Cell phone battery mod

[todmacher]

I decided it was time to made a mod of my own, and I had an old Palm Treo battery and its standalone wall charger lying around. The combination was begging to be turned into a mod.
End result:


I maintained all of the charging components for the battery, so when it comes charging time, I just flip off the e-cig portion and plug the whole mod in. I literally just finished it, and thus far it's producing vapor on par with, if not better than, my Bartleby.

Parts:
Cell battery & wall charger
Small, horn-type switch
Small sliding on/off switch
280Ohm, 1/4 Watt Resister
Green surface-mount LED
Joye 510 connector & Cone butchered from non-functioning Ego (battery exploded, and I couldn't let good parts go to waste >.<)

Update: Size comparison vs cigarette pack. This is a large mod, but it fits comfortably into a breast pocket and feels good in my hand.

 

[WillyB]

280Ohm, 1/4 Watt Resister

What's that for?

 

[melder215]

great mod man. my idea is to have it kinda like a passthru, with the cell phone battery in my pocket. then have a clip and button (or automatic parts) on the atomizer, and it can just hang on your shirt

 

[todmacher]

What's that for?

The LED. It was rated for a lower voltage than 3.7v; I think it was 2.5V. I did the math, and it turns out it needed to be 100ohm or better.
Formula, if memory serves: Ohmage = (Battery voltage - LED Voltage) / LED Current (In amps, not mA)

Quick question: What are the odds of this thing blowing up in my face?
I mean, what purpose does a protection circuit serve? How do I identify one on the battery?
If I can't identify one, could someone hook me up with a schematic for one? I'm generally good at soldering and following schematics, but I'm not the best at the electrical engineering portion of it all.

 

[Caddyman]

very nice, the convenience of having the plug built in is great....

 

[melder215]

all cell phone batteries have a protection circuit and fuse built in. if you take apart the cell phone battery you will see it. just use it like it is. if you bought a straight lithium battery you would have to add these. better to use a cell phone battery.