Re: [Phys-l] How much energy can a battery discharge

["paul beach" <sniffyraven@fastmail.fm>]

Details of battery operation are done by the site, 
http://www.av8n.com/physics/battery.htm#sec-contents

My apples and oranges approach, divide gram-moles by coulombs, was a bit
closer since the result was for hydrogen = 1 gram/mole, nickel is a
little heavier. 

Also the theoretical upper limit is much less than the practical limit.
As soon as the electodes are connected, the plates become fouled with
ions. Internal resistance (and heat production) goes up, and so on. 

My class assignment gets a failing grade; however it is clear, batteries
are heavy. Electric cars and electric contruction equipment are doomed
to failure with present battery technology. 


On Fri, 24 Oct 2008 00:30:15 -0400, "Michael Edmiston"
<edmiston@bluffton.edu> said:
> Without thinking about the calculations, I can tell you that your result
> is 
> a lot different than reality.  A typical Nickel-Metal-Hydride
> rechargeable 
> AA cell (which is considerably more energy than a AA alkaline cell) is
> about 
> 2 amp hours, and it is perhaps as big as 5 sugar cubes.  Therefore, your 
> result is off by at least 50-fold.
>
> Michael D. Edmiston, Ph.D.
> Professor of Chemistry and Physics
> Bluffton University
> 1 University Drive
> Bluffton, OH 45817
> 419.358.3270
> edmiston@bluffton.edu
>
>
> --------------------------------------------------
> From: "paul beach" <sniffyraven@fastmail.fm>
> Sent: Friday, October 24, 2008 12:01 AM
> To: <phys-l@carnot.physics.buffalo.edu>
> Subject: [Phys-l] How much energy can a battery discharge
>
> > How much energy can a Battery Hold? Can I just divide grams-moles by
> > Coulumbs?
> >
> > 1 Coulumb = 6.2 x 10^18 electrons or 1 A / sec
> > Avogadro's number = 6.02 x 10^23 gram-moles
> >
> > Coulumbs for a gram-mole = 6.02*10^23 / (6.2*10^18)
> >        = 97096.77419
> >
> > Divide by 60*60 to get amp hours = 26.97132616
> >
> > Therefore something the size or mass of a sugar cube, could give about
> > 27 amp hours on the negative terminal.
> > -- 
> >  paul beach
> >  sniffyraven@fastmail.fm
> >
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-- 
  paul beach
  sniffyraven@fastmail.fm