Apple and advertised battery life

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My five year old Power­Book has been hav­ing trou­bles for some time. I’ve been doing repairs along the way in order to post­pone the expense of replac­ing the lap­top, but when the hard dri­ve start­ed mak­ing sounds like a mar­ble dropped on a steel table­top, I knew it was all over and time for a new laptop.

After a bit of search­ing and research­ing I decid­ed on a refur­bished 15″ Mac­Book Pro. I found one with an anti-glare screen, which was the most impor­tant feature—at least the most impor­tant fea­ture in a field of mod­ern proces­sors. As it hap­pens the Mac­Book Pro I found has the i7 proces­sor but I think I would have hap­pi­ly tak­en a slow­er proces­sor and a small­er screen so long as it did­n’t have one of those glossy screens all the new lap­tops have. 

I’m learn­ing more about what tax­es the bat­tery on the Mac­Book Pro. I guess hav­ing a fresh bat­tery (not to men­tion that it is non-user-replace­able) moti­vates me to try to take care of the bat­tery. Appar­ent­ly Apple’s claims of «up to 8 – 9 hours of bat­tery life» are based on hav­ing Safari and iTunes run­ning, but iTunes not actu­al­ly play­ing any­thing. So actu­al­ly get­ting 8 hours out of the bat­tery is like­ly total­ly unrealistic.

How­ev­er, I’ve been get­ting con­sis­tent­ly between three and four hours on a charge. That’s a lot less than 8 – 9.

The NVIDIA GeForce graph­ics adapter in this thing appar­ent­ly sucks down a lot of elec­tric­i­ty. OS X auto­mat­i­cal­ly switch­es down to the Intel inte­grat­ed graph­ics chip when the NVIDIA is not need­ed, but it is hard to know when it switch­es on. 

For­tu­nate­ly some­one wrote a lit­tle util­i­ty called gfx­Card­Sta­tus that sits in the menu bar and indi­cates which graph­ics card is in use. Well, lots of web­sites (I’m pret­ty sure it’s only ones with Flash) «need» the NVIDIA chip, even when they aren’t on a vis­i­ble tab. So now I watch that indi­ca­tor and if I see a site that switch­es the indi­ca­tor from «i» to «n» I don’t leave it open. 

Today I got 6.5 hours on a charge before I had to plug in, while I was work­ing, which means two browsers open, mail, instant mes­sen­ger, IDE, a cou­ple ter­mi­nal win­dows and a web­serv­er. I haven’t been tak­ing it easy on the proces­sor, just not leav­ing Flash sites open. This, com­pared with the ear­li­er results means that Flash sites chew up near­ly half my bat­tery life.

I’m not sure how much of a per­for­mance dif­fer­ence there is with those Flash sites with­out the NVIDIA chip. There is a set­ting in gfx­Card­Sta­tus to force the NVIDIA chip on or off depend­ing on whether the pow­er adapter is plugged in. I may try forc­ing the NVIDIA chip off when run­ning on bat­tery. I can’t imag­ine that Flash will run notice­ably slow­ly just because I’m run­ning the sec­ondary graph­ics accelerator.

Even at its short­est bat­tery life, this Mac­Book Pro still has a longer-last­ing bat­tery than any lap­top I’ve owned, but I still find it a lit­tle dis­ap­point­ing to be so far off of Apple’s claims. Apple claims the iPad has ten hours of bat­tery life and I’ve seen the iPad run con­stant­ly for twelve hours. For Apple’s claims on the Mac­Book Pro to be based on unre­al­is­tic met­rics (come on, who runs one appli­ca­tion at a time these days?) seems less like over-opti­mism than like misrepresentation.

Published by splicer

3 Replies to “Apple and advertised battery life”

  1. Batt life

    As the new own­er of the afore­men­tion 5‑year-old Power­Book, I am lucky to get an hour from the bat­tery. A replace­ment hard dri­ve got rid of the clank­ing, though. Basi­cal­ly we keep it plugged in to its pow­er adap­tor as the liv­ing room cof­fee table com­put­er. Nice for that.

    1. The part of that that makes

      The part of that that makes me sad is that the bat­tery you’re lucky to get an hour’s charge out of was pur­chased in Novem­ber from PCParts in La Habra. Per­haps I need to write a caveat ven­di­tor post about them.

  2. Bat­tery life

    All com­put­er man­u­fac­tur­ers say “Up to.…” when describ­ing bat­tery life. That means you can’t expect any­thing bet­ter than that. 🙂 To achieve those num­bers you have to have ALL of the ener­gy sav­ing fea­tures set to their max­i­mum val­ue. I would assume that would mean only using the inte­grat­ed graph­ics, with the screen bright­ness cranked down, and the proces­sor and hard dri­ve in sleep mode most of the time. Maybe the wifi radio turned off, too. For me, I’d rather have the per­for­mance. I keep all my “green” fea­tures turned off except for the very rare times when I won’t be near AC pow­er. Of course, my per­for­mance lev­el at best is no where near what the i7 will do while rest­ing, so I have a lit­tle more incen­tive. Also, I can replace my bat­tery myself when it dies.

    As usu­al, I can’t find any sol­id tech­ni­cal info from Apple on their bat­tery usage. Just a lot of mar­ket­ing mumbo-jumbo.

    Dad

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