[wildchevy]

People add two batteries for plowing to help keep voltage up at low rpm plowing as mentioned already. But that will not stop you from draining it down completely if all you do is start it up, plow then shut it down. Eventually it will die, it would just take longer. So with plowing, you still need to run it good to charge back up.

If your adding for plowing, and if your only plowing your own driveway, you may want to consider some kind of charging "station" as opposed to a second battery(having a charger in your driveway under something to keep it dry).

Or you can do what I'm doing. After Im done plowing I will set my remote starter to keep the truck running after I pull the key out. That way it can charge back up after I'm done. I'll shut if off after 10 minutes from inside.

10 minutes run time will not even come close to recharging a low battery/batteries after plowing. I made up a battery tender with a 25 foot extension cord and trailer plug, left the charger in the garage and plugged the cord into the trailer plug, worked like a champ. I do the same thing with my ATV plow rig with a 2 prong plug hooked to the aux group 78 battery that I put in the cargo box every fall for the plow winch.

 

[wildchevy]

To the OP if you chose to wire it like the OEM plow option dual batteries be aware that the batteries are not tied together until the truck is running, you will still be starting the truck with only 1 battery.