So here's the deal. I have been in to screwing around with stuff for a long time i always tend to find the answer i need somewhere. but for this i cant seam to find a good option out of the tons i have found.

I have a Bluetooth device that i want to install in my car. It has a 3.7v battery that powers it but it can not be charged and used at the same time. so i want to convert the 12-16v from my car down to 3.7v and connect it directly to the pads on the board were the battery once was. Thus allowing me to hide the small device in the dash somewhere and not having to worry about charging it every day. So please everyone give me yous thoughts or options i could use to drop the voltage. i would like to do it using as few components as possible and also stay away from anything that converts the un-used power being dropped in to heat. Thanks in advance.

 

Use Switching regulator.

 

Do an EBay search for, "step down regulator board"

 

So here's the deal. I have been in to screwing around with stuff for a long time i always tend to find the answer i need somewhere. but for this i cant seam to find a good option out of the tons i have found.

I have a Bluetooth device that i want to install in my car. It has a 3.7v battery that powers it but it can not be charged and used at the same time. so i want to convert the 12-16v from my car down to 3.7v and connect it directly to the pads on the board were the battery once was. Thus allowing me to hide the small device in the dash somewhere and not having to worry about charging it every day. So please everyone give me yous thoughts or options i could use to drop the voltage. i would like to do it using as few components as possible and also stay away from anything that converts the un-used power being dropped in to heat. Thanks in advance.

Are you still looking for a solution to your problem?

 

3.7 v is a standard lithium battery.
You could simply buy a battery charger for RC cars/airplanes that is powered from a car battery. A small charger should be readily available.

 

You can use 3,7V cell phone battery, just put it in the phone to recharge.