The 4 x 25's are in a folding canvas bag with clears on the pockets so I treat it like "normal" ones and pop 'em in teh sun as I like to have the Van in the shade.
The 2 x 50's are seperate... don't usually need them but if I do then I just chuck 'em wherever IE on the roof basket of the Ute etc.
At home I might have 1 x 50 keeping the Ute up to charge and 1 x 50 doing the same for the van and the 25's packed away