Home > Blog > 3 Things You Should Already Know About Your Lithium Ion Battery

3 Things You Should Already Know About Your Lithium Ion Battery

Too many people I’ve met have misconceptions, wrong understanding or simply no idea at all about how to maintain the batteries inside their new spanking new electronic gadgets. More often than not, it will be one of those nifty, super-slim lithium-ion variants. So I decided to write this little primer to help you, erm, I mean, your techno-phobic friends along.

Note that my recommendations are catered along the lines of practical convenience as well as pure battery maintenance facts alone. As with everything, there is often more than a way to skin a cat. I do try to explain my rationale behind my recommendations, so do try to read on before clobbering me on the head with your PhD in advanced materials science.

Tip #1: Lithium-ion batteries are limited by their life-spans
Found an e-bay offer for a lithium-ion battery pack for your ageing notebook or PDA at bargain prices? Or saw that battery pack for your gadget in its dusty sealed package at the corner store of the flea market? Before you jump and snap it up, be sure to first check the manufacturer date.

We all know that all batteries are limited by a finite number of charging “cycles”. However, it is a little publicized fact that the lifespan of lithium-ion batteries are also limited by their manufacture date.

The fact is, your lithium-ion battery starts dying the moment it leaves the factory! Of course, the actual life-span of an unused lithium-ion battery can vary by a fair amount based on its internal charge as well as the external temperature. But suffice to say that you can expect to irreversibly lose 20% of a lithium-ion battery’s charge every year from its original date of manufacture.

PDA came with more than one spare battery? Take it out of its shrink-wrap and use it interchangeably – today. Thinking of buying a “spare” battery for use in future? Well, just save the money and buy it only when you are ready to use it.

Tip #2: Avoid allowing your device to discharge completely
Every wondered why your modern phone, PDA or iPod is able to cheerfully tell you that “Your battery is now exhausted” for several seconds on its brightly-lid LCD screen before switching off? The reason is simple; there is an artificial circuit that shuts off the device when the charge in the battery is too low.

This extraneous circuit is built to protect from the damage that could result if the charge of your lithium ion battery falls too low. If you still don’t get it: if the charge of your lithium ion battery falls too low, the battery can get irreversibly and permanently damaged. So since Lithium Ion has no “memory effect”, it is better to simply charge your portable device as and when you can or remember.

To set your mind at ease, a “charge cycle” means a single iteration of depleting followed by a re-charge until 100% of battery charge. If you consume 50% of your iPod’s battery on day 1, recharge to 100% at night, and do the same thing on day 2, then you would have just finished up one charge cycle of its battery life.

Hence constantly recharging a lithium ion battery does not shorten the battery life more than normal usage would. Avoid letting it sit on empty for too long; instead, keep it charged-up if you can.

Tip #3: Take the battery out of your notebook computer when connected to AC helps… not!
Well ok, actually, taking out the battery from your notebook computer might help, but the reason it does is not really what you think it is.
It is not because of over-charging as most people might believe. There are some really smart circuits monitoring your lithium ion battery (See reason #2 above), and these circuits also ensure that your precious lithium ion never gets overcharged. So leaving the battery in when the AC is on has no detrimental effect whatever on the health of the battery.

However, if there is another killer of lithium ion batteries other than old-age, then it would be heat. Long term exposure of a lithium ion battery to temperatures higher than 40 degrees Celsius permanently reduces its total charge capacity by noticeable percentages chunks per year. Having said that, I would hazard that modern processor like the Centrino Duo runs quite coolly overall.

On the other hand, it is really painful to see someone plug their AC adapter to their laptop, carefully remove the battery and put it aside, then finally sit down and switch on their laptop. Then have someone trip over their AC adapter an hour into an unsaved document. Ouch.

