Well, a lot depends on what your draw is on the battery. If you pull say an average of 12 amps for 6 hours, you would have to run the truck charging at 12 amps per hour for 6 hours to replace that juice.
If you drew 6 amps from the battery for 6 hours, you would need to run the TV for 3 hours at 12 amps to replace that juice.
most common 12 volt items.
LPG detector draws .2 amps
Single dual bulb light (198 bulbs) 2.3 amps
Single dual bulb light (LED panels) .1 amps
Light fixture over dining table (4 198 bulbs) 4.5 amps
Single reading light over bed (1 198 bulb) .8 amps
Recessed Halogen lighting, living room (6 lights) 8.4 amps Full on
2.1 amps Fully dimmed
Recessed Halogen lighting, over sink (1 light) 1.4 amps Full on
.4 amps Fully dimmed
Recessed Halogen lighting, over couch (3 lights) 4 amps Full on
1.2 amps Fully Dimmed
Refrigerator 1.2 amps
Furnace (Suburban SF35) 7 amps
Water Pump (Shurflo Smart Sensor 5.7) 11.9 amps running, 12.6
Exterior porch lights (3 incandescent bulbs) 2.8 amps
Exterior Porch Lights (3 LED bulbs) .8 amps
Trimetric 2025 Battery Monitor
NOTE: Nothing here mentions an inverter. Converting 12 volt DC to 120 volt AC requires HUGE amounts of amps. Watts DC is Watts AC. For example, a 1500 watt coffee maker running on the Inverter pulls 125 amps from the battery. That will suck the batteries dead before you can say "Is it still perking?"