Archive for the ‘Cellphones’ Category


Suggestions for Optimizing Battery Life in Mobile Devices

November 22, 2006

I found this article that I wrote for a local techie magazine a couple of years ago on mobile power and battery life. The devices are old, but the suggestions are still valid. Unfortunately, its a pretty long article. Happy reading…


Published in mPH Magazine – July 20, 2004
by Christopher H. Cheng

This month’s Primer was supposed to be on batteries for mobile devices. However, I have taken the liberty of stretching the original concept of this article to a topic that I believe is quite a bit more useful in daily life – Power. All mobile devices today are faced with a number of limitations, CPU speed, hard disk space, memory, video and sound quality, network connectivity, and others. However, the critical factor of battery life often remains overlooked by many mobile device buyers. This article will briefly discuss power or battery life as it relates to the individual’s purchasing decision for a new mobile device and will likewise talk about my experiences as a mobile user focusing on power conservation and things I’ve picked up over the years on the topic.

Life is Always a Balance

In general, the smarter a mobile device gets, the more important battery life fits into the buying decision. The important thing to know about mobile devices is that there is always a trade off somewhere – a flash memory based MP3 player will always have better battery life than a higher capacity, hard disk based iPod, a lower CPU and lighter OS based Palm or BlackBerry would generally have better battery life than a fast, powerful, but heavy OS based PocketPC, while a basic cellphone would almost always have better battery life than these hot, new, full featured smartphones. With notebooks, it’s a little different because the balancing act is made on two dimensions, size and power. In general, big notebooks with those 17 inch screens and 3 GHz processors may be really cool to look at and use, but due to the power requirements of driving such a high spec device, usually have less battery life. The thinking of the manufacturers is that these behemoths would generally not be very portable anyway. On the other hand, an ultraportable is very different. Computing power is often sacrificed for weight, form factor, battery life, heat dissipation capability, and size. Business notebooks (sometimes called “thin and light” models), on the other hand really balance out the manufacturers’ product offering.

So why is this bit of knowledge useful for purposes of this discussion? Simply put, the mobile device buyer should be aware of the features and limitations of the device he wishes to purchase to enable him to make an informed comparison and decision based on his intended use. When people think of buying their next mobile device, whether it is a mobile phone, a notebook, a PDA or PDA-Phone, or other similar devices, more often than not, the first things people check are CPU speed, memory, disk capacity, screen size and resolution, built-in cameras, Bluetooth, WIFI, physical appearance or style, and other similar features. Battery life is generally overlooked completely or would fall within the second or third tier of the purchase criteria. Again, while mobile devices are getting smarter and arguably more PC-like with every release, it is dangerous to base buying decisions of these devices on a PC based purchase-decision model, as there is one major difference between mobile devices and PCs: the mobile device user simply does not have access to something that a PC user would take for granted – immediate availability of a power outlet.

Therefore, the game of mobile power really starts by the buyer internalizing what exactly he wants to do with the mobile device and should base his product purchase from there. For instance, I have a desktop in the office but need a second computer for work. I am often mobile both here and abroad but would generally just use my notebook for presentations, demos, note talking, surfing, and email. I therefore switched to a Mac because it provided a balance of mobility, power, excellent battery life, a fresh, new user experience, while still keeping full compatibility to my windows based network. From a PDA-Phone perspective, I needed a device that I could use heavily for voice, SMS, and particularly corporate email. Again, battery life was pretty important because I am usually mobile (either in a meeting room in the building or outside the office) and a heavy cellphone user for both voice and data. I selected the Treo 600 as it had the qwerty keyboard for SMS and email, had basic PIM functionality I needed in an acceptable, but not exceptional, color screen, and had 6 hours of talktime which is excellent for a PDA-Phone device. Had a wanted to listen to MP3s, watched videos, take pictures, worked with email attachments, and have easy access to a power outlet, I would have probably chosen a PocketPC Phone. I am now using a BlackBerry device because my PDA-Cellphone use profile has not changed but the BlackBerry provides much better power management and the critical BlackBerry push email and OTA calendar sync provided by GlobeSolutions.

Bottom line is not just to study the products out there before you buy, but more importantly to determine exactly what you will use the device for and narrow down your search and compare mobile devices that fit your usage profile (now and in the near future). As a more extreme example, I carry a personal cellphone line as well, used simply to contact friends or family via voice and SMS. All I use is a Nokia 8310 for this and I have been satisfied for years.

Interesting devices I am looking at to fit my profile are the following:
SE K700i – I understand that battery life is not great but I will only use it for my extra line and connectivity for GPRS with my Mac.

