Hi....In my case, the DC-DC converter is appraised for 220mA and is giving 5.2 volts, which I am dropping down to 3.3v for the GPS with a controller. Dopey, I know, yet this is a proof of idea. At any rate, the GPS and Bluesmirf turn out great off of the battery. I even snared the LCD directly to the GPS and got coherent NMEA information, yet regardless of whether I attempt to control the PIC off of 5.2v or the 3.3 volts out of the controller, nothing but bad. Different parts keep on working, yet I get, best case scenario, a weird person consistently or two on the LCD out of the PIC. However, I plug in the breadboard power supply and everything is dandy. Any thoughts?