What is optimised or adaptive charging, and should I leave it on?
It holds the charge partway overnight and finishes just before you wake, because hours pinned at full is what ages a lithium cell. Leave it on; override it on the nights you need a full battery early.
- Difficulty
- beginner
- Time
- 12 min
- Read
- 4 min
Short answer
Leave it on. A lithium cell degrades faster the longer it sits at a high state of charge, particularly when warm, so the feature charges to around four-fifths, waits, and completes the charge shortly before your usual alarm. It needs a week or two to learn your routine, and both platforms let you override it for one night with a long press on the charging notification when you need a full battery early.
Apple calls it optimised battery charging, Google calls it adaptive charging, and several Android manufacturers have their own name and their own extra options. The mechanism is the same everywhere, and understanding it settles most of the folklore about overnight charging in one go.
Step by step
- Understand what actually wears the cell.Two things dominate: time spent at a high state of charge, and heat. Charging to full and then sitting at full for seven hours is a lot of time at maximum voltage. Neither the act of charging overnight nor the number of times you plug in is the problem — the problem is the plateau at the top.
- See what the feature changes.It charges quickly to a partial level, holds there for most of the night, then completes the charge in a short final climb timed to finish around when you normally unplug. The battery reaches full when you want it, and spends an hour at full instead of seven.
- Give it time to learn.It works from your observed routine, so for the first week or two it may finish the charge at the wrong time or not engage at all. Unusual nights — a late shift, a holiday, a different time zone — will also confuse it. This is expected and not a fault.
- Know how to override it.When you need a full battery at 3am for an early flight, press and hold the charging notification on the lock screen and choose to charge fully now. Both platforms offer this. Doing it occasionally costs nothing measurable.
- Look for a hard charge limit if your phone offers one.Several Android manufacturers, and recent iPhones, offer a setting that caps the charge at a fixed percentage permanently rather than just overnight. That is the stronger version of the same idea and it is worth using on a phone that lives on a desk charger or in a car cradle all day.
- Deal with heat, which matters more.A thick case left on while charging, a phone under a pillow, a sunny windowsill, or wireless charging in a warm room all raise the cell temperature during the hours it is held high. Removing a heavy case overnight and charging somewhere cool does more for battery life than any software setting.
- Do not bother with charge cycling myths.You do not need to run the battery to zero, you do not need to charge to full to calibrate it, and topping up during the day is fine. Modern battery management does the calibration itself, and shallow frequent charges are gentler than deep ones.
Tips
- If the phone is regularly at a low charge in the morning, the feature is not broken — check whether something is draining it overnight, because optimised charging still reaches full before your usual wake time when it is working.
- The feature does nothing if you charge in short bursts through the day, because there is no long plateau for it to avoid. That charging pattern is already gentle on the cell.
- On a phone you use as a bedside clock while charging, the screen keeps it warm all night. That is worse for the battery than the charge level is.
- Battery health falls fastest in the first year and then more slowly. A steep early decline is normal and is not evidence that anything you did was wrong.
Questions people ask
Does it slow down my charging?
Only in the sense that it delays the last portion. The initial fast charge is unchanged, so a phone that has been on charge an hour is as full as it would have been.
Will turning it off make my phone last longer through the day?
Marginally — you would start the day at full rather than possibly slightly short if you unplug early. It costs battery health to buy that, and if you are consistently unplugging before the feature finishes, the honest fix is a longer charge window or a battery case.
Is it worth it on a phone I plan to keep only two years?
It costs you nothing and the phone's resale value depends partly on battery health, so yes. It matters far more on a phone you intend to keep four or five years.
My phone charges to 80% and stops permanently. Is that a fault?
Check whether you have enabled a charge-limit setting, and whether the phone is hot. Both platforms also throttle or pause charging above a temperature threshold, which is a protection rather than a fault.