iPad 3's power behind the throne

Summary:Apple didn't call out the new iPad's most striking internal feature during the launch, but from an engineering viewpoint it is extraordinary for one standout component.Teardowns reveal that the battery capacity has been doubled to more than 40 watt-hours.

Apple didn't call out the new iPad's most striking internal feature during the launch, but from an engineering viewpoint it is extraordinary for one standout component.

Teardowns reveal that the battery capacity has been doubled to more than 40 watt-hours. As chemistry doesn't move at the same speed as Moore's Law, that means it's practically twice the size of its immediate ancestor's — the iPad 3 is basically one huge battery with a rather nice display attached.

New iPad in box

The new iPad's battery capacity has doubled to more than 40 watt-hours. Image credit: Bonnie Cha/CNET News

From a practical point of view, the biggest change will be apparent if you try and charge your new gizmo from a standard USB port. These deliver two and a half watts, meaning you'll be hanging around for the best part of a day to get your tablet fully juiced. Best pack that power supply, or make sure the thing's plugged in as much as possible throughout that day.

While we don't know for sure what inside the iPad 3 demands that huge reservoir of power, it's a safe bet that the 3 megapixel Retina display is the major culprit. The rest of the upgrade — the faster, more-cored processor with its extra graphics and the LTE wireless — can be throttled back in software or otherwise optimised, at least as far as creating a headline battery life figure. The display doesn't have a low-power mode.

That's a shame. While it's no crime to enjoy resolutions at the limits of what can be discerned and it's the nature of technology to improve until there's no point in going any further, the iPad is primarily a portable device where weight and freedom from cables are both at a premium. Anecdotal evidence suggests that in normal use, there's no particular difference to be seen between this display and the previous one.

It's possible, conceptually and practically, to make displays with different modes of operation. The One Per Child laptop took that to extremes, switching to a monochrome, reflective out from its backlit colour option, with a large drop in power consumption as a result. And the very first pocket calculators got usable battery life from tiny cells by very aggressive power management of their displays, alongside running their logic circuitry at near-starvation. Eating sparingly leads to a long life, in electronics as well as in biology.

It also feels like a bit of an abdication of Apple's fabled design nous, which has in the past been as evident internally as externally. The Bauhausian concept of form following function doesn't just mean eye-friendly minimalism, it asks for machines that match our life in every aspect of their operation. It also requires engineering genius of the sort that Apple has been proud to deploy before: while nobody would be impressed by a tablet that lapsed into a ZX81-compatible display in order to eke out the power, proper compromise is the very essence of making smart things.

We'll see how much of a burden the keeping and feeding of a new iPad will become. Most smartphone owners have become accustomed to spending rather more time than they'd like ensuring their devices are topped up, after all. But this is a compromise we users have to make, one that our gadgets should be making on our behalf.

It could well be that a short life in gay colour is preferable to more muted companionship with a less demanding partner. But at some point the addiction to status becomes self-defeating. Like the fabled white elephants that were kept in splendour, eating from gilded troughs in stables hung with priceless tapestries, there comes a point where you're better off keeping war horses instead.

Topics: Emerging Tech

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Editor, ZDNet UK. Ex technology/technical editor of ZDNet UK, IT Week, PC Magazine, Computer Life, Mac User, Alfa Systems, Amstrad, Sinclair. Micronet 800, Marconi Space and Defence Systems, and a dodgy TV repair shop in the back streets of Plymouth. Can still swap out a gassy PL509 with the best of 'em.Dear Reader - contact me via our m... Full Bio

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