Battery life on T42p models - 14.1" vs 15"

[MrBeta]

I have two brand new T42p Thinkpads - 14.1" SXGA and 15" UXGA - and a serious question on the power consumption of the 15" model.

With the extended battery in both of them, the 14.1" reports ~7.5 hours worth of juice on full charge... realistically I've been able to get about 6.5 hours of usage out of it without major problems, which is great and I love it!

On the 15" model, the battery meter reports 4 hours 35 minutes on fully charged battery. Is this normal? That's *3 HOURS* less than the 14" Thinkpad on the same 9 cell battery! I expected the 15" to use a bit more power because of the larger screen, but 3 hours sounds very excessive.

Could someone with a 15" UXGA T42p and 9 cell battery please confirm the battery life on full charge (brigtness all the way down for this test), or confirm whether this is normal?

Thanks.

[Kenn]

Hey Mr. Beta,

Looks like we're T42 twins - from your info we have same machines

I just plugged it in to the 15", and after being in the refrigerator for 3 weeks and at 87% charge,it says 4:23 remaining. I remember getting more than 5:15 out of it (turned it off when it got to about 10%) the first time I used it, but 4:45 at 100% sounds a tad low. Is your wireless active? Do you have a lot of apps running (mp3 playing in the background, etc.), or powered peripherals like a USB mouse attached?

If I recall correctly, on the 6-cell my 15" gets just under 3.5 hours with general internet/ms office usage, while the 14" gets close to 4.

[MrBeta]

Thanks Kenn.

No apps running on either machine when I was testing this, but yes, wireless was on, on both of them. Still, the 14.1" reports ~7.5 hours, and the 15" ~4.5 hours - that's quite a bit of a difference between the two (both on 9 cell batteries). The only difference is the 14.1" has the Intel Centrino b/g card, while the 15" has the IBM a/b/g card. Surely that card doesn't use THAT much more power, though.

<sigh>

As much as I like the 15" screen, the 14.1" just seems much more of an all around killer laptop - much smaller than the 15" model, better form factor (less dead plastic space on the sides of the keyboard and around the screen), lighter, 3 hours longer battery life, don't need to hold the bottom of the laptop when adjusting the screen (the 15" is so top heavy you HAVE TO hold the bottom to adjust the screen, open or close it, etc), has faster CD burner (the 15" has the DVD multi drive which only burns CDs at 16X and CD-RW at 4X, vs the 14.1" which has a CD-RW/DVD which burns both CD-R and CD-RW at 24X).

<sigh>

When people see the 14.1" they always admire how compact and THIN this thing is (1"). When they see the 15" it's about the size of most other HP or Dell or Toshiba laptops (~1.5" thick). Nice machine, but... gawd, how I wish IBM made the 14.1" with Flexview - that would be the ultimate killer laptop to have...

Anyway, back to run some more battery tests. At this rate the 15" feels like it needs not one, but TWO 9 cell batteries to last "all day" while on the road, while the 14.1" needs just one for close to the same overall time.

[Kenn]

I agree with pretty much everything you say regarding the 2 machines. Flexview is nice, but the biggest benefit to the 15" is UXGA - for my purposes it's worth all the drawbacks the 15" carries. If only the 14" had it

I'm running off the 9-cell on my 15" all weekend, I'll report back and let you know how much juice it draws under a variety of conditions.

First of all, lid-closed on slowest cpu speed running itunes in the car for 3 hours straight: down to 61%, 3:05 hours remaining. I love how the math never adds up.

[mouse@cheese.storage]

Hi,


Sounds like interesting practicle data, but if you are comparing, shouldn't you discuss what you are running, as there will be a large difference between simply typing, typing with some Mp3's and doing a compilation every couple of minutes because you are designing, or even doing some graphical work ?? Only in this case you can probably have maths that work

[Kenn]

Hi,


Sounds like interesting practicle data, but if you are comparing, shouldn't you discuss what you are running, as there will be a large difference between simply typing, typing with some Mp3's and doing a compilation every couple of minutes because you are designing, or even doing some graphical work ?? Only in this case you can probably have maths that work

Good point, mouse I guess I figured trying standardize our personal usage would be pretty futile, and if I hit 4:45 while running apps, that should be enough to say something about MrBeta's 4:45 while idling.

But for the good point of clarification, I'm going to be running office/email/web surfing most of the time, adaptive CPU + lowest screen brightness. Nothing remotely demanding, and probably no more than 1hr of mp3 playing in itunes via headphones.