[My battery thoughts were prompted by some discussions and posts by Patrick Moorhead from AMD. He has done a good job of questioning battery life stats. I think there are a few battery life posts I need to write soon to continue this dialogue, or is it a soliloquy?]
Okay here’s a great metaphor for the “battery life” issue.
I have a 2006 Toyota Prius and the fuel indicator has an eight bar indicator for gas level. I also reset my trip meter after I fill up. And here’s where I think Toyota has missed the mark. I can go upwards of 120 miles and the gas meter still shows FULL, all 8 bars are still lit.
The car actually gets around 340-370 to a ten gallon tank. I average 38 mpg combined, even when I’m driving pretty aggressively. So, at the top of the gauge the measure is useless. But as the car moves closer to that magic 340-350 range the lights practically go out at in pairs. And if you see that last LED marker flash and the “add fuel” message on the dash, DO NOT PASS ANOTHER STATION. Get gas immediately.
So the fuel gauge is useless in the Prius. I know I get near 350 miles per tank with a gallon or so to spare. And the only indicator that causes me to take action is the flashing light, and if I have let the fuel get THAT LOW then it IS an idiot light.
My laptop battery has similar issues.
When unplugged, my laptop does its best to calculate time remaining to standby. And the accuracy of the minutes to black is less important than the final “please plug in your laptop to avoid standby” message. Or the equivalent of the flashing “add fuel” message.
So in the real world my laptop with a 2.4 Intel Core Duo 2 gets approximately three to three-and-a-half hours on a full, overnight, charge. But the real measure, the real indicator I look for is that final “add fuel” warning.
Now, I am waiting with anticipation for a new laptop with an “enhanced” Li battery. Advertised and marketed at eight hours battery life, I am not so concerned or worried about “exactly” how long the battery will last, but more about how much additional warning I will have between when the battery says, “add fuel” and when the machine powers down in the middle of my Spore victory dance.
In terms of reporting battery performance, doesn’t some of the problem originate with the battery itself? Does an ATI battery and a Sony battery and a who-knows-what-brand battery all perform the same?
And what I learned recently in doing some “battery” research is, that HEAT is a bigger issue for Li batteries than anything else. So even in standby, if your Li battery and laptop are in a hot car with the windows rolled up, the battery will drain much faster than if it were on a shaded table in a coffee shop.
FACT: Short battery life in a laptop is mainly cause by heat rather than charge / discharge patterns. 
I would like to see battery ratings gain more reputable metrics and here are some things I’d like to see:
- I want the battery to last a long time (anything beyond 3 or so hours is pretty good, but I don’t travel a lot.);
- I want the battery to not die prematurely (1 – 1.5 years seems like a reasonable amount of time before a replacement battery is necessary.);
But, more important to me than any spec (3DMark06 or MMO7) is this:
- I’d really really, really like the battery to be GREEN. Less lead, less bad stuff, less waste.
Then we should really think about how to cool the battery better, so my palms aren’t on fire atop my 140 degree, and my thighs aren’t blistering red. If we can keep it cool, while under duress (like when running 3DMark06 benchmark), guess what? The battery performs better and lasts longer.
Now, back to cars for a second, I understand that the Prius outside the US has been offered with an EV override button that forces the car to use more electric power than it does in “normal” mode. It was taken off the US models by pressure from somewhere. (Not hard to imagine where that lobbying pressure came from.)
So with my laptop I would often hit the “TURBO” switch to keep the machine running at top performance even if that meant having to keep it plugged in. But I would like an “ECO” mode as well.
The upcoming 2010 Prius comes with three modes including “EV.”
By all means, let’s keep getting better and honest about our metrics. But let’s not obsess about a 91 3DMark06 vs a 95 3DMark06. Quite frankly, even if you tried to explain it to me, I don’t know what that 4 point 3DMark06-spread means in terms of actual battery time.
So when manufacturer says the new laptop will get 8-hours runtime (or is it 12?) I don’t really know what that means. Will my Prius really get 42 city 48 hwy? I don’t care. But when that “add fuel” message pops up on my laptop or my Prius, then I will sit up and take immediate action.
Ref: #1. The Battery University for all you ever wanted to know about battery stats.
That’s it, Power On!
- Technologizer: How Bright Do You Keep Your Notebook Screen? By Patrick Moorhead, June 12, 2009
- ARSTechnica: Good news and bad news regarding the new MacBook Pro
- Uber.La – Battery Life: Does Anybody Really Care What Time It Is? – Until Their Laptop Goes Black?
- Uber.La – Laptop Battery Maintenance and Good Habits – Scientific Studies Reveal