2 is 1, 1 is none. But what about my BOV/GHV?

From my experience having 2 bug out/get home vehicles is a great advantage.
But that is not always practical.
I can only drive 1 vehicle safely to and from work.

I felt a need to make my vehicle as reliable as possible and carry some tools and spares in case of breakdown.
But I can't afford to have a spare everything.

One spare can be carried and will add reliability to your vehicle.
Many older Chevrolet gasoline trucks came with 2 battery trays already installed from the factory, but only 1 battery.
When I bought my current truck several years ago I decided to make sure it had 2 battery trays.

Shortly after I bought my truck I put in my dual battery system:

Adding a second battery to your truck involves more than just buying a second battery and bolting it into the truck.
If you add a battery then it will fight with the existing battery pulling power from one then another.
Soon you will end up with 2 dead batteries.
What you need is to isolate them from each other, but also have them both connected to the alternator.

Below is a basic diagram of my setup:

I decided to use a Sure Power battery isolator from NAPA Auto Parts.

All the parts (except the second battery) cost me under $100.

This system has performed flawlessly for several years now.
The nice thing is I can jumpstart myself using the other battery and 1 jumper cable.
I have had to do this at 5:00AM in the parking garage at work.
I just recently added the Optima battery after having my other DieHard die on me.
I like not getting stuck due to a dead battery.

I do recommend using a "normal" truck battery for a starting battery and a deep cycle for the accessory battery.

Starting battery: (Soon to be replaced with a Red Optima)

Accessory battery:

Time Estimate:
It took me about 2 hours to install mine.
Time it took to install:
5 minutes to disconnect the battery (became the starter battery)
20 minutes to figure out where to mount the isolator.
5 minutes to mount the isolator.
15 minutes to disconnect the alternator from the old battery and connect a new cable from the alternator to the isolator
5 minutes to mount the accessory battery in existing secondary battery tray.
15 minutes to run the new cable from accessory battery to isolator
10 minutes to connect new cable from isolator to starter (original) battery
15 minutes to connect accessory battery to fuse box.
15 minutes to run control wire (12 gauge) from fuse box to isolator
5 minutes to connect control wire (12 gauge) from alternator to isolator
10 minutes to connect new ground cable for accessory battery
5 minutes to reconnect the ground wire for starter battery

Then testing everything probably took 15 minutes.