A few bays before the pandemic we, (wife and I ) had left the house for 4 to 5 day trip ,,grandson's birthday,,,, when we got to the middle of the state and the stay at home thing came along,so we srayed in our condo , I had left the crossfire and our fusion in the garage ,batteries connected, planning to return within a few days, now two months later we are headed home .what will i find?.. batteries on both cars are connected and probably both cars have dead batteries. I hope that is all i find wrong. I am thinking I will charge the crossfire about half charge,, put it in the carm connect it then fully charge it. if the batt is no good then that is out. new batt. be installed.

but to answer the question I have disconnected the negative post and left my car for 3 months,, reconnected all was good i have done this a few times