Switched fuse or Relay location?

[HeRoze]

2001 986 S

I'm in the process of installing a solar powered battery maintainer. The goal would be to wire a NC relay to the solar panel output. In order to energize this relay, I would like to tie it to something that was 'on' when the engine was running. I would prefer a location in a box like the fuse-box. Idealy it would be a relay position ready to do what I want (energize a NC relay when running). I do know where the phone jack is under the e-brake and would prefer not to use that (I have other plans for that power...). I've looked through the fuse sections of the schematics and can't tell what I should tap off of, or if there is a spare someplace. Fuse locations D4, D10? Relays BS 3-1, 4-1, 8?

To say it another way, does anyone know of a switched fuse or relay location to rig up the following for a solar battery maintainer. Diagram has some of my guesses. Swirly areas are what I suspect are in the car somewhere, one or the other. 2001 986 S

[Lew]

The Wife's VW Beetle came with a Solar Panel for keeping the battery up when parked for long periods of times, etc., like at an airport lot. It's about 14" x 10" overall, and the charging panel is about 8" x 9". It also has suction cups on the four corners to attach to the windshield. It plugs into any cigarette lighter. Part # is 1CO 915 687 max power 3.2 W voltage at max power 18.8 v current at max power is 170 ma. We have never used it. I did check it out by attaching my volt meter to the + and - sides of the cigarette plug. In the bright sun I got 12+ volts right away. Been thinking about taking it along in my fishing boat. Could run a 12 volt bait bucket, or keep charging the battery on anchor. That's the ticket!