Recently I have been having alot of problems with my charging system. After replacing the battery and having the alternator rebuilt, it seems I am still having problems. Here is the problem. I checked voltage of battery with car off, read 12.6 volts, with car on only read 12.4 volts. It seemed as though the alternator was not supplying enought current to the battery. But when I disconnect the negative battery terminal, voltmeter reads 14.4 volts at idle. Went to mechanic and explained the problem. He told me that voltage regulator does not supply between 13.6 to 14.4 volts to the battery constantly because that would overcharge the battery. The battery hopefully should have been fully charged, because the entire weekend I drove only during the day, with no accessories on whatsoever. He informed me that it is completly normal for the voltmeter to show low 12s as a voltage reading, if the battery is fully charged, to avoid overcharging the battery. But the problem is that the more load I put on the electrical system, compressor at max speed, headlights, radio, with 2 500watt amplifiers, and rear defroster, the closer that 12.x gets to 12.0. With all these systems on, the alternator read 12.1 volts. This seems like the opposite way the alternator should be functioning, correct?? The higher the load, the more voltage needed to maintain battery supply. Alternator shop said that something is wrong with the battery and that I should have it swapped out, but the battery is only a week old?? What is going on here??