I have a side note question in terms of battery, what do you mean by fully discharge? do i have to disable the automatic shutdown and use the laptop till the battery runs out and the laptop is dead before i charge it again. I've tried this once and when I check my battery life, the meter lost almost 30 min of its life. how do I make my battery last longer? I read here that you can store with 30-40% charge remaining and in the refrigerator when not in used but is this really true?
Yes and no.
When a battery is being stored, it has a self-discharge rate
, which is a tendency to lose charge by internal chemical processes. Self-discharge is affected by both age and ambient temperature, so a battery in storage can be preserved longer in a cold environment (but not freezing, which can damage the internal chemistry). A typical laptop battery that is stored at ambient temperatures may lose a few percent (like 2-5%) per week.
When a battery is charged, it permanently loses a fraction of its ability to be recharged. In general, that fraction is dependent upon how much the battery was discharged, and whether it was slow-charged or fast-charged (your laptop charger won't give you a choice). For example, a lithium-Ion laptop battery that is fully discharged during each use might only survive 500-800 charge cycles, but the same battery used at just 50 or 60% of its capacity might survive a couple thousand or more. If the battery is used with AC power most of the time, then it will self-discharge slightly when not in use, and take a slight recharge during the next use, over and over again. It may survive many thousands of these cycles but eventually it will wear out.
The long term lesson, IMO, is don't even worry about it. If you buy a laptop, then the battery is there to serve you, not the other way around, and pulling the battery while running on AC power doesn't make sense because you lose the benefits of having an uninterruptible power supply. Good-quality lithium-Ion cells are fairly robust. The worst battery behavior was in the old days when laptops still used Ni-Cad cells, which would tend to develop a "memory" effect when partially discharged and then recharged, reducing the usable capacity. With modern lithium-ion batteries, the worst behavior usually comes from low-rent Chinese replacement cells that sometimes fail suddenly or swell up from overheating, or IOW, if you want to pick up a spare battery for your laptop make sure you trust the source.