svoboy, the charger is a complete variable, I do not know anything about random cell phone charger x or its current capacity or any other issues it might introduce, nor if the cigarette lighter it plugs into is constantly powered or if it loses power when the key is in start and/or off. I aint supporting random cell phone charger x. If anyone wants to use a cellphone charger, that is svoboys idea and department, talk to him
For powering the iduino, I recommend at least the following circuit (note, you can replace the 7805 with a 7812 and power a freeduino or other board with an onboard 7805 with no ill effects except maybe a minor wallet dent and have some extra protection):
