Power Consumption

I am impressed by how long a rechargeable AAA cell can last. The package indicates that the unit operates (plays MP3) for 12 hours with one AAA battery. This is most likely based on alkaline type batteries with 1150mAH of capacity (with a cut-off at 0.8V).

A NiMH AAA cell has about 650mAH to 700mAH. In other words, it has about one half the capacity of an alkaline cell. This calculation, however, does not take into account that a NiMH cell specification uses a cut-off at 1.0V.

The specifications of BP300 does not indicate when it considers a battery drained, but it is unlikely to use a battery all the way down to 0.8V. In other words, in terms of actual usable capacity, a NiMH AAA cell may be much more than one half of that of an alkaline AAA cell.

One problem of using a NiMH cell instead of alkaline is that the battery indicator will indicate almost empty even with a freshly recharged cell. This is because the ``full'' voltage of a NiMH battery is 1.25V instead of 1.5V. I find that the player continues to operate for quite a bit of time even after the battery indicator is completely empty with a NiMH battery. This means it may be difficult to really estimate the remaining capacity of a battery.