[fhammond]

I got 2 hours and 45 minutes of battery life on my 1.24Ghz 15" PowerBook today. I'm using the completed version of Panther. I didn't do anything special; just left the energy saver setting on automatic. I was writing email but I was also playing music from iTunes the whole time, so the hard disk never spun down.

It's not as good as a Centrino laptop but it's not bad.

fh

[PowerMatt]

Originally posted by fhammond:
I got 2 hours and 45 minutes of battery life on my 1.24Ghz 15" PowerBook today. I'm using the completed version of Panther. I didn't do anything special; just left the energy saver setting on automatic. I was writing email but I was also playing music from iTunes the whole time, so the hard disk never spun down.

It's not as good as a Centrino laptop but it's not bad.

fh

Jaguar gives me 3:45 or over with similar conditions as you describe. 2:45 is pretty low, especially compared to what Apple advertizes.

[fhammond]

Originally posted by PowerMatt:
Jaguar gives me 3:45 or over with similar conditions as you describe. 2:45 is pretty low, especially compared to what Apple advertizes.

Wow, you're the first person I've heard who gets more than 3 hours. Amazing. I wonder why there's such a difference between computers? I might have got more life if I'd turned down the brightness of the screen but not an hour more life. Very odd.

fh

[slider]

Well, I am another. I am getting 3.5 hours with Jag. 10.2.8. What did you get before panther?

[cambro]

Originally posted by fhammond:
I might have got more life if I'd turned down the brightness of the screen but not an hour more life.

A screen on high brightness draws power very quickly. Turning it down to 1 or 2 bars will definitely add an hour.

[mrmister]

I am also seeing a big boost with the final of panther--with airport on, 4 bars and an external mouse I am getting 4 hours and 8 minutes with the energy saver set to automatic. Very nice, very nice.

[nate_02]

I'm getting about 2.5 hours so far. I think it is important to condition your battery at first by doing a full charge and running it down about 2 times.

[nobitacu]

I am only getting around 2:30 hours as well, but this is with 10.2. So I sure hope this will be better once I install Panther on here on the 24th.

Ming

[SplijinX]

Are you guys just reading what the timer shows for the battery status or are you actually using a stopwatch and timing how much power you have until it goes to sleep?

[slider]

Originally posted by nate_02:
I'm getting about 2.5 hours so far. I think it is important to condition your battery at first by doing a full charge and running it down about 2 times.

I don't this that's right, this use to be true with older style batteries, but not the new ones. Perhaps someone that actually knows why could post.

[fhammond]

Originally posted by cambro:
Turning it down to 1 or 2 bars will definitely add an hour.

That's very interesting. I'll have to try it out. Of course, when I really get down to it, it's kind of a hard thing to test, as I so rarely need more than 2 hours of battery life. I guess that's a good thing. Hopefully before too long, we'll be debating 8 hours vs. 10 hours i.e. battery life will no longer be a relevant issue, much in the same way hard disk space isn't for most people any more.

[PowerMatt]

Originally posted by cambro:
A screen on high brightness draws power very quickly. Turning it down to 1 or 2 bars will definitely add an hour.

The tasks described, email & iTunes, do not require more than 2 or 3 bars of brighness anyway. When Apple claims 5 hours of battery life, it is more than likely with the brighness at one bar, BT off, APX off, processor speed reduced, etc.

[pptiger]

Are you guys talking about the remain time shown on the menu bar or the exact time you got with your battery? I didn't test it, but I think they might be different. My powerbook shows with fully charged battery the remain time is 4:08.

[Drakino]

Originally posted by slider:
I don't this that's right, this use to be true with older style batteries, but not the new ones. Perhaps someone that actually knows why could post.

The Powerbook manual does advise doing a full charge/discharge cycle once. And to quote another forums post about batteries:

Most rechargeable batteries (NiCD, NiMH, Li-Ion) need a few "very full" charges (and not quite so deep discharges) cycles to fully activate or "set up" the battery chemistry, and thereby maximize the available capacity of the battery.

Once that has occurred, you maximize battery life and capacity by conforming to the appropriate charge/discharge needs of the battery type.

"Memory Effect", which could be better described as "voltage depression" during discharge, primarily affects NiCD type batteries. It occurs when slow/partial discharges followed by recharges causes the chemistry in the battery to partially crystalize, which raises internal resistance, and shortens the discharge time before the battery voltage reaches the lower limit for the device being powered. If the partially crystalized NiCd battery is then fully discharged, then charged, after a few cycles, the internal crystalization dispates, and most of the usable battery capacity is again available.

NiMh batteries are so much less suceptable to voltage depression that even when it has occured, the loss in capacity may not be noticed by the user (maybe only 5% capacity loss).

For most NiCd and NiMH batteries, the primary killer is poorly designed battery chargers. Many chargers continue to push substantial power into the battery after it has become fully charged. This continued overcharging causes chemical degradation of the battery chemistry, and is not reversable once the damage has been done. Frequent overcharging (which can occur even if the batteries don't feel "hot" in the charger) will substantially shorten the battery life and reduce the effective capacity.

If you are getting significantly reduced capacity and short lifespans from NiCd or NiMH batteries (even if you are recharging them before they are empty), you should suspect the charger is overcharging the batteries. If a few full discharge, then recharge cycles don't bring them back to life, then either the batteries are truely worn out, or the charger has done them in prematurely.

Li-ion batteries (which have impressive power density and light weight) are so sensitive to charge and discharge requirements that they are always managed by a very smart power management circuit, which relieves the user of concerns regarding the best charge/discharge strategy.

For Li-Ion powered devices, just use the device, recharge it when you want, and don't worry about the battery (other than _fully_ charging, and significantly discharging, the first few times to fully activate the battery chemistry.)

[slider]

Thanks for that info, I was surprised to see that in the Apple manual. Although based on the your post, it would seem to be less of an issue with Lithium ion batteries. It simply says during the first week of use. I am doing it now. I am really curious about what panther will do.

[Spheric Harlot]

I'm getting 2.5 hours with Panther, 1st-gen 12" Powerbook, full brightness, full speed, APX & BT on.

Pretty much what I got in Jaguar.

-s*

[nate_02]

Originally posted by slider:
I don't this that's right, this use to be true with older style batteries, but not the new ones. Perhaps someone that actually knows why could post.

I worked at a battery store for a year. I think I know what I am talking about!

Most rechargeable batteries need a conditoining charge, not just NiCad

[baglunch]

I get 2.5 using 10.2.8 on my 17" rev a albook w/ 1gb ram.

APX on, BT off, highest performance, brightness 100%