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I have several ibook batteries that have gone bad and I was wanting to open them up and make some good batteries out of all of them by taking out the bad cells and putting other ones in there place, but my question is, on the back of the batteries it says a 14.4 volt battery but when I test the cells individually they are testing 3.72 volts individually and if there is 8 cells in the battery how does that add up to 14.4 volts? If each cell is 3.72 volts then the battery should be a 29.7 volt battery, Right? I could use some insite on this thanks.

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Please don't do this - the chips inside the batteries are a safety feature to ensure that a cell that is outside normal usage parameters will not get charged and cause a short or a fire. If you are schooled well enough to do a full cycle charge / discharge cycle on each cell and reprogram the chip that controls the battery I'd say you have the ability to pull this off in a manner that is safe, but encouraging this without some level of safety disclosure seems like a bad idea. – bmike♦ Oct 4 '12 at 17:23
all I am trying to do is find out what cells are bad and replace them. I have done this with a few 18 volt tool batteries. With the 18 volt batteries all I had to do was test each cell and which ever cells tested lower voltage than the rest I replaced them. – Stephen Oct 4 '12 at 17:30
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I know - my point is that you need more than one voltage measurement to know if a cell is good or bad and unless you are recording the full charge cycles of each battery (presuming the chip is even reporting this correctly on the batteries at this point) as well as more in depth testing to know the health of each cell. I'm OK with someone answering it - but I felt it was important to make sure everyone reading this is aware it's not as simple as you describe. – bmike♦ Oct 4 '12 at 18:39

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