W7J Battery charges to 120%

Hi,

I recently purchased another W7J (mine Core Duo, new one Core 2 Duo) for my girlfriend, was wondering why her laptop shows 30-40min more battery life than mine so I threw it into my laptop and took a look at it with RightMark, and there I saw it, it can be charged over its full capacity unlike my battery, I have used my battery to near flat less than 20 times so its still pretty fresh.

Both battery information is exactly the same in RightMark except maybe for the unique id and the fact that her battery can charge up near the designed capacity. Windows shows the battery at 100% until right mark drops frm 120% until under 100%.

Anyone have any idea why?

 

Because the ACPI driver is confused.

Actually the battery has worn down less than the ACPI driver believes (roughly 20% = 51200 - 42700), to roughly 4% (51200 - 49900). The situation is not good either way for a new battery, although 4% is acceptable as the initial transient evolution of the max charge of the battery. How many times did she do a full discharge-recharge cycle? 3 to 4 times?

Your girlfriend's computer might be affected by the battery wear problem, see here: http://forum.notebookreview.com/showthread.php?t=106773 . It is by no means certain to infer this from just 4% wear; but watch out nevertheless.

You could try first a windows restart, and then a battery calibration to see if you can get the readings to match. But be warned, if you do suffer from the wear problem the calibration will add an additional 1 to 5% of wear to the battery.

 

Thanks for the tips, the pic shown was not fully charged yet.

Also since my batter shows that "my" battery's fully charged capacity is 42700 and designed is 51200, are you sugesting that my battery has 20% wear? I've hardly used it, I've never calibrated it, why is the fully charged capacity so low?

Thanks

 

I'm not suggesting, I am stating it plainly and unequivocally. The definition of the wear level is the difference between the designed max charge and the current max charge.

You might also be suffering from the wear issue. 20% is way too much for 20 charges, in my opinion (although you will find differing opinions on the forum). If the wear is indeed correlated with the number of discharge cycles, then at this rate, you will lose all battery life in 100 charges, which is too soon. Check that news item and the attached thread, and follow closely your wear level for abnormal increase.

Let us hope you are not suffering from that issue.

Also make sure you are not discharging the battery past 3-5%, that might accelerate wear.

 

I will keep an eye on it, I hardly use my battery and always store it at about 70-80% charged when not in use. The laptop's only 8 months old, this is ridiculous and saddening to know.

I thought that if theres any battery wear I would've noticed as I always thought when it happens I won't be able to charge to 100%, or does the battery itself auto calibrate?

 

Shelf-storage of batteries should be done at 40%.

However, shelf storage is unnecessary when the battery is used more than say once a month.

Indeed, the battery will recompute its max charge. The wear is defined as designed max charge minus current max charge. Windows will declare 100% whenever the batt reaches current max charge which may be smaller than the designed max charge, i.e. the battery may have wear.