I bought a 2013 used CMax hybrid. Two weeks off the lot and had a dead battery. Took it back and they replaced the battery. 30 days later, dead battery. Took it to a different dealer and had them test the battery and vehicle (they did not find any electrical leakages). Six months later, no issues with the battery. Why? Am not sure, but I recalled when the battery lost its charge the second time, I did not turn off the climate control system (left the fan and maybe heater/ac in the on position). Now every time I park the car, I turn off the climate control system and fan. And I have not had a battery problem. I bought a unit to check my battery status and charging and everything is showing "good." So, I am hoping that by turning off the fan/climate control system I will not have a dead battery problem. You may want to try this and see what happens.