Re: quattro-digest V3 #240

[ptimmerm@mashtun.JPL.NASA.GOV]

Steve,

You are referring to the two most popular battery
configurations for lead acid batteries, prismatic
with cast grids, and jellyroll configurations with
rolled lead grids.  The conventional starter/lights/
ignition SLI battery is a cast grid prismatic.  The
jellyroll cells arent typically used for SLI for 
several reasons.  First is power, or as they like to
say Cold Cranking Amps (I hate that term).  The SLI
batteries are flooded, meaning the plates are swimming
in acid.  The jellyroll cells are starved, so as to 
allow for gas recombination.  Thus they conduct less
current at max power.  Energy and cyclability is a 
different story. The jellyroll cells have better 
gravametric energy density, that is more ampere hours 
per pound.  But they don't pack into a battery package 
too well, so they aren't that much better in volumetric
energy density.  They generally are better for high
drain applications where you have the room, but auto
applications are something else.

That being said, I am not sure what you saw.  There are
many variations on this theme, and I could go on for 
several days, but you AUDI  <see I did mention it> should
probably have a square one, not a cylinderical one.

<<<<<<<<<<<<<<<<SB wrote:>>>>>>>>>>>>>>>>>

I remember seeing an ad in either EC or GRM for some kind of "coiled" 
battery, where the cells are arranged into some kind of coil.  In the ad it 
was reported that the battery was much more robust than standard batteries.  
I had never seen anything like it before, but it sounded intriguing.  Has 
anyone out there seen them in the flesh or have any experience with them?  
I figure that they are probably $$$$.