I did not have a Xantrex Echo Charger or Big Boy in my earlier Beaver coach. It also did not have as much of a draw down on the chassis batteries as the new ECMs do but at least once a month while in storage you did need to charge the chassis batteries to keep them up. I changed the momentary boost switch to a regular rocker switch so about once a month I would leave it on for a day and the house charger would bring up the chassis batteries also. If you have a continuous duty solenoid, but no other chassis battery charging system, then this is another option for you.
Later Ed