How Often Should I Charge My Phone To Prolong The Battery Life?

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Your phone's battery lifespan vs the norm

Does your phone’s battery last as long as it should?

Typically, a modern phone battery’s (lithium-ion) lifespan is 2 – 3 years, which is about 300 – 500 charge cycles as rated by manufacturers. After that, the battery capacity will drop by roughly 20%.

But does yours seem to get shorter way earlier? If yes, then perhaps your charging habit all through the years has been silently wrecking your phone’s battery health

How often you charge will affect the battery life, for better or worse. In short, the more often you top up your battery, the better. To REALLY minimize battery degradation, top up for every 10% drop in battery level. And keep your battery level as close to the middle (50%) as possible. Impractical and unrealistic, yes they are. But these are only for maximizing battery health. There are much room for tweaking to add more convenience into the mix.

Why are these recommended? Because unlike the old Nickel, lithium-ion batteries get stressed by:

  1. Depth of discharge a.k.a how much battery is used before recharging.
  2. Extreme battery levels, both low and high.

Side note: If you want an easy way to prolong battery life, an auto cutoff charging cable might be handy for you.

The widespread, outdated beliefs about battery

Surely, you must had also heard the opposite, which are:

  1. Batteries need to be drained completely and recharged to 100%
  2. Batteries lose capacity if they are repeatedly recharged after only being partially drained.

And these two suggest that frequent charging will degrade battery capacity instead, which WAS true—for the Nickel-based batteries; for they are cursed with memory effect. Simply put, they will “forget” their full capacity if they aren’t discharged and charged from 1% to 100%.

Now, cycling your lithium-ion battery from 1% to 100% habitually will take a chunk of its battery life away.

How deeper discharge & low battery level degrade battery capacity

To clarify, battery by itself, regardless of your habit, will deteriorate. Even when just sitting on a shelf. As you cycle the battery, irreversible internal structure changes happen. The lithium count gradually drops as more and more get lodged onto the anode during normal usage; they form a restrictive layer (named solid electrolyte interface) that grows and increases battery’s internal resistance, which ultimately lowers the battery capacity.

Tying this to your charging habit, the restrictive layer grows faster with the following factors:

  1. High discharge rate (how fast the battery is consumed)
  2. Deeper discharge
  3. Low battery level (as is high battery level, but with different structural change)

Worse is, the degradation of deep discharge escalates the further the battery is in its life cycle. The older your phone is, the more your unhealthy charging habit damages your battery.

How much discharge is considered deep?

There is no boundary: the deeper you discharge it, the more stress it inflicts on the battery. Meaning that topping up frequently extends battery life for lithium batteries. In this regard, doing a full discharge, which is to run your battery down to 0%, is the most stressful. The table below detailed the number of usable cycle depending on the habitual depth of discharge.

depth of discharge and battery health

(Source: Battery University – How to Prolong Lithium-based Batteries)

What battery level is considered low?

Again, the same concept applies: the closer it is to 0%, the more harmful it is to the battery. (And same goes to battery levels closer to 100%.) The least stressful battery level is around the middle (50%). Also a reason why Apple suggests storing batteries at half-charged.

Except this time, there is a boundary set by phone manufacturers.

Recharge reminder

Something we’re all too familiar with …

Definitely a standard you can fall back on. Plus it’s convenient: your phone will never fail to remind you when it gets this low. Though if you’re feeling particularly protective of your battery, you can recharge before it gets to 20% battery.

The exception to the rule

That you should, on certain occasion, run your battery down to 0% (full discharge).

What occasion?

  1. Your battery percentage drops suddenly, say, it stays unusually long at 50% then jumps to 35% in the blink of an eye.
  2. Your battery shuts down when there’s battery left.

If these happen, do a full discharge followed by a full charge for recalibration.

To calibrate your phone’s battery:

  1. Run your battery down until the phone turns itself off (without charging in between)
  2. Charge your phone to 100% while the phone is off
  3. At 100%, unplug from charger and power on your phone
  4. If after powering on the battery isn’t 100%, charge it to 100% and unplug
  5. Done! The full discharge and recharge cycle has recalibrated the battery’s reading

Note: this does nothing to save battery life; in fact, it achieves the opposite …

Why does this happen?

