9 LED flashlight batteries question

Have a sh** load of the above. Get them free when shopping at Harbor Freig ht. Lately, when batteries fail, I started checking with a voltmeter. Turns ou t that two of the three batteries always register circa 1.4 volts, while th e third is about 0.6± volts. Naturally, I started keeping the two higher voltage cells instead of trashing all three. Is this typical? Have I bee n needlessly wasting batteries this last 50 years? Never occurred to me to check voltages. BTW, these are all AAA cells.

Ivan Vegvary

Reply to
Ivan Vegvary
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reight.

s out that two of the three batteries always register circa 1.4 volts, whil e the third is about 0.6± volts.  Naturally, I started keeping the two higher voltage cells instead of trashing all three.  Is this typical?   Have I been needlessly wasting batteries this last 50 years?  Never occur red to me to check voltages.  BTW, these are all AAA cells.

Maybe just cheap batteries. (?) When you replace with new 'good' batteries do the cells discharge at the same rate?

George H.

Reply to
George Herold

that two of the three batteries always register circa 1.4 volts, while the third is about 0.6± volts. Naturally, I started keeping the two higher voltage cells instead of trashing all three. Is this typical? Have I been needlessly wasting batteries this last 50 years? Never occurred to me to check voltages. BTW, these are all AAA cells.

Are you testing them under a load? Nine paralleled white LEDs use a lot of current from those cheap Chinese AAA Carbon Zinc cells, so unloaded readings are misleading.

Reply to
Michael A. Terrell

reight.

s out that two of the three batteries always register circa 1.4 volts, whil e the third is about 0.6± volts.  Naturally, I started keeping the two higher voltage cells instead of trashing all three.  Is this typical?   Have I been needlessly wasting batteries this last 50 years?  Never occur red to me to check voltages.  BTW, these are all AAA cells.

I usually check batteries by measuring short circuit current with a DMM on the 10 amp range. Good alkalines read about 5 amps, (D,C,AA,AAA) are all about the same. Carbon zincs read about half as much, or 2 amps. Voltage is misleading, the acid test is short circuit current.

-Bill

Reply to
Bill Bowden

Weird.

Normally, an unloaded battery reads close to its nominal voltage regardless of whether it's brand new or completely flat. The difference is in the internal resistance, i.e. how quickly the voltage drops as the current drawn increases.

Reply to
Nobody

"Ivan Vegvary"

Have a sh** load of the above. Get them free when shopping at Harbor Freight. Lately, when batteries fail, I started checking with a voltmeter. Turns out that two of the three batteries always register circa 1.4 volts, while the third is about 0.6± volts. Naturally, I started keeping the two higher voltage cells instead of trashing all three. Is this typical?

** Yes.

Very unlikely for three cells to be identical - one cell is likely to be the weakest.

The effect seems to be worse when the load current is high - as in your example.

Saw this over and over with groups of 4 x alkaline AAs used in RC receivers.

Why I changed to using NiCds.

.... Phil

Reply to
Phil Allison

"Nobody"

" Lately, when batteries fail, I started checking with a voltmeter. Turns out that two of the three batteries always register circa 1.4 volts, while the third is about 0.6± volts."

** Not all all.

3.4 volts is where the LED torch begins to fade out - under load it will be much less.

** Absolute GARBAGE !!!
** That is a separate fact.

Cell voltage does relate to remaining capacity fairly well and very well if the cell is under its normal load.

Not true for rechargeable types though.

... Phil

Reply to
Phil Allison

Really? sounds a little bogus to me.. Since i've seen a good many cells exhibit low voltage after drain.

If you are referring to rechargeable's, that could be a different story.

Jamie

Reply to
Jamie
< Lately, when batteries fail, I started checking with a voltmeter. Turns out < that two of the three batteries always register circa 1.4 volts, while the < third is about 0.6± volts. Naturally, I started keeping the two higher [ ... ]

I had the same problem with my microcontroller. The nine-volt battery tested o.k. but The pic-micro "needs" 9 volts to operate. I was sampling light with a phototransistor... my aunt figured it. She said your batteries are probably dead.

I had the other problem of trying to run the micro at 9 volts while using a LCD display. The blocks on the LCD went all black - I started using an adjustable wall-wart plug in transformer. Set it 7.5v and all went well. Took me several years to figure to ask my little cousin who figured that one...

< voltage cells instead of trashing all three. Is this typical? Have I been < needlessly wasting batteries this last 50 years? Never occurred to me to < check voltages. BTW, these are all AAA cells.

Some times rotating the batteries works.

Reply to
Steve Gonedes

They probably wouldn't be giving them away free if the batteries in them were any good.

Reply to
Ian Field

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I don't know. IN the old days "batteries not icluded" wsa pretty normal,= =20 but most things I've bought in recent years did have batteries when=20 applicable. And I find the batteries generally fairly good. Not=20 noticeably bad.

I don't know where the pricing comes from. I keep buying LED flashlights= =20 (torches in some countries), and they come with batteries. And then it=20 often seems to make sense to buy a new one when the batteries do die out=20 An exaggeration, but I keep buying the LED flashlights because they keep=20 adding LEDs to them, making them brighter.

