My iPad Mini 2 came with a larger USB charger to plug into the wall. Is it OK to use that larger charger to charge the iPhone 6S? Will it charge faster? Second, I have extra official Apple lightning charger cables to use in the cars. I just need a USB charger to plug into the cigarette lighter port. Is this something that needs to be Apple approved? Or only the cable matters? I've heard of people having problems in the past. Also, is there a certain amperage that I should look for in order to charge it faster?