Have you looked at Lithium Ion batteries? No maintenance no overheating no changing and 5 year 3,000 cycle warranty. Price has always been the issue, but I have sourced the for about 2 times the cost of a lead acid battery and they last as long as 4 lead acid batteries. All come with battery monitors and can be diagnosed quickly if they have an issue.
Just a thought.
This is ONLY to be used to report flooding, spam, advertising and problematic (harassing, abusive or crude) posts.