QUOTE(Renee @ Jul 21 2011, 01:35 PM)
Iphone 4 charger stated 5V DC
Ipad 2 charger stated 5.1V DC
So ?
I don't see my ipad2 adaptor got write 5.1vdc? Anyway 0.1vdc won't blow your device. If the voltage is 6v, 9v 0r 12v, than bye bye to your device.
Added on July 21, 2011, 3:32 pmQUOTE(joshting @ Jul 21 2011, 01:48 PM)
Actually the difference that make up the Watts here is not the voltage ... its the Current.
(Physics 101: P(Watts)=V(Volts) * I (Amperes))
For most cell phones, PDAs and small mobile devices, they charge well simply with 5V and 1A or less. Even at 500mA (USB port), which is 0.5A, it can charge iPhone without problems, maybe a bit slower.
But 500mA would not charge iPad. The recommended current for iPad is 2.1A (which gives the power of 10W) and hence the official charger has this rating. 1A will barely charge iPad. So if you are looking for chargers for iPad (whether wall or car), make sure its about 2A.
Just to add on about charging iPhone with iPad charger ... its perfectly fine ... voltage is more of the key here to blow something up

500ma can charge the ipad. Just slower. Example, you can plug into your laptop usb and it will charge your ipad. Laptop usb provide only 500ma, 5vdc.
This post has been edited by ozak: Jul 21 2011, 03:32 PM