That's hogwash. The difference in the batteries is not how they're charged, it's that a true deep cycle does not have the construction to provide the starting amps for the truck, it may work for awhile but it won't last. Deep cycles are designed to provide sustained power over longer periods of time vs starting batteries providing a high amount of power in short bursts. I've got 4 big 6 volt batteries at my camp and 400 watts of solar power, they put out 18 volts and in full sun can pump 25+ amps into the batteries, these are real off grid type batteries and that's not a trickle charge. I usually get 8-10 good years out of them. Btw Advance guy's an idiot, how can you charge a 12v battery with 4-5 volts lol.