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Look, you stated that "After driving for a while (commute 2 hour to work twice a week) the battery is drained and will not start without being jump-start"
Only a system that is not charging can do that. You may have checked it yourself, but you probably checked it wrong. The ONLY thing that can cause a car to start on it's own when you leave and not start when you arrive is a charging system that is not working properly. Only checking voltage doesn't tell you much. The amperage output has to be tested also.