If you are using a car or house USB charger "There is no such thing as a Universal Charger".
No matter what the seller says.
It's either non-iPhone or iPhone.
I have two of the Griffin chargers. They are not made for the S3 and that is why they take so long to charge.
The non-iPhone protocol from 2007 and 2009 that iPhone did not follow shorts the two data pins in the charger. Then you get the 1.0 Amp.
Most of the generics went after the iPhone and iPod market. So you have to check close.
There are dual USB car and house chargers that have a 1 Amp non-iPhone protocol on one side and a 2 Amp iPhone protocol on the other.
Just drove 7 1/2 hours with everything running radio, GPS, Navigator, Sports scores, traffic and it charged the whole way on the 1 Amp side.
If your charger says it's universal and works for both the iPhone and your S3,
it is not.
I have a several of both.
If you are using a USB cable from your PC it is a whole different deal and does limit it to .5 Amps to protect the PC. Unless you have one of the newer color coded USB PC ports that can supply more than .5 Amps. Not many of those out there.
It depends how the phone see the charger. If the phone see it as Usb, it will limit itself to 0.5 amp which will charge the phone very slowly. If it see it as AC charge, then it will attempt to use all the charge it can which will get past 0.5 amp which make it quicker to charge. Your phone possibly see the charger as USB and putting it to USB Charging mode. It took my phone to be completely charged for four hours from 10% on Griffin Powerjolt Mini which only have 1.0 amp on shared dual port. If I use the car power inverter and use my wall charger it will charge completely within two hours.
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