Can the 3.2V LiFePo4 battery power the cell phone through the cell phone’s micro USB port?


I have a large LiFePo4 battery cell made by Headway (model 40152S 15AH single CELL, 3.2v). I'd like to use it to power my Samsung Galaxy S3 phone. On the original phone battery it says that it is a 3.8v. The phone has a micro USB input to charge the phone.

I bought a cable that has a Micro-B connector at one end. I haven't cut it yet, but after cutting the cable I'm hoping that there will be about 4 or 5 wires, where one of them would be for the positive and one for the negative power.

Can I use this 3.2v battery to power the phone even though the battery that comes with the phone works with 3.8v? Will using just the two power leads be enough to make the phone work?

If my headway battery is too low of a voltage to work, would I need to use a 3.7 volt Li-ion battery instead? Is 3.7v close enough? I haven't been able to find any batteries that are exactly at 3.8 for a single cell.

edit after searching for a DC-DC Regulator Module:

I found a module that is designed to do this:

Step up DC-DC regulator
Designed for convert 1 cell Li-Ion / LifEPO4 battery pack to 5.0VDC output
Running / charging most popular 5.0VDC devices such as cell phone/MP3/MP4/PDA/iPod/PSP/GPS from Li-Ion / LifEPO4 battery pack

Input Voltage
2.0 ~ 4.2VDC via "VIN+" / "VIN-" Soldering spot

Output Voltage
5.0VDC 2.0A Max via USB Female Jack
5.0V 1.0A Max each

Will this module be enough to place between my 3.2V battery and the cable that I can use to go from the USB in the regulator to the micro USB on the phone?

Thanks very much for your help.

Best Answer

The USB port on the phone expects 5 volts in. I doubt the phone will do anything if you give it less than 4.5 volts or so, though it might be possible.

But if you were to use a boost regulator to generate 5 volts from the external battery, at least that would work for powering the phone. Connecting to the +5V and ground lines of the USB connection should be enough, but phone chargers also connect some resistance to the data lines (or connect them together) to indicate that they're a charger instead of a real USB host.