Why do people add two batteries to their truck?

All about individual power out our needs, for example all the high speed camping gear N lights require power albeit perhaps not much but over the course of 2+ days it can drain a single one. So ones for aux power and the other for starting.
There is simpler solutions like a battery bank such as goal zero or home made one. I’ve got a single huge group 31 battery with a cheap 80w solar panel on the roof rack it does fairly well.

 

For me it was a mix of things.
I really like electronics and wiring shit, so it's a cool project. Also, we go out solo frequently and we try to kill our single points of failure, like a dead battery.
We use heated blankets in the winter that absolutely suck down juice.
And my winch is thankful for 2 batteries

 

This is the path I think I'll follow. I'd rather manage a separate, contained system as I don't *need* a fully integrated solution... yet!

 

Awesome it’s worked beautifully for me I also carry a battery bank jump starter in case it does go dead.

 

As a millennial and an engineer, I think we should stay away from generalizing groups of people. Different people have different skillsets, each and every one should be praised.

 

Chock this all up to this...... "Different strokes for different folks..." and "run what you brung"...... lol

 

Oh, then you are used to old people blaming you for everything that's wrong with products and the world even though neither are your fault.

 

Im old and work with engineers... that millennial is getting blamed for both being a millennial AND being an engineer LOL

 

You might be better off with a jackery 1000 W or something. Way less than a second deep cycle battery, management system, etc. and way easier to "install" in the truck. Run it off a 200W solar system back into the battery and it'll last damn near forever. (IIRC only the 1000W model will accept 200W in. The other smaller capacities will only take 100W of solar in)

 

Many add a battery kits can intelligently charge both crank and 2nd battery, even if they are different.

Helps prolong life of battery, and provides peace of mind that everything will work when you need it. Can be a big deal in bad weather or if carrying perishable items that depend on functional fridge etc.

I find that you don't need to go with the $500 setup unless it's life critical like blizzard use etc.

 

Sometimes the second battery is of a different chemistry or requires different charging.

So management may not matter in your specific setup, but for someone buying an expensive secondary battery for their mission may opt for a smart charging system and it may even save them money in the long run.