Thinkpad battery gauges

[JonathanGennick]

My niece is seeing two battery gauges on the Z61t that I recently bought her. She's asking me why two, and especially why the two gauges report different lifetimes. She's not nearby, so I can't just go and look at what she's seeing.

I believe she is seeing one gauge run by Windows, and another run by Thinkvantage software. Is that likely correct? I get two gauges on my X30, and it's one of those things I find annoying. There should only ever be one.

More concerning is that her two gauges report lifetimes up to an hour different. What's with that? Which gauge should she believe?

[ryengineer]

Remaining time is calculated based on the current remaining capacity divided by the average current battery consumption (wattage). Depending on the current battery wattage consumption, remaining time calculated can change. For example, with the system running at the Maximum Performance setting for the processor, the system consumes more battery power, so the remaining time is shorter. A good analogy would be driving a car. When you drive faster, you use more gasoline; slower uses less. If you speed up and slow down frequently, it is more difficult to estimate how much driving time you have left.

The system continuously calculates, if you ask her again she may also tell you the time in both gauges jumps back and forth also.

She can disable Windows (XP) gauge through the Control panel:

Control Panel > Performance and Maintenance > Power Options > Advanced > uncheck always show an icon on the task bar.

[JonathanGennick]

Thanks Ryan. I'll let her know that she can turn off the Windows gauge, though I may recommend that she just leave it be. She gets confused easily, so I don't know that I want her mucking about too much in the control panel settings (else I'll get more phone calls for help). OTOH, having two gauges has already confused her.

This battery gauge business is an area where I believe Lenovo, and IBM before it, sort of fell down on the job. On my X30, there are two battery gauges, and the functionality they provide is both different and overlapping. For example, the list of power schemes is different between the two, and yet some schemes show up in both lists. That's a very confusing situation, and I'm surprised to find that it still exists in recent models. If Lenovo is going to include their own battery gauge, then they should disable the Windows gauge. There should only ever be one. Not a huge deal, but it's the sort of minor, user-interface issue that I wish people would sweat more often. Steve Jobs wouldn't let it pass, I'm sure. I want Lenovo to be just as picky as Steve.