Hey All:

Quick question regarding USB charging.

I have a 3G iPhone. Of course it charges via my PC's USB.
Also came with Apple 110-240 wall adapter.

I also have the

Jawbone 2 (USB into wall adapter) and some random accessory DC-USB cigarette lighter adapter (wish I new what it used to go with).

The funny thing is all the "output" seems to be different.
5.3V DC
5.0V 1A
5.0V 550 mhA

I do not want to stick my 3g into bad charge and fry it. So the question is is is safe charge my 3G in any of the above as well as other USB supporting devices?

This is not horseshoes and I don't want to make a mistake just by being close.

Thanks, Scho