How do I maximize my battery life?

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Hi Leo,

Two important things that I did not mention when we talked about batteries are aging and storage.

Lithium-ion batteries start to deteriorate from the day they are manufactured. The mechanism is an increase in internal resistance. For a spare battery the ideal storage conditions are at a 40% charge at 0C (32F). In practice, store it in the refrigerator (not freezer) in a sealed bag after you discharge it to 40% of capacity as measured with the fuel gauge in your laptop. At these ideal conditions, the battery will still have 98% of its capacity after a year storage. But store it with a 100% charge and it is reduced to 94%. If you store it just above room temperature at 25C (77F) with 100% charge you drop to 80%. This is the way I stored my spare before I knew better. This capacity loss is non-recoverable. The capacity is gone forever. If your computer is always on and in use, the battery temperature may sit in an environment of 30C (86F) and drop to 65% capacity in a year. If it reaches 40C (140F) you can drop to 60% capacity in only three months! You get the idea why keeping your battery cool is so important. From the battery perspective, removing the battery while on AC power would reduce its temperature and help battery life, but from a power supply designer's perspective, this is not recommended. The presence of the battery provides substantial design margin to your laptop as well as protecting it from power surges and sags.

The increased internal resistance has an additional effect besides increasing internal battery temperature when current is drawn. When there is a current surge caused by hard-drive access or heavy CPU usage, the surge of current working against the age-increased internal resistance can drop the terminal voltage so that the protection circuits trigger and won't let you use it. There is still capacity, but you can't get to it in an aged battery.

An excellent website on batteries for your readers is the Battery University. This is the source of the percentages I quote above.

Jerrold Foutz
http://www.smpstech.com/

Great article thanks

> If you have your laptop on your lap and it is burning you, you are shorting the battery life and charge-cycle capability because you have interfered with its cooling system.

To say nothing of your own libido and fertility, if you happen to be male!

Take care, Leo!

-cw

I think using the laptop battery in complete cycle helps. Meaning to charge it fully, then discharge or use it fully, then charge it again.

Charging every 30 minutes or for short time, many times uses up the cycles of the battery.

I have increased the life of my mobile phone battery this way, even after 5 years my Nokia 3100 gives me 24 hours charge.

I only charge it when it is down to its last hours and charge it fully.

Actually, Khurram, Lithium batteries life decreases after every full cycle, aka discharging to 10% or less and then charging to 100%.

Lithium batteries do not have the memory problems that NiCd and NiMh had.

Full cycles are NOT reccomended :)

How can I increase the power of the generic batteries such as Energizer, Duracel, or Enercell 9V?

is there a software to keep ur battery charged for a considerably longer time????

I see replacement batteries that say they will match my laptop but they have higher voltage. For instance, my battery says DC10.8v and 400 mAh. Replacement that says it will work for me is 11.1 and 450. I do not use an external charger, jsut recharge within my laptop...

Great article, Leo (with appreciation from Jerrod, of course)! I just ordered a new Dell Inspiron E1505, and I'll take the advice given on this page to heart. Thanks, guys!

I purcahsed this refurbished HP DV5224NR laptop on boxing day 2006 from futureshop. I have two problems with it. The short battery life and the used up harddrive space.
The battery life lasts a maximum of 1.5 hours - 2 hours under regular usage of surfing the internet and maybe listning to music at the same time. I have noticed that roughly every 1 minute, a percentage of battery is used up.
Secondly, the avaliable harddrive space to use when first opening the computer is approximately 50 GB. The 30 GB that is used up is the 12 GB taken up in the recovery partition and the rest in the programs that come pre-installed from HP.
These are my two cons, if anyone has the same peevs, please share.
Otherwise, so far the laptop is going well.

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