Originally Posted by Lotus7
You will be fine. Each of the "lighter" sockets is independently fused at 10 Amps (the fuses are in both the front No.1 fuse panel behind the glove box and the larger, No. 2 panel in the rear fender).
The USB port is good for 500 mA, but not more. You are wise to use your iPad adapter in one of the 12 volt sockets, since it draws too much for the USB port, but will easily be accommodated by any of the other accessory sockets.
FYI: You may be interested in this lighter socket/USB power adapter.
I have one and it works great. It will supply 1.2 amps, which is plenty for most USB accessories. It's tiny and reduces the wire clutter near the lighter socket. They also sell a 2.1 amp version that is recommended for iPads.
The phone chargers probably draw less then 1 amp each, and the Garmin about 2 amps, so are no problem at all.
I wouldn’t plug in a 10 amp tire compressor, however.
Also, please be aware that the accessory sockets are switched off after a 5 to 15 minute delay after the vehicle has been shut off. Your chargers will not work, but then again, they won't run down your battery while the car is stopped.
Many thanks for the detail. Much appreciated.