Car chargers can be hit-or-miss when it comes to how fast you can get juiced up before your drive is over. Ideally, a high powered charger will get you up to speed, at least as fast as your stock iPhone 6s wall charger would.
Scosche's reVOLT is a dual port car charger that connects to your vehicle's power accessory outlet (otherwise known as the cigarette lighter). It packs 12 watts of power for 2.4 amps per port, so you can charge your most power hungry devices fast.