Isolator Battery Isolator?

Do most of you "old timers" unplug from your tow vehicles or do you depend on the battery isolator to make sure you don't draw down the tow battery? And by the way, if you're plugged in to shore power, do the 12v options run off an inverter so that no battery power is used?
Thanks in advance for all your help.

 

We have the battery isolator better to be safe than sorry. When you are plugged into shore power it chargers the battery for 12vdc.Steve

 

Battery isolater easily pays for itself in worryfree camping.

 

I added a relay in the tow vehicle that closes when the ignition is on. This relay closes the circuit from the battery in the TV to the TD via the trailer plug. Total cost of about $12.
I know that I will have to add this relay to each TV. But it is easy to do when I wire the TV for towing.
Steve

 

The relay was picked up at the local auto parts store. I think it was 10 amp rated. I wired the coil to the lighter circuit. I took a heavy gauge wire, 10awg or 12awg, from my battery thru the relay to the 7 pin connector at the rear of the car. When the car ignition is on the relay is closed.
Works very well,
Steve