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Laptop Battery use and storage guidelines.

laptop batteries One of my laptop's batteries had died a little while ago and couldn't figure out why, so I've been reading around the subject to try to find out what can be done about it and what I can do to prevent it in future.

First of all, I've learnt that it is possible (for the more technologically ept of us) to replace the Lithium Ion batteries inside of laptop batteries. However I wouldn't recommend this unless you are an expert at wielding a soldering iron.

To avoid this and an expensive new battery I decided to simply buy one cheaply second hand from Ebay, this was not necessarily the best approach however as laptop batteries (which I will refer to as Li-ion batteries from now on) have a definite shelf life which affects the storage capacity of the battery (and therefore how long it keeps your laptop powered). This shelf-life can be be prolonged by various means.

The best guidelines I found was at the excellent Wikipedia , in an article on Li-ion batteries which I found extremely informative and I am now citing here. 

Guidelines for prolonging Li-ion battery life

  • Unlike Ni-Cd batteries, lithium-ion batteries should be charged early and often. However, if they are not used for a longer time, they should be brought to a charge level of around 40%. Lithium-ion batteries should never be "deep-cycled" like Ni-Cd batteries.
  • Li-ion batteries should be kept cool. Ideally they are stored in a refrigerator. Aging will take its toll much faster at high temperatures. The high temperatures found in cars cause lithium-ion batteries to degrade rapidly.
  • Lithium-ion batteries should never be depleted to empty (0%) and then stored.
  • Li-ion batteries should be bought only when needed, because the aging process begins as soon as the battery is manufactured.
  • When using a notebook computer running from fixed line power over extended periods, the battery can be removed and stored in a cool place so that it is not affected by the heat produced by the computer.

Storage temperature and charge

Storing a Li-ion battery at the correct temperature and charge makes all the difference in maintaining its storage capacity. The following table shows the amount of permanent capacity loss that will occur after storage at a given charge level and temperature.

Permanent Capacity Loss versus Storage Conditions
Storage Temperature 40% Charge 100% Charge
0 °C (32 °F) 2% loss after 1 year 6% loss after 1 year
25 °C (77 °F) 4% loss after 1 year 20% loss after 1 year
40 °C (104 °F) 15% loss after 1 year 35% loss after 1 year
60 °C (140 °F) 25% loss after 1 year 40% loss after 3 months
Source: BatteryUniversity.com

It is significantly beneficial to avoid storing a lithium-ion battery at full charge. A Li-ion battery stored at 40% charge will last many times longer than one stored at 100% charge, particularly at higher temperatures.

If a Li-ion battery is stored with too low a charge, there is a risk of allowing the charge to drop below the battery's low-voltage threshold, resulting in an unrecoverably dead battery. Once the charge has dropped to this level, recharging it can be dangerous. An internal safety circuit will therefore open to prevent charging, and the battery will be for all practical purposes dead.

In circumstances where a second Li-ion battery is available for a given device, it is recommended that the unused battery be discharged to 40% and placed in the refrigerator to prolong its shelf life. Batteries should be allowed to completely warm to room temperature over up to 24 hours before any discharge or charge.

Very useful! Thanks Dan

Very useful! Thanks Dan White!

To maximize the performance of laptop battery, I found similar contant at:
http://www.go-shop.com.au/batterybrands.php/Laptop-Battery/HP

It seems that their "battery use tips" arenot as particular as you

Cut down external devices -

  • Cut down external devices - USB devices (including your mouse) & WiFi drain down your laptop battery.
  • Remove or shut them down when not in use. It goes without saying that charging other devices (like your iPod) with your laptop when on battery is a surefire way of quickly wiping out the charge on your laptop battery.
  • Keep the battery contacts clean: Clean your battery’s metal contacts every couple of months with a cloth moistened with rubbing alcohol. This keeps the transfer of power from your battery more efficient.
  • Hibernate not standby - Although placing a laptop in standby mode saves some power and you can instantly resume where you left off, it doesn’t save anywhere as much power as the hibernate function does. Hibernating a PC will actually save your PC’s state as it is, and completely shut itself down.
  • Turn off the autosave function MS-Word’s and Excel’s autosave functions are great but because they keep saving regular intervals, they work your hard driver harder than it may have to. If you plan to do this, you may want to turn it back on as the battery runs low. While it saves battery life in the beginning, you will want to make sure your work is saved when your battery dies.

Thank you for that post. I

Thank you for that post. I will point out the slight difference in what we are describing here. To use an analogy. My story is about keeping a water jug as big as possible, and your post is about pouring the water out of that jug as slowly as possible.

I'm providing information on maintaining overall battery capacity. So, to give an example, when you charge your laptop battery to 100% it lasts for 3 hours under whatever load you put on it. If you allow the battery to degrade with time, heat and storage charge the next time you charge the same battery later on it will only last for 2 hours under the same circumstances.

Your post is about lightening the load you put on the laptop while you are using it. This is good advice, and will help your laptop last longer while in use. However the battery capacity is not being affected.

I will add to this list:-

  • the autosave tip probably has very little effect though and leaves you exposed if you forget to turn it back on.
  • if you use a screensaver, put it on "blank", other screensavers can eat CPU time and hence power
  • Go into power profiles and put Hibernate on the power button
  • Set your power settings for as short a time for sleep and hibernate as you can put up with
  • Naturally, keep the screen as dim as you can. Use the "Fn" button on most laptops in conjunction with the little sunshine icons to manually raise or drop the backight

Any others people can think of?