[3798j]

What I wanted was to be able to plug a CTEK3300 to the Z4 without going under the hood or going into the interior (for the cigarette lighter outlet).
In the middle of the firewall is the positive terminal for jump-starting the engine and further to the left, there’s a threaded ground stud. By attaching the pig-tail here, I would have the plug exiting just to the left of the drivers windshield wiper (at the base of the windshield).
Unfortunately the supplied CTEK hard-wire hookup was too short (about 22”) on the positive wire to allow this placement. The solution was to splice an additional length of wire with an M8 round connector on the end.
Pulling the plastic cover away from the positive jump-start terminal you'll find there is plenty of room to attach the CTEK’s positive wire. Blue Locktite was used to insure the nuts would stay fastened. The negative wire’s round connector is size M6 while that threaded ground stud is M8. Using a round file the opening was easily enlarged.
The installation took about an hour. I took some photos and I'll post them next.