Battery readings are thrown off because unlike the actual electrochemical battery, the digital battery (the smart chip on the battery) that shows us the reading doesn’t age. The graph below visualizes the inconsistency between the two created over time.

Digital battery vs electrochemical battery

(Source: Battery University – How to Calibrate a “Smart” Battery)
Note: the values are for demonstration only.

How often should you calibrate your battery?

  1. Whenever your battery starts showing inaccurate reading; otherwise, refrain from full discharge as it degrades battery capacity.
  2. When the phone isn’t used for a long time.

Now, putting everything together.

How often should I charge to prolong battery life?

It’s a matter of balancing convenience with battery longevity. To recap …

The best but unrealistic way:

  1. Recharge once the battery drops 10%; deeper discharge degrades battery more.
  2. Keep the battery as close to the middle range as possible. Extreme battery levels, which are levels closer to 0% and 100%, reduce battery capacity.

But that defeats the purpose of using a smartphone, which is CONVENIENCE. That said, what you can do instead are:

  1. Recharge whenever convenient. Don’t let it fall below 20% (or higher) and avoid fully discharging the battery unless calibration is needed.
  2. Unplug at battery level between 80% (or lower) and 100%. Don’t let your phone stay at 100% level for too long, i.e., plugging to charger after fully charged.

There’s no absolute rules to follow. Most suggest the 20 – 80 rule, which you can definitely follow. You can even do 45 – 75 or others.

As long as you understand what’s harmful to your battery, you can tailor your charging habit according to your needs and daily routine. Because while you can definitely improve battery life significantly, it’s pointless if it demands sacrificing your enjoyment and convenience, which is what your smartphone is supposed to bring you.  

P.S. If you prefer charging to 100% for maximum runtime, check out the cable that auto disconnects the battery at full charge for you.


Editor’s note: This post has been completely revamped and updated to improve comprehensiveness and accuracy.

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130 thoughts on “How Often Should I Charge My Phone To Prolong The Battery Life?”

  1. Avatar

    hi sir! I have a realme 6i phone with 5000mAh Li-Po battery. what percent should i plug it in and what percent should i unplug it? how can i take care of it sir? I usually plug it when it hits 20% and I always unplug it at 90%. is it safe to do that? and can i charge my phone frequently?

  2. Avatar
    Prosper Johnson

    I have a Samsung galaxy a01 smartphone, at what percentage should the battery drop to before i charge it. Thanks.

    1. Avatar

      Hi admin, my new phone came up with a fast charger 30W Flash Charge 4300mAh Battery, you said that fast charger is not good for the battery’s health how would I maximize my battery’s life span?

  3. Avatar

    Is it okay if I let my battery drop to about 45% and then charge till almost 100%? I have a Samsung Galaxy m21 with a 6000 mAh battery.

  4. Avatar

    Hey there good sir, I’m planning on getting a new phone, and that is the Umidigi F2 (5,150 mAh). I was planning on having my own way of at least using 75% of it, but then I read about your good article. I had changed my mind and decided to use 65% like 20%-85% or even70%! But I’m quite anxious and worried about damaging my phone’s battery more than the 20%-80% rule. Does it really affect the battery more significant than the 20-80 rule? And should I do one discharge/charge cycle when I get the phone? And finally, is it good or ok to do a calibration every 6 months, once a year, or so???

    Please respond, and thank you so much if you will respond in time!!!

  5. Avatar

    Hi, if i am going to leave my phone for a few hours, lets say i am sleeping, should i keep it at 50% or 80%, Samsung says if i am not going to use it, best leave it at 80% or at least 80% and if my battery is at 45 %, is it okay to charge to at least 50% before storing it?

    1. Avatar

      I have new phone realme 5i which has 5000mA battery and 10watt charger. Realme website says “Charge your phone when your battery level goes down to 10%”.But I find in internet that I should star charging my phone when it is 30-40 % . Which % should I really star to change my phone for battery long life?

  6. Avatar

    Hey, I’m gonna let a phone of mine run 24/7, always plugged in, but turning off the power supply with automation when necessary. I was thinking to let it attached to a Raspberry Pi USB port. My first idea: When the battery is more than 80%, turn off the power supply (USB port). Wait for discharge. When the battery is below 20%, turn on the power supply again. Then I read your article and came up with a second idea: Turn off the power supply when the battery is more than or equal to 50%, turn on otherwise. What idea do you consider to be the best in this very specific situation? Maybe something in between?

