I have four batteries and plan a road trip next weekend. It's an off-road day trip so the only power source would be an inverter in my Jeep where I would connect the charger. Furthermore, I only have one charger. How to charge the batteries in preparation for the trip? Charge them the day before and top them off the next day while driving to the trail? Not much time. Only a two-hour drive to the trailhead. Any precautions?