PalmOne Treo 600 – The first usable PDA-Phone device in my book with excellent battery life, qwerty keyboard, available corporate email services from Globe, and decent screen. It has some support for multimedia which is unimportant for me.
BlackBerry 7230 – My current device of choice because of the excellent battery life, qwerty keyboard, premium corporate email and calendaring solution from Globe. A zero frills device with no support for video, no camera, etc., made for business.

IBM X31 / X40 – These are both ultraportables in size and weight with decent processing power. The X31 is a bit larger than the X40 but has a faster processor with something like 4 to 5 hours of available battery power. The X40, on the other hand, is smaller and lighter than the X31 but with slower processor and only 2.5 to 3 hours battery life on the standard, small battery but significantly longer, I think 6+ hours on the large battery.
Apple 12 inch Powerbook G4 – An all in one package with a fast processor, excellent graphics, great OS experience, and excellent battery life, while remaining lighter than the iBook. My current notebook of choice.


There are always a number of steps that can be taken to squeeze every ounce of power from your mobile devices, whether new or current. Being mobile quite often, I have picked up a few interesting tidbits and practices here and there to make the most of the precious battery life at my disposal:

1. Turn Those Radios Off! – Most mobile devices now come with either or both WIFI and Bluetooth built-in. Typically, users would leave either or both these features on due to ignorance of the implications of this or simply convenience of instant availability. It is important to note that keeping these radios on actually drains quite a bit of battery power as they are constantly searching for signal. A cool trick I learned from a fellow Mac user is to set different “Locations” corresponding to how I connect to different networks. For example, I have a Location for “Mobile – WLAN” that I use when I am in a WIFI hotspot, and one for “Office” which turns off WLAN but turns on my Ethernet port. Bluetooth is always off except when I intend to connect via GPRS, in which case I set my location to “Mobile – GPRS” and manually turn on Bluetooth. I actually notice the remaining uptime on the battery monitor increase or decrease depending on the mode I am in.
2. Eject Unused Peripherals – Techies know that powered peripherals without external adaptors like USB CD ROM Drives and PC Cards actually draw their power from the USB or PC Card slots themselves. While the device may not actually be in use, just keeping the device connected and powered on actually does consume power from the notebook. It is therefore a good idea to keep unnecessary peripherals disconnected, again without unduly hampering user experience. For instance, during my TabletPC days, I only connected my CD ROM drive when needed, and just for the period it was in use. On the other hand, I did have a Nokia D211 multi-mode GSM/GPRS/WIFI radio card permanently plugged into the notebook just because it was so convenient to just turn the software on and connect immediately. All in all a pretty good balance between usability versus effect on battery life.
3. Custom Configure Power Management – This is an absolutely critical step on all mobile devices and ranks as the second most important thing I do whenever I get a new or reformatted device (the most important for me being configuration of network/connectivity settings). I just noticed that default power options presented just could never just match my usage habits and battery requirements. I therefore adjust everything with careful attention to the screen (both brightness and being on or off), and for notebooks hard disk access and CPU power. As a guide, I always set my “on battery” settings such that I get minimum acceptable screen brightness (which I further adjust while using depending on ambient light), backlight shutoff of about 1 minute or less for PDA/PDA-Phones and cellphones, and screen blackout of about 3 minutes for notebooks and PDA/PDA-Phones. In addition, I set my hard disk on my notebook to turn off as often as practicable as a spinning hard drive is a real battery hog. I even had a notebook once that went as far as to allow me to set variable CPU speed, screen brightness, and hard disk speed depending on the battery level, i.e., 80% to 100% battery would allow the CPU to run at 100% speed but 20% battery power would only allow the CPU to run at 30% speed.
4. Be Battery Aware – Being a “battery aware” mobile user really means a whole lot of things:
a. Turn off unused applications – You may not notice it, but applications running in the background actually use up CPU cycles periodically. Turning off these applications, aside from making your computer a bit faster by freeing up more RAM, will reduce CPU load, which should marginally increase battery life.
b. Manage sound and vibration modes – Sound can really eat up your battery, especially when at loud volumes for ringtones and especially speakerphone mode. I normally fully configure sound for each device not just for battery purposes but also to lessen irritation from a noisy device. On a Windows PC, in particular, the startup and shutdown sounds are a large battery drain. Depending on the device, turning on vibrate mode is also a large battery drain.
c. Go to sleep – For notebooks, sleep mode offers a great way to increase battery life. Note that the startup process for a notebook is a huge battery drain because the CPU and hard disk is running at full speed. Sleep mode will avoid this while making startup time quite quick. I noticed that some platforms actually manage this better than others.
d. Avoid unnecessary multimedia usage – This is important for all devices but in particular for PDA-Phones and color cellphones. While it is tempting to watch music videos, dvds, porn, or streaming audio or video on your device, note that video and sound also significantly shorten battery life. The worst thing you can have while out of the office all day is a PDA-Phone with no battery, or what the people in Mapalad fondly call a “paperweight”.
5. Charge When You Can – No need to talk about this in great detail, but suffice it to say that batteries of today are nothing like the Ni Cd batteries of old where a full drain is necessary to avoid the “memory effect”. Charging can be done at any time, subject to what your device instruction manual says about battery calibration, periodic conditioning, or other similar items.

