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Modern electronics and battery life (or the lack thereof)

Juni 18, 2007

I’m pretty amazed at the latest gadgets coming out from the R&D departments of consumer electronics companies, such as Nokia and Apple – the N95 is a super-duper, do-it-all, cellphone (sorry, Nokia wants us to call it a ‘multimedia computer’), featuring multiple bands, HSDPA 3G (Europe only), WiFi, GPS, and a 5Mpixel camera, apart from a wide array of software tools for blogging, posting pictures online, navigation and more. What price does this device pay? A meager 950mAh battery, which lasts less than a day under normal use, considering ‘normal’ as actually using the functionality it offers. I guess you can get more if you turn off the GPS, WiFi, don’t use the camera, and make almost no calls…but then what good are all the bells & whistles for?

The iPhone case is even more interesting, as the device has not been released yet, but Apple has already reported an increase in battery life with respect to the initial quoted value. The iPhone will have 8 hours of talk time, and some 250 hours of standby time, with 5 hours of video and 24 hours of audio playback. Apple’s stock has jumped $3 since the announcement, something that will make losers in the fake email crash happy.

Let’s try to make a simple breakdown of power consumptions, and see if manufacturers are being overly optimistic.

WiFi

One of the biggest power drains, as there is no built-in power management into the WiFi protocol, contrary to GSM and 3G. When transmitting over GSM, a phone makes calculations from data received from the network and its own measurements in order to adjust RF power to the minimum required to reach the cell’s base station. Thus, in areas of good coverage, a phone can be consuming far less power than in rural areas with more spotty coverage. While on a 3G network, the rate of adjustment is even higher. WiFi chipsets in mobile phones have basically two settings, “high” and “low”. Most times, unless you are sitting right next to the access point, and without any major interference, the setting the phone will use is “high”.

Assuming that the WiFi chipset used by the Nokia N95 and the iPhone use little power, for example, by fitting the Nanoradio solution, the power consumption would stand at 130mA in transmit mode, 53mA in receive mode, and 50uA in standby mode. Assuming we are receiving 80% of the time, for example, by browsing the web, the average consumption would stand at around 68mAh. The N95’s battery would last 13 hours, if it had to power the WiFi chipset alone.

GPS

Even though GPS technology has advanced a lot since the early days, GPS chipsets can draw upwards of 80mA. Special trickle-power configurations (which also impact performance) can reduce this to 50mA or so. Thus, the N95’s battery could power the GPS for around 19 hours.

Processor

The Nokia N95 features an ARM11-based Texas Instruments OMAP2420 running at 330MHz, featuring 2D/3D video acceleration on top of whopping performance. What does this mean in electrical power terms? Even though this processor features SmartReflex technology, which reduces static leak currents (a good technical overview is available here [pdf]), the net current drawn is around 30mA. The N95 battery could power the main processor for around 32 hours.

Display

The display on the N95 is very good, beautiful, 16M colors, 240×320 pixel resolution. It is also power hungry, taking around 30mA, thus, the battery could also power the display for around 32 hours.

Phone

Assuming that you talk 5% of the time on the phone, the average power consumption by the phone subsytem alone would stand around 20mA, resulting in a battery life of 47 hours.

Adding things up

So far, we have seen how much the battery could keep running each individual system on the phone, but adding things up, we have a power consumption of about 100mA (taking into account that we are not using everything at once, I halved the figures). This results in around 9.5 hours of operation, more or less an average day. This ties in with most users’ experiences, as shown in many reviews done so far on the N95.

The iPhone, being much thinner, wider and taller than the N95, probably won’t have that much larger battery capacity – why does Apple give the figures they do, I can only blame on the marketing department. This is not as uncommon as it seems, R&D provides a set of carefully calculated and actually measured results, then the marketing guys take them and multiply them by two. Anyone who has used a modern, high-end phone or PDA, will attest to the fact that quoted battery life figures differ from reality by far. I don’t know of many companies that can raise their stock $3 by simply increasing the value of the battery life in one of their products – this shows how much hype there is around the iPhone (of which I’ll most definitely get one…they are soooo sexy!).

The weirdest MacBook Pro problem so far

April 17, 2007

Almost a year since I got a 17″ MacBook Pro, not one of the earlier problem-prone models, so it should have worked out better – half way through the year though, a series of darker spots, like soot smudges, started appearing on various places of the screen. I am waiting for parts to arrive before taking it in and have it fixed, otherwise you can be laptop-less for days or weeks, and now the machine has developed a new symptom. After resuming from sleep, the display is all corrupted, with top third of the display one solid color, and the bottom two thirds another, plus an annoying flicker. If I close the lid, flip it upside down, and open the lid again, the display goes back to normal. The problem can be consistently reproduced, but I really cannot imagine what combination of electrical and/or software problems are causing this.

