Laptop power & battery

Laptop takes much longer to charge than it used to

A weaker charger, heavy background use while charging, or a battery that's simply aged are the most common reasons charging has slowed down.

Difficulty
Easy
Time
15–30 minutes to test
DIY cost
$0–$60
Pro cost
$80–$150

Symptoms

  • Full charge now takes several hours longer than it used to
  • Battery percentage climbs very slowly even when idle
  • Charging seems fine at first but slows dramatically near the end
  • Laptop was recently used with a different or weaker charger

Likely causes

  • CommonUsing a lower-wattage charger than the laptop originally shipped withA 45W charger on a laptop designed for 65–90W will charge noticeably slower.
  • CommonHeavy CPU/GPU use while charging competing for available powerGaming or video editing while plugged in can slow the charging rate significantly.
  • PossibleAging battery charging more conservatively to protect its remaining healthSome battery management systems intentionally slow charging as cells age.
  • PossibleCharging port or cable degradation limiting current flowA partially damaged connection can restrict how much power gets through.
  • Less commonThermal throttling of the charging rateIf the laptop or battery is running hot, charging speed is deliberately reduced.

What to do

  1. Confirm the charger's wattage matches what the laptop originally came with, printed on the underside of the adapter.
  2. Close demanding apps and let the laptop sit idle while charging to see if speed improves.
  3. Check battery health/condition in system settings for signs of aging.
  4. Feel whether the laptop or battery area is warm while charging, since heat slows charging on purpose.
  5. Try a different, correctly-rated cable and charger to rule out a degraded connection.
  6. Note if slow charging is consistent every time or only near a full charge, which is often normal trickle-charging behavior.

Tools and parts

  • None required
Correct-wattage replacement chargerSearch: “[laptop model] original charger wattage”

When to call a pro

If a correctly-rated charger and idle charging are still much slower than expected, have the battery and charging circuit tested by a professional.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.