Replacement Battery Compatible with Samsung Galaxy S21 FE 5G
Restore dependable battery performance to a compatible Samsung Galaxy S21 FE 5G with this replacement lithium-ion battery.
This internal replacement battery is designed for Galaxy S21 FE devices experiencing reduced battery life, unexpected shutdowns, excessive battery drain, charging irregularities related to battery condition, or a physically swollen or otherwise degraded original battery.
The Galaxy S21 FE 5G was originally designed around a 4,500mAh typical-capacity battery, with Samsung specifying a 4,370mAh rated minimum capacity for the device.
This replacement component is intended to replace the internal battery only. It does not repair faults caused by the charging port, charging daughter board, main logic board, power-management circuitry, software, or other internal components.
Compatible Models
Designed for compatible versions of:
- Samsung Galaxy S21 FE 5G
- SM-G990 series
Common Galaxy S21 FE regional model families include:
- SM-G990W – Canadian version
- SM-G990W2 – Canadian revision
- SM-G990B / SM-G990B/DS – international version
- SM-G990B2 / SM-G990B2/DS – international revision
- SM-G990E and applicable regional variants
Samsung Canada identifies both SM-G990W and SM-G990W2 as Galaxy S21 FE 5G models, while Samsung also lists international SM-G990B/DS and SM-G990B2/DS variants.
Important: Always confirm the complete device model number before installation.
How to Confirm the Model Number
The complete Samsung model number can normally be found under:
Settings > About phone > Model name / Model number
It may also appear:
- On the original device packaging
- On the purchase receipt
- Through the carrier account
- On internal product labels
- Through Samsung diagnostic software
Do not order solely by:
- Phone colour
- Storage capacity
- Carrier name
- Processor version
- External appearance
- The general “Galaxy S21 FE” product name
Not Compatible With
This battery should not be assumed compatible with:
- Samsung Galaxy S21
- Samsung Galaxy S21+
- Samsung Galaxy S21 Ultra
- Samsung Galaxy S20 FE
- Samsung Galaxy S22 series
- Samsung Galaxy S23 FE
- Other Samsung Galaxy models
Similar physical dimensions or connector styles do not establish battery compatibility.
Always compare the replacement battery with the original battery before installation.
Product Type
This listing is for an internal rechargeable replacement battery.
It may also be described as:
- Replacement phone battery
- Internal lithium-ion battery
- Li-ion replacement battery
- Samsung S21 FE battery
- Galaxy S21 FE replacement battery
- Battery cell assembly
Depending on the exact inventory supplied, printed battery numbers, regulatory markings, manufacturing dates, labels, and packaging may vary.
Battery Capacity
The Galaxy S21 FE 5G was originally specified by Samsung with:
- Typical capacity: 4,500mAh
- Rated minimum capacity: 4,370mAh
Samsung also specifies support for up to 25W wired charging and 15W wireless charging on the Galaxy S21 FE.
Replacement-battery labeling may show rated capacity, typical capacity, or both.
Capacity terminology should not be confused:
-
Typical capacity represents an estimated average battery capacity.
-
Rated capacity represents the minimum capacity specified under applicable testing conditions.
Actual runtime depends on much more than the printed battery capacity.
Package Contents
This listing includes:
- One replacement battery compatible with Samsung Galaxy S21 FE 5G
The following are not included unless expressly stated:
- Samsung Galaxy S21 FE phone
- Battery adhesive
- Rear-cover adhesive
- Charging-port board
- Wireless-charging coil
- NFC assembly
- USB-C cable
- Wall charger
- Repair tools
- Installation service
- Diagnostic service
Components shown in generic photographs should not be assumed included unless specifically identified.
Key Features
- Replacement internal battery for Samsung Galaxy S21 FE 5G
- Designed to replace a degraded, worn, or defective battery
- Suitable for compatible SM-G990-series devices
- May restore improved usable battery runtime
- May resolve shutdowns caused by a degraded battery
- May resolve rapid battery-percentage drops caused by battery deterioration
- Rechargeable lithium-ion battery technology
- Designed for use with the phone's original charging system
- Compatible with the device's supported wired and wireless charging functions when all other components are functioning correctly
- Advanced internal installation required
- Professional diagnosis strongly recommended
- No tools or adhesive included
- 30-day limited parts-only warranty
Common Battery Failure Symptoms
Battery replacement may be appropriate when the phone:
- Has substantially reduced battery life
- Requires charging multiple times per day
- Loses battery percentage unusually quickly
- Shuts down unexpectedly
- Shuts down while displaying remaining battery percentage
- Turns off during demanding applications
- Experiences sudden battery-percentage drops
- Cannot remain powered without a charger
- Charges normally but discharges unusually quickly
- Has become unreliable in cold conditions
- Experiences significant battery degradation
- Displays battery-related diagnostic warnings
- Has a physically swollen battery
- Has a damaged battery connector or battery assembly
Similar symptoms may also be caused by other hardware or software faults.
