OSUChE

Is there a simple way that I can wire my 12V lighter outlet to remain on with the key switch in the accessory position like the radio?

503C43 ////AMG

splice the lighter outlet power wire to the power wire on your radio

OSUChE

Touché. My question should be more sophositcacted then: By tapping into the radio feed to run an Iphone and Jabra wireless charger do I risk the wrath of Kirchoff's laws by pulling too many amps and hence frying a "too touchy" MB designed radio?

appatula

By tapping into the 12V radio feed you are essentially creating a parallel circuit. Amperage thus branches off into each load accordingly while voltage stays the same. In a series circuit voltage drops off while the current is constant through the circuit, thus in series would you have to worry about pulling to much amperage "through" the radio so to speak. Should not have any issues tapping into ANY switched 12V source whether it be the radio feed or any others.

Only thing that can fry is the fuse, as that is the only part of the wiring that will supply full current to the devices until the current be branched off to its corresponding loads (chargers, radio, ect.) I hope that makes sense.

503C43 ////AMG

This is correct..... If you are really worried about it (which you shouldn't be) you could throw in an inline fuse before the cig-lighter.

appatula

If he does tap off the radio 12V ignition, it is allready fused (should be ). A trickle charger and iphone should be fine current wise, however, if you plug anything power hungry into the socket after this mod it will pop the radio fuse, that includes the cigarette lighter, emergency light, pumps, ect. If you are worried about this you can easily wire in a relay using the 12V ignition from the radio as coil activation and use the stock cig lighter wiring on the contacts. This will keep everything seperated, allow power to the socket, and still allow you to use the cig socket as originally intended.