FOr that matter, I've needed button cells to replace worn out button cells= =20 in various things, and for those that need the size, it's cheaper to buy a= =20

99cent or $1.49 laser pointer for the batteries than buy the button cells= =20 separately. Yes, you can get the cells cheap in some circles, but=20 generally not as handy as where the laser pointers get sold.

Ironically, the one LED flashlight that I care most about is faulty. I=20 have a 2AA Maglite, and a few years back got an LED replacement bulb,=20 which worked fine, but now has gotten flakey. I'm not sure if it's the=20 contacts, the LED module, or the Maglite. Ironic since the Maglite wasn't= =20 cheap, and neither was the LED replacement, but the cheap LED flashlights= =20 generally are fine.

Michael

Reply to
Michael Black

I hate flashlights that use button cells. While LR44 or 2CR2025 cells are relatively inexpensive, they really don't have a lot of capacity. I have a 2AA maglite and a Fizer I-Beam X1 which takes 1 AA. I used to have a Gerber "Infinity Ultra Task Light" 22-80010, but someone stole it; 60+ hours on one AA. Button-cell flashlights are for day- outings.

Regards,

Uncle Steve

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Reply to
Uncle Steve

Actually my need for button cells is for that kitchen timer I have lying her waiting for a battery. I've bought laser pointers for the button cells for those kitchen timers before, I think I got an analog battery operated clock going with a button cell from a laser pointer too.

I also have a battery powered pocket watch that needs a new battery. WHen I finally got the back cover off, I discovered it used "button cells" like you find in computers, CR2026 or whatever, for the built in LED flashlight, which still works fine (it used a red LED, so I never used it that much). But the clock runs off a separate battery, and that one is smaller, I think smaller than the laser pointer batteries. SO that too sits opened, waiting for me to get around to looking for a suitable battery.

Michael

Reply to
Michael Black

For certain items like kitchen timers, clocks, and calculators I often use a trick: Old 9V batteries from smoke detectors, etc, still have a lot of juice left when they are no longer useful in their original application (at least compared to the low-voltage trickle needed by LCD display devices). I build a tiny voltage regulator using a couple of NPNs and LEDs (forward biased through a high R to serve as a sharp-cutoff Vref). The whole works can be soldered together on top of a 9V battery clip, though I've also made tiny PCBs from scraps.

The result is that the 9V battery typically powers the device for a year or 2, at least, before it can't maintain the 3V needed for the device. By then I've usually collected plenty more 9V batteries. Snap the old one out and the new one in!

Of course, the Frankenstein timer/clock/whatever with a hulking 9V battery strapped to it is not likely to appeal to anyone with delicate sensitivities or fine aesthetic sense (or maybe *any* aesthetic sense!), but I get a kick out of the whole idea of running it "for free".

Best regards,

Bob Masta DAQARTA v7.21 Data AcQuisition And Real-Time Analysis

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Scope, Spectrum, Spectrogram, Sound Level Meter Frequency Counter, Pitch Track, Pitch-to-MIDI FREE Signal Generator, DaqMusic generator Science with your sound card!

Reply to
Bob Masta

I once bought a nice LCD clock for a couple of dollars, it was nice because the readout was larger than what I'd found at that price level. And when the button cell wore out, I didn't even bother looking for a button cell, I just soldered in an AA battery, hanging it off the back. The AA battery does last forever, I can't remember when I soldered in the first one, but it was at least a decade ago, and I've replaced it once, and it keeps on ticking.

I guess I wanted the kitchen timer to be more portable.

And yes, I do change the smoke detectors after a year or so, and thus the "old" batteries get used for something else, that isn't as important, so the smoke detectors run fine but the batteries aren't wasted.

Michael

Reply to
Michael Black

Naaaah! Button cells are for my pocket Nano Light, for occasional use, to peer into a mailbox after dark, etc. ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
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Reply to
Jim Thompson

Just lately we've had numerous discount stores spring up all over the place like Poundland where everything is 1 GBP, usually there's quite a few places you can buy a card of button or coin cells for around £1. IIRC the button cells are about 30 in assorted sizes per card, the coin cells are only 8 -

4x 2032, 2x 2025 & 2x 2016.

The coin cells mostly go in the outside temperature sender for my desk clock-thermometer, they don't last quite as long as the expensive named brand ones, but at that price, who cares.

Reply to
Ian Field

These days I avoid any flashlight that isn't LED, I make the further distinction that it should be a 2 cell design, as this requires an inverter to make the LED Vf. Many 3 cell LED lamps I've seen don't even have a current limiting resistor - instead relying on the cell's internal resistance to protect the LED.

If I saw a pricey 3D lamp - it might have a buck/boost converter - but I'd check the small print before parting with any cash!

Reply to
Ian Field

You could tidy up your uPower regulator quite a bit - pry the end out of a metal jacket 9V battery and shake out the cluster of cells - you now have a neat little case to build in.

Strip 2 batteries and you can re-assemble the metal jacket with a connector clip at both ends, one end is the low battery in and regulated out at the other - soldering to the out terminals avoids any future confusion about which end is which.

Reply to
Ian Field

Ah, so that's you I see out at night rooming the streets?

Jamie

Reply to
Jamie

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