What's a way to use up old 9 volt transistor batteries? I've got a couple dozen that still have some charge. I figure with a couple battery clips, I could put two in series. Dump the charge into 12 volt lead acid batteries to keep my devices going some day when the power is out.
One of the charge bases for my FRS walkies takes 9 volts in. Maybe rig something up, and parallel a couple transistor batteries to keep FRS walkie charged.
Just hate to throw them all away.
They aren't much for curent output or capacity, maybe 100 - 200 mah for good alkalines, the individual cells inside are just too small. I just use them up for the things designed for them - meters, transistor radios, my Raytemp thermometer, etc. before I buy more.
The 'Heavy Duty' ones are even less robust, and aren't even worth bothering with. I don't waste the money buying them. And on either type, if it's past it's pull date...
You do NOT use a questionable battery in a smoke detector or anything that is Life Safety related, for that you buy a fresh pack of alkalines - if the smoke detector I'm installing came with a HD, that gets replaced with a known good alkaline. Use that HD battery up in a meter that won't kill someone when the battery goes flat the wrong night.
It doesn't make much sense to charge small batteries with other small batteries, you are trying to dump 200mah into a 7 AH battery - it won't even notice unless you waste a large pile of transistors.
If you want to run things, you make an external pack to run the device drect. Probably several 9V batteries in parallel to get the needed current.
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What is your time worth?
Your commodity alkaline 9 V battery takes about 11 hours to discharge from 7 V to 4.8 V at 10 mA (70 F) So that is an average of say 5.9 mW for a period of 39,600 seconds. Could that really be ~ 233 Joules?
One $0.14 kWHr delivers 3600000 Joules of energy. So for 14 cents, you get the equivalent of ~15,450 "flat batteries'" worth of energy.
:)
--Winston
I use them up in a DVM. They draw so little power that they last long on a weak battery.
Lick 'em for a burst of flavor. Great way to stay awake on those long road trips out there in Utah when your wives aren't entertaining you.
Or several in series to get more voltage, and then parallel the series groups to get more current at that higher voltage. Note that to connect them in series, you don't *need* and clip leads or other connectors -- you just snap the button of one into the cage of the other, and keep doing that until you have enough in series. That is one of the nice things about those battery connectors, though I would use new batteries for anything which matters, as the output voltage of the old cells will be a function of how discharged they are when you start.
Enjoy, DoN.
(...)
The most-discharged batteries in that string would soon go 'reverse polarity' on you. Better to use a bunch of independently - powered Joule Thieves with paralleled outputs protected by blocking Schottkys.
It is still a massive waste of time, IMNSHO
--Winston
Christopher lives in New York.
They aren't much for curent output or capacity, maybe
100 - 200 mah for good alkalines, the individual cells inside are just too small.CY: Right, they are AAAA , or four A.
I just use them up for the things designed for them - meters, transistor radios, my Raytemp thermometer, etc. before I buy more.
CY: That's a good idea.
The 'Heavy Duty' ones are even less robust, and aren't even worth bothering with. I don't waste the money buying them. And on either type, if it's past it's pull date...
CY: Heavy duty means carbon-zinc.
You do NOT use a questionable battery in a smoke detector or anything that is Life Safety related, for that you buy a fresh pack of alkalines - if the smoke detector I'm installing came with a HD, that gets replaced with a known good alkaline. Use that HD battery up in a meter that won't kill someone when the battery goes flat the wrong night.
CY: Right. Smoke detectors get new batteries of good quality.
It doesn't make much sense to charge small batteries with other small batteries, you are trying to dump 200mah into a 7 AH battery - it won't even notice unless you waste a large pile of transistors.
CY: Got enough of them sitting around.
If you want to run things, you make an external pack to run the device drect. Probably several 9V batteries in parallel to get the needed current.
CY: That did occur to me. By the time I build a jig, I could have done other things.
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That's my thought. For charging lead acid batteries, so much easier to plug into the wall. Might tinker with it, someday when the power is out.
I've done that -- clip several in series. Not sure I'd want a higher DC voltage. But, who knows?
That, and the LDS church gave up on plural marriage in 1890.
You're gonna need a *lot* more power to charge lead acid batteries.
--Winston
Great links. I do have a 1.5 watt dashboard solar panel for my jumper pack. Run my key machine off the jump pack, now and again. Of course, not much power in the transistor batteries. I just hate to pitch em out.
Someday I will get bored enough to take two new alkaline 9V batteries and snap them together. Gerry :-)} London, Canada
They get really warm, or so I'm told. :)
--Winston
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