The value of an accurate electric diagram.
Since building our house with the tall garage we store our Voila inside. Last year before going for the 3-month long trip I disconnected the battery bank with the remote Intellitec panel. After return batteries were dead at about 11V, ouch.
A quick look at the electric diagram reminded me that I wired the Morningstar solar charge controller upstream the disconnect relay. It was a while when I finish wiring my van. The charge controller drained my batteries. I added turning off solar charge controller to my long trips check list.
After coming back from this year trip a few days ago I turned the Intellitec on and got a very rewarding 12.8V. Placing a solar charge controller upstream main disconnect could be debated but having an accurate electric diagram made my RV troubleshooting life easier.