Got to take you to task there BrianH. A correctly maintained lead acid battery will last a minimum of 10years and we've had some go to 15 years with little drop off. The catch word here is properly maintained ie topped up to a schedule and cleaned to ensure a minimum of earth faults etc. Yes Lithium Ion might be the future but they are still way to expensive while looking after a battery costs very little. Most lead acid batteries come with a 5 year warranty any way so the warranty you claiming isn't any better. No way will a lithium Ion battery last 4 times longer than even a poor lead acid battery that would be a minimum of 20 years lol. Sorry what your saying just doesn't stack up