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From: cyborg@rata.vuw.ac.nz (Alex Ivopol)
Newsgroups: sci.electronics
Subject: Re: Why Are 9v Rechargables Not 9v??????
Message-ID: <1991Feb11.204414.18631@comp.vuw.ac.nz>
Date: 11 Feb 91 20:44:14 GMT
References: <1991Feb11.005844.1630@julius.cs.uiuc.edu> <1991Feb11.051216.10343@comp.vuw.ac.nz> <16552@sdcc6.ucsd.edu>
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In article <16552@sdcc6.ucsd.edu> cs161fhn@sdcc10.ucsd.edu (Dennis Lou) writes:
>>Most rechargable 9V batteries are made of 6 cells in series, each providing
>>1.2V thus the 7.2 volts.
>
>Why not use 7 cells for 8.4 volts?  Couldn't they use the higher
>capacity technology they use in the 1800 mah C cells to make up for
>the lost space?

I'm no expert, but I suspect it's got something to do with the size of the
battery. Using 7 cells would make the battery larger or alternatively the
cells would have to be smaller. I think that the cell's capacity is related to
its size. The bigger the cell the bigger its capacity. This is why the D size
batteries are bigger and have higher capacity than the AA ones.
Of course new technology could alter all this... in the 9V rechargables they
must be using cells 1.5V each instead of 1.2V

--
cyborg@rata.vuw.ac.nz