T&T: Xantrex Link-20 battery monitor (or equivalent product)

[Alec McLocklin (amclockl)]

  I use it constantly. If your at anchor, it is a fantastic method of
determining your DC usage. If your good at DC installations, you'll be
fine with it. Requires breaking having a single DC ground point and
breaking in series with your house battery ground. Very clear
instructions. I don't view the starting batteries amp hours, just its
voltage on the second battery selector.

Alec