If your phone spends all night plugged in, it probably sits at 100% for hours before you wake up. That long stretch at a full charge is exactly what wears a lithium-ion battery down over time, and all three big phone makers now ship a built-in way to stop it: a charge limit. Set it once, and your phone simply stops charging at 80% on ordinary days, leaving the full 100% for the days you actually need it.
Why stopping at 80% helps
A battery does not wear out only because you use it. Apple, Google and Samsung all describe the same principle in their own words: spending less time fully charged reduces strain on the battery and helps it keep its capacity for longer. Capping the daily charge at 80% is simply the most direct version of that idea, and it costs nothing once it is set.
That does not mean your battery will stop ageing. Every rechargeable battery loses capacity as it chemically ages, and no setting can restore capacity that is already gone. Think of the limit as slowing the decline, not freezing it. It is also a trade-off you should make with open eyes: you start each day with about a fifth less charge than before, so the limit suits you best if you usually end the day with charge to spare or stay near a charger.
Set a charge limit on iPhone
Apple's full charge-limit control is available on iPhone 15 models and later. On those phones you can pick any limit from 80% to 100% in steps of 5%, so 80%, 85%, 90% and 95% are all available, not just 80%.
- Open Settings, then tap Battery.
- Tap Charging.
- Choose 80% as your charge limit.
Your iPhone will charge to within a few percentage points of the limit and then stop. If the level drops more than 5% while the phone is still plugged in, charging starts again up to the limit. Apple also notes that a phone with a limit below 100% will occasionally charge all the way to 100% to keep its battery-level estimates accurate, so a rare full charge is normal and not a sign that the setting broke.
If you have an iPhone 14 or earlier, you will not find a charge-limit slider. What you do get is Optimized Battery Charging, in Settings, then Battery, then Battery Health and Charging. With it on, the phone learns your routine, holds at 80% for most of the night, and finishes charging shortly before you usually unplug. Apple says this learning needs at least 14 days and at least nine charges of five hours or more in one location, so do not expect it to work perfectly in the first week. On iPhone 15 and later, Optimized Battery Charging is available only when the charge limit is set to 100%, so you choose one approach or the other.
Set the 80% limit on Pixel
Google's version lives under Charging optimization, and the path is the same across recent Pixel phones, though menu labels can vary slightly by model and software version.
- Open Settings, then tap Battery.
- Tap Battery health, then Charging optimization.
- Turn on Use charging optimization.
- Choose Limit to 80%.
Google describes this option as ideal if you usually end the day with some charge left. The alternative on the same screen is Adaptive Charging, which still charges to 100% but times the finish for shortly before you normally unplug, so the phone spends less of the night full. Adaptive Charging also needs about 14 days to learn your routine, and it may not switch on when your schedule changes, such as when you travel.
One Pixel detail is worth knowing before you judge the setting: Google says the phone needs a full charge at every tenth cycle to keep its battery-capacity readings accurate, even with the limit on. When the screen shows 100% on that cycle, leave the phone plugged in for at least 30 minutes to finish the process.
Set Battery protection on Samsung Galaxy
Samsung calls the feature Battery protection, and it offers the most choices of the three. The exact options depend on your One UI version, so check which of these your phone shows.
- Open Settings, then tap Battery.
- Tap Battery protection and turn it on.
- Choose Maximum, then pick 80% as the charging limit if your phone offers a choice.
On One UI 7.0 and later, Maximum lets you choose the limit yourself: 80%, 85%, 90% or 95%. On One UI 6.1, Maximum simply stops charging at 80%, with no choice of percentage. On models running software older than One UI 6.1, the only battery-protection option is a cap at 85%. After reaching the limit, Samsung says the phone runs directly on charger power, and charging starts again when the level falls about 2% below the limit, so seeing 79% on an 80% limit is normal, not an error.
The other two modes are worth understanding before you pick. Basic, the default, stops charging at 100% and starts again at 95%, which only avoids repeated topping-up at full charge. Sleep time protection (called Adaptive on One UI 6.1) holds the charge at about 80% while you sleep and finishes to 100% shortly before you wake up, but it needs your sleep pattern to be fairly regular and, on newer versions, agreement to Samsung's Customisation Service. If you want the simplest long-life setup and you charge overnight, Maximum at 80% is the straightforward pick; if you need a full battery every morning, Sleep time protection is the better middle ground.
