Having just tried Rayovac’s new Active Core batteries against their Extra Advanced batteries, I’ve concluded they last two hours less!
Battery life in my phonak aids varies by only about half an hour difference between the two aids. So I inserted the new Active Core battery in my right aid and their usual one in my left aid.
My right aid lasted two hours less than the left aid. Next, I did the opposite. This time I fitted the active core battery in my left aid which again lasted two and a half hours less the the battery in my right aid.