my 2007 c230 cigarette lighter socket does not have power once the vehicle is turned off and I'd like to be able to leave my phone charging in the car when I turn the vehicle off. any one know a safe easy way to supply constant power to it?

 

Have a DC per outlet installed to run off constant power. That is my only suggestion. Good luck.

 

any one have any suggestions for a good location to get power from? Is there a spare fuse location?

 

Look up this post; though it is for the E class, there may be something similar for your C class.

https://mbworld.org/forums/e-class-w...er-always.html