Proper diagnosis is recommended before replacing the battery.
Symptoms a Replacement Battery May Improve
A correct and functional replacement battery may improve:
- Battery runtime
- Standby time
- Power stability
- Unexpected shutdown behaviour
- Sudden percentage drops
- Performance under higher electrical load
- Charging consistency where battery degradation was the cause
- Overall reliability of an ageing device
Actual improvement depends on the condition of the phone and the condition of the original battery.
Problems a New Battery May Not Repair
Battery replacement may not resolve problems caused by:
- Damaged USB-C charging port
- Defective charging daughter board
- Damaged charging cable
- Defective wall charger
- Main-board charging failure
- Power-management IC failure
- Main-board short circuit
- Liquid damage
- Corrosion
- Damaged battery connector on the main board
- Wireless-charging failure
- Excessive device temperature
- Software problems
- Background applications
- Poor cellular reception
- High display brightness
- High refresh-rate usage
- Processor-intensive applications
- GPS-intensive applications
- Defective replacement charging components
Do not assume every rapid-drain or charging problem originates from the battery.
Battery Runtime Notice
Installing a new battery does not guarantee a specific number of operating hours.
Battery runtime varies according to:
- Cellular signal strength
- 5G usage
- Wi-Fi usage
- Display brightness
- Display-on time
- Refresh rate
- Gaming
- Video streaming
- Camera use
- GPS and navigation
- Bluetooth
- Background applications
- Push notifications
- Ambient temperature
- Device temperature
- Software version
- Application behaviour
- Battery charging habits
- Overall device condition
Samsung similarly notes that battery performance can vary according to usage patterns and operating environment.
A new battery can restore lost capacity caused by battery deterioration but cannot eliminate power consumption produced by normal device operation.
Charging Capability
The Galaxy S21 FE 5G supports up to:
- 25W wired charging
- 15W wireless charging
- Wireless PowerShare
according to Samsung's published specifications.
Installing a replacement battery does not increase the phone beyond its original charging capability.
Charging speed depends on:
- Battery percentage
- Battery temperature
- Phone temperature
- Charger output
- USB cable quality
- USB Power Delivery compatibility
- Charging settings
- Software
- Battery condition
- Charging-port condition
- Main-board condition
The phone does not necessarily draw maximum charging power throughout the entire charging cycle.
Fast-Charging Notice
For supported fast charging, use compatible charging equipment.
A damaged or incompatible charger or cable may cause:
- Slow charging
- Intermittent charging
- Charging disconnections
- Excessive heat
- No fast-charging indication
- Failure to charge
Test the device with known-good charging equipment before concluding that a battery is defective.
Lithium-Ion Battery Technology
Samsung Galaxy smartphones use rechargeable lithium-ion battery technology. Samsung describes Galaxy batteries as integrated lithium-ion batteries and notes that rechargeable batteries are consumable components with limited lifespans.
Lithium-ion batteries gradually lose usable capacity through normal use.
Battery ageing is affected by factors including:
- Number of charge cycles
- Time
- Heat exposure
- Charging temperature
- Storage temperature
- Extended high state of charge
- Deep discharge
- Heavy power consumption
- Charging habits
- Manufacturing variation
Gradual deterioration over time is normal and is not necessarily evidence of a manufacturing defect.
Battery Calibration and Percentage Behaviour
After installing a replacement battery, the displayed battery percentage may require normal charge and discharge usage before behaviour becomes fully consistent.
Initial observations can include:
- Percentage changing faster than expected
- Percentage remaining at one value for an extended period
- Different runtime compared with the original battery
- Charging rate changing at different battery levels
The phone's battery-management system estimates remaining capacity based on electrical measurements and operating behaviour.
Do not intentionally deep-discharge a lithium-ion battery repeatedly in an attempt to “calibrate” it.
Repeated deep discharge can accelerate battery wear.
Battery Safety
Lithium-ion batteries contain significant stored energy and must be handled carefully.
Do not:
- Puncture the battery
- Bend the battery excessively
- Crush the battery
- Cut the battery
- Fold the battery
- Overheat the battery
- Short battery contacts
- Use sharp metal tools beneath the battery
- Apply uncontrolled heat
- Install a physically damaged battery
- Reuse a swollen battery
Stop immediately if a battery:
- Swells
- Smokes
- Hisses
- Leaks
- Produces a chemical smell
- Becomes abnormally hot
- Has torn outer wrapping
- Has been punctured
- Shows visible physical deformation
A damaged lithium-ion battery may ignite, vent hot gases, or release hazardous material.
