I went to start my 05 Roadster and the battery was too low. I placed my charger on for 10 min and started it. As I was driving down the road I could hear a strang roar from under the hood. The electric radiator fan was running at full tilt. I turned off the car and restarted, instantly the fan started. When I got home I took off the Neg battery connection and left it for 5 min. Reconnected the terminal and started the car. All back to normal. I will be replacing the battery ASAP. Hope this helps if others run into electical problems.