Starting engine with house battery

I need some input from you car guys. I just returned from storage where I go to visit my RV and exercise its parts.  The engine battery was dead. (I usually go about once a months but it had been almost two months of very cold Rocky Mountain winter. Don't know if the temps and length of time since last visit was the problem or I left something on at the last visit, but am usually very careful about that.) I tried to activate the house batteries which were in storage mode so I could use them to crank the engine using the dash board switch. No luck and I feared they were also dead. Once I jumped the engine and got it started, I could activate the house batters and, as per the light panel, they were half-full.
Question 1--does the switch that puts the house batteries in storage mode require juice from the engine battery to take them out of storage mode? If so, is there any other way to activate stored house batteries to start a dead engine?
Question 2--We have chatted with other people in our storage lot and one uses a small solar trickle charger on the engine battery. Does anyone know about these or have knowledge/experience with them? Is there any particular one you would recommend? Are they hard to instal?

Thanks to anyone with some wisdom about this situation.

Nicki Loth
Dillon, CO

Nicki,

One of the first things I noticed when we got our new PC was the periodic high current draw from the engine computer as it checked stuff when you were not using the engine.  From various Ford forums it was clear this frequent drain would bring a battery down to unserviceable levels in a few weeks.  Accordingly I added a cut-off switch directly onto the negative battery post.  When we are not using our PC it sits at the side of our house so I have shore power.  That way a trickle charger keeps the engine battery happy.  However,  if we were to leave our PC say for a cruise, I can disconnect the battery.

Please never try to start the engine by use of the coach battery switch on  the dash.  This is solely for charging the engine battery.  The wiring is unsuitable for the very high current needed for jumping the engine battery.  For this emergency, carry jumper cables that will reach your house battery.

With our older 2007 PC2350, the only way I can assure the batteries won't drain during storage, is to disconnect them.  I disconnect only the ground terminal, leaving the red power terminal connected.  I do this for both the chassis battery and the twin coach batteries.  If you do it, just make sure the batteries are fully charged before disconnecting them.  It helps in preventing the batteries from freezing.

I appreciate the great suggestions. It sounds like the best idea is to disconnect the battery when in storage to prevent this from happening again.