iphone car charger will not have any impact, because the car charger voltage is not as large as the original voltage, so don't worry. 12V car power supply through the DC-DC power converter into 5V, you can charge the phone.
Another way is to first use the inverter to become 220V, and then use the mobile phone charger to charge the mobile phone. At present, the mobile phone on the market is 5V charging interface, if directly connected to the 12V vehicle voltage will burn the mobile phone circuit.
Because the vehicle power supply environment is relatively bad, the voltage fluctuation is relatively large, and the environmental temperature difference is also very large, so the purchase of 12V-5V converters must pay attention to the purchase of good quality and guaranteed big brand products.
Avoid using cheap copycat products that can damage your phone or even cause a fire.