Tom Walker wrote in a message to Wayne Chirnside:

-> Never owned or used sealed lead acid batteries intended for 
-> non-vehicle use so about them I've no experience.

 TW>  There is a very expensive Gell CEll battery that is sold for use
 TW> in Vehicles.                    
 TW>  I suspect they will not work out. Gell Call batteries are Heat
 TW> Sensitive and dry out easily at high temperatures. And there is
 TW> Nothing Cool about the Underhood Temperatures of the Modern Car.

And it's getting worse.  The changes in body styles in recent years to
enhance aerodynamic qualities has let to much more stuff being crammed into
a much tighter space,  and temperatures jumping from what they used to be.

I know the unit you're talking about,  a molded plastic package with six
cylindrical cells in it.

Supposedly used in "race cars",  though what type isn't specified.

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