Swollen Battery Warning
A swollen battery should not remain installed in a device.
Possible signs include:
- Rear cover lifting
- Screen lifting
- Housing separation
- Pressure marks
- Unusual gaps around the phone
- Battery visible through an opened rear cover
- Internal pressure against components
Do not:
- Press the cover back into place
- Puncture the battery
- Continue charging the device unnecessarily
- Apply excessive pressure to the phone
- Attempt to flatten the battery
A swollen battery requires appropriate handling and disposal.
Installation Difficulty
Replacing the Galaxy S21 FE battery is an advanced internal repair.
The procedure may require:
- Heating the rear cover
- Separating the rear cover from the frame
- Removing the original adhesive
- Removing internal covers or brackets
- Disconnecting the battery
- Removing the wireless-charging/NFC assembly where required
- Applying battery-removal techniques
- Removing the original battery
- Installing appropriate battery adhesive
- Reconnecting internal components
- Installing new rear-cover adhesive
- Testing the phone
- Resealing the rear cover
Professional installation is strongly recommended.
Installation Preparation
Before installation:
- Confirm the exact device model.
- Compare the replacement battery with the original.
- Inspect the battery connector.
- Inspect the replacement battery for swelling or physical damage.
- Back up important data.
- Power off the phone.
- Remove the SIM tray where appropriate.
- Work on a clean, static-safe surface.
- Prepare appropriate rear-cover adhesive.
- Prepare appropriate battery adhesive where required.
- Review a model-specific repair procedure.
- Use suitable battery-safe removal tools.
Do not install a visibly damaged battery.
Installation Notes
During installation:
- Apply controlled heat when loosening the rear-cover adhesive.
- Avoid inserting opening tools too deeply.
- Disconnect the battery before disconnecting or reconnecting other major internal components where appropriate.
- Do not pry directly into the battery cell with sharp tools.
- Avoid excessive bending of the battery.
- Do not puncture the battery pouch.
- Remove old battery adhesive carefully.
- Keep screws organized by their original positions.
- Inspect the battery connector before connection.
- Align the replacement battery correctly.
- Ensure no cable or component is trapped beneath the battery.
- Test the phone before resealing the rear cover.
Improper installation may damage the phone or create a battery-safety hazard.
Components That May Be Damaged During Installation
Improper battery replacement may damage:
- Rear cover
- Battery
- Main logic board
- Battery connector
- Display
- Display flex cable
- Wireless-charging coil
- NFC assembly
- Interconnect cables
- Antenna cables
- Cameras
- Loudspeaker
- Internal brackets
- Rear-cover adhesive surfaces
Installation-related damage is not covered by the component warranty.
Battery Connector Handling
Battery and board connectors are delicate.
Do not:
- Force a misaligned connector
- Press directly on nearby surface-mounted components
- Pry connectors with unsuitable metal tools
- Connect the battery while another connector is partially seated
- Damage the main-board battery socket
- Apply excessive pressure
Connector damage may cause:
- No power
- Intermittent power
- Charging failure
- Unexpected shutdowns
- Battery detection problems
- Main-board damage
Testing Before Final Assembly
Before resealing the phone, test:
- Phone powers on
- Battery is recognized
- Battery percentage is displayed
- Wired charging
- Fast charging where available
- Wireless charging
- Charging stability
- Display
- Touchscreen
- Cameras
- Loudspeaker
- Earpiece
- Microphones
- Cellular signal
- Mobile data
- Wi-Fi
- Bluetooth
- NFC
- Fingerprint reader
- USB data connection
- Device temperature
Allow the device to operate long enough to identify unusual heating or unstable power behaviour.
Do not reseal the rear cover until all relevant functions have been confirmed.
Post-Installation Battery Test
A practical battery test may include:
- Confirm that the phone powers on normally.
- Confirm battery percentage is displayed.
- Connect a known-good charger.
- Confirm that charging begins.
- Monitor charging behaviour.
- Confirm battery percentage increases.
- Monitor battery temperature.
- Disconnect the charger.
- Confirm the phone remains powered.
- Use the phone under moderate load.
- Check for unexpected shutdowns.
- Test wireless charging where applicable.
A short charging test cannot determine the full long-term runtime of a battery.
Rear-Cover Adhesive
Opening the Galaxy S21 FE normally compromises the original rear-cover adhesive.
New rear-cover adhesive is not included unless expressly stated.
The installer should obtain suitable model-specific adhesive.
Improper sealing may cause:
- Rear-cover lifting
- Cosmetic gaps
- Dust entry
- Moisture entry
- Loose fitment
- Reduced structural security
Adhesive installation does not guarantee restoration of the original factory ingress-resistance rating.
Water-Resistance Notice
Opening the Samsung Galaxy S21 FE compromises the original factory seal.
