Rachael,

I'm thinking a marine dual battery switch like this:

http://www.westmarine.com/images/full/300aswitches_f.jpg

Wired into a simple voltmeter like this:

http://www.westmarine.com/images/full/30024_f.jpg

Total cost around $70.00

Available at: http://www.westmarine.com

You would be able to monitor the voltage of either or both batteries ..
Depending on which you select.

There are integrated units available .... But those I have seen cost
over $250

"Don't let your Dreams be Dreams."
  - Jack Johnson

Larry Chase
Email: RoadGuy@RoadHaus.com
Web: www.RoadHaus.com
Cell: 480 620 8966
What: North American Road Trip
How: RoadHaus - 1990 White VW Westfalia Syncro
Today: Roaming the Yukon & Alaska.

- - -

Date:    Sat, 9 Aug 2003 14:09:06 -0600
From:    Gnarlodious <gnarlodious@MAC.COM>
Subject: Battery monitoring panel needed

I need a device to monitor the charging and discharging of two batteries
connected or separately. Is there a commercially available panel to do
this?

--Gnarlie