Why the Apple iPhone may not fail

Dezember 23, 2006

Reading an article in The Register by Bill Ray, he thinks the Apple iPhone will fail, actually, fail badly. I somewhat doubt his conclusions.

The main argument to support his analysis is that since network operators have to like the phone, then Apple has to do a good job convincing them. Remember the ROKR? It was rather a failure due to the fact it could only be loaded with iTunes music over cable, and thus mobile operators were left out of attractive data chargers levied when buying music directly from the phone. There was even speculation that Apple allowed it to launch on purpose, to protect their audio player market.
Where Bill goes wrong in my opinion is that the handset market is heavily controlled in the US, but not in Europe – go to any shop in the latter and you will have a very large variety of handsets to buy unsubsidized. Why? Because a lot of people value the ability to switch operators as they see fit, without having to enter into contracts involving their soul. In the US, there isn’t a culture of operator hopping, but rather of staying with one just to get a phone $50 or $100 cheaper.

One thing I have never understood is why people get themselves tied into a two year contract for a $50 saving. If they worked out how much they could save by moving operators taking advantage of special offers, they may think twice.

There is a very large number of paths Apple could follow, first, they have a nice distribution network with excellent shops placed in key areas, second, they have a large and loyal crowd of followers, who would probably not mind paying an unsubsidized device, and third, there are already a number of MVNOs and fixed-line operators that are willing to take a bite from the large networks. As for the subsidy, I wonder…are iPods subsidized by anyone? Apple costumers are used to pay for quality, and in my view, the iPhone will be no different.

Vodafone HSDPA with the Huawei E220 USB modem

November 22, 2006

Went to my local Vodafone store to pick up the new Huawei E220 HSDPA USB modem, which with a 49 Euro monthly contract gives you 1GB of transfer at 1Mbps maximum, and free mobile to fixed landline calls – pretty good deal if you ask me. For 59 Euro you get 5GB of transfer, at the full 3.8Mbps that HSDPA offers. These are theoretical rates, as they will depend on a number of factors, such as how many people are also using the same cell, your coverage and the quality of the link.
We can argue all we want about how convenient WiFi is, being omnipresent et al, but in reality, it’s rather hard to get connected while on the road. Let’s examine the following scenarios, and you tell me the chances of getting connected over WiFi:

  • Riding the train or bus home.
  • Getting a lift from a friend in his/her car.
  • Opening your laptop at a random location (cafeteria, bar, etc. that you haven’t before scouted for open WiFi).
  • On a plane, waiting for the next free takeoff slot that you hope the pilot won’t miss because he was checking the fatness of his wallet.

Let’s be honest – free open WiFi is great once you have identified the locations where you can get connected, such as a friend’s house or the local coffee shop. Other solid commercial alternatives make it easier to find WiFi, as they tend to be present at well-known locations. Walk into any Starbucks or hotel, and you’re bound to find at least for-pay wireless.
For me, on the 30 minutes to 1 hour it takes to get home on the train or bus, being able to get connected is great. The convenience of simply opening the Mac and getting online beats the guesswork of WiFi. I tried getting the Mac working with my Nokia N93 over Bluetooth, but it was just too unstable – one day it worked, the next simply refused to even connect. A more in-depth review of the device is coming, once I get a chance to roam about with it for a while.

So far, installation on the Mac was pretty straightforward, download the setup package from Vodafone’s site (they don’t tell you this in the manual), which then enables the modem as a networking device. If you don’t follow this step, it can get recognized as a storage device, which is not particularly useful for a modem. The one thing I don’t understand is why it comes with a miniUSB cable that ends in two USB connectors, my guess is it’s power-related (some USB ports don’t provide the full 500mA they are supposed to provide).

So Macs cannot cut and paste files, either…

September 10, 2006

Bother of the day. For the two months I have been using my MacBook Pro, I hadn’t really looked into this one, but today was when it became “peeve of the day”. You cannot cut and paste a file in Finder. And Apple’s decision is final.

How can they honestly ask Windows users to switch, when extremely basic features that have been in Windows at least since 95 (I believe in 3.1 too, but cannot confirm this) are simply not there. In this thread at macrumors.com some explanations are “this is not present in order to prevent lost files”, and “what if you forget to paste?  the file is gone” – if this had ever been a problem in Windows, do you think it would not have been fixed? In Windows, if you “forget” to paste a file you have cut, it is never deleted. It never goes to the trash without passing Go and collecting $100. It just sits there, until the OS decides you have indeed forgotten to paste it.

Whatever you do next, Steve, get yourself a copy of Windows XP and copy all the features people find normal, before you ask them to switch. Oh, and I still love the Mac.

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