Portable mobile charger using Li-ion battery

Intro-

A portable powerbank is comprised of a special kind of battery placed in a small case with a circuit to control the output power. These are commonly used for emergency charging of the mobile phones.
The most commonly used battery is Li-ion(18650 battery).

Components required:-

1. TP4056 5V 1A Li-ion/Li-po battery charging module.

2. 3 to 5V 1A DC-DC Boost module.

3. Diode, resistor and LED (1N400X, 220ohm)

4. 2 switches.

5. Li-ion battery.

6. PCB and connection wires.

Circuit schematic-

Connections:-

1. Connect the battery positive to the B+ of the TP4056 module and the negative to the B- of the module.

2. Connect the DC-DC boost module's positive to the OUT+ of TP4056 through a diode(forward biased to the TP4056 and reverse to the boost module).

4. Connect the negative of the boost module to a switch and then connect the switch to the OUT- of the TP4056.

5. Place a LED with a resistor and a switch in series and connect it in parallel to the circuit as shown in the circuit diagram.

Working:-

When the battery is connected to the circuit and the switch is turned on, the current starts flowing in the circuit. The DC-DC boost module steps up the input voltage of 3.7 volts to 5V, which can be used to charge your mobile phones. As the chosen battery is Li-ion, the peak voltage at full-charged state is 4.2V, but when the voltage will drop due to drain the DC-DC module will cut-off its supply(prevent over-discharge) and the powerbank will not work, you have to recharge the battery in order to reuse it.

The greater the mAh of the battery used, greater will be the capacity of the powerbank.

Lithium-ion battery voltage range-

Nominal voltage - 3.7 V

Typical end-of-discharge - 2.8 - 3.0 V

Max charged voltage - 4.2 V