How much gas does the alternator take to run?

Hmmm... How much gas will my truck use to power my refrigerator? I’ve been worrying about the wrong problems my whole life.

 

There's the issue of these trucks not properly charging agm batteries. You can idle your truck all you want but it won't fully charge an agm as well as a proper solar setup will. My stock alt charges around 13.7-13.8v. My solar controller charges at 14.6v. If you just have the stock battery this doesn't apply.

 

I valeted at a big money Country club 35 years ago. We had a number of Rolls and Jags from the 80s that were comical in the electrical gremlins that popped up. Lights that wouldnt shut off to windshield wipers that turned on when the car was put in reverse.

 

Well look at that! I decided to remove my belt for science and bam! It really works! Can’t believe Toyota didnt think of this!

 

Thee ole timer's used to say... you could drive your car from coast to coast and still, not have a fully charged battery. The Alt/Gen only maintains a battery and only a charger can give give a full charge.

https://www.carcareportal.com/how-l...attery by,to keep a few pointers in your mind.
HOW LONG DOES IT TAKE AN ALTERNATOR TO CHARGE A DEAD BATTERY?
Generally speaking, your alternator will not be able to charge a dead battery. While it provides charge and maintains your battery during driving, a dead battery is too much to revive.