I have three devices, Nobis nb7022 s, droid mini, asus memo pad 7 (me170cx). I am using a charger that has a rated out put of 2000ma. The nobis draws 8 to 10 watts from the wall outlet. the droid mini and asus can only pull 3 watts from the same charger and cord. the asus is only a few weeks old while the droid and nobis are a about a year old.

What is the reason for the difference in power draw? the droid came with a 2 amp charger. Is there anything I can do to make the droid and asus draw more power and charge faster?