There apprears to be some confusion as to the wire sizes feeding the
refridgerator relay.  In my '85 Westy, the relay is fed by a 2.5 mm2 (10 AWG)
wire, not an 1 mm2 (18 AWG). This 2.5 wire comes directly from the battery--not
from the dash!  Does anyone know what the rating of this relay is?  If it is
good for 30 amps, you could simply upgrade the 10 AWG wiring to a 4 or 8.  Then
tie in the aux battery between the relay (#30) and the "refridgerator heater"
fuse.  I would upgrage this short section to 4 or 8 AWG too.  You would not be
charging the aux battery through the trigger wire!  Am I right?

                                                        Jay
                                                        '85 Westy