91Hours of battery life

[notsofatjames]

My MacBook tells me my battery life is 91Hours!! How cool would that be if it was true!

 

[0007776]

That would be great if it was true, My powerbook occasionally does that except it tells me that I have 200+ hours, I really wish that that was true. Any idae why it does that.

 

[Andrew D.]

Wow, that would be crazy! You could travel around the world without it dying on you.

 

[savar]

That would be great if it was true, My powerbook occasionally does that except it tells me that I have 200+ hours, I really wish that that was true. Any idae why it does that.

Because it's not very easy to read the battery life remaining in a modern battery. With older NiCd batteries it was a little easier because the batteries had a "discharge profile"...that is as the energy in the battery drained, the voltage would decrease proportionally. The relationship wasn't perfectly linear, but by encoding the shape of this discharge curve into the battery management software, they could get a pretty good idea of how much longer the battery would last.

With more modern batteries (LiOn, NiMH), the voltage doesn't decrease as much and the shape of the discharge curve isn't as distinctive or predictable. As a result, the battery management software has to take into account other factors, such as historical data, in order to make statistical projections. Sometimes this leads to wacky overestimates.

I noticed on my old ipod the opposite effect -- take the ipod off the charger and a minute later it thinks the battery is dead. A few minutes after that and it shows that it has a full battery again.

 

[itsallinurhead]

Mine does that sometimes. It, however, only lasts a few seconds right after my MBP is unplugged from the a/c power.

 

[MalcolmJID]

Some people get in the 1000's


I've had a battery life of around 1543:47 shown once.

 

[Vidd]

Doesn't beat the 89 million GB iPod that iTunes cliaimed that I had.
Wait, that was just the video, it had 70GB left.

 

[zephead]

1083:35. I win.

 

[00hkelly]

1083:35. I win.

damn, i thought my special super battery was good.