Now Reading: Samsung Galaxy A21s Battery Replacement Guide | DIY Repair
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Samsung Galaxy A21s Battery Replacement Guide | DIY Repair
Samsung Galaxy A21s Battery Replacement Guide | DIY Repair
Replacing a worn-out battery is one of the most effective ways to restore your smartphone’s performance and extend its lifespan. If your Samsung Galaxy A21s is draining quickly, shutting down unexpectedly, or overheating during normal use, a battery replacement can bring it back to reliable daily performance.
This detailed DIY repair guide explains how to safely remove the old battery and install a new one using proper tools and professional repair techniques. Whether you are a beginner learning mobile repair or an experienced technician, following each step carefully will help prevent damage to sensitive internal components.
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Repair Difficulty ⭐⭐⭐☆☆ (Moderate)
Estimated Repair Time: 45 — 60 Minutes
Device Type: Smartphone
Repair Type: Internal Battery Replacement
Reasons for Battery Replacement
You may need to replace your Galaxy A21s battery if you notice:
- Battery draining very fast
- Phone shutting down randomly
- Device overheating while charging or using apps
- Battery swelling or back cover lifting
- Charging percentage jumping suddenly
- Phone not turning on without charger
Replacing the battery restores stability, improves standby time, and prevents motherboard damage caused by unstable power delivery.
Before You Begin
Compatibility and Model Numbers
- Samsung Galaxy A21s 5G
This repair guide based on Samsung Galaxy A21s Model.
Model Numbers | SM-A217F, SM-A217F/DS, SM-A217F/DSN, SM-A217M, SM-A217M/DS, SM-A217N
Tools Required
- Mobile phone heating pad or hairdryer/heat gun
- Plastic pry tool / card pry
- Suction cups
- Phillips #00/#000 screwdrivers
- Tweezers (for connectors)
- B7000 glue or double-sided adhesive (for back cover)
- Rubber bands or bonding clips to secure the back cover
Using proper tools reduces the risk of damaging the phone.
How to Find Tools and Parts
- Heating pad – https://amzn.to/3H0tHzJ
- Portable Heat Gun – https://amzn.to/4mszih1
- Clamps https://amzn.to/3GYJT4w
- STREBITO 142 Piece Repair Tool Kit https://amzn.to/3UO1jUx
- Glue | Adhesive https://amzn.to/46exVxe
- Compatible Parts –
- Battery – https://amzn.to/4njjTjG
- Screen – https://amzn.to/4m8qk8n
- Other Parts – https://amzn.to/46bNQeC
- Silicone Work Repair Mat https://amzn.to/45Emz5l
Step-by-Step Samsung Galaxy A21s Battery Replacement
Step 1 — Remove SIM Tray
Power off the device completely.
Use a SIM ejector tool to remove the SIM tray. This prevents internal frame obstruction during disassembly.
Step 2 — Heat the Back Cover
The rear cover is secured using adhesive.
Gently heat around the edges of the back cover using:
- Heating pad (recommended), or
- Hair dryer / heat gun.
Apply heat evenly until the adhesive softens.
Avoid overheating to prevent damage to internal plastic parts.
Step 3 — Remove the Back Cover
Attach a suction cup near the edge of the back cover to create a small opening.
Insert a plastic pry card or opening tool into the gap and slowly slide around the edges to cut the adhesive.
⚠️ Be careful while lifting the cover because the fingerprint sensor flex cable is attached.
Disconnect the fingerprint sensor connector before fully removing the back cover.
Step 4 — Remove Mid Frame Screws
Remove the 15 Phillips screws securing the rear mid-frame.
Use a plastic pry tool to gently separate the mid frame from the device body.
Work slowly around the edges to release all plastic clips.
Lift off the mid frame carefully.
Step 5 — Disconnect Battery and Flex Cables
Disconnect:
- Battery connector
- Main flex cable connectors (top and bottom)
This prevents accidental short circuits during battery removal.
Step 6 — Remove the Old Battery
The battery is glued firmly to the frame.
Apply gentle heat underneath the battery area to soften adhesive.
Insert a plastic pry tool underneath and slowly cut through the adhesive.
⚠️ Never use metal tools or excessive force.
Pull the battery out carefully using the pull tab or bright hole provided.
Step 7 — Install the New Battery
Apply fresh adhesive inside the battery compartment.
Place the new battery correctly into position.
Reconnect:
- Main flex cable
- Logic board connector
- Secondary board connector.
Ensure connectors click firmly into place.
Step 8 — Reinstall Mid Frame
Reconnect the battery connector.
Place the mid frame back onto the body.
Check that all clips are properly secured.
Install and tighten all 15 screws.
Step 9 — Reinstall Fingerprint Sensor
If required, gently heat the fingerprint sensor area on the back cover to soften adhesive.
Push out the fingerprint flex carefully.
Reconnect the fingerprint cable to the logic board.
Step 10 — Reattach Back Cover
Check whether adhesive remains strong on the rear cover.
If needed:
- Apply B7000 glue, or
- Use double-sided adhesive.
Align and press the back cover firmly.
Use rubber bands or binding clips to hold pressure while the adhesive cures.
Leave secured for some time before use.
Frequently Asked Questions (FAQ)
Q1. How do I know my Galaxy A21s battery needs replacement?
If your phone drains quickly, shuts down suddenly, overheats, or shows battery swelling, replacement is recommended.
Q2. Can I replace the battery without heating?
No. Heating is necessary to soften adhesive safely and avoid bending the battery or damaging internal parts.
Q3. Is battery replacement safe at home?
Yes, if proper tools are used and steps are followed carefully.
Q4. Will replacing the battery delete my data?
No. Battery replacement does not erase data. However, backing up important files is recommended.
Q5. Should I fully charge the new battery immediately?
Charge normally to 100% after installation and avoid heavy usage during the first charging cycle.
Troubleshooting (Q&A)
Q1. Phone not turning on after battery replacement?
Check battery connector seating and ensure flex cables are properly connected.
Q2. Fingerprint sensor not working?
Reopen the device and reconnect the fingerprint flex cable securely.
Q3. Back cover not sticking properly?
Apply new adhesive or B7000 glue and secure using rubber bands or clips.
Q4. Phone overheating after repair?
Ensure battery adhesive is flat and connectors are not loose.
Q5. Battery draining fast after replacement?
Allow 2–3 full charge cycles for battery calibration.
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