Glyn Hall probably has the most accurate answer: "It requires a cell phone car charger with 5v 2A output". Though I'd like to add that even when charging from a domestic 2A power supply it can take the best side of a day to be fully recharged. With that in mind you'll be having to run the car for at least a day, probably longer to be able to fully recharge it. As far as I'm aware the Anker battery can't be charged while it's discharging (and vise versa). Lastly most car adapters promising 5v 2A output spread that over two ports. All this means that you can't charge the Anker in one port while charging your phone/tablet in the other port, which takes you back to square one.
Without knowing more about your specific problem the best advice I could offer would be to buy two or more of these. Charging one domestically while you use the others.