Symptoms
- Charger has no light or the laptop shows no charging indicator
- Laptop charges very slowly with the new charger
- Laptop only powers on but doesn't charge the battery
- Laptop shows an 'unrecognized adapter' warning
Likely causes
- CommonCharger wattage too low for the laptop's power needsA charger rated below the laptop's requirement may power it but not charge the battery.
- CommonWrong connector tip size or polarityUniversal chargers often need the exact correct tip, and getting it wrong prevents any connection.
- PossibleLaptop firmware rejecting non-approved chargersSome brands, especially with USB-C, require handshake-compliant chargers.
- PossibleDefective replacement chargerCheap aftermarket chargers have a higher failure rate out of the box.
What to do
- Confirm the charger's voltage and amperage match the original charger's rating exactly, printed on the bottom of both units.
- Check the connector tip size and polarity against the original if it's a barrel-style connector.
- For USB-C laptops, confirm the charger supports Power Delivery (PD) at a high enough wattage, not just USB charging.
- Look for any on-screen warning about an unrecognized or insufficient charger and follow any prompt to allow it.
- Try the charger on another compatible laptop, or try your laptop's original charger, to isolate what's failing.
- Return or replace the charger if it doesn't match specifications, rather than continuing to use a mismatched one.
Tools and parts
- Multimeter (optional, to check output voltage)
Manufacturer-certified or correctly-rated replacement chargerSearch: “[laptop brand model] charger wattage volts amps”
When to call a pro
If you're unsure about matching specifications, buy a charger explicitly listed as compatible with your exact laptop model rather than a generic universal one.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.