Is iPhone Battery Usefulness On the Decline? 222
jfruh writes "Every time a company rolls out a new version of a product, it extols how much better it is than the previous version. Thus, Apple spent a part of its iPhone 5 rollout touting the staying power of the latest version of its battery. But have iPhone batteries really seen improvement since the original came out in '07? Kevin Purdy crunches the numbers and concludes that, while the 5's battery beats the 4S's, we still haven't returned to the capabilities of the original phone."
Apple pretty accurate on battery estimates (Score:5, Informative)
It remains to be seen if the iPhone 5 can really pull off 8 hours of LTE browsing
Yes, but remember that in every device Apple has shipped (from laptops to iPhones to iPads) the battery life estimates have been pretty much spot on.
as that would be impressive (blow through your data cap on a single charge)
Browsing is not watching media only. Browsing is loading pages, reading them, moving on and reading more. It's not about constant data streaming, so it's not overall something that will destroy your bandwidth - you can only read so much in eight hours!
Yes you could blow through bandwidth fast if you sat watching extremely high quality video for hours on end. But that is why mobile app developers are not giving you those really beefy data streams, instead over even LTE you'll get reduced quality video from most things unless you force the issue.
Re:Oh, the milliamp-hours! (Score:5, Informative)
Actually, simple hydraulics and electronics have natural analogies [gsu.edu], in that similar equations can be used for both. Milliamp-hours is a unit of charge, 1 mAh == 3.6 coloumbs, or about the charge in 3.73e-05 moles worth of electrons, so yes, it would be accurate to say that mAh can be analogised to the volume of a tank of petrol, as charge would be the equivalent of fluid volume in hydraulics. However, voltage, being in units of energy per unit charge (a volt is 1 joule per coloumb), is more like fluid pressure in hydraulics (joules per cubic metre or pascals), or at how much pressure the fuel is being sent out the gas tank, so the article is completely wrong on that score. The "amount of fuel the device is drawing" is more like current, which is measured in amperes (coloumbs per second), which would be the equivalent of flow rate in hydraulics (cubic metres per second). Thus, if you had a battery rated at 1500 mAh used on a device that drew 100 mA of current from it on use, you'd be able to use it for about 15 hours before you needed to recharge the batteries. In a similar way, if you had a tank with a volume of 1500 cubic metres and were pumping liquid out at 100 cubic metres per hour, you'd need to refill it after 15 hours.
Re:False Comparison (Score:5, Informative)
In other words, nothing is known.
Re:Oh, the milliamp-hours! (Score:4, Informative)
The kilowatt hour, or kilowatt-hour, (symbol kWh, kW h or kWh) is a unit of energy [wikipedia.org]
Re:False Comparison (Score:5, Informative)
Sure there is. General>Network and top of the page is enable/disable 3G
Re:False Comparison (Score:4, Informative)
You can turn off 3G/4G data in the settings if you want to match.
Actually for many, you can't. Carriers can disable the 3G toggle on the iPhone 4S. AT&T does so.
http://www.idownloadblog.com/2012/03/09/ios-51-brings-3g-toggle/ [idownloadblog.com]
Re:False Comparison (Score:5, Informative)
This is both carrier and iOS version-specific. I believe iOS 5.0 and 5.0.1 did not have the option at all, while 5.1 restored it, but not on some networks, including AT&T. (I have a 4S with iOS 5.1.1 on AT&T, and can confirm that there is no option to disable 3G in the Network settings.)
Re:False Comparison (Score:5, Informative)
I see the option on iOS 5.1.1 on Fido (Rogers).
Re:False Comparison (Score:5, Informative)
For some, it makes sense. Bell, for example, has no GSM network; they migrated from CDMA (EVDO) to HSPA+. Disabling 3G on a Bell iPhone would simply cut all connectivity.
Re:Oh, the milliamp-hours! (Score:5, Informative)
The whole article is fluff link bait. It's a blog post on someone's opinion spread over three pages (2.25 actually, 5 sentences on the last page) to increase ad revenue.
