Ive researched a bit on this type of project, but most of the stuff I find is in regards to motorcyclists who connect their jackets to their vehicles batteries. I was thinking of dosowing similar jacket design with a small portable battery source (maybe a 7.4v lipo battery), but can't seem to find much regarding the best parts to put this together. I figured I'd use some .30 AWG Teflon coated wire as the heating element. Its been a while since I've tried anything like this, so forgive me if this is something I am overlooking.. I am a novice. I want to be able to adjust the output for the heat, but can't seem to find an appropriate voltage regulator. If anyone can point me in the right direction tha would be great.

So far, my parts list is:

.30 AWG Teflon coated wire
On/off switch
Voltage regulator to control temp.

If there is any ideas on how to improve this, or if I'm missing something, p,ease let me know. I appreciate any assistance.

 

The most efficient way to control the current is to use a variable PWM controlled switch. A 555 configured as an adjustable PWM astable driving a MOSFET as a switch should work for that.

 

...jacket design with a small portable battery source (maybe a 7.4v lipo battery)

You need to think about how much power the heating element uses versus battery capacity. A "small" battery might not last long.

Take the PWM advice and forget the voltage regulator - it's not a good choice for this. It might be overkill to include a thermostat, but you could easily do so by putting the PWM under control of an LM35 thermometer IC. This may all sound too complex, but it's not as bad as it might sound.