[sirmaru]

No one knows how Amazon ran its battery tests. They could have relied on one employee with one unit. They could have run exhaustive tests using statistics on thousands of units.

All of us have different PW units all of which may vary in performance. Plus, all of us use them differently with different settings and different eBooks.

Thus, each of us must rely on their own experience with their own specific unit to gauge battery time over several weeks and then rely on that.

I wouldn't put too much stock in comparing our individual battery performance with the Amazon statement of expected battery time.

With the Kindle Fire there is a standard way of measuring battery time if all participants use the GSam Battery Monitor. Then a reading of the Screen Time value right before a charge combined with the percentage of battery use would be comparable over many units. However, even then the way each of us use our KF and the variety of settings plus the differences in different units would also tend to give a wide range of values.