  7. Avatar

    Hello admin. I’m always charging my phone from 30-100 all the time? Was it really bad for my battery?
    I just bought my phone 1 month ago
    I charged it once a day. Please notice this!

  8. Avatar

    Hallo there admin,just wanted to say is it recommended to do charging when in off mode?I usually charge my phone once in a day by turning it off.Also,I noticed one thing is when I charge upto 90% it automatically gets down to 85% in 2 hrs after charging.Is it normal?Please help,thanks in advance!

  9. Avatar

    Hi, is it okay to charge my phone from 30 – 40% to 80 – 85% ? and is it okay to charge my phone at around 50-60% to 85%?

  10. Avatar

    I use Battery Charge Limit app on my rooted OnePlus5T and I keep the charging limit to 80% and now 3 years with good battery health. Thanks for God.

  11. Avatar
    Robert Vandello

    Hello. May I ask some question? I have used my phone for 3 years, and I also have removed the broken battery. Now it’s been 5 month. I think my phone isn’t as health as before. When the battery percentage shows 70%, it’s drop. But the problem is when I charge my phone, sometimes I forgot if the battery reach 100% because I’m sleep. Is it okay for my phone?

  12. Avatar
    Tom Stalpaert

    I have a practical question. I use my phone a lot for navigation (Waze). What do you recommend the most. Running Waze without charging the battery. But knowing that Waze just eats your battery alive and seeing the % drop every minute. Or charging the phone in the meantime with a car charger. The second option isn’t recommended ether because of the heat that’s generating by charging the battery and the CPU because of running an heavy app.
    I know that neather of these are healty for the battery’s life expectation but wich is the least destructive?
    I use a standard car charger without fast charging technology (max charging current 1500mA) to prevent excessive heating. And is enough to run Waze and charge the phone a little bit. I also use a phone holder that’s placed in front of a ventilation vent so that cool air is blown over the phone.

  13. Avatar

    Can I charge my device twice a day (20%-90%)? Will it reduce the battery life?
    My device usage is quite heavy…

  14. Avatar

    Hi sir I am using nokia 6.1 plus, it has 3060 mah . Many times i had unplucked after 100% and it switched off automatically after 0 %. Is it effect my battery?

  15. Avatar

    Hey! I’m always charging my phone between 30 to 80 and it hadn’t reached 100 for a quite long time. Is this bad for the device!?

  16. Avatar

    Hey, I just got a new phone, and I have been practicing charging up to 100% and you said it’s not good for battery life. What should i do with it? i charge around 60-70 is it all that bad? I don’t use my phone as often. Am I doing good at that? I’m afraid I will do it further damage. how do i minimize this :)?

    Also, is charging techniques still the same these days? Have they not improved or what?

  17. Avatar

    Greetings Charbyte. I’m currently using this app called Accu Battery. In your opinion how is the accuracy of the app l? I practice 30-80 most of the time but sometimes I am doing something else and never notice that it’s more than 80% but I rarely charge it to 100 and below 30.

  18. Avatar

    Hey Admin, I decided today to discharge my battery to 0% since I felt that the readings had turned inaccurate and my device probably wasn’t giving me as much juice. The article I just read above was kinda unnerving and I’m a bit worried.
    However, do note that this is only my second or third full discharge during the entire lifetime of the phone (Asus ZF Max Pro M1 5000mAh), which has lasted me for a good 2.5 yrs now. Will this discharge severely affect my battery life or is it okay?
    Thanks in advance!

  19. Avatar

    Hi bro! I have bought new OPPO A1k 2weeks ago.I don’t let it’s battery down below 25%.But I often charge it 100% or 92_95%.After Reading above information,I am a bit worried.Kindly Give me piece of advise.Can I charge my mob to 90% or 85%. 80% is not possible for me to charge.This phone has 4000mah LI_ION Battery.

  20. Avatar

    If I charge my phone higher than 80 e.g 95-99 is it okay? or there still a damage on the battery? what is the specific percent close to 100 that is okay to charge?is 95 okay or 99?

