Difficulty

Moderate

Steps

10

Time Required

                          1 - 3 hours

Sections

1

  • Reuse Old Batteries As A Power Bank
  • 10 steps

Flags

Member-Contributed Guide

An awesome member of our community made this guide. It is not managed by iFixit staff.

  • BackBattery

  • Full Screen

  • Options

  • History

  • Save to Favorites

  • Download PDF

  • Edit

  • Translate

  • Get Shareable Link

  • Embed This Guide

  • Notify Me of Changes

  • Stop Notifications

Introduction

All batteries have a lifespan. For example, when a phone’s battery capacity is below 80%, the phone’s battery life will become very short. It’s necessary to replace the new battery with a new one. For old batteries, simply throwing them away is a waste and can pollute the environment. Batteries are made from a number of materials including acid, lead, nickel, lithium, cadmium, alkaline, mercury, and nickel-metal hydride. When battery disposal is not handled correctly, the battery can leak, potentially contaminating the soil and water, and possibly harming human health. Therefore, REWA will share a way to convert old phone batteries into a power bank, turning trash into treasure.

Terminology: Anode = Positive terminal, Cathode = Negative terminal

What you need

Video Overview

Step 1

              Remove the protection board
  • CAUTION: Before starting this guide, make sure that the batteries are fully drained (0%)
  • We are using old batteries from the iPhone 7 Plus and iPhone 8 Plus. Peel off the tape on the battery protector off with tweezers.
  • Please use non-conductive tweezers to avoid short-circuiting the battery.
  • Apply tin to the anode and cathode of the battery with a soldering iron at 365°C. Heat to remove the protection board.

CAUTION: Before starting this guide, make sure that the batteries are fully drained (0%)

We are using old batteries from the iPhone 7 Plus and iPhone 8 Plus. Peel off the tape on the battery protector off with tweezers.

Please use non-conductive tweezers to avoid short-circuiting the battery.

Apply tin to the anode and cathode of the battery with a soldering iron at 365°C. Heat to remove the protection board.

1024

Step 2

              Measure the battery voltage
  • Measure the battery voltage with a multimeter. The voltages of the two batteries we have are 3.66V and 3.76V respectively.
  • As you can see, both batteries have the anode on the left and the cathode on the right.
  • Anode (Positive terminal)
  • Cathode (Negative terminal)
  • We are combining a 2900mAh iPhone 7+ battery with a 2675mAh iPhone 8+ battery and turning it into a 5575mAh power bank.

Measure the battery voltage with a multimeter. The voltages of the two batteries we have are 3.66V and 3.76V respectively.

As you can see, both batteries have the anode on the left and the cathode on the right.

Anode (Positive terminal)

Cathode (Negative terminal)

We are combining a 2900mAh iPhone 7+ battery with a 2675mAh iPhone 8+ battery and turning it into a 5575mAh power bank.

Step 3

              Solder the terminals
  • Apply double-sided tape to the battery and align the anodes and cathodes of the two batteries.
  • Solder together the anode and cathode of each battery with a soldering iron at 365°C.
  • Measure the voltage with a multimeter. Ensure the voltage is 3.7V.

Apply double-sided tape to the battery and align the anodes and cathodes of the two batteries.

Solder together the anode and cathode of each battery with a soldering iron at 365°C.

Measure the voltage with a multimeter. Ensure the voltage is 3.7V.

Step 4

              Solder wires to the terminals
  • Get a red wire and a black wire. Strip each end of both wires to expose the copper wire and apply tin on the copper wire with a soldering iron at 365°C.
  • Next, solder the red wire to the anode and the black wire to the cathode.

Get a red wire and a black wire. Strip each end of both wires to expose the copper wire and apply tin on the copper wire with a soldering iron at 365°C.

Next, solder the red wire to the anode and the black wire to the cathode.

Step 5

  • Press down the anode and cathode.
  • Apply electrical tape, making sure to fully cover the anode and cathode.
  • Install the button on the middle frame and the power board.

Press down the anode and cathode.

Apply electrical tape, making sure to fully cover the anode and cathode.

Install the button on the middle frame and the power board.

Step 6

  • Apply tin on the bonding pad of the anode and cathode with a soldering iron at 365°C.
  • Anode (Positive terminal)
  • Cathode (Negative terminal)

Apply tin on the bonding pad of the anode and cathode with a soldering iron at 365°C.

Step 7

              Solder to the power board
  • Solder the anode of the battery to the anode of the power board.
  • Solder the cathode of the battery to the cathode of the power board.

Solder the anode of the battery to the anode of the power board.

Solder the cathode of the battery to the cathode of the power board.

Step 8

              Secure the battery
  • Press the button. For this project, the power bank is 33% full.
  • Apply foam to secure the battery.

Press the button. For this project, the power bank is 33% full.

Apply foam to secure the battery.

Step 9

              Reattach the casing
  • Install the middle frame to the housing and put on the bottom plastic cover.

Install the middle frame to the housing and put on the bottom plastic cover.

Step 10

              Test charging
  • Connect the phone to the power bank. The phone can be charged.
  • Connect the charger to the power bank. The power bank can be charged too.

Connect the phone to the power bank. The phone can be charged.

Connect the charger to the power bank. The power bank can be charged too.

Cancel: I did not complete this guide.

                                                                                      3 other people completed this guide.

Author

                                      with 5 other contributors 


                    REWA

Member since: 11/24/2020

11,219 Reputation

                                      53 Guides authored                  



                       Badges:
                       14







                                                        +11 more badges

Mark Anderson - Sep 18, 2021

Reply

Do the batteries automatically stop charging at full? Like can I add iPhone batteries to the powerbank I already have?

shingle - Jul 6, 2022

Reply

@rewatech Hey, would you mind adding the power bank frame and board you bought as a required part? This guide might not work if people don’t know what parts you are using