You know the Bunny. The Energizer one. The one that never, ever, bloody STOPS.
The one that betrays the much–discussed myth that multitasking drains the battery. I’ll name no names.
Regardless of that misconception, the battery–life of the N900 is of quite some interest to me. From my favourite Palm T|X I regularly got two weeks between charging, but I do not expect to beat that record with a device designed to be «always online». But … what CAN I expect? A few experiments are in order.
Test no. 1: At 18:38 one lovely spring day — and I admit the time was poorly chosen — I unplugged the fully charged N900 from main power. Running at the time was the Pidgin IM client, connected to MSN via 3G, as well as a few other bits and pieces including the FBReader e–book application. A few hours later I started xchat, and connected to freenode to have a talk with a friend. At 03:30 the morning after I finally gave up and crashed with a little bit of power left. As near to nine hours as makes no difference. Satisfactory is but one word for it.
Test no. 2: 15:42, and I plug a pair of AKG K242HD full–size 55 ohm headsets into the fully charged N900, push both the hard– and soft volume to max, and set a song (Black Sabbath’s «Black Sabbath» if you really, really need to know) on continuous repeat. After five hours the battery was down to roughly 50%; after six ca. 39%. A sloppy calculation later and I can estimate ca. 8 hours of continuous music (and, of course, background processes, BatteryGraph, and 3G communication). It’ll do very nicely indeed.
Test no. 3: So far we’ve cheated a bit, so lets up the ante somewhat. This time I’ll add some video to the device; any video, and set the display to stay on permanently. Among other things it’ll give me a fair estimate of how long I’ll be able to read e–books. Speaking roughly still, I’m getting around 3 hours of video+audio. That’s … not so good.
Test no. 4: There’s no test number four; but one would be interesting. Perhaps turning bluetooth, wifi, 3G, weather widget, and everything else not currently required off, turn the screen brightness down, and see if I could get 16 hours of e–book reading out of it? Wonder what’d give first — my eyes or the battery?
The conclusion? The N900, even multitasking, has a battery–life easily comparable to modern laptops, and in some circumstances much better. For a device which, with the keyboard extended, is the size of a small pocketbook I’ll dare label it «excellent».
PS: Yes, of course running the CPU harder will drain the battery faster. The point to be made with the above is that it won’t drain it so fast that multitasking isn’t a Very Good Idea Indeed.