Easy Fix for Phone Charging but Battery Not Increasing

Step 1: Testing the Voltage

First things first, let’s check the voltage going into the board.

1. Plug in your charger.
2. Get your multimeter and set it to 20 DCV (Direct Current Voltage).
3. Place the black probe on the ground (negative) and the red probe on the positive battery terminal.

In this case, the reading shows about 1.05 volts, which is way too low. Normally the battery terminal should receive about 4 volts to charge the device.

Now, check the voltage at the charging port. You will notice it’s about 5.10 volts which is correct. This tells us the charging port is working fine, but the voltage is not reaching the battery properly.

Step 2: Understanding the Problem

So here’s what’s happening: the charging port is supplying the correct 5 volts, but the board isn’t distributing around 4 volts to the battery terminal.

To fix this we will use a rectifier diode. The model you need is 1N4007. You can find this in any electronics shop, and it’s inexpensive.

Step 3: Setting Up the Diode

Take a look at the circuit diagram. Current flows from the charging port’s positive terminal into the positive side of the diode. The diode only allows current to pass in one direction so it directs the flow straight into the battery’s positive terminal reducing the 5 volts down to around 4 volts which the battery can accept.

• The negative side of the diode (marked end) connects to the battery positive terminal.
• The positive side of the diode connects to the charging port positive terminal.

Before soldering always test the diode. Set your multimeter to continuity mode. Place the red probe on the positive terminal of the diode and the black probe on the negative. If the reading is around 546 ohms the diode is good to go.

Step 4: Making the Connection

Now it’s time to solder. You can use a jumper wire but I recommend using earpiece wire it’s stronger and more reliable.

1. Solder the negative terminal of the diode to the positive terminal of the battery.
2. Solder the positive terminal of the diode to the positive terminal of the charging port.
3. Secure the diode with masking tape so it stays in place.

Once you have done that reassemble the phone and reconnect the flex cables.

Step 5: Testing After Repair

Plug the charger back in and test the voltage at the battery terminal again. This time, you should see about 4.1 volts—exactly what’s needed to charge the battery.

Now the phone will charge normally. For example:

• At the start, the phone was at 3%.
• After a short while, it increased to 4%, then 5%.
• After charging for about 30 minutes, the battery reached 17%, and continued to rise steadily.

That confirms the phone is now charging properly.

Final Words

This simple diode bypass method is an easy and effective fix for phones that show charging but don’t actually add power to the battery. Instead of replacing the charging IC, which is more complex, this method saves time and money.

The phone tested here was an Itel P33, and as you can see, it’s working perfectly after the repair.

So, if this solution works for you, don’t forget to share your experience so it can help other technicians too. Every little bit of shared knowledge makes repairs easier for everyone.