Portable phone charger using RC lipos?

[BrianG]

Well, it's not that easy. See, a normal USB cable has 4 wires: +5v, ground, data+, and data- (the data lines are balanced). And it has a shield, which is tied to the metal plug case. But the micro plug itself has a fifth contact, which doesn't have an associated wire in the cable. That contact is left "floating" in a computer USB cable, but in a brand-specific charger, that contact has a resistor tied to the ground wire - and that is done INSIDE the plug molding (surface mount).

For computer USB cables, that 5th contact is left floating, but the computer sets the data+/- lines in such a way (via the driver) to tell the phone to charge.

In stand-alone chargers, there is only 5v and ground wires that go to the plug. The data+/- contact are either floating or resistor set to something (essentially not used), and the 5th contact is tied to a resistor.

The easiest thing would be for you to just get another charger. Unless of course, you can carefully remove the plug molding and add the required itty bitty surface mount resistor between the programming pin and ground.

In the past, I had a mains charger that stopped working. So, I cut the wire and re-used the connector end, which has the programming pin set. Then it was just a matter of using any regulated 5v source.