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

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