5V Wall Wart Supply loading

[sp3twg]

I have a network router power supply (input, standard USA wall voltage - output 5VDC, 1A) that I have stripped the wires to try and hook it up to a USB cable phone charger. I cut off the USB port and soldered them together.

I am measuring 5V on open circuit, but as soon as I plug in the cable to a phone, it drops and measures 4.3V and the phone does not charge (needs at least 4.7-4.8V) ... anything I can do to remedy this?

 

[jtrent]

I would first be absolutely certain that I have the two cables wired together properly. In my experience these wall worts have poor regulation so if you measure 5v with an open circuit, you should expect it to drop when connected. How much it drops depends on your load, the phone. Maybe your phone needs more than 1A.

 

[sp3twg]

it's an iphone ... at home, the little cube-like white wall charger that the USB cable plugs into says 5V 1A ... just like my netgear router wall wort says 5V 1A ... I thought that since they matched, it should work just fine ... and I'm absolutely sure I have +5V tied to the right wire (red) and ground to black.

 

[ark5230]

Usually phone charging does not take current to the tune of one ampere. When the voltage drops from 5 V to 4.3 volts, it means load is consuming and current is consumed by the phone !!

I am measuring 5V on open circuit, but as soon as I plug in the cable to a phone, it drops and measures 4.3V and the phone does not charge (needs at least 4.7-4.8V) ... anything I can do to remedy this?

This seems uncommon ! may please check again !