Lights from cell (StarTac) phone batteries?

[John N]

I've ended up with some StarTac batteries and chargers and was wondering what flashlight possibilities they might have.

Specifically, what does each contact do? I would expect two contacts from a "normal" battery.

Thoughts?

Thanks,

-john

 

[highlandsun]

I've had a hard time tracking down these pinouts. On the main batteries, the center two pins are power. I think the outer two pins may be for a temperature sensor. I think the auxiliary battery pins are in a different order.

When charging, the rapidcharger in the phone will pump up to 725mA, so I know the battery will allow at least that much current to flow. You'll need some kind of step-down/current regulator. A full charge for most of these is 4.20V, some of them are less.
The desktop chargers usually peak at 500mA.

 

[JoeyL]

Hello John N!

You hit on one of my favorite mods. I hate to waste batteries, specially when they cost a lot.
I have taken the Star Tac batteries when they no longer power the phone for long. When you first get them, they have a little holder they snap into for safe keeping (to prevent shorts). If you put an LED into it so that the leads contact the two central battery contacts, it makes a neat bright led light, good for about 10 hours. No resistor is needed for a standard white nichia LED.