What would it take to use a higher amp relay or = manual switch?  How would these be set-up?

-----Original = Message-----
From:   harald_nancy [mailto:harald_nancy@EARTHLINK= .NET]
Sent:   Wednesday, January 27, 1999 7:33 PM
To:     vanagon@GERRY.VANAGON.COM
Subject:       = Flash Alert! Dual Battery = Relay

To all westfalia camper owners, and = especially those
using a dual battery. If you bought a = used camper with a "dual" batt.
setup, it would be a good idea to = check this out.
I did some research at my VW dealer = today about the different relays
used in VW vanagons and = campers.
We came up with the following.
1.)
 The vanagon westy camper with = the 3 way refrigerator
 (propane, 110 and the 12 volt = while driving only)
does not have a factory installed = auxiliary batt. system.
 It is equipped with a small = shutoff relay located under
 the driver's seat in the empty = batt. box. It is a small
  1" by 1" cube. This = relay is called a :
 Refrigerator 12-volt heater = relay.
 Part Nr. 231 069 = 555    price: 32.72
 This relay is not designed to = be used to charge a second battery.
 To do so could damage your = camper. In addition the wire to the
 relay is only a 2.5 mm wire = routed through the fuse panel.
 This factory setup was not = designed to handle the load to
 repeatedly charge an empty = battery.
 Reference, Bentley 80-91 page = 97.32b, 97.33b
 2.)
 Some vanagons did come equipped = from the factory with a
 dual battery system. Some of = these are also called campers
 in the Bentley, but appear to = be weekenders. (no 3 way fridge)
 VW does list a relay = called:
 Relay for 2 batteries.
 Part Nr. 411 915 511 = B    Price a hefty 60.39
 ( maybe someone with a = weekender camper with a factory
   dual batt. setup can = verify this part number.)
 If the vanagon was factory = equipped with a dual batt system, the
 second battery is shown in the = Bentley diagram for that vehicle.
 The second battery is always = conected via a
 6.0 mm2 cross section wire, to = prevent overheating and insure
 efficient charging.
 Reference, Bentley 80-91 page = 97.34a, 97.222, 97.225

In summary: If one wants an efficient = dual batt. system in
a full westy camper with the 3 way = refrig., it is necessary to
install a new system.
You have your choice, one of the = following:
1.) install a  manual switch, or = 2.) install a 30 or 40 amp relay
or  3.) install a batt. = isolator.

Also note:  Bentley sometime = shows wire sizes in standard
(awg) gauge, and in the later = Bentleys mostly as mm cross-section.

Harald
90 westy with a dual batt = system.