Even when new adhesive is installed, the original factory water- or dust-resistance rating cannot be guaranteed after repair.
Avoid exposing a repaired phone to:
- Water
- Rain
- Steam
- High humidity
- Condensation
- Showers
- Swimming pools
- Liquid spills
Liquid damage is not covered by the component warranty.
No Tools or Adhesive Included
No repair tools or adhesive are included.
The installer may require:
- Rear-cover adhesive
- Battery adhesive
- Controlled heating equipment
- Opening picks
- Suction tool
- Precision screwdrivers
- Plastic disconnect tools
- Fine tweezers
- Battery-safe removal tools
- Static-protection equipment
- Cleaning materials
- Controlled clamping equipment
The purchaser and installer are responsible for obtaining all required tools and consumables.
Product Condition and Packaging
Unless otherwise stated, this product is supplied as a replacement battery intended for repair use.
Product appearance, labels, printed markings, manufacturing codes, and packaging may vary according to:
- Supplier
- Manufacturing batch
- Production revision
- Manufacturing source
- Packaging revision
Possible differences include:
- Label design
- Printed codes
- Regulatory markings
- Connector appearance
- Pull-tab design
- Protective wrapping
- Production-date markings
Do not rely solely on a generic product photograph.
Compatibility should be confirmed through the complete device model and physical comparison with the original battery.
Important Notes
- Replacement battery compatible with Samsung Galaxy S21 FE 5G
- Designed for compatible SM-G990-series devices
- Original Galaxy S21 FE capacity specification is 4,500mAh typical / 4,370mAh rated minimum
- Designed to replace a worn, degraded, swollen, or defective battery
- May improve battery runtime when deterioration of the original battery is the cause
- May resolve battery-related unexpected shutdowns
- Does not repair charging-port faults
- Does not repair main-board faults
- Does not repair power-management IC faults
- Does not eliminate normal battery consumption
- Lithium-ion battery requires careful handling
- Advanced internal installation required
- Professional installation strongly recommended
- Rear-cover adhesive is not included unless expressly stated
- Battery adhesive is not included unless expressly stated
- No tools or adhesive included
- Original water resistance cannot be guaranteed after repair
- Test the device fully before final reassembly
- 30-day limited parts-only warranty
- Product appearance and markings may vary
30-Day Limited Parts-Only Warranty
This replacement battery includes a 30-day limited parts-only warranty against confirmed manufacturing defects, subject to the applicable 3C-Easy Markham Component Warranty.
Potential covered defects may include:
- Battery does not accept charge when installed correctly in a confirmed compatible device
- Battery cannot power a confirmed functional compatible device
- Abnormal battery behaviour confirmed to originate from the supplied component
- Premature failure caused by a verified manufacturing defect
- Another verified battery manufacturing defect
The warranty does not cover:
- Installation labour
- Removal labour
- Diagnostic charges
- Shipping costs
- Damage to the phone
- Data loss
- Incorrect model selection
- Improper installation
- Damaged battery connector
- Torn battery flex
- Punctured battery
- Bent battery
- Crushed battery
- Physical damage
- Impact damage
- Liquid or corrosion damage
- Excessive heat exposure
- Damage caused by unsuitable tools
- Damage caused during removal or installation
- Main-board failure
- Charging-port failure
- Charging-board failure
- Power-management IC failure
- USB-controller failure
- Software problems
- Excessive battery consumption caused by applications
- Poor runtime caused by device usage patterns
- Charging problems caused by incompatible chargers or cables
- Wireless-charging faults unrelated to the battery
- Damage caused by repeated deep discharge
- Damage caused by improper storage
- Reduced water resistance after repair
- Removed, altered, or damaged warranty labels
The battery must be inspected and tested before final reassembly.
Warranty coverage applies only to the supplied component and does not include labour, installation, removal, device replacement, data recovery, or consequential damage.
Battery Disposal and Handling
Do not dispose of lithium-ion batteries in household garbage.
Removed batteries should be handled according to applicable local battery recycling and hazardous-material requirements.
Protect exposed battery terminals from short circuits during storage or transportation.
Damaged, swollen, punctured, or overheated batteries require additional care and should not be transported or handled like normal undamaged batteries.
Intellectual Property Disclaimer
Samsung, Galaxy, Galaxy S, Galaxy S21 FE, Samsung Super Fast Charging, Wireless PowerShare, Android, USB Type-C, USB Power Delivery, and related names, logos, and trademarks belong to their respective owners.
3C-Easy Markham is not affiliated with, authorized by, sponsored by, or endorsed by Samsung Electronics, Google, the USB Implementers Forum, or any applicable mobile carrier.
All brand names and model references are used solely to identify product compatibility and intended use.
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