Just got my HP-2 today and see that it does not have the same charging cord as my HP-1. With discussions that I see you have to use a 1amp or more when you use ac current. What can you use for a power source if you want to charge & use in a automobile to get 1 amp output & 5 volts? Do they make a 1 amp pigtail or one that you can plug into cigarette lighter. I do understand that a person should charge batteries with a separate charger.