I have had one for a while, using it from the cig socket mostly as a
crude charging system indicator. I am just today in the process of
setting it up to monitor my 3 batteries. I am adding a quality cig
socket to the driver side of the dash for it and am using the old rear
heater 3 speed fan switch as a selector switch for my 3 batteries. I
removed my rear heater 15 years ago so the switch and wiring for it is
free and convenient. If you want consistent readings from the batteries
you need to connect wires that are not shared by anything else. You must
use wires run from the batteries just to the meter and nothing else or
the readings will be affected by whatever else is running on the wires.
If the wiring is heavy enough this is less of an issue and may not be an
issue anyway unless you are a heavy user of aux batteries.

Mark

Michael Sullivan wrote:
> Since I am putting in the aux battery, a VoltMinder was suggested.  any
> reviews on this?  How can I hook it up to monitor both batteries?  Thnaks to
> all.
> Michael in San Antonio
> 91GL Weekender AT 2.1L 'Gringo'
> 73 Beetle
>