Symptoms
- Battery shows 0% and stays there no matter how long it's plugged in
- No charging light or activity at all when connected to power
- Laptop was left unused and uncharged for weeks or months
- Laptop only powers on directly from AC with battery removed, if possible
Likely causes
- CommonDeep discharge protection preventing the battery from accepting a charge normallyLithium-ion batteries can enter a protective state after sitting fully depleted for a long time.
- CommonBattery cells have degraded beyond usability from long-term full dischargeExtended time at 0% accelerates permanent capacity loss and can kill a battery outright.
- PossibleCharging circuit fault rather than the battery itselfWorth testing with a different laptop or a known-good battery if possible.
What to do
- Plug in the charger and leave it completely undisturbed for at least 1–2 hours before checking again, since deeply discharged batteries can take time to respond.
- Try a different, known-good charger to rule out the charger being the cause.
- If the battery is removable, try running the laptop on AC power alone (if supported) to confirm the laptop itself still works.
- Avoid repeatedly unplugging and replugging in frustration, since deeply discharged batteries need sustained, uninterrupted charging time to wake up.
- If there's still zero response after several hours, the battery has likely failed and needs replacement.
Tools and parts
- None required
Replacement laptop batterySearch: “[laptop model] replacement battery”
When to call a pro
If extended charging shows no response at all, have the battery professionally tested and replaced rather than continuing to try to revive it.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.