Unless you are setting up the laptop at Wal-Mart or Carrefour to run practically 24/7 until its time to sell it off at “display unit” pricing, my recommendation would be to save yourself the trouble and just leave the battery in. Actually, I think the real motivation to take the battery out of shop display units is to prevent theft. Really, why make it so inconvenient for yourself when the battery will be literally unusable in a few years time.

So there you go – just my 2 cents worth. Feel free to leave your comments.

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  1. tan man
    October 17th, 2011 at 22:07 | #1

    battries are stupid

  2. ionic
    November 2nd, 2011 at 04:23 | #2

    @tan man
    Yeah man, i also tought about that. I always enjoy it when i have a 1KM cable hanging out of my pocket for my cellphone when I go to school, try it!

  3. chami-Sri lanka
    November 6th, 2011 at 20:31 | #3

    Good Advises!! thanks a lot Bro!

  4. arthur blenkinsop
    November 10th, 2011 at 03:00 | #4

    hello there thanks for the tips, i have an aeg lithium ion drill it is about 30months old i have used it for diy jobs so it has had the batteries charged a few times, i took it out the case to do another project and the batts wouldn’t take any charge it just showed broken batt symbol could this mean batts are finished their lifespan if so they don’t seem as good as ni-cads but much more exspensiveregards Arthur.

  5. IOP
    January 10th, 2012 at 03:35 | #5

    I think Tip #3 is not quite clear.
    According to
    Table 3
    If you mainly (95% of time) use you notebook connected to AC (at 100% state-of-charge) at 25°C you will “20% loss in 1 year; 80% remaining”.

    If could rely on your AC and you could keep battery out of your notebook at 0°C at 40% state-of-charge you may get “2% loss in 1 year; 98% remaining”.

  6. Paul Mah
    January 10th, 2012 at 07:29 | #6

    @IOP I’m aware that storing lithium ion batteries at a certain temperature/charge will make it last a lot longer. Because few users and no vendors would store their lithium ion batteries at 0 degrees however, it would be more practical to present the typical use scenario based on average room temperatures instead.

  7. Rajdeep Singh
    January 13th, 2012 at 09:54 | #7

    Very helpful and informative

  8. IOP
    January 17th, 2012 at 14:18 | #8

    @Paul Mah
    Here is my use scenario:
    I have notebook and work on it at home in my room (almost always ~95% of time or even more).
    I have refrigerator at home.
    So I follow my recommendation. Maybe somebody else with similar use scenario will try it…
    Another use scenario:
    In our shops, I see a lot notebooks without batteries. And all notebooks are plugged in to AC.
    I guess that batteries for these notebooks could be stored in right way.

  9. roslin
    January 28th, 2012 at 11:25 | #9

    Can i knw the life span of laptop new and unsold replacement batteries (sitting in the store)

  10. yo
    February 5th, 2012 at 22:57 | #10

    thanks a lot! i just bought a phone that came with a spare mobile charger, and was considering whether to use it interchangeably, or (under the misconception that not using the mobile charger will conserve its life) rely only on my phone’s primary battery. Thanks for your tips!

  11. February 14th, 2012 at 00:53 | #11

    Someone called to sell me lithium/ion battery keychain flastlights (small ones). He told me they would last for years. Is this true with normal usage?

  12. jennyjoyful
    June 4th, 2012 at 13:41 | #12

    okay so i have a sanyo phone and the battery is a standrd li ion battery andive had it for almost three years. and my phone died an i try to turn it on and let it charge while the screen is on becaus i need to use it, but it wont sty on and sometimes i ave to take ou the bttedy and put it backbn just for it to turn on.

  13. nutjob
    November 19th, 2012 at 03:39 | #13

    Use ur device inside a freezer.

  14. Besim
    December 16th, 2012 at 14:37 | #14

    Great article…thanks!
    I thought that Lithium batteries should not get overcharged but still wanted to see what others thinks about it. I’m leaving my bluetooth charge overnight in my truck. Its really cold out so shouldnt be a problem.

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