After some user feedback it now features messages to warn you of critical battery levels and when you switch from one type of power to another. It does this in an unobtrusive way.. unlike the standard Windows power meter! ;-)
You can also define a threshold for when your battery is effectively full, because some laptops stick at around 98%. This meant that when charging, the power meter remained on the screen indefinitely.
Let me know if you have any bugs (or feature requests) to report and I’ll get them fixed ASAP. But don’t ask me for a version for Dell laptops which warns you when your battery is about to explode :-D
Wander over to the Power Meter Plus page for the download.