Turning Car Outlet into a Battery

[Spikertk]

I have this FM Transmitter I use for my car. I want to make it so I can just put a AAA battery or AA battery in it and have it run off that instead of plugging it into my car outlet since I use that for charging my phone and I do not want to buy a splitter. How would I do this?

http://img526.imageshack.us/img526/7610/img0018e.jpg
http://img218.imageshack.us/img218/8743/img0019dfx.jpg

 

[jimlovell777]

From just a quick look at the pics it seems like you could use four "AA" or "AAA" batteries in series to power the device. Buy the proper battery holder from a local store (likely Radioshack) and solder it to the PCB after the onboard voltage regulator. Do you have any electronic test equipment? Multimeter, etc...? The circuit appears to be powered by 5V or 6V DC, 5V being the most probable and common. In the case it is 5V a simple diode would drop the battery voltage to get 6v fairly close to 5v. The previous is the less than ideal solution but if you're unwilling or unable to buy a splitter I'm guessing the same applies for the parts to go about the project "the right way". Hope this helps, post back if you have any more questions.

 

[crutschow]

Seems like a car outlet splitter would be a lot simpler.

 

[Spikertk]

Mkay, so I have it all taped up and wrapped up now, but I just connected a 9V Battery connecter to the 2 ends and it works fine, and I had it on last night for about 2 hours and nothing happened other than the device screen started dimming and then static, but I unplugged the battery and plugged it back in and it worked flawless again for another hour or so.
Any ideas what is going on there?

Also, what would I do to increase the signal strength, could I make an antenna for it of some sort?

 

[audioguru]

The little FM transmitters have a signal attenuator at their output to reduce interference to other nearby radios.