I'm such a nerd, right now, I need no less than six car chargers in my car. Here is what I need:
# Escort 9500i. This actually has a dedicated cord that attaches to its own charger. Shame on them for not just using 5V, but OTOH, it works super well I have to say. There is a new model out that let's you download radar traps online like the TomTom does. It has a GPS, so its logical. Wish I had the new one. So I need one adapter for this.
# iPhone 3G. Just need a USB adapter that is USB
# Jawbone headphone. Has a strange head, but is just USB on the charging end.
# TomTom 720. This is mini USB on one end and regular USB on the other
# Blackberry. This is my chinese phone. Need a mini USB here. It is a high current device, so needs more than 500mA, so doesn't work with all car adapters.
# MacBook Air. For those long trips, nice to plug it in. Require unfortunately a 120V AC adapter as for some reason the MacBook only has an airplane adapter. Everything fits, but it doesn't work. This draws 45 watts VAC for the MacBook, so need about 4 amps without losses at 12VDC. Most of these circuits are 8-10 amps out of the car, so that means it should work OK.
Even a new 2008 Mazda with two 12V adapters doesn't have enough, so here's a solution:
# Two port USB, I can get the TomTom and the iPhone working. That's two devices.
# Four adapter on the inside has the 120VAC adapter, then two splitters with a total of four USB ports for the Jabra, Blackberry, Escort, MacBook with one left over.