If your coach is equipped with device called B.I.R.D. made by intellitec it will charge your chassis battery while plugged into shore power. My thor motor coach came with this device already installed in it.
If your coach does not have the "BIRD" device, you can install a device called "amp-L-start" . This device will also charge your chassis battery while plugged into shore power.
AMP-L-START Starting Battery Charger/Maintainer - Overview Page
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