A use for carbon-zinc cells

[Fallingwater]

As many of you probably know, DealExtreme has the habit of selling AA-powered gadgets with in them the cheapest, nastiest carbon-zinc AAs on the planet.
I now have about a dozen of them that don't get any use because I don't trust them to power flashlights or gadgets, but that I don't want to throw away since their voltage is quite good on the multimeter.

I went to the local €1 store today and, inbetween the various crap that's always sold in those places, I found a nice LCD alarm clock. As luck would have it, I just so happened to need one for my kitchen.

So I bought it, got it home and cracked it open. It was powered by two tiny AG10 button cells that were already exhausted (the display wasn't very easy to read). No wonder it was selling for €1.

You can probably see where this is going.



Aah, nothing like hacking the simplest things to bring a smile to my face.

On a more serious note: don't throw away the carbon-zinc cells that manufacturers and/or resellers foist on you. I've seen people take new gadgets out of the box, remove the cells, toss them straight in the trash and replace them with alkalines before even turning on the gadget for the first time.
But carbon-zinc cells they are perfect for low-power appliances, especially if said appliances are so cheap you won't care should the cells leak inside.

 

[scott.cr]

Did you solder wires directly to the cells? Haha, you're a madman!! ;-)

When I was in college, a friend of mine needed an extended runtime power supply for his FM wireless microphone. We tossed the button cell and soldered in a D-cell holder. The mic was zip-tied to the D-cell holder and the cell was much much larger than the microphone! Ran like a champ for like nine months straight!

 

[Fallingwater]

Did you solder wires directly to the cells?

Why not?
I do have 2xAA holders, but I didn't bother. The clock has a low enough power consumption that it doesn't even register on my bench power supply's ammeter. I'd be very surprised if the cells lasted less than one year. They'll probably last rather longer.
And when they do eventually crap out I'll just solder on new ones (provided the clock still works).
Oh, and I hot-glued the cells on the back of the clock, so I can lift it without straining the solder joints every time.

Haha, you're a madman!!

Thanks

When I was in college, a friend of mine needed an extended runtime power supply for his FM wireless microphone. We tossed the button cell and soldered in a D-cell holder. The mic was zip-tied to the D-cell holder and the cell was much much larger than the microphone! Ran like a champ for like nine months straight!

This reminds me: a few years ago I had one of those cheap "electronic notebook" thingies that ran on three CR2032 cells. It ate very little power by itself, but the backlight spiked the draw considerably, so I used it sparingly.
After those cells died I ripped open an alkaline 9-volt battery, got the AAAA cells out, soldered them appropriately and glued them on the back of the gadget.
Ran like a champ, and I could use the backlight without imagining tiny screams of agony from the cells. It ran about three times as long as it did with the CR2032s, and then the gadget died - the cells had plenty of juice left in them.

Up next: running a PDA from three F cells