How to Change an iPhone 12 Battery Safely

Before starting, back up your iPhone and check Apple’s current repair guidance for your model and region. A battery replacement can affect water resistance, and opening the phone may damage the display, cables, or battery. Do not begin if the battery is swollen, punctured, hot, or otherwise damaged; arrange professional service instead. Use a replacement battery intended for the iPhone 12 and follow its supplier’s instructions.

What You’ll Need

Compatible replacement battery and new display adhesive designed for iPhone 12.
Pentalobe screwdriver, tri-point screwdriver, and small Phillips screwdriver as required by the fasteners.
Suction handle, plastic opening picks, and a plastic spudger.
Heat source with controlled, gentle output, such as a purpose-made phone-heating tool.
Tweezers, a clean work surface, and a container or magnetic mat to keep screws organised.
Eye protection and gloves. Avoid metal tools around the battery and use no open flame.

Step-by-Step

Back up and prepare. Make a current backup, turn off the iPhone, and disconnect all cables. Let the phone cool. Remove the SIM tray if it obstructs your work area, and keep the phone and replacement parts on a clean, well-lit surface.
Remove the bottom screws. Take out the two pentalobe screws beside the Lightning connector. Keep track of their positions; screws of different lengths must go back in their original locations, because an incorrect screw can damage internal parts.
Warm and lift the display edge. Apply gentle, even heat around the display edges to soften the adhesive. Attach a suction handle near the bottom edge and lift just enough to create a narrow gap. Insert a plastic pick, not a metal blade, and slide it carefully along the edge to loosen adhesive. Do not push the pick deeply into the phone.
Open the display carefully. Work around the perimeter, avoiding the right side where display cables are located. Lift the screen from the left edge and open it like a book, keeping it supported and not pulling on the cables. If it resists, apply a little more controlled warmth rather than forcing it.
Disconnect the battery first. Remove the shield covering the battery and display connectors, noting each screw’s position. Use a plastic spudger to disconnect the battery connector before unplugging any other cables. Then disconnect the display and any other connectors that must be moved, following a model-specific repair guide. Never pry against the battery.
Remove the old battery. Locate the battery adhesive pull tabs and draw them out slowly, low and parallel to the phone. Keep steady tension and avoid stretching them upward. If a strip breaks, do not stab, bend, or lever against the battery. Stop and use a model-specific safe removal procedure or seek professional help; puncturing or crushing a lithium-ion battery can cause fire.
Fit the replacement. Remove leftover adhesive without scraping or bending the battery area. Apply fresh battery adhesive as directed by its maker, place the new battery in the correct orientation, and press it into position without creasing or squeezing it. Connect the battery temporarily and check that the connector sits flat.
Reconnect and test before sealing. Reconnect the display and other disconnected cables, then the battery last. Replace connector shields and screws in their original locations. Power on the phone and check the display, touch response, cameras, speakers, buttons, and charging. If anything is not working, turn the phone off and inspect the relevant connection before proceeding.
Reseal and close the phone. Turn the phone off again, disconnect the battery, and clean the frame’s adhesive surface. Apply new display adhesive according to its instructions, reconnect the battery, and lower the display into place without pinching cables. Press around the edges evenly, then reinstall the two bottom screws. Do not assume the original water resistance has been restored.

Common Mistakes

Using force instead of heat: Excessive pulling can crack the display or tear a cable. Rewarm the edge gently and work gradually.
Opening too deeply: A pick inserted far into the gap can cut cables or damage components. Keep it shallow and follow the screen edge.
Skipping battery disconnection: Unplugging display connectors while the battery is connected risks electrical damage. Disconnect the battery first and reconnect it last.
Using metal tools on the battery: Do not pry, puncture, fold, or crush it. Stop if safe adhesive removal is no longer possible.
Mixing up screws or reusing old seals: Organise screws as they come out and install fresh display adhesive. Incorrect screws or poor sealing can cause damage.

Tips

Photograph each stage before moving connectors or shields so their routing and screw positions are easier to restore.
Use plastic tools for connectors and keep screws away from the battery and exposed circuitry.
Read the replacement battery and adhesive instructions before opening the phone; repair-kit designs and procedures can vary.
After reassembly, monitor charging and operation. If the phone becomes unusually hot, smells odd, swells, or behaves erratically, stop using and charging it and seek qualified service.
A repaired phone may no longer have its original water resistance. Keep it away from liquids after the repair.

Troubleshooting

The display will not lift: Check that both bottom screws are removed. Apply gentle, even heat again and retry with a suction handle and a thin plastic pick. Do not insert a blade or force the screen.
An adhesive strip snaps: Stop pulling and do not lever against the battery. If the battery cannot be freed safely using the repair kit’s specific instructions, stop and take the phone to a repair professional.
The phone will not turn on: Disconnect power, open it only if safe, and check that the battery connector is properly seated and no cable is trapped. If there is damage, heat, or swelling, do not continue troubleshooting internally.
Touch or display functions fail: Turn the phone off and inspect the display connectors for alignment or damage. Do not press hard on connectors; seek service if a cable or socket is torn or bent.
Battery status shows a warning or unfamiliar message: Check Apple’s support information for battery and parts messages. Do not assume the battery is defective solely from a status notice; contact Apple or a qualified provider if performance or safety is uncertain.

Frequently Asked Questions

Can I replace an iPhone 12 battery myself?

It is possible, but the phone is tightly assembled and the battery is secured with adhesive. The repair carries risks to the screen, connectors, and battery, so professional service is preferable if you lack suitable tools or experience.

How long does the replacement take?

Allow about 90 minutes for a careful repair, and more if this is your first time or adhesive removal is difficult. Do not rush the battery removal or cable reconnection.

Will the phone remain waterproof after battery replacement?

Do not count on it. Opening the phone disturbs its seals, and new adhesive does not guarantee the original water resistance.

Can I reuse the old display adhesive?

No. Remove the old seal and fit new adhesive made for the iPhone 12. A reused or poorly applied seal may leave gaps.

What should I do with the old battery?

Do not put it in household rubbish or ordinary recycling. Keep it undamaged and take it to an appropriate battery recycling point or ask a repair provider to handle it.

Should I continue if the battery is swollen?

No. Do not heat, press, puncture, or attempt to remove a swollen battery. Stop the repair and contact a qualified service provider for safe handling.

Sources: Apple Support. Menus and buttons can differ slightly by version. Spotted something out of date? Tell us.