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Samsung Galaxy S21 Battery Replacement

Battery Replacement guide for the Samsung Galaxy S21

Moderate
~46 min
23 steps

Before you begin

Tools

  • Precision screwdriver set (Phillips #000)
  • Plastic prying tools
  • Suction cup tool
  • Heat gun or hair dryer
  • Tweezers
  • Spudger tool

Parts / materials

  • Replacement battery for Samsung Galaxy S21
  • Battery adhesive removal strips
  • Pre-cut back cover adhesive gasket
  • Isopropyl alcohol

Safety

  • Discharge battery below 25% before disassembly to reduce risk of fire if damaged.
  • Wear safety glasses when applying heat to glass panels to protect against shards.
  • Never use sharp metal tools directly against the soft battery pouch.

Overview

# Samsung Galaxy S21 Battery Replacement Repair Guide Action-specific battery replacement walkthrough for the Samsung Galaxy S21. About 46 minutes across 23 steps. This DIY guide walks through battery replacement on the Samsung Galaxy S21 (Galaxy S series phone). Before you open the device, confirm the exact model number on the Samsung settings screen or rear housing so your replacement part matches the Galaxy S21 specifically—not a similar Galaxy S sibling. Most DIY techs finish this Samsung Galaxy S21 battery replacement in about 46 minutes when parts and tools are ready. Difficulty is rated intermediate for this model. Recommended tools for this Samsung Galaxy S21 job: Precision screwdriver set (Phillips #000), Plastic prying tools, Suction cup tool, Heat gun or hair dryer, Tweezers, Spudger tool. Parts and supplies: Replacement battery for Samsung Galaxy S21, Battery adhesive removal strips, Pre-cut back cover adhesive gasket, Isopropyl alcohol. Power the Galaxy S21 off completely, remove SIMs/SD cards if present, and work on a clean, well-lit surface with a magnetic mat for screws. If a step feels wrong for your Samsung Galaxy S21, stop and compare the connector layout to the photos in this guide. When you prefer a same-day pro repair in Seattle instead, LML Repair can handle battery replacement for this model with tested parts and a workmanship warranty.

Step-by-step

  1. 1

    Power off the phone

    1 min

    Press and hold the Side key and Volume Down button, then tap Power Off. Ensure the phone is completely shut down before starting.

  2. 2

    Heat the back glass

    2 min

    Apply a heat gun or hair dryer set to low heat along the perimeter of the back glass for two minutes. This softens the strong frame adhesive beneath.

  3. 3

    Attach the suction cup

    1 min

    Press a suction cup onto the lower portion of the back cover just above the USB-C port.

  4. 4

    Insert an opening pick

    2 min

    Pull up on the suction cup to create a small gap, then slide a plastic opening pick beneath the back glass.

  5. 5

    Slice the bottom adhesive

    2 min

    Slide the plastic pick horizontally across the bottom edge to slice through the adhesive layer.

  6. 6

    Slice the side adhesive

    3 min

    Guide the pick around the bottom corner and move along the side edge of the frame. Reheat the glass if you feel heavy resistance.

  7. 7

    Slice around the camera bump

    2 min

    Carefully slide the pick near the top camera assembly corner, keeping the tool shallow to avoid damaging internal flex cables.

  8. 8

    Remove the back cover

    1 min

    Lift the rear panel completely off the chassis and lay it aside on your clean workspace mat.

  9. 9

    Unscrew the top bracket

    2 min

    Use a Phillips #000 screwdriver to remove five screws securing the upper motherboard cover and NFC shield.

  10. 10

    Detach the wireless coil

    2 min

    Gently peel up the black wireless charging coil pad from the battery surface and lift out the top plastic bracket.

  11. 11

    Disconnect the battery cable

    1 min

    Use the flat edge of a plastic spudger to pry the battery connector straight up from the motherboard socket.

  12. 12

    Unscrew the speaker assembly

    2 min

    Remove six Phillips #000 screws securing the loudspeaker assembly at the lower end of the chassis.

  13. 13

    Remove the loudspeaker

    1 min

    Insert a plastic pry tool under the loudspeaker housing edge and lift it up out of the frame.

  14. 14

    Disconnect the interconnect cable

    2 min

    Pry up both ends of the main interconnect ribbon cable connecting the motherboard to the sub-board, then remove it.

  15. 15

    Disconnect the display cable

    1 min

    Use a plastic spudger to detach the screen flex cable from its connector on the main motherboard.

  16. 16

    Apply isopropyl alcohol

    3 min

    Dispense a few drops of high-concentration isopropyl alcohol into the gaps around the battery perimeter to weaken the glue.

  17. 17

    Pry up the battery

    4 min

    Insert a flat plastic spudger beneath the battery bottom edge and carefully lever it upwards to break the adhesive bond.

  18. 18

    Remove the old battery

    1 min

    Lift the old battery out of the frame cavity. Handle carefully to avoid bending or puncturing the pouch.

  19. 19

    Clean old glue residue

    2 min

    Wipe the battery recess clean of leftover adhesive using a cloth dampened with isopropyl alcohol.

  20. 20

    Apply new adhesive strips

    2 min

    Place replacement battery adhesive strips into the chassis recess and peel off the protective backing film.

  21. 21

    Install the new battery

    1 min

    Press the replacement battery firmly into place within the frame recess to set the adhesive.

  22. 22

    Reconnect internal flex cables

    3 min

    Reattach the display flex cable, main interconnect cable, and battery connector to their respective board sockets.

  23. 23

    Reassemble brackets and back cover

    5 min

    Reinstall the loudspeaker and wireless coil assembly with their screws, then apply fresh back cover adhesive before pressing the rear panel closed.

After your Samsung Galaxy S21 battery replacement

Power the Galaxy S21 back on and test the battery replacement function before you put every screw away. Check touch/display response, charging, cameras, buttons, and wireless as relevant to this repair. If something fails after closing the device, reopen carefully and reseat the connectors for this Samsung Galaxy S21 job before assuming the part is defective. Keep leftover adhesive and screws labeled in case you need a second pass.

Keep learning

Explore more Samsung Galaxy S21 repair context in the encyclopedia, or open related DIY guides.

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