iPhone battery & charging

iPhone barely charges overnight

Overnight charging that leaves the phone at a lower percentage than expected is usually Optimized Battery Charging working as intended, not a fault. It's easy to confirm and adjust.

Difficulty
Easy
Time
5 minutes to check

Symptoms

  • Phone shows less than 100% in the morning despite charging all night
  • Percentage climbs quickly at first, then pauses for hours before finishing
  • Phone reaches 80% early and stays there until near wake time
  • Charging completes right around the usual wake-up time

Likely causes

  • CommonOptimized Battery Charging delaying the final chargeiOS learns your schedule and holds charging around 80% overnight, finishing just before you usually wake up to reduce battery wear.
  • PossibleLow-power adapter extending charge timeA weak adapter can genuinely fail to reach 100% overnight.
  • PossibleApp activity overnight consuming power faster than it chargesHeavy background downloads or notifications can slow net charging progress.
  • Less commonA loose cable connection interrupting charging periodicallyAn intermittent connection can leave the phone well short of full.

What to do

  1. Check the battery percentage right when you wake up versus a bit later, since Optimized Charging often finishes close to your usual alarm time.
  2. Look in Settings > Battery > Battery Health & Charging to confirm Optimized Battery Charging is on and see its explanation.
  3. If you want a full charge sooner, turn Optimized Battery Charging off, understanding it may slightly increase long-term battery wear.
  4. Confirm the adapter is a standard 5W or higher; a working iPhone adapter should reach full charge overnight regardless.
  5. Check that the cable stays firmly connected overnight rather than shifting loose.
  6. Reduce notifications or background downloads scheduled for overnight hours if drain seems unusually high.
  7. If it's still not reaching 100% well past your normal wake time, treat it as a charging speed issue instead.
  8. Rule out a charging port or cable issue using the general slow-charging steps if Optimized Charging isn't the explanation.

When to call a pro

If disabling Optimized Battery Charging doesn't fix a genuinely incomplete overnight charge, the cause is likely the charger or port rather than software.

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.