Why not make it simple?
There are manual battery on/off switches available (kill switch). They are
cheap and simple. Install batteries parallel with appropriate heavy gauge
wiring. Auxiliary battery is on switch. When you are camping or standing
for extended periods turn auxiliary battery off. All electricity will now
only be drawn from regular battery. When you have drained the original
battery switch on auxiliary battery and start engine immediately.

Note: use the same batteries. When the original battery expires replace
with auxiliary battery and buy a new one when you get a good deal.

Bj�rn

Bj�rn Ratjen
Mill Bay, B.C.

1987 Vanagon est alia (self camperized)
1978 VW Bulli (self camperized)
1995 Passat TD Wagon (hers)
1970 VW Beetle (son's)