Battery power remains weak

The old battery was more than getting on in years, since he had been purchasing the Nokia 6310i in it. The use in the car with Bluetooth - connection charge kept getting shorter, only 2 - 3 hours ago. Therefore, the purchase of new, original Nokia - batteries. Result: The charge is now depleted after only 3 days. Because I had expected a longer period of use. And it is rarer than rare that I call out of the car. But the Bluetooth - connection swallows apparently abundant juice.