There are two battery icons in the system tray. Both show a different battery life number. At times they are close to one another and other times they can be far apart.
Which one do we believe over the other guys. Had absolutely nothing else to do today as you can guess..![]()
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John Ratsey Moderately inquisitive Super Moderator
See my post on this subject in the T420s thread.
It's difficult to trust any of the programs since they update their forecasts based on remaining battery capacity and current power usage and each program uses its own method for measuring the current power usage. I tend to do my own mental arithmetic based on what I think is a reasonable power drain for my expected usage taking into account that Windows like to stop work before the battery is empty.
John -
The green one on the left is the Lenovo one. The window you have open is the Windows 7 default one. Neither is right or wrong. Both are estimates based on your current very recent usage pattern.
There can be many reasons for the difference in times- Perhaps the Lenovo one updates every 15 seconds and the Windows 7 one updates every 25 seconds, and the slightly different usage pattern (what you're doing on the computer AND background services) causes a different time.
Another example- perhaps the Lenovo one knows the exact wattage at all brightness levels of your screen, and the Windows 7 one has to make an estimate. -
Take the two and pull an average.
Its what I do. (Although i'd trust the Lenovo Unit more) -
To me it seemed that Windows one is more accurate each time I checked
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But really, this seems to be the perfect case of "have one clock, and you'll always know the time, have two, and you'll never be sure." -
Just thought it was interesting from looking at the programs result of battery life and how they vary. For me, I just wait until I get that low battery warning and plug it in.
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Battery Bar definitely does some more things that aid in accuracy such as comparing current runs to previous runs, and keeping a longer running average of your usage pattern. The problem with Battery Bar and the windows meter however is that they don't have access to the same battery information that the Lenovo power manager does. The Lenovo power manager has the capability of accessing the data in the onboard control chip on the battery. After you calibrate it, it's pretty accurate in it's determination of how much power is remaining. Battery Bar relies on the ACPI information that Windows stores from the battery which isn't always right. For example, right now Windows and Battery Bar both report my main battery as having 104Wh full charge capacity. This is just plain wrong. The battery is designed for 93Wh, and the Lenovo power manager shows it at a much more believable 94.06Wh.
What I typically find is that because the Windows ACPI information is typically a little inaccurate, the windows "percentage remaining" will have a sudden drop out near the end of your battery life (ie: 25, 24, 23, 22, 21, 6% remaining). I've found this to be fairly consistent across numerous brands of laptop as well.
So while the Lenovo power meter might be a little more twitchy than something like Battery Bar, I think as your battery ages it'll provide much more reliable numbers. If the "estimated" time annoys you, just flip it over to show percentage remaining only. -
I've found that Windows one updates faster and as such gives more erratic numbers, but good for an instantaneous reading. (as in, if you were to continue exactly as you are doing at that moment, the number will be correct)
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I believe Lenovo Power Manager is more accurate. Windows 7 initially thought that I could pull nearly 13 hours out of my W520 on a 9 cell battery. Though after using my battery for a while, the two get pretty close in terms of estimated runtime. I prefer to do my own calculations, though.
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I find the Windows 7 one tends to be a little too optimistic in real use. The difference between the two isn't too great, and neither of them could possibly be 100% accurate (no software program could predict what kind of activities you are going to do before you do them), so basically both are right and both are wrong at the same time.
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BatteryBar averages your usage over however long you've had it running(across days and months) and gives you a battery life estimate from that.
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The Lenovo one is more accurate. They designed for the Thinkpads, while the windows one have to cater to every machine that uses windows.
Remaining battery program to believe in
Discussion in 'Lenovo' started by SR45, May 13, 2011.