yeah I know you aren't suppose to put regular batteries on there side. But I never thought far enough to realize optima's are ventless, and can be set on their sides. lol If I knew that when my battery died I might have considered buying one and mounting it like that. Although when my battery died I never looked into see if there is one that is stubby either. I just new the stub battery is more expensive, and figured the opitma would be equally if not a greater expense.