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I want to know if using battery at 40% in temperature 34 Celsius would degrade battery life fast. Maybe i should consider buying cooling pad? Will this help preserve battery life?

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possible duplicate of Is it safe to store a battery in the freezer? – soandos Mar 15 '12 at 8:51
up vote 1 down vote accepted

You are right. In fact in EV cars(tesla etc) specialized firmware maintains charge between 30 & 80%. The battery never actually chrages upto 100%. It is also liquid cooled. This is to increase the life time of the battery. So two things are actually important: Heat and 100% charge. Both are harmful. You should not use it always at 100% charge, which is what will happen if you are always plugged in to AC adapter.

There is built in app for Samsung laptops & netbooks called Battery Life Extender which will limit charging to 80% in order to extend battery life. Try and find out if it is available for your laptop.

If you can't find an app, the only option is what I do in my ASUS G53, manually unplug it when it charged to 80-85% and replug when it is 20-25%. BatteryBar is Taskbar widget with modifiable settings for reminding you of ideal range.

Don't block the cooling vents on the laptop. That means using it on a hard surface. A cooling pad is even better.

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34C (93.2F) is pretty hot for the outside of a computer. I don't know if it will preserve your battery specifically, but I think a cooling pad is a good idea anyway. I think it will help preserve your laptop as a whole.

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What can possibly go wrong with laptop if not battery? – Boris_yo Aug 7 '11 at 5:53
I have had a number of processors that were high-end that ran so hot, the motherboards eventually failed. – KCotreau Aug 7 '11 at 10:48
What can possibly go wrong? Fans, capacitors, semiconductors in various ways. – Daniel R Hicks Aug 7 '11 at 12:27

I don't know about LiIon batteries, but NiCad and NiMH batteries do not like to be hot, especially when charging. Charging a hot NiCad or NiMH is a good way to kill it.

On the other hand, you can increase the life of a LiIon battery by setting the charger to not charge to 100%, but stop at 60-80%. (Though, to keep the "charge meter" calibrated you need to discharge to 20% or so then recharge to 100% every few months.)

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Why not fully discharge it? – Boris_yo Aug 7 '11 at 5:53
It's generally not a good idea to discharge rechargeable batteries totally flat -- it can lead to a problem known as "cell reversal" which destroys the battery. LiIon batteries of necessity have a charge controller built in that is supposed to prevent this, but it's a question of how much you want to trust them. – Daniel R Hicks Aug 7 '11 at 12:25

On the internet I found out that the batteries should be completely discharged before charging.

In the case of laptop batteries, the charging will start whenever the battery is at 80%. So it is better to try to fully discharge the battery and fill it once a day.

This will help you to improve battery life and performance.

The most important thing about all rechargeable batteries is that they should not be overcharged, so it is better not to connect the power adapter other than for charging – and when the battery is full, it should be removed.

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This doesn't answer the question, and I'm not certain that any of this post is true. Can you provide references? – sblair Dec 26 '11 at 14:59

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