Been working on the SHO all winter but have been seeing battery issues and have had to charge it each time to start. It was fine all last year up to the point i put it into storage for winter. Today when i went to set up the tuner the car was dead....dead 100%. Plugged in the battery charger and just heard clicking and lots of lights flashing. Then i switched it to 6 volts and it just went faster. Even plugged in the car is completely dead. Any thoughts. Its a 2015 but it has sat a lot from the first owner and me stored three winters since new and 6 months at the dealer. Basically half its life thus far....parked. Regards, Dave