Just use the battery as the way it is design to, do not too care to protect it, because at the end one may found out it is worthless to do so.

If anyone interested in ultra long battery life, try replace it with LiFepo4, it have more than 1000 cycles, some say up to 10'000 cycle and still retain 80% capacity, depending on the discharge rate. 5-10years in notebook is okay I guess as it is ultra robust and safe. But sacrifice the capacity to half of your original capacity.

And note that LiFePo4 operate from 2.5V to 3.6V per cell, make sure that you know how to modify the charging voltage, midrange correction(if any), linear EDV fit, max cell cut-off voltage of the battery. Any notebook internal charger that are design to smart battery specification should not have problem to charge LiFePo4 because it is able to regulate the voltage up to 4.2V per cell. Notebook can accept voltage range of cell from 2.5V to 4.2V per cell. The only problem remain is the secondary protection is bias to cut fuse at 4.3-4.5V, which render it useless in this case.

Beside, LiFepo4 is very cheap, just ~RM5-RM10 each because the process and raw material is cheaper than LiMnCo use in laptop battery cell. (cobalt is more expansive than phosphorous I guess). 6 cell only cost RM30 to replace your laptop battery, bear in mind, half or less than half it capacity at the same size.

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Added on December 4, 2010, 6:15 amThat claim is correct in the point of view of battery manufacturers. If a battery is designed to have a cycle count threshold of 4400mAH, every discharge of 4400mAH will be recorded as 1 cycle. It doesn't matter if you use it to 0% or use it to 50% and charge back. The data I collected base on battery send by my customers' original battery is normally 150-300 cycles. If you use your battery frequently(everyday 1-3cycle), someone may actually get more than 400 cycles for a not power hungry notebook, hi quality Li-ion for notebook are very active and strong at the first year. At the second year, cell start to lose it unity more obviously and become not uniform, primarily because of heat zone affected particular segment of cell and cause the particular cell die younger than the remains. One segment lose, you lose whole battery. Occasionally, I get some customer which only get less than 100 cycle out of their battery, but battery life is well more than 1 year, even the best brand have very short life in power hungry system, it may also mean that the user seldom use the battery, it will die anyway after 2-3years.

That is however, user are free to self-define, every charge/discharge activity is considered 1 cycle. If this is the case (float charge), user are more likely to get more than 1'000cycles out of original battery, up to 10'000 also no problem I guess, depending on the period you switch off the main power. But switch on/off main power in fast periodic (let say every 10 minutes) may also damage the system faster, because every time some capacitor in motherboard or power adapter charge up, it draw some surge current, depending on the quality of the component the manufacture use, it may have differ level of harm...

This post has been edited by Altrafield: Dec 4 2010, 06:34 AM

Sonata I never heard or see the real thing for my self, if it is as great as it manufacturer claims, prismatic cell usually more expansive than cylindrical, but have longer life. Sonata only 4400mAH consider it already fill up the empty space of normal cylindrical cell, it design constraint is more looser than cylindrical cell, thus may allow longer life (in term of years). Consider the best Japanese have is up to 6000mAH for the same size already. Choose battery that last more hours or more years but not both! One must sacrifice one to get the other clear, so call uncertainty principle.

I just browse it datasheet here:

http://www.boston-power.com/sites/default/...20DataSheet.pdf

but I didn't see particular advantage of using Sonata cell, you pay higher sum for the battery at the moment you purchase it, Japanese also have this kind of long lasting cell long ago, I see those cell made by Panasonic at years 2000 last up to 5 years in IBM notebook also, may be notebook no release so much heat last time, but they slowly migrate to short lasting cell because of the cost and market life of a notebook, seen like they reduce the use of cobalt I guess.

Most people that so care about the battery life (in term of years) is people that purchasing low to medium end(1k to 3k) laptop. If one are capable to buy a RM3-10k laptop, he won't border with the small sum of let say RM300-RM500 to replace a new battery. If let considered 1 Sonata = life of 2 normal cylindrical, and considered 1 sonata is 1.5x price of normal cylindrical cell, does it really worth is depending on if one really need a long life battery. Some people just plug in the power to main power the entire life of the notebook, without a need for a battery or use it occasionally only.

This post has been edited by Altrafield: Dec 4 2010, 07:22 PM