I have experienced this several times now - Auto battery tests out as GOOD (dealership & AutoZone both tested it) - but it will not hold a charge. Is there any way to really test a car battery so you can be sure it is still good? Even when it was so dead it would not even turn the engine over it was still showing 12.2 volts per my multimeter. I assumed that the test equipment used puts a load on the battery as part of the test. I am considering buying one of these [ame="http://www.amazon.com/Schumacher-BT-100-Battery-Load-Tester/dp/B000AMBOI0/ref=sr_1_6?ie=UTF8&qid=1407352658&sr=8-6&keywords=battery+tester"]Amazon.com: Schumacher BT-100 100 amp Battery Load Tester: Automotive@@AMEPARAM@@http://ecx.images-amazon.com/images/I/41DwVt1qhSL.@@AMEPARAM@@41DwVt1qhSL[/ame] But if the tester a dealer & AutoZone use doesn't pick up when a battery is bad - will this do any good?