What are the respective voltages of the Nickel-Metal-Hydride (NiMH) battery when it is: full, at first battery low warning, at the second battery low warning, and then at the final battery low/going to sleep warning?

The following is a list of the voltage measurements for the NiMH battery used in both the Macintosh PowerBook 190 and 5300 series computers:

Full Voltage:                      16.1 volts +/- 0.1v
First Battery Low Dialog:          14 volts
Second Battery Low Dialog:         Approx. 13.6v*
Third (Final) Battery Low Dialog:  Approx. 13.1v*

* This approximate reading is a result of an extrapolation.

Note: Voltages shown here were measured on Fluke 77 Voltmeter on 10 batteries in the Apple Reliability Laboratory. Please keep in mind that you might not get exactly the same readings from your batteries, but they should be similar.