2002 sebring computer/battery issues?

anybody here had or know of battery/computer issues with these 2002 sebrings? i've got one thats draining the battery when it sits a couple of days. i think the charging system is o.k. because i get 13.5 volts to the battery at idle. could the computer slowly drain the battery when the car is not in use. the car drives good, 2.7DOHC automatic convertible, 52,000 miles. i have had some issues with the engine light coming on and getting a "small evaporative leak in the fuel system". i'm looking at new cars and want to sell this car, but don't want someone to buy a problem. thanks for any help.

You have probably already checked but make sure under hood light, trunk and glove lights aren't staying on.

Mitch