Things About Mobile Device Batteries You Probably Didn’t Know

It’s sufficient to say that a phone is nothing without its battery. This is why so many portable electronics users look for guidance in how to make their batteries perform better and live longer. However, when you look to the internet, you’ll find either misinformation or advice that omits crucial details and repeats regurgitated advice that you probably already knew about. In this day and age, we probably have very high expectations for our batteries, despite the fact that batteries haven’t advanced nearly as quickly as mobile technology has. As a consequence, device batteries are very pretentious beasts. Let’s talk about what you really need to know when it comes to battery care.

 1: The whole “discharge your battery completely to prolong its life” concept is a myth.

At least it’s a myth nowadays. This myth started back when portable electronic devices were using nickel-cadmium (NiCad) batteries. NiCad suffered from the incapacity to fully understand its own charge. If you charged your electronic device before it discharged completely, this would backfire on you and create what is known as the “memory effect.” This effect essentially cuts the device’s battery life significantly unless it is discharged once in awhile. Oh, and you don’t have to worry about that anymore.

In the modern mobile era, we no longer use NiCad batteries. Instead, we use lithium-ion (Li-Ion). You may be aware of this, but you’re probably not aware of the fact that completely discharging a Li-Ion battery may damage it. Each time you drain the battery, it risks going below the 3.3-volt mark. Battery charge is determined by voltage, and most Li-Ion batteries operate between 3.3 (empty) and 4.2 volts (fully charged). If you fall below or rise above this range, the battery will overcompensate the shock and lose a little bit of its charge capacity (measured in milliamp hours).

Once your battery reaches 30-50 percent charge, just stick it in the charger and that’s the end of it!

2: Temperature affects battery life.


If you’re letting your mobile device sit in your car unattended in the middle of the summer, it will lose some of its capacity permanently. The battery’s chemicals are stuck inside a tube that doesn’t give them a lot of wiggle room. Batteries get exhausted just like humans do from heat. Although some people may tell you to avoid putting your battery in cold temperatures, it’s really no big deal. In fact, storing an unused battery in freezing temperatures might help it retain more of its charge than it would at room temperature.

3: Never store a drained or full battery for a long period of time.


You should never drain your Li-Ion battery. End of story. However, you might think that it’s fine to store a fully-charged battery for a prolonged period of time. The more, the better, right?

Wrong. Batteries are more chemically active and store more potential energy when fully-charged. The more juice they have, the more likely they are to crystallize their internal chemicals over the long run. This results in a permanent loss of capacity. You should always store batteries at a maximum of 70% capacity. Ideally, you should store them at 50%.

Got more tips?

Batteries remain some of the most enigmatic things that appear in electronics, so it’s no surprise that some people just don’t “get it.” Leave a comment below to let other fellow readers know important information about their batteries!

Miguel Leiva-Gomez Miguel Leiva-Gomez

Miguel has been a business growth and technology expert for more than a decade and has written software for even longer. From his little castle in Romania, he presents cold and analytical perspectives to things that affect the tech world.


  1. You leave out an important point: a mobile device battery should be taken through a full charge cycle every 30-90 days in order to keep the device’s battery meter accurate. This means

    * letting the device completely drain until shutdown;
    * charging up with the device off;
    * turning it on and letting the device completely drain again before charging in any fashion.

    This will recalibrate your device’s battery meter.

    1. Completely draining it is OK, as long as you’re doing it once in a blue moon and you’re charging the battery right away.

      The problem is that Li-Ion batteries have a 3.3-4.2 V operational range. When the battery drains below 3.3 V (when it’s left alone uncharged for a long period of time), it risks undercharging itself and may short-circuit because of chemical homogenization. This may also lead to gas leaks, among other things. You still have to be careful not to over-drain batteries.

  2. For those who claim that Li-Ion batteries have a memory effect, here’s a good article written by someone who knows his way around batteries:

  3. i am a bit confused! Can anyone advise me, please? I have a new Apple air. It is on most of the day as I use it to listen to the BBC. I have been charging it fully then unplugging it and letting it run on battery until it is nearly discharged, or sometimes it goes off as I haven’t noticed it is running down, then plugging in again. Is this good practice or not? Also there is an extension lead (a bit thicker cable). I have noticed that if I use this the battery doesn’t get so hot – or is that just my imagination? Thanks for any advice, Robert

    1. It’s best not to discharge your Li-Ion battery below 20%. Charge it up whenever you feel the need. Don’t follow unnecessary (and possibly harmful) discharge/recharge cycles. Trust me, I’m a battery guy.

  4. Hi,

    The battery on my Sony Vaio laptop has died (only keeps charge for a few minutes at most), but I can still work using the normal power lead and since I basically don’t take my laptop anywhere I have been so doing for quite some time now.

    1. Should I remove the battery completely or is it safe to leave it attached to the laptop? By safe I mean safe both for me (as in the battery is unlikely to blow up or anything) and safe for the laptop (as in no damage is being done). I do not really wish to buy another battery as I am working fine as I am and the laptop is now around 4 years old anyway.

    2. Could it be that I actually damaged the battery myself simply because I always have the mains power lead attached to the laptop? I am asking because although it may be too late for this battery, maybe I might avoid making the same mistake again next time round – but is it a mistake?



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