Power Peripherals

Regardless of how much a battery is optimized, the user will inevitably need charge the device. Since I carry quite a number of mobile devices (notebook, personal cellphone, work issued PDA-Phone, iPod) the cables and power adaptors would probably add up in weight quite significantly. To keep myself traveling light, I have tried to move as much as possible into USB based charging devices. For example, I have two Brando retractable cables in my notebook bag, one for my iPod and one for my T68i (which I use to connect the notebook via GPRS). I also have a USB to cigarette lighter adaptor in the car and a USB to AC power adaptor which I leave in my room so I can plug into my notebook while mobile, but can just plug into the car or AC if available.

On my to do list from a power management perspective is to try out these mobile power inverters that are available in the market. There are generally two flavors, one for car power and another for airplane in-seat power. The car power inverter is more relevant to me as I rarely get to sit in an airline seat with in-seat power. I heard that these inverters sometimes break the battery of the device, so I will tread carefully, but this should be an interesting proposition for the true road warrior.


Treo 650 User Review

January 27, 2005

I have been using the Treo 650 on and off for quite a while now, but
have seriously started using the device for the past few days.
Following are my impressions:

1. Excellent Screen! The screen of this device is the best I have ever
seen on a PDA-Phone, hands down. If you put the 650 beside the 600, the
600 looks, well, just kawawa! It is very bright and the resolution is
excellent! The best way to demonstrate this, however, is using the
camera. Unlike the 600, the 650 display in camera mode is extremely
sharp. Both devices have the same camera resolution so it is definitely
the screen that significantly enchnces the image.

2. The 650 is an EDGE device, and using Blazer you can really notice
the speed increase. Downloads are quick, and there is really nothing
like looking at the top portion of the screen while downloading the
page and watching the kb meter just zoom along. Watch out for your GPRS
bills! The screen resolution further enhances the image and makes
browsing a plain joy.

3. Keyboard layout and key size have improved significantly. While the
keys are still a tad cramped, the layout and the actual shape of the
keys make it much easier to type. In the 600, I had the problem of my
thumbs starting to get sore because of the size and shape of the keys.
No such issue with the 650. The white translucent keys are also great
since it is easier to work with especially at night.

4. Bluetooth is pretty good. I paired it with my Bluespoon AX (which I
reviewed in and it was quick, painless, and works
great. Audio is loud and clear. Unlike my BlackBerry 7290, the
Bluetooth connection to the headset terminates after some period of
inactivity so I can actually use both the 650 and my K700i on one
headset quite seamlessly. Its good for battery life of the headset too.

5. The OS was pretty snappy and seemed al lot quicker and more
responsive than the 600 as well. I havent used a Palm in a while so I
dont quite know if there were a lot of application level enhancements
but usability is pretty good.

6. As in the 600, the 650 makes one handed operation quick and easy.
Unlike the 600, the 650’s keyboard makes one handed texting much easier
as well.

7. Battery life is pretty comparable to the 600, which is pretty good
already. There may have been an improvement in battery life but I am
not quite sure.

8. I havent used the later Palms so I dont know if this is now an old
feature, but the Palm Desktop seemed to have gone through a rehash. It
looks much better now, particularly for installing new apps. You can
also install apps directly to an SD card. PocketMirror was also
integrated better so there is no need to setup that third party app to
sync to outlook.

9. I dont know how to sync a Palm to my Mac. I was able to
successfully pair the 650 with my Powerbook but when I fired up iSync,
I couldnt really do anything. However, that was a pre-production ROM so
I dont really know.

10. The handset is similar in weight to the 600 and, in my view, is
just a bit too heavy for comfort. But is generally acceptable.

11. My office PC doesnt have Bluetooth so I couldnt try out Bluetooth
hotsync. But there is a wizard on the device to set it up.

12. The 650 comes with a cool anodized aluminum looking stylus, which
looks and feels really cool. However, I hardly get to use it because of
the great one-handed usability.

13. Voice quality was great. No more buzzing and other related sounds
found on the 600. Speaker phone seemed to be a limitation, because it
almost seemed to sound like it was half duplex! But I havent tested
this on the new ROM since I use my Bluespoon AX with it all the time.

14. Dock connector is now totally different from the old 600. Charger
connector is also totally different.

Overall Rating: Highly Recommended bordering on Must Have!