At some point you have to figure out the battery isn't being recharged after you start the engine. With an electric fuel pump and electronic fuel injection, the engine will run on a fully charged battery for about an hour. It's not the fault of the battery. You have a charging system problem. To prove it, once the engine is running again after a jump-start and the jumper cables removed, use an inexpensive digital voltmeter to measure the battery voltage. It must be between 13.75 and 14.75 volts. If it is low, the battery will not recharge after starting the engine. Most of the time the generator is the problem although it should be tested before you buy a new one.
Also be aware that when the battery is completely discharged, it will take a good 15 to 20 minutes before it starts to take a charge. That means while the engine might start right up with a jump-start, it probably won't charge the battery enough to keep the engine running in that minute or two the jumper cables were connected. The battery should be charged at a slow rate for one to two hours.
Monday, April 25th, 2011 AT 3:11 PM