Here is the problem. First, I own a 1997 Ford Expedition, 4.6l, 4wd, 126k miles. Recently, the Ford won't stay running, the battery wouldn't hold a charge. I replaced the battery. Problem persisted. It would run til battery charge was gone. I took the alternator in for testing at an auto parts store. The lady didn't really know how to use the testingunit, but " thought the alternator was good". I purchased a new one. Problem was still there. I tested voltage at the regulator, it was approximately 9v. New voltage regulator. Ran it tonight, it ran fine for about 20 minutes, then battery died again. What now? My wife stopped me from shooting it with my rifle. So you guys are my last stop. I hope you can help. In the meantime I will be loading my AR-15 rifle.