I have a small battery-operated calculator that I rarely use, but when I do need it, I want to be sure the battery hasn't run down. The button cell can be a LR54, LR1130, D189, RW89, 389, SR54, or one of several other codes, Either silver or alkaline. Does anyone know which type of battery has the lowest internal self-discharge?
Keep in mind, that a lot of battery chemistries have the following quirk:
shelf life years!, unless... measure the battery's voltage under load [in other words, use it once] and a process starts that runs the battery down very quickly with shelf life into even the 3 month range. [which means it's not good to test the batteries in those emergency kits]
Anyone have numbers for this effect?
On 3/4/2010 4:01 PM Robert Macy spake thus:
The Heisenberg uncertainty principle? Schrödinger's cat?
-- You were wrong, and I'm man enough to admit it. - a Usenet "apology"
I don't "know", but I suspect the silver cells have a longer shelf life. They also have a higher energy density.
That's also what I found in going to Wikipedia, so I'll look for the silver cells at my local Menards Hardware store. It's enuf closer to where I live than HD or Lowes to make it my store of choice, as long as I get a name brand. For unnamed stuff, I am dubious about the quality Menards sells ever since I bought some unnamed boxed finishing nails and found them to be about as durable as uncooked spaghetti.
I often sort of hate it when people undermine an OP by suggesting something entirely different from what he wants, so please forgive me for doing just that.
How about a solar-powered calculator? I have a cheap one that does so many functions I'll never use a bunch of them that runs off the ceiling light, or the desk lamp. It may have been 20 dollars, years ago, when there was a sale at Radio Shack. But no batteries. Here it is, Radio Shack 10-digit Scientific Calculator EC-4032. It has logs and trig and exponenets and I got it because it has hex, bin, and oct arithmetic which I once in a while used as a programmer. Probably something similar with a different model number now.
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Thanx, it turns out that the ribbon connector from the calculator PWB to the LCD display also came off when I opened it to take the batteries out, and I ended up throwing eerything into the trash, I probably don't need anything more than sine, cosine and tanget and exponents so another calculator I have can handle those.
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