Anyone know what's up with my laptop battery?

It’s probably dieing out. How old is it?

About a year.

It might be specific programs you are running or not. Laptops are often set to shut things down when not needed, but some programs use the CPU and/or drives (which can also lead to more fan use) all or most of the time, while other programs may not use them much at all. That affects the rate at which power is used.

It may not be obvious which programs use more or less power. A program which is written to only do things in response to the user may not require the CPU to do much of anything the rest of the time, while a program written to constantly loop and process may require the CPU to run at full speed (this could be a very simple program).

@Zaku it’s almost always Mozilla Firefox, Microsoft Word, and Microsoft Outlook that are the programs open.

And when using Firefox, I normally have a tab for fluther, a tab for youtube, and one/two/three for researching.

I should probably clarify a bit more. when I turn on my laptop I tend to check battery life before I open any programs and here is when I notice my battery’s tendency to have an inconsistent lifespan.

So you mean sometimes it shows “90%, 8 hours” and sometimes it shows “90%, 1.5 hours”? Perhaps it estimates life based on current rate of consumption, which changes.

With Firefox open, it might have to with what’s in your tabs. Active content in web pages (whether in Javascript, Flash, or whatever) can either require your CPU to do things constantly, part of the time, or only when you are doing something with it.

@Zaku more like I check immediately (as I said prior to opening programs) and it’ll say 100% 10 hours (once I start opening things in drops to 8) and sometimes it says 100% 2 hours (and then drops to 1½ when I start using programs).

Ok, well that makes sense, as long as the percent is not dropping suddenly many percentage points. The percentage is an estimate of charge remaining, while the time, is an estimate of time remaining at the current rate of drain, which can vary a lot based on what the computer and its hardware are doing.

What kind of laptop? I’m not aware of many that come close to getting ten hours. It is normally around 3–5 hours.

What I would do is run the computer until the battery dies. Then fully charge it overnight while you are not using it. That should help the computer “learn a little bit more about the battery so you might get a more accurate report of the status of the battery.

It’s a Dell Precision M2400, and yeah I was a bit weirded out when I got the eight hour streak. Normally it’s between 3–5 hours but recently, the battery life has increasingly been either above or below the usual 3–5 hour, mostly below, but not without the occasional ridiculous spike in battery life.

My laptop reads around 6 hours at 100% under normal use but when I do CPU and/or GPU-intensive tasks it will drop to around 3:30 without the percentage dropping. That time is an estimate based on current current; the amp draw on the battery right now.

I also use Battery Bar (the free version) as it seems to learn the battery quite well and thus generally be a bit more accurate.

I recently had battery problems and someone suggested my charger may have been broken, and sure enough, after buying two batteries in an effort to figure out the problem, i found out it was the charger. the guy at Staples told me the battery will often outlive the computer. Now I have two batteries and a great charger, but the two batteries will probably definitely outlive the computer.

charger is a cheap thing to check and replace.