Simple Power Bank Circuit to Charge Mobile Phone

Simple Power Bank Circuit to Charge Mobile Phone is discussed in this article.

This circuit is easy to make at home using few parts.

It is good for emergency when there is no power.

It also help to charge phone anytime and anywhere.

Parts Needed for Power Bank Circuit:

Li-ion Battery 7.4V 2600mAh:

• This battery give power to phone charging circuit.
• When full charged it make around 8.2V.

Voltage Regulator IC 7805:

• IC 7805 is popular part for controlling voltage.
• It is linear voltage regulator its main job is to make battery 8.2V go down to steady 5V for phone charging.

How to Build:

Parts List:

How to Connect Everything:

• Connect Li-ion battery positive to 7805 input (Vin).
• Battery negative connects to ground of circuit.
• 7805 gives output steady 5V from output pin (Vout).
• Use wire to connect 7805 output to USB port positive pin.
• Connect 7805 ground pin to USB port negative pin.
• USB port positive and negative then connects to phone charging cable.
• USB port must give 5V to charge phone properly.
• We can also add protection parts like fuse or over voltage circuit to keep things safe.
• Also can put LED or voltage meter to see battery level or charging status.
• This whole circuit uses IC 7805 to change battery 8.2V or 8.4V down to stable 5V.
• Then this 5V connects to USB for charging phone or other smart device when outside.
• It work with normal phone charging rules.

Parts for Charging Power Bank Battery at Home:

9V AC-DC Adapter:

• This adapter give 9V DC from home power.
• It keep the circuit powered for charging.

9V Zener Diode:

• Zener diode control voltage to TIP35 transistor base.
• It gives steady 9V reference.
• This circuit uses 9V Zener diode for stable working.

TIP35 Transistor:

• TIP35 work like emitter follower here.
• Emitter gives almost same voltage as base just little less because of diode drop.
• It help pass right voltage to battery for charging.

Connection Details:

Parts List:

• Connect Zener diode anode to 9V adapter positive.
• Zener diode cathode connects to circuit ground.
• From Zener cathode wire connects to TIP35 base pin.
• TIP35 emitter pin also connects to ground.
• TIP35 collector connect to Li-ion battery positive.
• Battery negative must connect to ground too.
• Can use resistor or sensor to check charging and control current as needed.
• This will help charge battery safely and properly.

Formulas and Calculations:

Important Things while using Power Bank to Charge Phone:

Here is easy formula to know charging time:

Charging Time = Battery Capacity / Charging Current

where:

• Charging Time (t) means how long it take to fully charge phone battery.
• Battery Capacity (C) is size of phone battery shown in mAh or Ah.
• Charging Current (I) is how much current power bank gives in mA or A.

Example:

Say phone battery is 3000mAh and power bank gives 1000mA current.

Charging Time = 3000mAh / 1000mA = 3 hours

So to charge phone from 0% to 100% it take around 3 hours with 1000mA power bank.

But this is just simple guess a teal charging time can change because of charging circuit, battery condition or its efficiency.

Circuit Working:

How does the charging circuit works is mentioned below:

Simple Power Bank Circuit to Charge Mobile Phone get steady 9V DC from 9V adapter.

Zener diode keep TIP35 base voltage around 8.6V after small drop.

TIP35 work in emitter follower mode so output at emitter is little less to around 8.4V.

This 8.4V is good for charging 7.4V Li-ion battery.

TIP35 emitter and battery share the same ground.

Battery positive is connected to TIP35 collector.

This simple charger circuit help charge Li-ion battery safely at home using 9V adapter.

After battery is full it can be used in power bank to charge phone when there is no power which is good for emergency.

Conclusion:

This Simple Power Bank Circuit to Charge Mobile Phone is easy to understand with no hard math used so anyone can follow it.

Most people just want safe way to charge phone and does not need big calculations so it also show ready-made modules that are easy to use.

This saves time and there is no headache in building full circuit.

Short and simple explanation is better to read and remember.

Also make less mistakes so charging stay safe.

References:

Analysis of Specified Capacity in Power Banks

Powerbank