At work every Monday, we have an editorial meeting at work where we discuss the current queue of articles, what’s going on in the news, and assorted other topics.

A frequent topic of conversation  recently has been around the strength of iPad sales and how Android tablets can’t seem to make a dent, and how Windows tablets that really try to draw on the strengths of touch are not really hitting any home runs.

For a long time, one peer has highlighted the lack of strong battery life and the ability to deliver truly thin and light Windows tablets as one contributor to the weak sales of Windows tablets (the same holds true of Android, too). Sure, there are many other subtle and not-so-subtle reasons why the iPad is leading the touch-based tablet charge by a longshot, but battery life is a huge problem to tablets attempting to attack, and hopefully unseat, the iPad from it’s sales throne. If you look at tablets other than the iPad, those touting low weight nearing the iPad do it by delivering mediocre battery life, and conversely those that promise respectable battery life do so by the system either being significantly heavier or by only delivering that battery life with a “battery slice” or other external battery unit that adds weight and thickness to the device, which also hampers the real-world usability of the device.

During Monday’s meeting, another peer threw out a comment to the tune of, “if only there was some measure of hours of use per pound”. It was a really insightful comment. The iPad is one of the lightest tablets in existence. It’s also got some of the best battery life.

So I started thinking ab out how you could fairly break this down so that the result can’t be gamed by just throwing in more battery. Initially I just divided hours of duration by weight in pounds. But this can be gamed by delivering long battery life with significant weight. I noticed that the Sony Vaio Z, a competitor of the MacBook Air wound up with a good result because it delivers good run-time, but does it by weighing almost twice as much as a MacBook Air (2.5 lbs vs. 1.33 lbs). So I realized if you divide it again by the weight, you get a good result that truly indicates the role that weight plays in delivering that run-time. So my formula for HPP is:

 HPP = (hours of battery life/weight in lbs)/weight in lbs 

So what’s interesting is that if you take a look at “hours per pound” using this formula, I think it’s a pretty interesting result.

	iPad 2	eee Pad Transformer	Galaxy Tab 10.1	TouchPad	IdeaPad P1	eee Slate 121
Weight	1.33	1.6	1.6	1.5	1.8	2.6
Time	10	10	8	5.5	6	4.5
Display	9.7	10.1	9.7	10.1	10.1	12.1
Price	$499	$499	$449	$379	$599	$1,099
HPP	5.65	3.90	3.13	2.44	1.85	0.67

Note the iPad’s HPP of 5.65. This is based upon the iPad’s touted number of 10 hours – but even if you downgrade it to the 8 or 9 hours most report when using the device it still yields a 4.52. Only the eee Pad Transformer and new Galaxy Tab 10.1 even approach it.

The higher the HPP, generally the better indication of how a system emphasizes battery life in concert with weight. Systems that add weight to gain battery life and systems that compromise battery life to save weight will stand out quite well against systems such as the iPad and new Galaxy Tab 10.1, by having lower HPP numbers.

It’s possible that the idea of HPP isn’t as valid as it first appears – but at first glance it seems highly applicable. Thoughts?

I posted earlier today on Twitter that it is becoming increasingly important for tablets to have fairly assessed battery life; something that is reflective of real-world use, some mix of streaming video, gaming, web browsing, email, and GPS (and other processor intensive uses). When I worked in compression, the Canterbury Corpus served as an interesting way to test how well a given compression routine worked. Though perhaps not entirely reliable anymore, it enabled an apples to apples comparison of compression algorithms. I would like to see something like this, or something like the TPC, that truly lets consumers know what they can expect out of their tablet device as far as run-time. Truly calculating a fair HPP depends on a fair battery life number being understood in a way that can be assessed across devices. Too many tech manufacturers over-claim battery life – and using HPP requires some level of understanding how far off manufacturer claims are from real-world expectations of device battery life.