  21. Avatar

    Is It okay if I set my own rule let say 20-99? cause 80 isn’t enough for me especially my phone have only 3300 mAh of battery
    hope to notice 🙂

  22. Avatar

    MY huawei mate 30 pro uses lithium-po and it is not lithuim-ion, can i still do thesame thing to prolong its life?

  23. Avatar

    1 question when it say 20%-80% charge idea do I only have to charge my phone when it reach 20%-29% or can I charge my phone between 20%to 80% but stop in 80% please help me.

  24. Avatar

    Hi there, and thank you for this wonderful piece of info. I just wanted to know that i read somewhere smart phone manufacturers recalibrate the battery in such a way that if you charge it to 100% its actually charges to 80% of the total capacity. Meaning companies already set the 80% limit and your screen shows it as 100% to prolong battery life. Is it true? Please guide me.
    And is it good that you use your phone while its plugged in? Like gaming watching videos while its charging?

  25. Avatar

    I used to charge my Samsung Galaxy A10 at 0-100%. Can I change to the 20-80% rule for the better battery performance and life time?

  26. Avatar

    Okay Charby noted. I will try and keep charge at 85 but not exceed 90(if I really need more juice).

    Now my next question is on regualrity of the top up during the day. Considering what you said earlier about Depth of Discharge. I want to balance DOD with battery health and longevity. If for instance my battery drops to 60 from 85…Do I need to charge it back to 85 or allow it to drop further to say 40 or 30 % before I plug back in. How many TIMES can I top up back to 85 in a day without battery being damaged or weakened? If I don’t allow my DOD to go a bit lower, will it destroy the battery considering I don’t go lower? Thanks.

  27. Avatar

    Hello Charby, Good day. I intend to use my smartphone Xiaomi (4,000mah battery) for four years at least. I appreciate the 80/20 rule but a lot times I feel like charging to 100 lasts me more during the day than 80. If I charge fully to 100% and recharge when it drops to 20% DAILY without in-between top ups(I also heard charging frequently weakens the battery) , will I still have a capable battery lasting a day at that time(in 4 years) or the only way to have a strong battery is 80/20 charging rule? Will the difference be significant? Will charging to 100 make the battery unusable then or it will still be in good condition considering the charging pattern I mentioned? Thanks

  28. Avatar

    Just curious if manufacturers already use the 80-20 rule in their charging strategy to prolong life and prevent catestrophic failures. I.E. when your phone reads 100% it is actually at 80% of actual battery capacity. Conversely, if your phone shuts off at 0%, your actually at 20% of actual battery capacity. I’m specifically curious about Samsung as I have an S10+. Thanks.

  29. Avatar

    hi there…….I have new A30 Samsung phone and does affect my battery when I play pubg on my phone?? alot….Is there any recommendation for my battery use…it been 1 month know since I have bought it..

  30. Avatar

    hi i bought a new vivo phone the battery type is lithium polymer does the rule 20%-80% applies to lipo as well? and for 1st charge do i need to discharge it to 0% then fully charge it? Thank you

  31. Avatar

    Hi. Hope u r good. I am forever charging my mobile n when.it doesn’t need it. Is this nad for the phone? Do master phone cleaners really work?

  32. Avatar

    Hi,
    I can confirm this rule 20/80 was really powerful and I can keep my old Meizu pro 5 during 3 and an half years without any pb, just starting now to have problem.
    I’ve switched to S9+ and start with the same rule, but I have an overall feeling that It can’t make the day in that condition.
    So I’m wondering if my new device has a problem (completely new out of the box, accubattery apps rates the battery capacity 85% of manufacturer’s value (3500)).
    or if because of modern device, samsung consider already the 80% rule builtin and when charging 100% you are at 80%, and I should now decide to charge until the 100% ?
    Any advice are welcome
    thanks

  33. Avatar

    I typically plugged my phone before going to bed and let it charge overnight so that when I wake up, it’s showing 100% and ready to tackle a new day. I’m pretty sure I am not the only one doing this, but obviously we don’t wake up at intervals during the night to check if the phone is now fully charge to disconnect it.

    So I assume leaving your phone to charge overnight may be convenient, but not a good idea to prolong battery life?

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