If you use your vehicle a couple of times a month you should not have to charge your battery with a plug-in the wall charger. Our smaller batteries have a shelf life of 1 year while our larger batteries have a shelf life around 2 years due to the extremely low self-discharge rate. If you have a vehicle with a parasitic drain even if the key is off, (Harley’s definitely do) then you will need to charge them every 1-2 months of inactivity (depending on how much of a draw there is determines the length of time it can sit). We do recommend topping off the battery after an “off season” before first engine start attempt.