How does charging a phone beyond 80% decrease the battery’s lifespan?

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Samsung and Apple both released new phones this year that let you enable a setting where it prevents you from charging your phone’s battery beyond 80% to improve its lifespan. How does this work?

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16 Answers

Anonymous 0 Comments

Higher cell voltage means reduced battery cycle life. Typically the higher % charge you go the higher the voltage gets. 80% is sort of the cutoff threshold where you see diminishing returns in amount charged vs voltage increase.

Anonymous 0 Comments

Well… yes and no. Ultimately, you’re not going to see much of a difference between charging “normally” and charging up to 80%. By the time you see battery issues, it’s time for a new device or battery change anyways.

You have to remember that batteries are still a chemical process. The lithium ions are what run your phone. And lithium ion batteries do not like to be fully discharged or fully charged (hence the general consensus of 30%-80%). Basically, when your phone is fully dead, it takes a lot more energy to get it charged than when it already has an existing charge. And when your phone battery reaches towards its max charge, it is much more difficult to actually achieve that 100%. The battery wants to charge and discharge. Sorry if this isn’t the best explanation

Anonymous 0 Comments

Think of a battery as a bus and the “energy” as passengers on the bus.

If you fill the bud with 80% of its capacity (let’s say max is 100 people for a nice round number), then you’ll have it pretty full, but there’s a lot of room to play around with. Not every single seat needs to be filled, people can stretch out, loading takes little time as it doesn’t need to be as precise.

If you try to fill the buss with 100% capacity, things change. The closer you get to max, the more and more complicated it becomes to load the bus. At max capacity, every single seat needs to have a person in jt. Loading takes longer because we have to make sure no single seat is skipped, otherwise we won’t be able to fit everybody we can on. It being so crowded makes people more likely to make a mess and less likely to clean up after themselves. If they drop some garbage in the flood, it’s harder to pick it back up when you have people shoulder to shoulder than when you got some breathing room.

This makes the bus “dirtier” over time. It also causes more wear and tear on the seats, the windows, the tires, the transmission, the breaks, etc causing the bus to last slightly shorter than if it had carried a few less passengers over its life.

Basically, fully charging a battery causes more wear and tear because you have to be “fill” every nook and cranny with energy in a battery. That energy adds heat to the battery which causes chemical changes to the makeup that can’t be reversed. They’re small, but they add up over time.

Anonymous 0 Comments

Just a note. Samsung has had this feature for awhile. My 2 year old S-series phone allows me to do this. It’s just Apple that has this as a new feature this year.

Anonymous 0 Comments

its because it degrades the anode and cathode faster, this also happens when you discharge it below typically 20-30 percent. as simple as i can possibly put it when you charge and discharge a battery you are slowly coating the anode with the cathode material and vice versa if you look up electroplating you will understand this process more. This effect is much more pronounced at the extremes of the battery voltage capacity.

Anonymous 0 Comments

think of it as a rubber band.

stretch it to it maximum (100%). over a period of time, the rubber band would lose its elasticity.

stretch it any amount less than that would “preserve” the elasticity and let’s you use the rubber band more effectively for longer than if you 100% it to its limit all the time.

Anonymous 0 Comments

Your phone will likely be replaced before your battery lifespan even becomes an issue

So i wouldn’t lose sleep ovrer this

Anonymous 0 Comments

Think about the battery as of several balloons you store energy in. You can pump it almost full and deflate thousand times and it will be ok.

You can also pump it up until the balloons almost bursts, that way you can store a bit more in there. But when you deflate the balloon it will be stretched. After hounded cycles some of them will be so stretched that they will finally burst. So as a result you will have less and less capacity.

This is almost exactly what happens when you try to charge a battery until it is 100% full – the insides of the battery get heated, some parts inside change volume, some gas is released. This all bends and stresses internal structure of the battery until small pieces break. This decreases capacity.

It is know effect for many years, so batteries were never charged to the 100% full level, but to a level where they can survive being charged and discharged many times.

But as people wanted the batteries to last longer and longer. But there was no new miracle technology to do so. Either the batteries could be made bigger and heavier or they could be charged a bit more, halving their lifespan. So this overcharging become a standard since people change the phones so often that the battery being damaged was not an issue. it was even better for manufacturer because they could both brag about the time device works on a singe charge and have the users replace the device sooner because battery would go bad.

Now, phones are so expensive so the people don’t want to change them so often, so you have an option to trade some battery capacity for a better battery lifespan.

Anonymous 0 Comments

Constantly gimping your phone to 80% for years so that in 3 years time it can charge to 85% of its original capacity (which you never do though, youre charging to 80% of 85% still at this point..) vs using 100% of your battery every day for 3 years and it only charging to 70% down the track

Youre gimping your phone for years to have it less shit later (but inevitably still deteriorated some). You might as well have used it at 100% youve already front loaded shittier battery life. Can someone explain this to me…

Anonymous 0 Comments

is this actually still a thing? I thought for hte past few years this was basically a non-issue now?