As the LJ engineers

[beetiger]

So, I've been playing with LEDs. Really simple playing, as in "put leads of flashy LED on battery, maybe embed in small jewelry object or something, watch flashing, be happy." I'd been using CR2032 batteries, since those are the kind that people who make piles of flashy things and toss them around as pretty graffiti use, but they're big and heavy, and I wanted to make earrings. So I got myself a CR1025 watch battery. They're both 3 volt lithium batteries, but the 1025 somehow doesn't seem to be quite sufficient to run all the colors in the flashing cycle of some of the LEDs I have, or to run the single color ones quite as bright as the 2032.

Any ideas? Is there a small button battery that would be more comparable to the 2032? Is there a factor besides voltage that I'm not accounting for? Did I just get a bad battery (which would be annoying as I paid a price-gouging $5.49 for it at Radio Shack).

Any help would be appreciated.

ETA: It's the amperage, isn't it. OK, anyone know a good higher amp button battery?

Comments

[varjohaltia.livejournal.com]

Well... Depends. I'm assuming you're doing something to limit current (resistor, or part of the flashy circuitry). It might be that the smaller battery just can't provide enough current at its nominal voltage -- this would probably mean quite short battery life too.

I'm not that familiar with watch batteries, beyond the 2032, but if/when you find a suitable one, see if you can get them off the internet. I know the CR123 lithiums which sell for $8+ at stores could be had for $1.50 online back in the day.

[beetiger.livejournal.com]

The flashy circuitry does all the resistor work, I believe. Once I find the right battery, I'll definitely buy them online. The singlet was just for proof of concept. Which failed. :(

[featheredfrog.livejournal.com]

I have some rgb flashies that run well on cr2016s, half the thickness of the cr2032.

I bought a hunnerd of 'em. Want some?

[beetiger.livejournal.com]

Is the CR2016 smaller in diameter than the 2032, or just thinner? I've got 100 of the flashies I am playing with. Maybe we could trade some. :)

[olszowka.livejournal.com]

There is a standard to the numbering of button cells. The first 2 digits is the diameter in mm. The 3rd and 4th digits give the thickness in 1/10 mm.

[beetiger.livejournal.com]

Thanks! I figured that out last night. :)

[cattitude.livejournal.com]

Getting the most light for the least power from an LED is a weird and complicated problem. There's a good discussion at http://www.talkingelectronics.com/FreeProjects/LED-Torch/LED-Torch-P1.html that's very heavy on the electrical engineering. The short version is that if you treat an LED like it lightbulb, your power usage will suck. If, on the other hand, you pulse it as often as you have current enough to drive it, you wind up getting more light for less energy. It's complicated, and a little beyond my understanding of circuitry. Still, if it fits with what you're trying to do with an LED, there are some useful circuit diagrams there.