why yes, I do intend to wear them.

September 29, 2008 6:23 PM

Looking for battery operated Christmas/LED lights with the smallest possible battery pack.

I have found ones that run on three AAA batteries but am hoping for smaller. Watch batteries would be perfect.

posted by Lucinda to clothing, beauty, & fashion (8 comments total)

Watch batteries don't contain enough energy for that kind of use. They'd last about ten minutes. 1.55 volts, 115 mAH, is 0.18 joules.

An alkaline AAA battery is about 1000 mAH, 1.5V, or about 1.5 joules. Times 3 batteries == 4.5 joules, about 25 times as much energy.

Or else you'd have to pack a swarm of them into the power pack, which would kind of defeat the purpose
posted by Class Goat at 6:41 PM on September 29, 2008

Oh, heck, I botched my calculation. Multiply all the numbers by 3600 (seconds per hour). The watch battery is 642 joules. A single alkaline AAA is 5400 joules; three of them is 16,200 joules.

But it's still 25 times as much energy in three alkaline AAA's as in one silver watch battery.
posted by Class Goat at 6:43 PM on September 29, 2008

these solar christmas lights may do the trick for what you're trying to do. You'd have to rig your own batteries, but Im guessing these draw very little power to allow it to be solar powered.
posted by edman at 11:27 PM on September 29, 2008

I used to have a set of lights from Ikea that had a 4xAA battery pack. There were about 15-20 bright LED lights on a strand. The battery pack was a little bulky, but not terrible (easy to fit in a pocket), and I didn't have to change the batteries even once in about 2 years.

I'd love to replace them, so I'll be watching this question. I haven't gotten around to making a trip to Ikea yet, but I doubt they still carry them since Ikea's stock changes all the time. But they do exist!
posted by qvtqht at 12:07 AM on September 30, 2008

Oh, and Class Goat, an LED will run on a watch battery for days! See LED throwies.
posted by qvtqht at 12:09 AM on September 30, 2008

edman, those solar powered ones would be perfect, but even if I could finangle my own power source, but four meters is way too long.

I am contemplating wrapping my derby skates in Christmas lights for a bout, hence the need for as tiny a power source as possible (since, if it's legal to do and all that, I'd need to tape the power source to my leg/shove it in my skate/whatever).
posted by Lucinda at 7:11 AM on September 30, 2008

They do seem to still/again have those light strings at IKEA; they're called KALLT. (I realize it's still AA's, but at least it's only 2 instead of 3.)

I'm glad to hear they don't burn through batteries too quick - looks like this is the year I pick some up.
posted by killerinsideme at 7:47 AM on September 30, 2008

As a followup to my thread, I found some LED lights that run on two AA batteries at my local Wegmans, in the Halloween section of stuff.
posted by Lucinda at 7:45 AM on October 30, 2008