I would think that any test that is done without any testing equipment might not help you pinpoint the problem area. As long as connections are tight, turning the headlights on and cranking the engine, the lights should still be fairly bright while it's turning over. If they all but crap out, then it's likely the battery. Just take your car to Advance, they'll load test it. And yes, they've tested batteries for me and told me I didn't need a new battery before.