I needed a new alternator because of a broken voltage regulator. This alternator solved the problem, but now the voltage on my car regularly drops to 12.0 volts at idle. This usually happens when the air conditioning and/or radio are on, but sometimes they go off without being used. I'm not sure if I have a bad alternator or if something else is wrong, but my alternator with a bad normal alternator puts out enough voltage so I'm guessing it's an alternator. It was still a good generator for the price and I had no more power surges.