I have never had any problem with this before, went to start my car yesterday battery flat dead! I quick jump and it up and running fine. The gauge in dash shows 14 Volts so alternator fine. Do not think i left lights, maybe alarm went off but i did not notice, or radio button jumped out and turned radio on? What else could cause a drain? Everything is standard in car no mods? Maybe cold weather and old battery but it has always been perfect no sign at all of loosing its charge. If I take it out and put it on charge will it do any harm to ecu or radio code or anything else? Radio is standard Bose concert.