But many E32 also, depending on the electronic wizzards which were originally ordered. If you ordered a phone or parked heating in those days, most probably the second battery was also needed.
Highline even have a second alternator.
This shows you the relais in the trunk, battery is not installed there but you can see the brackets. Always installed on the right side in trunk.
click
The small battery has 25 aH originally.
And yes, the online wiring diagrams show you all the wires and relais you have to install, if you want a second battery. Actually no need.

E32 750iL 11/88, E32 750iL Highline 03/90
7 series Tech tips URL:http://tinyurl.com/3486c

• How to screw things up..... (pic) - eliasazem 2008-07-09 13:29:31 (372 views)
  • I have the same problem..... - mcf 2008-07-28 10:29:23 (57 views)
  • whoooo hell yeah whats your trick for making the engine look so good!!! (nt) - beach911 2008-07-10 00:21:08 (83 views)
    • I want to know that also (nt) - steinway 2008-07-10 11:16:52 (69 views)
      • I had chromed all bolts, clamps and whatever I got my hands on.. (url) - eliasazem 2008-07-10 17:01:41 (111 views)
        • www.flickr.com/photos/bimmer_750 (nt) - eliasazem 2008-07-10 17:32:32 (108 views)
          • that looks exquisite - steinway 2008-07-11 05:44:18 (60 views)
            • left the engine in it's place and removed some parts...look (pic) - eliasazem 2008-07-11 08:33:10 (159 views)
              • what's that in the trunk at the right? - steinway 2008-07-11 13:58:28 (62 views)
                • Looks like a storage compartment where the 2nd battery usually is at with a 750 (nt) - Johan750 2008-07-11 17:53:13 (65 views)
                  • Never heard of a second battery usually in a 750..... (nt) - eliasazem 2008-07-11 18:04:23 (61 views)
                    • so have you looked what's behind it? - steinway 2008-07-12 02:55:51 (52 views)
                    • It's not big enough....do you have a pic to show me...thankx (nt) - eliasazem 2008-07-11 18:05:29 (53 views)
                      • all Highline for example have a 2nd battery (url) - shogun 2008-07-11 23:14:41 (91 views)
  • Change the oil - erwin 2008-07-09 14:40:45 (91 views)
  • Rings probably OK - Patrick C 88 750 160K 2008-07-09 14:09:05 (92 views)
    • i was burning oil at same rate 400mi/qt - ridgelyrocket 2008-07-10 21:19:08 (69 views)
    • Patrick is right. - alv12 2008-07-10 11:36:44 (70 views)
      • Re: bring banks in sync - steve209 2008-07-10 14:03:42 (87 views)