Arduino Leonardo USB Power Supply


New to the forum (and to Arduinos)
I'm working on a little data logger project for my car using an Arduino Leonardo
Looking at utilising a 3 axis accelerometer and the adafruit ultimate gps logger board to store g-force and gps co-ordinates onto an SD card.

My question is about power supplies. I realise I could run it on a 9v batter but I've read that I'm only likely to get 3hrs use out of it.
The camera in my car has a usb cable running to it from a cigarette lighter usb adaptor so that it charges constantly.
Could I put a 5v 1a cable into the arduino from the cigarette lighter usb adaptor to charge that as well?

I read on the Leanardo specs that the USB power can't exceed 5.5v and I'm not sure how regulated the voltage is on the cigarette socket adaptors. If it spikes over 5.5v does it permanently damage the Arduino?

Thanks for your help

Yes, it's possible to kill the Arduino if the voltage spikes over 5.5v. However, a properly engineered 12V-USB power adapter will provide fairly clean power. You should be fine if you're using a name-brand adapter from Apple, Samsung, Motorola, something like that. If you've got the bargain $3 adapter then throw it in the trash.

In any case, using a decent size input power capacitor will help soften any spikes or sags (particularly when you start the car's engine). I'm no EE so I'd just stick a 1,000uF cap on there (bulk) and a ceramic 1uF (noise) and call it good, but some of the more knowledgeable members here can probably recommend better values.

what about the mA?
I've seen that the Leonardo shoud have max 500 mA.
What if i plug to a 1A power supply?