I cringed at that notion as well and it was misinterpreted from it's source by a dipwit that claimed to do research at the outset of the article but simply Google'd some links together that are basic speculation and rumors.
There were no tests done, there were no graphics, not even a source for the technical data (not that the author would be able to interpret it correctly). Also, mixing the 3G and 2G capabilities and not understanding or explaining the difference and which one would be used at any point in time. Also, the iPhone's don't have Li-Ion batteries, they have Li-Polymer, a huge difference.
From the sparse sources claimed and misinterpreted in this article I can see:
On 2G:
iPhone - 8h talk time, 250h standby
iPhone 3G - 10h talk time, 300h standby
iPhone 3GS - 12h talk time, 300h standby
iPhone 4 - 14h talk time, 300h standby
On 3G:
iPhone - non-existent (but we'll take 8 as the base)
iPhone 3G - ~8h talk time
iPhone 3GS - ~8h talk time
iPhone 4 - 7h talk time
iPhone 4S - 8h talk time
iPhone 5 - 8h talk time
Has the battery decreased? Not really. Give or take a few given the circumstances (signal strength etc.) but probably not noticeable.
Have the features and speed increased? Yes.
When does your phone (any, not just limited to iPhone) use 3G vs 2G: It depends. The cell phone operator (or more accurately the tower) makes that decision based on the capabilities of your phone, availability of the spectrum and congestion. Which is better: 3G. Why: less congestion and more bandwidth. Why does it use more power: better voice quality, different frequencies and also continues receiving other data (e-mail and such) in the background.
There, I re-wrote the article probably much better from a technical viewpoint and it fits in a Slashdot comment.
Re:False Comparison (Score:2, Informative)
Apple from a profit standpoint would much rather have a big cheap battery than the incredibly expensive light thin batteries they have. Heck they would rather sell the phone hooked up to a car battery and give you 1000 hrs talk time. Light and thin is costing them money, this isn't about penny pinching.
That serves them right for twatting on about how fucking thin and light their products are, when it actually makes zero practical difference to most people if their phone is a few millimetres thicker and a few grammes heavier.
Re:More power for the same battery life is Good (Score:5, Informative)
Probably not. In some situations, LTE can actually use less power than 3G. Mine, for example. I got all-day-plus performance on my Galaxy Nexus (with the 2100mAhr battery) at my old office. That was in Philadelphia, in a very old stone building... very good 4G signal, in fact, much better in-building than 3G ever was (most of the cells in the city are going to use 1900MHz on Verizon, for the increased bandwidth, which gets more attenuation through old stone walls than the 700MHz used for LTE).
These days, I'm in an office in Downingtown, PA, in a pretty fringy 3G area. Same phone won't last a work day on standby without sitting on a charger when not in use.
Going forward, LTE will eventually save power over any form of 3G. Right now, not necessarily -- the digital protocols still take more power than either sort of 3G, but that's going to vanish as chips shrink. What you can't shrink is the need for the power amplifier (PA). Most phones want to be able to put out a signal of at least 1/2W (27dBm). The typical OFDM modulation schemes used in 3G, however, basically sum a large number of independent carriers (subcarriers) to deliver the full signal. When things line up unfortunately, you have too many signals summing high, creating a temporary power "crest".. this is known as the crest factor of a modulation scheme. For 3G as a class, this is a 6-10dB crest factor (also sometimes expressed as a PAPR -- Peak to Average Power Ratio). This means that the PA actually has to be able to support no just 27dB signals, but 37dB signals... a peak of 5W. Now, certainly, your phone isn't constantly transmitting 5W. But the PA has to be able to transmit at 5W without crushing the signal. That means the PA is going to be much less efficient than it could be at 1/2W.
Now to LTE.. the new SC-FDMA uplink modulation, presents only a single carrier on transmission, greatly reducing the PAPR/crest factor. Basically, it's a conventional OFDM modulation fed into a fourier transform, which has the effect of averaging out the high peaks. This can deliver 64QAM with a crest factor under 5dB. So you'd need an amplifier peaking at about 1.5W, rather than 5W, for the same uplink in 4G LTE vs. 3G HSPA. That's a huge win for the handset.