When I got my last phone, a Sony Ericsson k850i, I was recommended to charge it fully once before I even turned it on. Does this apply today as well, for my coming HTC Desire HD?

Why was I recommended to do so in the first place?

3 Answers 3


All newer phones use Lithium polymer batteries.

Why is it Partially Charged?

To decrease their aging they are intended to be stored at 40% charge. This means when you receive your phone it should be at 40% charge, otherwise they will have aged your battery for you. (you are probably used to the effects of aging, like a 2 year old phone seeming to have very short battery life). When you get your phone you can use it until it is discharged, but they normally say 'charge it' because people will not notice the partial charge.

Do Not Fully Discharge

You should not fully worry about fully discharging, this is superstition to earlier battery technologies. Fully discharging a lithium battery is one of the best ways to make it fail. below a certain charge they will have their overcharge protection circuitry fail and you cannot charge it at all. I have seen studies that show that this makes up more than 75% of "failed" lithium batteries.

Lithium Battery Aging

Lithium batteries have a set number of charge discharge cycles before they fail. This might be a number like 500 cycles. You actually get more like 1000 cycles if you only discharge to 50% before recharge. Lithiums really do not like a deep discharge, I cannot stress this enough.

If you would like more information about lithium battery technology let me know, I can get you many links, just drop me a comment. I have a few answers on the electronics and robotics stack exchange about it.

Can I leave it plugged in all the time?

Yes, and no. This is very dependent on whom makes your device.

For example, my Lenovo laptop will not apply a charge to the battery unless it is under 97%. When it does charge the battery it charges directly to 100%, then stops until the battery sags below 97%. Many laptops did not do this, on most just applying charge if it is not 100%. This would put the battery through thousands of charge cycles in a week when you are not using the battery. This ages a battery quickly.

If your phone maker took the time and paid the extra cash then your phone will stop charging once it reaches full charge and just power the system from the wall outlet. It is significantly more likely that your phone is charging your battery on a short cycle and aging it thoroughly.


Some people have some confusion from some of the myths that go about. The primary one is memory. As Battery University will say, this is mostly extinct, and actually applies to nickel-cadmium batteries. As was stated in a comment about crystals Battery university has in reference to nickel-cadmium:

With memory, the crystals grow and conceal the active material from the electrolyte. In advanced stages, the sharp edges of the crystals penetrate the separator, causing high self-discharge or electrical short.

Now, talking about Lithium batteries, which your phone uses, there is even more difference. To quote them battery university directly from their simple guidelines:

Avoid frequent full discharges because this puts additional strain on the battery. Several partial discharges with frequent recharges are better for lithium-ion than one deep one. Recharging a partially charged lithium-ion does not cause harm because there is no memory. (In this respect, lithium-ion differs from nickel-based batteries.) Short battery life in a laptop is mainly cause by heat rather than charge / discharge patterns.

I understand how this may go against what you have been taught, but I am someone who not only has researched this, but uses lithium batteries in my day to day work as an engineer.

  • -1: If I can't fully discharge my battery, how am I to counter-act the crystal forming in it? If you keep discharging it to 50% and then charging it again it will gradually lose capacity until it's completely unusable.
    – Arda Xi
    Commented Nov 20, 2010 at 20:06
  • @Arda Xi, you can discharge it until it says it is dead, but if you give it any time to continue that way you will have the self discharge take it below the safe charge.
    – Kortuk
    Commented Nov 21, 2010 at 3:59
  • 1
    @Arda Xi, You are also incorrect, this does not happen with Lithium batteries. I will add links to answer. I work at a job where I use lithium batteries in the thousands every day.
    – Kortuk
    Commented Nov 21, 2010 at 4:01
  • 4
    @faken, I think Arda Xi mixxed up battery technologies, nothing major, I kind of expected it.
    – Kortuk
    Commented Nov 21, 2010 at 14:19
  • @Kortuk: I have my phone on my desk every day while at work. Would it help to charge it every day at the start of the day ? Meaning, charge it even though its still 90% charged , just to make sure it's always full whenever I leave the office ? Now I am just waiting until my phone tells me to recharge after which I , mostly , charge it overnight.
    – Edelcom
    Commented Nov 22, 2010 at 13:56

No. You do not need to fully charge ANY battery to the max until usage. It does not matter if it's new, old, a phone, or even a remote. It does not affect the battery unless that battery has been over-used. So, what I am saying is, no. You do not need to fully charge something new before usage.


Most of the time, yes you have to charge the phone fully and then sometimes fully discharge it the first time you use it. Most of the time you'll be fine with the phone turned on while you charge it the first time, as long as it gets fully charged before unplugging it.

There are a few reasons for this, some historical, some practical. The historical reason is that with older battery tech, the battery had to go through a full charge/discharge cycle in order to keep the battery life high. Phones would be shipped with batteries that only had enough power in them for initial set-up, forcing the owner to do a full charge when they got home. The practical reason is that batteries don't maintain their charge indefinitely when they're unplugged, so although your phone may have been shipped with a battery that started off with a full charge, by the time it gets to you, it may already be very low.

  • Lithium batteries are never shipped full charge, and you should never take the battery through a full charge discharge cycle for "lifetime". This is quite bad for a lithium if you take your discharge to too low a charge.
    – Kortuk
    Commented Nov 20, 2010 at 14:24
  • You're absolutely right. However, as I said, older generations of batteries are not like Li-Ion and Li-poly batteries in that they could degrade severely without a full charge/discharge cycle.
    – MBraedley
    Commented Nov 20, 2010 at 21:28
  • 1
    This question is about an HTC Desire HD. This uses a lithium battery htc.com/www/product/desirehd/specification.html The original phone he mentions also uses a lithium battery, that took some looking. It is speced here: mobiletechreview.com/phones/Sony-Ericsson-K850i.htm
    – Kortuk
    Commented Nov 21, 2010 at 4:36

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