Recommendations for Constant 12V power supply

[bmikew]

Hey guys, quick question here.

I have a 2011 E93 M3 w/o any bells and whistles, which means no navigation or upgraded sound system. With the help of musicarNW (which they are the best btw), I managed to install a brand new audio system complete with a Pioneer AppRadio4 head unit (Pictures to follow). I am having some issues that are being worked out, but one I need some help from the forums.

Currently my radio does not have a constant 12V power supply, which means after 1 hour the radio resets and I have to input all my settings again - very annoying. After researching the forums, it seems like there are 2 solutions to this problem. The first is to run a wire from the battery directly to the head unit, and the second would be to attach a wire to the fuse box via "Add-a-Fuse" attachment, or whatever its called.

Reading the forums I feel that running a wire directly from the battery would be a better option, as that would bypass the BMW electrical system, so should their be a problem it will not affect the rest of the car. However I heard that this 12V constant supply may drain the battery to the point where the car may kick-back an error message and "lock down" the car - which i believe it requires an ECU reset, or something like that.

So, is it better to do a direct line to the head unit from the battery? Will there be any errors on the car side that will prevent me from using it (and thus have to reset the ECU)? Has anyone done an aftermarket radio install and came across the same issue for the 12V power supply (which from the forums yes)?

First post here, so if I am not doing anything by the book let me know!

[bmikew]

IF anybody care, I installed a direct line from the battery to the radio.