NEWS: iPad Study: The More You Know, The Less You Want One

No clue on the iPhone. However a new iPod Touch battery was fairly close to Apples claims. There are huge variabilities in how people use these things. I know one sales personality that is yacking on his iPhone constantly. He complains that the battery won't make it through an 8 hr day (plus his commute). I'm not surprised. Others mention that they charge theirs every 2-3 days. There are various apps that can predict battery life based on past usage. I have one and it's fairly accurate.

We also have a unique problem in my area. Coverage from all the providers in the San Lorenzo Valley is spotty. If you spend some time in places where there's no coverage, the stupid phone will "hunt" for a suitable cell site. This runs down the battery. I'm sure it happens with Verizon (because that's what I use), but apparently, it's also a GSM problem. Without a cell site to keep the phone inactive, my battery is dead in about 4 hours without ever having made a call.

Nope. It's way more complexicated than that. Deterioration is heavily dependent on temperature and state of charge:

Plenty of others available. Google for "Li-Ion battery capacity fade" or capacity loss, deterioration, etc.

Ahem... Isidor Buchmann is the founder and prez of Cadex, a manuafacturer of battery chargers and analyzers. I have one of their chargers and it's excellent. He's the author of a book on the subject which is generally recognized as authoritative:

Incidentally, I have a West Mountain Radio CBA-II battery analyzer:

I've found that battery capacity varies considerably from vendor to vendor. Some barely achieve the labelled specifications. Others exceed the specs by as much as 75%. Many vary dramatically in capacity depending on discharge rate. Never mind user variability, there's also large variations in capacity.

One catch. I can't reliabily test the larger laptop batteries. The CBA-II is limited to about 100 watts discharge rate, which is about what one of the older wide screen "desktop replacement" laptops burn.

There are several commercial battery life test suits available. In all cases, the laptop initial conditions and test applications are carefully defined so that the comparisons are valid. For example:

There are others, but I'm late for lunch. Not everyone is happy with the defacto testing methodology:

I run my laptops at maximum CPU, maximum brightness, and everything I can possibly disable. I want speed, brightness, ease of use, and convenience. I fry a laptop battery about every 3 years, which is about typical.

What I *DON'T* do is leave the laptop on charge 24x7 cooking the battery inside the laptop. After about 3 years, the battery has become sufficiently common that the eBay prices are about $50 or 1/3 of the cost of an OEM battery. I also have a small collection of nearly dead batteries, which are good baking when used with the charger running.

Meanwhile, at the alt.internet.wireless Job Justification Hearings, Jeff Liebermann chose the tried and tested strategy of:

They bought the developer of a Unix printing framework called CUPS, so that sounds like the obvious choice.

On Wed, 10 Feb 2010 13:08:09 -0800, Jeff Liebermann wrote in :

It's much more a problem on older phones than on newer phones, which attempt to check in much less often. My GSM/UMTS Sony Ericsson TM506, for example, suffers very little extra battery drain when I'm out of coverage.

Been there; done that; stand by what I wrote. Check out Apple's page on battery life.

Who has an axe to grind, and isn't a battery engineer -- totally different science. Again, I stand by what I wrote -- he's at odds with real battery experts on some of his claims.

I've measured literally dozens of notebook computer batteries, and all were close to their rated capacity. Relatively current ThinkPads report both design capacity and current capacity in Wh, which is easily tested.

They try to, but I have intimate knowledge of the testing at two magazines, and it's anything but carefully controlled -- they don't have the budget or expertise.

I usually run mine with the CPU on Adaptive, which works wonderfully well to provide maximum CPU power when needed but otherwise throttle it back to save power and heat, which is nice even when running on mains power, and even the slowest speed of the 64-bit dual core processor is more than snappy enough for most tasks. (The effect of Adaptive on CPU-intensive tasks like video rendering is immaterial.) I likewise dim the screen down a couple of notches because otherwise it's just too damn bright, and I put other parts of the system to sleep when ther're not being used.

I do, because of convenience, and because it has no effect on battery life -- ThinkPad power management is excellent.

Some are good, but others are crap, and figuring out which is which is non-trivial, so I now usually stick with OEM batteries.

I remember being very surprised that the Apple store could get away with not printing receipts when I purchased something, saying they'd email it. Without any way of knowing if they'd entered my email correctly (they did).

Doesn't matter for how we'd use an iPad anyway. I thought I'd mentioned that we'd be using them as nothing more than remote terminals. Printing would be handled by the host computer.

--Mike Jacoubowsky Chain Reaction Bicycles