Last Thursday I turned the key to start the engine but the engine didn't start. The battery ran down due to inactivity. I have 2 cars but I seldom drive now. The Chevrolet Cobalt just sits in the garage. I think the last time I drove the Cobalt was in June. I popped the hood and connected my battery charger to the positive and negative terminals. It took less than five hours to get a 100% charge level. I started the car and relearned the tire pressures. This morning I drove to the hardware store just to drive the car. I parked and turned off the engine. When I opened the door, the digital display was showing the number 1. Does anybody know what this means?