I was asked to access this battery after it got returned.
User reported it only charged to 80%.
Externally the battery looks fine.
You have your usual Chinglish
"Do not dispose of in fire, but keep the battery away from fire."
-No thermal fuse or over current PTC.
-There is a thermal fuse next to the MOSFets on the control board. Not much good there as it would take a lot to heat them up. Probably from the cells dying, ie too late.
-Construction looks clean and tidy.
-The serial numbers on the cells are all over the place. Not a major as long as the cells are matched properly.
-Welding is good.
-Nice thick connector straps.
Cells are counted from the negative terminal, 1-4.
A cell is this case is 2 parallel cells.
The cell voltages were, Volts
3.91, 4.04, 3.89, 4.03
They accepted this much charge to 4.1v, mAh.
898, 127, 995, 284
Reasing this much energy at 2A to 3v, mAh.
3660, 539, 3707, 3543
I think we have found the problem with low capacity.
The (BMS) Battery Management System/Circuit was not doing it's job at keeping the pack balanced.
It may have also been poorly matched at the factory.
Either that cell is holding back the pack.
As a pack is only as strong as it's weakest link.
So is it worth buying a OEM battery for your laptop?
For up to 50% less than an original, yes.
As long as the supplier is reputable and stands behind their product.
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Comment by Shyloh Jacobs, on 27-Jan-2011 11:48
Thank you for this article! I was getting so frustrated, constantly having to a replacement laptop battery and lap top power supply and now I have a better understand as to why. So thank you again it was a really big help!
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