GMC Sierra is a beautiful SUV and no doubt about it.
Like any other vehicle, it will require battery power to supply its electronic.
When you travel at night and raining, you will need head light, wiper, music or television set, wifi routher and a lot more.
Usually when you arrive in your house, you leave your GMC Sierra turn on to enable to charge the battery with the electronics and light off.
That mean using additional gasoline to re-charge your batter however if you have dual battery system in your GMC Sieera, you will NOT need extra time charging you battery as the isolator will keep you car battery charging even you are using all the electronics.
Take out the worry and time of charging with TRUEAM technology. Get it here