Here are some documents you might like to read if you are interested in a shutdown controller



Aux connections, how to power an AMP, etc.
http://www.mpegbox.com/microsdc/usdc20d_AuxOC.pdf

Quick User Guide, how to get up and running
http://www.mpegbox.com/microsdc/usdc20d_QuickUG.pdf

Input connection Schemes, how to connect to battery etc
http://www.mpegbox.com/microsdc/usdc20d_InputCS.pdf

Detailed spec, Lots of Electrical Engineering jargon.
http://www.mpegbox.com/microsdc/usdc20d_Spec.pdf

-Jeff