You guys beat me to it, yes, I have found that you have less problems, dead batteries, etc. when you leave it plugged in.
This trickle charges the batteries a little more aggressive then in the stored stage which is no charge.
Here is the thing, people sometimes go in the coach and leave a light on then what do you have, dead batteries when your ready to go on a trip.
The bottom line - Leave it on shore power all the time, as there is a very very slight possibility that it could insignificantly shorten the life of your batteries. We do it out of convenience.
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