Feasibility Study
1) Make year and model of your pickup truck
2) Find out on options tag size of alternator or take image and post it here
The potential of the truck alternator in conjunction with proposed trip "leg" length of time, is a prime denominator of battery ampere hour limit.
The feasibility study is nowhere as easy as it once was. A vast array of alternator models and types teamed with yes/no ECU voltage regulator control must be taken into consideration. Too slow of voltage rise on some ECU charging systems can trigger a fault warning lamp (check engine). Would that force the system into "limp home" mode? Good question. It's time to not guess at this :)