When it comes to portable devices, their usefulness boils down to just a few little things: ease of use, expandability, and battery life. This last one is especially important if you intend to use the little machine more than the average person.
In the case of my HP iPaq 211, I use the little computer for just over four hours a day, every day. On a particularly slow day at work, I can easily use the digital assistant for more than 6 hours. Suffice to say, this makes battery life a primary concern whenever I’m walking out the door of my apartment. The first question that runs through my mind, right after confirming that the computer is in my pocket, is “how full is the battery?” followed immediately by “did I download my RSS feeds and email?”
For the last few months, I’ve been fortunate enough to get approximately five and a half hours of life from the battery if I’m using it mainly in Word, Excel, Egress, email, and Embink. If I’m watching the latest episode of Daily Show, Colbert Report, or something else that was re-encoded for the limits of the handheld PC, then I can expect to get just over four hours of operation. I had thought this was all I could expect from the standard factory battery but, thanks to a relatively new update on HP’s software site, I can get another hour or two out of the existing hardware.
A Welcome Software Update
HP released an update to their iPaq power management software this past May to resolve two rather important issues. The first is the ability to insert an extended capacity battery and actually charge it to 100% (which was something that wasn’t possible before this update), and the second is to get the most out of the factory slim battery.  While getting a 100% charge on extended batteries is certainly important (it would be had I dropped the extra coin on such a battery), I don’t have easy access to one of these to test just how well the software update resolves the issue. That said, I do have a factory battery installed which I know has an average lifespan of five hours.
The result? Seven hours of simple usage, five with WiFi on and active, and five when watching DivX movies.
Not bad, if I say so myself. This free software update just extended the life of my battery by upwards of 90 minutes.
Watch Out For Your Storage
Before I go too much farther, I should mention that there is a known issue regarding the use of SecureDigital and CompactFlash cards that do not support “Power Down Mode”. While it’s not a huge issue, it’s certainly something you’ll want to keep in mind if you want to squeeze every bit of power out of your battery in actual usage, rather than idle power drain.
No-name brand SD and CF cards have been known to drain anywhere from 8-15% of battery power during a six-hour off-period. There have been lots of forums reporting this issue all over the web, and I’ve noticed it myself when I’m just too busy to use the PDA during one of my rare full-day rushes. I use a 2 GB Patriot SD card and often find a 12% power drop between the hours of 12:30 PM and 9:30 PM if I do not use the machine. The PDA is not set to automatically come on during this time and, unless I foolishly have the WiFi or Bluetooth module activated when the unit is shut off, it will not wake itself up for any reason.
Since I’m not one to just accept a 12% power loss while the iPaq sits quietly in my pocket, I did a little research and found that if every program is completely shut down before getting down to work, I will lose about 9% of power rather than the 12% I had been accustomed to seeing. Considering how the only data stored on the SD card is a backup of my current on-device data, a few videos, a few dozen mp3’s, and about 200 eBooks, this surprised me. What could be causing a 9% power drain if only 3% is consumed by active programs that may not necessarily read data off the SD card?
Taking it a little further, I decided to remove the SD card before starting my day at work and ensure that all applications were shut down. Being the geek that I am, I had cut out a place in my Compact Flash plug big enough to hold two SD cards should the need arise. I have no CompactFlash devices anymore, and I often carry two SD cards. One has PDA-specific data, while the other has … umm … data that I’m not likely to share. So, after 9 hours of zero usage and no flash cards being installed, how much battery did I lose?
Negative two percent. Yep. I went from 83% to 85% in 9 hours while it was off.
Clearly this is due to several factors. Because the device wasn’t on for so long, it was able to cool off in the chilly 25 degree office. On top of this, I had been using the machine for over an hour before shutting it down. This would have caused quite a bit of power drain and may have led to a slightly pessimistic power read by the software at 12:30. Either way, the message is clear: my SD cards do not support low power modes, or shut down when instructed.
But Wait, There’s More
To make things just a little more interesting, I decided to install one of my really old SanDisk 256 MB SD cards to fully test out whether this power drain was the fault of non-power-downable flash memory. This particular card was purchased with my Palm m505 back in 2002, and currently occupies the “back up memory” position for my digital camera (also known as in-the-case-and-behind-the-batteries-just-incase-I-take-so-many-pictures-that-I-fill-every-SD-card-I-carry). How much power did this ancient card drain during a 9 hour off-cycle while sitting patiently in my shirt pocket?
Zero percent. The system showed 86% that day at 12:30, and showed 86% again at 9:30 when I finally got on the train home.
Interesting….
The good news is that the power drain is much less of a concern with the updated power management software made available by HP, but it’s still something less desirable than I’d like to see. Perhaps I’ll consider getting one of the recommended SD cards on HP’s site but, for the moment, I don’t think my piddly internet earnings could buy me an SD card at any of the local retailers here in Japan. Despite the massive price drops all over the world, flash is still priced at 2002 prices in this country.
Have you noticed any power drains with your portable device? Any ideas to the root cause?