so long ago.

I did a marketing project in college (1981ish) and chose Everready GP batteries as my product, so I always had a soft spot in my heart for them. For quite a few years after -- well into the 90's, I estimate -- whenever I bought my alkalines I'd look for them and usually find them sadly (and justly) sitting on the bottom hooks, lonely and dusty.

BUT they were always cheaper than the alkalines, so I figured there were these die hard (pardon the pun-ishment) old timers who'd be damned before they pissed away their hard-earned American greenbacks on them new-fangled commie Energizers: "They're all shaped the same, must work the same!" (No offense to your mom there; sometimes I go a little overboard in my roleplaying.)

I think the silver GPs may be gone for good now, but I bet ER is still making the GOLD-foil "Heavy Duty" cat-thru-the-nine ones -- easily mistaken for their silver cousins.
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Old 06-12-2000, 01:08 AM
scr4 scr4 is offline
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Quote:
If the old batteries could open garage doors for two decades, why the switch to alkaline?
The energy you can draw out of a battery is not fixed, but depends on current. Alkalines and non-alkalines (Manganese, I think?) batteries may last about the same in low-current devices such as clocks, smoke detectors and, of course, garage door openers. Put them in a high current device such as a flashlight or a boom box, and the alkalines last much longer. It is actually a waste of money to buy alkalines for low-current devices, which is why people still buy and sell non-alkaline batteries.

Incidentally, NiCd and NiMH rechargeable batteries do even better at extremely high current devices such as digital cameras.
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Old 06-12-2000, 09:24 AM
sailor sailor is offline
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scr4, i believe you are mistaken and that alkalines supply more energy in any case and that they have a much lower rate of self discharge. At least that is what I reacall from an article on this topic in Consumer Reports. Do I have to dig it out?
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Old 06-12-2000, 10:23 AM
stuyguy stuyguy is offline
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Yup, they're STILL making 'em!

Did a fast check of the Energizer web site and online battery suppliers. Yes, they're still making and selling those little silver guys to this day! (9v "square" battery = catalog #216) I guess that nine-lives logo is there for a good reason, right?

Bottom line: maybe your mom's "museum piece" ain't a "museum piece" after all; she may have bought it not-so-long-ago.

Sort of takes the fun out of the battery-that-would-not-die legend in the making, but as we all know here at the SDMB, the truth can be oh so cruel.

All my best to mother.
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  #8  
Old 06-12-2000, 12:20 PM
Ozone Ozone is offline
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The biggest problem with zinc-carbon batteries, is that they are usually more susceptible to leaking (at least from my experience). My company has done some testing with 9-volt batteries, and we've found that NiCd and NiMH seem to have a much faster "self-discharge" rate than alkaline. That is to say, if you have a fully charged alkaline, and a fully charged NiCd 9-volt sitting next to each other, the alkaline will hold its charge MUCH longer, assuming no current drain. "Theoretically", it's possible for a 9-volt alkaline, or carbon battery to last for many years. It's just not real likely.

BTW, if you really want a LONG lasting battery, go pick yourself up a lithium battery. Up to four times the battery life of an alkaline.
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Old 06-12-2000, 06:43 PM
QirQ QirQ is offline
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Different batteries for different applications. Batteries are measured using discharge curves of which there are two relevant rates. One is, rate of voltage over time, temperature and load. The other is, rate of current over time,temperature and load. Some electronic devices require high current rates but can tolerate fluctuating voltage. While others require constant voltage with a certain current draw. While still others require heavy start up current and then fall back to some nominal power draw. Thus the need for various battery types such as NiMh, LiOn, NiCad, Lead Acid, Manganese, Mercury, Carbon, Alkaline etc.
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  #10  
Old 06-12-2000, 08:07 PM
scr4 scr4 is offline
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Quote:

scr4, i believe you are mistaken and that alkalines supply more energy in any case and that they have a much lower rate of self discharge. At least that is what I reacall from an article on this topic in Consumer Reports. Do I have to dig it out?
OK, I might have remembered wrong. Maybe alkalines do last somewhat longer even in low current applications. However, I'm pretty sure that the difference is much greater at high current applications, and alkalines are not very cost-effective in low current devices.
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