My 2012 Mazda 3 will go completely dead if it’s not started at least 1x a week! This first started in the cold winter and I changed the battery! 2 weeks later the battery was completely dead again! Well I fully charged the battery and then installed a “BatteryTender” to the car and it seemed to keep everything working. Jump to last week, after 3 days of 109* and the BTender unhooked the car was dead again!! Took battery to autozone and had it recharged and tested, nothing wrong with battery! OK can this be something like the alternator or the voltage regulator? And if it is why does it only go out when the car is sitting?