and when the starter motor kicks out, and you get the 30 volt negative spike from the aulternator, what will your darlingtons do then,
OH, and cheap usb car adapters are just that, cheap.
large Mosfets are "normally" IMHE more rugged than darlingtons, they for one dont have thermal run away, and are a lot lower 'resistance' when hard on, and higher resistance when hard off, so assuming fast switching between on and off, power dissipation of MOSFETS is also lower than darlingtons.
As for TRV's, great things, if you have a 12 volt supply, you dont need 40 volt tvs's, rate them nearer to the expected voltage,
diodes. mosfets have an inherent reverse diode in them, so if its possible for the supply to the load to go lower than the load voltage, you need a series reverse current limiter. A diode would suit.
1. Halogen lamps take much more current for a short while when you first turn them on. That is temporarily overloading your power supply.
this means that I could drain potentially 16 x 5 = 80mamps from all output pins which I think is ok ?? Although it would be unlikely that all channels would be on at the same time