Skip to main content

Phone · Samsung · Galaxy S21 Plus

Samsung Galaxy S21 Plus Battery Replacement

Battery Replacement guide for the Samsung Galaxy S21 Plus

Moderate
~49 min
24 steps

Before you begin

Tools

  • Phillips #00 screwdriver
  • Heat gun or hair dryer
  • Suction cup tool
  • Plastic prying tools
  • Spudger tool
  • Plastic opening picks

Parts / materials

  • Replacement Galaxy S21 Plus battery
  • Battery adhesive removal strips
  • Rear glass pre-cut adhesive strip
  • 90%+ Isopropyl alcohol
  • Lint-free cloth

Safety

  • Work in a well-ventilated area when using isopropyl alcohol.
  • Do not bend, puncture, or apply sharp metal tools near the battery.
  • Wear safety glasses to protect against small glass shards if the rear panel breaks.

Overview

# Samsung Galaxy S21 Plus Battery Replacement Repair Guide Action-specific battery replacement walkthrough for the Samsung Galaxy S21 Plus. About 49 minutes across 24 steps. This DIY guide walks through battery replacement on the Samsung Galaxy S21 Plus (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 Plus specifically—not a similar Galaxy S sibling. Most DIY techs finish this Samsung Galaxy S21 Plus battery replacement in about 49 minutes when parts and tools are ready. Difficulty is rated intermediate for this model. Recommended tools for this Samsung Galaxy S21 Plus job: Phillips #00 screwdriver, Heat gun or hair dryer, Suction cup tool, Plastic prying tools, Spudger tool, Plastic opening picks. Parts and supplies: Replacement Galaxy S21 Plus battery, Battery adhesive removal strips, Rear glass pre-cut adhesive strip, 90%+ Isopropyl alcohol, Lint-free cloth. Power the Galaxy S21 Plus 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 Plus, 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 Phone

    1 min

    Press and hold the Side and Volume Down buttons until the power menu appears. Tap Power Off and confirm the device shuts down completely.

  2. 2

    Eject SIM Tray

    1 min

    Insert a SIM eject tool into the small hole at the bottom edge of the frame. Push straight in to release the tray, then slide it out.

  3. 3

    Heat Rear Cover

    2 min

    Use a heat gun or hair dryer set to low heat on the rear panel for two minutes to soften the internal adhesive.

  4. 4

    Attach Suction Cup

    1 min

    Place a suction cup onto the lower third of the rear glass. Press firmly to create a seal against the glass.

  5. 5

    Insert Opening Pick

    2 min

    Pull upward on the suction cup to create a slight gap at the bottom seam. Slide a plastic opening pick into the gap.

  6. 6

    Slice Rear Adhesive

    4 min

    Slide the opening pick along all four edges of the rear panel to cut through the perimeter glue. Reapply heat if resistance increases.

  7. 7

    Lift Off Rear Cover

    1 min

    Gently lift the back panel away from the frame and set it aside on a clean surface.

  8. 8

    Unscrew Wireless Charging Pad

    2 min

    Use a Phillips #00 screwdriver to remove the five screws holding the upper wireless charging assembly in place.

  9. 9

    Remove Wireless Charging Module

    2 min

    Peel the wireless charging coil up from the battery and lift the plastic cover off the motherboard.

  10. 10

    Disconnect Battery Cable

    1 min

    Pry the battery connector straight up from its motherboard socket using the flat end of a plastic spudger.

  11. 11

    Unscrew Loudspeaker Bracket

    2 min

    Remove the six Phillips #00 screws securing the bottom loudspeaker cover to the lower frame.

  12. 12

    Remove Loudspeaker Module

    2 min

    Insert a plastic prying tool under the edge of the loudspeaker assembly and lift it out of the phone.

  13. 13

    Disconnect Display Cables

    2 min

    Disconnect the main and display interconnect flex cables from both the motherboard and sub-board, then lift them away.

  14. 14

    Apply Isopropyl Alcohol

    3 min

    Apply a few drops of high-concentration isopropyl alcohol along the top and side seams of the battery bay.

  15. 15

    Pry Out Old Battery

    5 min

    Slide a flat plastic card or pry tool beneath the battery and gently lever it out. Never use metal tools or bend the battery cell.

  16. 16

    Clean Battery Recess

    2 min

    Wipe away remaining adhesive residue inside the battery cavity using a lint-free cloth dipped in isopropyl alcohol.

  17. 17

    Apply Battery Adhesive

    2 min

    Peel the backing off new battery adhesive strips and press them firmly into the battery bay frame.

  18. 18

    Install New Battery

    2 min

    Set the replacement battery into the frame recess and press down firmly to set the adhesive.

  19. 19

    Reconnect Interconnect Cables

    2 min

    Align the interconnect flex cables over the motherboard and sub-board sockets, pressing down until they snap into place.

  20. 20

    Reconnect Battery Connector

    1 min

    Align the battery flex cable over the connector port on the motherboard and press down until it clicks securely.

  21. 21

    Reinstall Loudspeaker Assembly

    2 min

    Fit the loudspeaker housing back into the lower frame and secure it with its six Phillips #00 screws.

  22. 22

    Reinstall Wireless Charging Assembly

    2 min

    Position the wireless charging pad and upper cover over the motherboard and reinstall the five Phillips #00 screws.

  23. 23

    Apply Rear Cover Adhesive

    3 min

    Apply pre-cut adhesive tape around the perimeter of the phone frame and remove the top protective film.

  24. 24

    Seal Rear Cover

    2 min

    Align the back glass cover over the chassis and press firmly around all edges to form a tight seal.

After your Samsung Galaxy S21 Plus battery replacement

Power the Galaxy S21 Plus 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 Plus 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 Plus repair context in the encyclopedia, or open related DIY guides.

logo_footer

Stay in the loop

Get new guides, reviews, and repair news.

© 2026 LML Repair. All rights reserved.