Why does my phone stop at 80% overnight? Optimised battery charging explained
You plug in at night and check at 2 a.m.: 80%, not moving. In the morning it's either at 100% or, annoyingly, still at 80% on the day you got up early. Nothing is broken; the phone is choosing to wait.
Why phones hold at 80%
A battery ages in two ways: with every charge cycle, and simply with time, faster when it's hot and when it's full. A phone that reaches 100% at midnight and stays plugged in until 7 a.m. spends hours at the highest stress level, topping itself up again and again. Holding at around 80% and finishing at the last moment avoids most of that. Over a couple of years it noticeably slows the loss of battery capacity.
What each phone calls it
| Phone | Feature (names vary by model and software version) | What it does |
|---|---|---|
| iPhone | Optimised Battery Charging; on newer models also an 80% Limit option (Settings, Battery, Charging) | Learns your routine and waits at 80%; the limit option stops at 80% every time. |
| Google Pixel | Adaptive Charging; on recent Pixels a charging optimisation setting with an 80% limit | Aims to reach 100% just before your alarm or usual unplug time. |
| Samsung Galaxy | Battery protection: Adaptive, Maximum (80% or 85%), or Basic | Adaptive waits overnight; Maximum stops at the set level all the time. |
| Other Android phones | Smart, optimised, intelligent or battery-care charging | Usually the same idea: pause, then finish before morning. |
Why it sometimes isn't full in the morning
- You got up earlier than usual. The phone predicted a later unplug time from your routine. Phones often use your alarm as a hint, but not always.
- Your routine changed. New shifts, holidays or travel across time zones confuse the prediction for a few days.
- A fixed limit is on. If it always stops at exactly 80% or 85%, day and night, a permanent limit is switched on, not the overnight feature.
- It got warm. Under a pillow or on a wireless pad in a warm room, phones pause charging to cool down (“charging on hold”). See phone hot while charging.
- The charger is weak. An old 5 W cube with a busy phone can genuinely take all night. See slow charging causes.
Should I turn it off?
For everyday use, leave it on: it costs nothing on a normal morning. Before an early start, a long trip or a day without chargers, either tap the “charge to full now” option when it appears, or turn the feature off for that night and back on afterwards. If you regularly need the full 100%, an 80% limit is the wrong setting for you; overnight optimisation still gets you to 100% most days.
Planning a trip with several gadgets? The power bank trip planner lets you set each gadget's starting % (80% if it was held overnight) and shows whether one bank covers the day.
Related
Does fast charging damage the battery? · Battery percentage jumps or drops · Why phones drain fast when travelling · Is it bad to charge a phone in the cold? · Interactive: why gadgets get hot
Questions
Why does my iPhone stop charging at 80% overnight?
Optimised Battery Charging learns when you usually unplug and holds the battery at 80% until shortly before then, because sitting at 100% for hours wears the battery faster. Newer iPhones also have an optional fixed 80% limit.
Is optimised charging worth leaving on?
Yes for most people. It slows battery wear and you usually still wake to a full phone. Turn it off for a night before an unusually early start or a long day away from chargers.
Why is my phone stuck at 85% all the time?
That's a fixed limit, such as Samsung's Maximum battery protection, not the overnight feature. Change it in the battery protection settings if you want to charge to 100%.
Does charging to 100% damage my phone?
Not straight away, but keeping it full for long periods, especially when warm, makes the battery lose capacity faster over months and years. Occasional full charges are fine.
Why does my phone say charging on hold?
Usually because it's too warm, often on a wireless charger or under a pillow, or because the overnight optimisation is waiting. Let it cool and it resumes.
Published .