my power supply can't charge phones

Hi, i'm trying to make a power bank with mb102 power supply
it powers my arduino and can light 3.3v led and also my portable hard drive but it doesn't charge my phone neither my wifi device, i can see phone needs 1000mah and my power supply sends 700mah but at least it should put the phone on charge or a single sign of charging, can anyone tell me how to fix this?

note: mb102 power supply sends 5v 700mah

-regards

forgot to say, my power input for the mb102 is totally well its 12v 20.000mah

This is the Arduino forum. What is your question about Arduino?

Hi,
What phone? Many phones require specific resistances between specific pins. How are you wiring this?

You don't send mah [sic] since mAh is a measure of capacity not current, which is mA.

A power supply can't send 700mA either, it can supply that if necessary, but the charging circuit in the phone decides how much current it draws from the power supply.

There are different ways for the phone to know how much current it can draw:

  1. It negotiates with the computer it's connected to over USB.
  2. The charger has voltage dividers on the data pins, that set a certain voltage on these pins, depending on these voltages, the phone knows how much current the charger can supply.
  3. The phone gradually increases current draw, until the voltage of the power supply begins to drop, indicating that the charger is reaching its maximal rated current.

There's no USB chip on your charger module, and there are no resistors next to the USB port, so it's probably the third scenario.
Normal chargers output slightly more than 5V, to compensate for voltage losses due to wire resistance. Your LDO probably outputs exactly 5.0V, and it's not rated for high currents (700mA is absolute max, but @700mA, the output voltage will most likely be significantly lower than 5V). Combine that with losses that happen in the PCB traces if they're too small, in the connectors and in the USB cable, and you'll probably end up with quite a low voltage on the phone's side. This may cause the phone to decide not to charge at all, because the charger is not powerful enough.

Pieter