Which setting fits your routine?
| Phone | Setting to choose | What happens | Best for |
|---|---|---|---|
| iPhone 15 or later | Charge limit, 80% | Charging stops near 80%, with occasional full charges for calibration | Daily use near a charger, keeping the phone for years |
| iPhone 14 or earlier | Optimized Battery Charging | Holds at 80% overnight, finishes before you unplug | Overnight charging with a full battery each morning |
| Pixel | Limit to 80% | Charging stops at 80%, with a full charge every tenth cycle | Days that end with charge to spare |
| Pixel, alternative | Adaptive Charging | Finishes to 100% shortly before you unplug | Predictable routines where a full battery matters |
| Samsung, One UI 7 or later | Battery protection, Maximum at 80% | Charging stops at your chosen limit, resumes about 2% below it | The strictest everyday limit, with 85% or 90% as gentler options |
| Samsung, overnight | Sleep time protection | Holds near 80% overnight, reaches 100% before waking | A full battery each morning without hours at 100% |
Other Android brands may offer a similar battery-care or charging-limit setting under a different name, but those paths were not verified for this guide, so check your own phone's battery settings rather than assuming the Pixel or Samsung steps apply.
Getting a full charge when you need one
A limit is meant to be switched off for a day, not lived with on a long travel day. The method is the same on all three phones: open the same setting you changed and move it back, then restore it afterwards.
On iPhone 15 or later, set the charge limit back to 100% for that day. On Pixel, turn off Limit to 80% (or turn off Use charging optimization) and the phone will charge to 100%. On Samsung, switch Battery protection to Basic or turn Battery protection off, and the phone will charge fully again. Do the change before you plug in, not after the phone has already stopped at 80%, or you may wait for it to notice the new setting.
If your phone still charges past 80%
First, check whether the extra charge is one of the documented exceptions rather than a broken setting. An iPhone below a 100% limit occasionally charges to 100% to maintain accurate battery estimates. A Pixel does the same at every tenth cycle. A Samsung on Maximum may show 79% for a while because recharging only restarts about 2% below the limit. None of these mean the limit has failed.
Second, check the temperature. If a phone gets too warm while charging, its software may pause or limit charging as a safety measure, which can look like a limit that is working at the wrong level. Move the phone somewhere cooler, take it out of a thick case while it charges, and see whether normal charging resumes.
Third, check for a second, temporary protection state. Pixel phones can show a "Protecting your battery" state after long periods plugged in at high temperature, which restricts charging to roughly 70% to 80% even without the manual limit. That state is separate from Limit to 80%, and Google documents a Charge to full control or a restart to clear it. If none of these explanations fit and the phone charges straight to 100% every time with the limit on, re-check the exact screen above: the most common cause is having picked the overnight or adaptive option instead of the hard limit.
FAQ
Does limiting charging to 80% damage the battery?
No. The limit is a battery-health feature provided by Apple, Google and Samsung themselves, and it works by reducing the time the battery spends fully charged. It does not damage the battery, and it does not void anything by itself, though it does leave you with less charge each day.
Will my phone ever reach 100% again with the limit on?
Yes, occasionally, and that is normal. Apple says an iPhone with a limit below 100% will sometimes charge fully to keep its battery-level estimates accurate. Google says a Pixel needs a full charge at every tenth cycle for the same reason. These occasional full charges are part of the design, not a fault.
Is 80% the right limit, or should I pick 90%?
It depends on how much charge you actually use. If 80% comfortably gets you through the day, it gives the battery the easiest daily life of the options here. If you regularly run low before bedtime, 90% or 95% is a sensible compromise: you still cut the time spent at a full charge, but you keep a usable buffer. There is no single correct number for every user.
Does a charge limit help a battery that is already worn out?
No, it cannot restore lost capacity. A limit slows further wear from here on, but a battery that already drops quickly or shuts the phone down early will not recover. In that case the honest fix is a battery replacement, and the limit is worth setting on the new battery from the start.
What if my phone does not show any of these settings?
Your model or software version may not include the control. iPhone 14 and earlier have Optimized Battery Charging instead of a limit slider, Samsung phones older than One UI 6.1 cap at 85% instead of offering Maximum at 80%, and Pixel availability varies by model. Update your software first, then search Settings for "charging" or "battery protection" before concluding the feature is missing.
Should I also avoid fast charging?
This guide covers charge limits only, and the official pages linked below do not present fast charging as something to avoid entirely. The practical advice they do agree on is simpler: keep the phone cool while it charges, avoid leaving it at 100% for long stretches, and use a compatible charger and cable. Heat plus a long time at full charge is the combination worth avoiding.
Sources and further reading
The iPhone steps, the 80% to 100% range in 5% steps, and the occasional full charge for calibration are set out in Apple's guide to Charge Limit and Optimized Battery Charging on iPhone. The Pixel steps, the choice between Adaptive Charging and Limit to 80%, and the tenth-cycle full charge are set out in Google's guide to maximizing charging on your Pixel phone. Samsung's Maximum, Basic and Sleep time protection modes, the 80% to 95% choice on One UI 7.0, and the 2% restart behaviour are set out in Samsung's Battery protection tips, and the One UI 6.1 version, where Maximum stops at 80% and older software caps at 85%, is set out in Samsung's Galaxy Battery protection feature in One UI 6.1.