The battery in your phone is a chemical reaction in a bag. It is not a fuel tank, it does not have a memory, and it is not sulking at you. It is an electrochemical cell doing exactly what electrochemistry does, which is to wear out a little every time it works and considerably faster whenever it is hot.
Most of what you have been told about looking after it was true once, about a different kind of battery, some time around 1994. The rest was invented on the internet by people who had a strong feeling. Let us sort through it.
What actually wears one out
Three things, and they are not equal.
In order of how much damage they do
- Heat, by a distance. A battery held at a high temperature ages faster whether you are using it or not, and a hot battery being charged quickly ages faster still. Everything else on this list is a footnote to heat.
- Time spent sitting at a very high or very low charge. A cell held near completely full is under more chemical stress than one sitting comfortably in the middle. Left near empty for weeks is a separate harm of its own.
- Full cycles. One cycle is a whole battery’s worth of energy used, whether that happens in a day or across four. Manufacturers rate a phone to keep roughly eighty percent of its original capacity for several hundred cycles, and that rating is where the number in your settings comes from.
Notice what is not on that list. The brand printed on your cable. The number of times you plug in. Whether you let it die once a month as a ritual.
Six pieces of advice, sorted
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“Let it drain to zero sometimes to keep it healthy.”
Wrong, and it is the oldest one. That was the memory effect in nickel-cadmium cells and it has nothing whatever to do with the lithium-ion cell in your phone. Deep discharges are among the harder things you can do to a modern battery. The one narrow truth left inside it: a very occasional full charge and discharge can recalibrate the software estimate of how much charge remains. That fixes the gauge. It does not fix the cell.
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“Charging overnight overcharges it.”
Wrong in the literal sense. The charging circuit stops at full and will not push more in. What is true is the second half of the worry: a battery sitting at a hundred percent all night, every night, for years spends a great deal of its life in the most stressful state available to it. Which is precisely why your phone now has a setting that holds it near eighty percent until shortly before your alarm. Turn it on. It is the best free thing in this article.
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“Fast charging destroys the battery.”
Overstated. The harm is heat rather than speed, and phones taper the rate down as they fill for exactly that reason. Fast charging a cool phone on a desk is fine. Fast charging in direct sun, under a pillow, in a hot car, or inside a thick case while running satellite navigation is not fine, and that is the same sentence written four times.
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“Closing background apps saves battery.”
Wrong, and it usually costs you. Force-closing an app removes it from memory, so the next launch is a cold start, which uses more energy than leaving it suspended would have. Modern phone operating systems already freeze what is in the background. Close an app because it is misbehaving, not as housekeeping.
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“Third-party chargers ruin batteries.”
Wrong for anything reputable, true for the worst of the cheap ones. Modern charging is a negotiation: the phone and the charger agree a voltage and a current, and the phone stays in control of the process. A properly certified charger from a real manufacturer is fine regardless of whose name is on your handset. The genuine risk in a two-dollar unbranded brick is not gentle battery wear. It is the insulation between mains voltage and your hand.
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“Once battery health drops, you may as well buy a new phone.”
No. A replacement battery is one of the few repairs still comfortably economic, and it returns the phone to roughly the runtime it had when it was new. A four-year-old phone with a new battery is a four-year-old phone that works. Price the battery before you price a handset.
What actually helps, which is a shorter list
- Keep it cool. Off the dashboard, out of direct sun, out of the pocket pressed against a warm laptop, and out of its case if it is getting hot while charging quickly.
- Turn on the optimised or adaptive charging setting, whatever your phone calls it. It exists to keep the battery out of the stressful zone while you sleep, and it costs you nothing.
- If you can top up during the day, do. Little and often around the middle is gentler than one deep drain followed by one long full charge, whatever the folklore says.
- Do not store a phone you are not using at zero. If it is going in a drawer for months, leave it around half full and look in on it occasionally.
- Before you blame the battery, look at what the screen is doing. Brightness, refresh rate and the always-on display are the three largest consumers on most modern phones, and not one of them is chemistry.
None of this requires a new charger. But if yours is the size of a bar of soap and gets warm enough that you notice, the modern gallium nitride bricks are a reasonable swap: smaller, cooler-running, and able to negotiate properly with a phone that wants to taper. Match the wattage your phone can actually accept, look for a real manufacturer and genuine certification marks, and ignore anything advertising a number far above what your phone supports. See GaN chargers
Some links on this page are affiliate links. If you buy through them, HowTo: Tech Edition earns a commission at no extra cost to you. A charger cannot repair a worn battery, and nothing on this page pretends otherwise.
The verdict, since you asked for one
Keep it cool. Keep it in the middle. Turn on the setting your phone already has and has had for years. Do those three and you will land at the good end of the normal range rather than the bad end, and over four years the difference is roughly the difference between a phone that lasts a day and a phone that needs an afternoon rescue.
That is the whole of it. There is no ritual. There is no calibration ceremony. There is a bag of chemicals that does not enjoy being hot, and a settings screen you have never opened.
Tested on a phone I have owned for three years and deliberately charge in the middle of the day, and on my mom’s phone, which lives on the windowsill above a radiator and is a controlled experiment I did not authorise.