im with woody14619 on this one.

The other solution i have is to cut a cable an use it with a 5V power supply without resistor, this will work to, did never measure the current but it charged pretty fast so it should be 500mA or more.

My charger was an normal nokia charger (800mA) with a 2mm DC plug, cut the plug off an soldered it to the cut micro-USB cable.
This works fine even if the voltage is 6V+.