When a Note20 or Note20 Ultra will not charge or charges slowly, run Samsung's checks in order: look over the cable and port, restart with Side plus Volume down, leave it an hour on a Samsung charger in a known-good outlet and hold Power for 15 to 20 seconds. Wikipedia lists wired charging up to 25W plus Qi wireless charging, so any weak or worn adapter will charge slowly. On a phone this old the USB-C port and cable are the usual suspects, and lint packed into the port stops the plug seating.
Differential
Likely causes of “Samsung Galaxy Note20 family will not charge or charges slowly”, and how to tell them apart
- 1
A weak or damaged adapter or cable
What separates it Charging is slow or cuts out when the cable moves
How to confirm Try a Samsung adapter and cable rated for 25W
- 2
Lint or corrosion in the port
What separates it The plug wobbles or does not click in because of lint or corrosion in the port
How to confirm With the phone off, look in with a flashlight and lift lint out with a wooden toothpick, never metal
- 3
Fast charging switched off
What separates it Even a good charger and cable give only a trickle of charge and the percentage barely rises
How to confirm Settings, Battery, Charging settings: enable fast charging and fast wireless charging
- 4
Protect battery limiting the level
What separates it Charging stops at 80 or 85 percent every time and the battery never reaches a full charge
How to confirm Samsung says to turn off Protect battery for a full charge
- 5
A worn cell
What separates it It charges but the level plunges or the phone dies early
How to confirm Run the battery test; the module repair includes a new cell
Before you touch a setting
Record this first — changing settings destroys the evidence
- Note20 or Note20 Ultra, and whether the fault is wired, wireless or one charger only
- The adapter and cable used and their ratings
- Any warning text about moisture or temperature
- Whether charging stops at a set level and whether Protect battery is on
Try in this order
0 of 7 completedInspect cable, adapter and port
ReversibleLook for fraying, bent pins, dirt and damage. Samsung says the cable should sit firmly with very little movement.
Restart
ReversibleHold Side and Volume down together until the Samsung logo appears, then release and let the phone finish starting.
Charge on a trusted set for an hour
ReversibleA Samsung adapter in a tested outlet; a completely flat battery can take up to ten minutes to show the charging icon.
Try a forced power-on
ReversibleUnplug and hold Power for 15 to 20 seconds; if it starts, switch it off and charge fully.
Clean the port gently
ReversibleClean the port gently, with the phone off, a flashlight in and the lint out with a wooden toothpick.
Turn on the fast charging options
ReversibleOpen Settings, Battery, Charging settings and check which charging features are turned on, since limits there can stop charging early.
Test in Safe mode
ReversibleRestart in Safe mode to rule out an app, and turn off Protect battery if charging ends early.
Model-specific
What is true of this model and not of its siblings
- Charging by model
- Wikipedia lists wired charging up to 25W and Qi wireless charging on both, with 4.5W PowerShare reverse charging.
- Age and wear
- Released in August 2020, so ports and cells have nearly six years of use; intermittent charging is usually hardware.
- Part numbers
- Adapters are identified by their printed ratings and the phone by its SM- number; Samsung does not ask owners for a part number.
- Tools and supplies
- A second Samsung charger and cable, a flashlight for the port, a wooden toothpick and a tested outlet.
- Repair cost
- Module repair with battery: $219 (Note20) and $269 (Note20 Ultra) on Samsung's US list; no port repair price is listed.
- Other models this page answers
- These steps also fit the Galaxy Note20.
Stop boundary
When this stops being a self-service repair
- !If nothing charges after an hour on a proven Samsung charger and a restart, book a Samsung repair
- !If the liquid indicator is pink or red, or the port is corroded, stop charging and have it inspected
- !If fast charging fails even in Safe mode, contact Samsung with the adapter model
Evidence ledger
Sources behind this answer
Charger, cable, fast charging setting, PC charging and the 80 percent cap.
Heat pauses charging.
Note20 and Note20 Ultra battery, charging, chip by region, storage and microSD, Wi-Fi, display, glass, frame and end of software support.
Samsung's suggested US screen module prices by model.
Exact questions
Common questions
How fast does the Note20 charge?+
Wikipedia lists wired charging up to 25W over USB-C, with Qi wireless charging on both models.
What is PowerShare?+
Wikipedia says it lets the phone charge another Qi device from its own battery at 4.5W. It drains the phone, so switch it off if the level falls unexpectedly.
Can any USB-C charger be used?+
Samsung recommends its own and says others can hinder charging.
Why does it stop at 80 percent?+
Protect battery limits the charge; turn it off under Settings, Battery.
Why is there no charging icon?+
A fully drained phone can take up to ten minutes to show it.
Can a computer charge it?+
Slowly. Samsung points to the wall charger for real charging.
Why does charging work only at an angle?+
Lint in the port or a worn connector stops the plug seating. Clean the port first; if it persists, the port needs service.
Is a slow wireless charge a fault?+
Not necessarily. The pad, a thick case, misalignment and warmth all slow it; center the phone and remove the case.
What does the phone do when charging is unsafe?+
Samsung's article says the phone can stop charging on its own when it detects moisture or when the temperature is too high or low, and shows a warning. Unplug, dry the port, let the phone reach room temperature and try again before assuming a fault.
Why does the level rise so slowly while I use the phone?+
Using the screen, especially for video or games, draws a large share of the power that the adapter supplies, so little is left to charge the cell. Charge with the screen off for a fair test, and use the fastest adapter you have.
Is a cracked charging port repairable?+
Samsung's US price list gives no port repair price, so the quote comes from the service center. Because the Note20 is out of software support, weigh the quote against the phone's remaining life before committing.
Could the battery be the reason it will not charge?+
Yes. A cell that has failed can refuse to charge, charge to a low ceiling or drop to zero without warning. The Samsung Members battery test and the module repair, which includes a new cell, are the routes to check and fix it.