First i want to say if you are using hybrid car it should running at least more than 4 days per week with daily millage about 100 km or higher value, also below points may help to increase life span of the hybrid battery 1.Regular maintenance - hybrid system - Clean battery cooling fan - Clean copper plates This will avoid battery over heating, Heating battery cells decrease life time - Cell balancing if necessary - check scanning report and balance same pack cells 2.Avoid regular parking at heat places 3.Avoid start and parking car long time without moving as a habit 4.Keep good auxiliary 12v battery 5.Regular service and maintenance petrol engine (tune-up),Gear oil change, That keep petrol engine in good performing ...