Hi,
If the RV is plugged in, then the battery will stay properly charged. DOn't worry about the switch being on or off, unless you are storing the RV someplace without 120 volt power. In that case, switch to off to slow the battery discharge.
Batteries will self discharge at about 5% to 10% of their capacity per month. In a RV, the CO meter will discharge it at about 10 amp hours per day. You can not shut off the CO meter in most models, except when the storage switch is off. Leave on the propane detector and it's solenoid to allow propane into the pipes, you will draw about 1 amp per hour, or enough to drain a pair of batteries in about a week.
The slide motor uses a lot of amperage, but not for a full hour. So while it might draw say 40 amps, because it runs about 1/30 of one minute, that means it only takes about 1.2 to 2 amp hours to move the slide in or out.
The water pump is also very energy efficient. While it can draw 7 amps per hour, it will pump 2 gallons per minute, or pump a 120 gallon tank dry with only 7 amp hours.
The CO meter is not as efficient. While drawing only a couple of watts, say 0.2 amps per hour, it is running all weekend, and in 3 days can draw 25 amp hours, twice what the water pump will use in a long weekend.
You can fix all of this with a pair of 100 - 120 watt solar panels. Now much less expensive than in the 90's when I bought mine.
SunElec.com sells some for about $1 per rated watt.
Fred.
Money can't buy happiness but somehow it's more comfortable to cry in a
Porsche or Country Coach!
If there's a WILL, I want to be in it!
I havn't been everywhere, but it's on my list.
Kangen.com Alkaline waterEscapees.com