New power consumption tests (Dell x51v, HP hx4700, PLoox720,HTC Universal and Wizard)
I’ve constantly been receiving requests (see for example this thread) to publish more and more power consumption measurements of current Pocket PC devices. Here you are :)
First, please read at least this article (if you haven’t already done so) to understand what this article is all about. I also highly recommend the other articles I’ve linked in from the Recommended links section.
HTC Wizard (a.k.a. imate K-Jam, T-Mobile MDA Vario, Qtek 9100, MDA Vario, XDA mini S, SPV M3000, VPA Compact II, Dopod 838) radio power consumption
As promised, I’ve run some long-lasting tests to find out more about the power consumption of the radio unit itself. It’s about 7.5% a day (I’ve measured it for two days; not counting in the ~2.5%/day battery life depletion needed to refresh the dynamic RAM memory) in inactive (no SIM is inserted but the radio is online and is ready to initiate emergency calls) mode. Again and again, these figures, along with the ~9% (there, not counting in the ~2%/day RAM refreshing-related depletion either) of Universal, are relative (show how the power consumption of these devices’ radio compares) and only show how they fare at a given geographical location. That is, they can ONLY be used to compare each device’s being power-hungry, NOT as an absolute result as “your device will consume that much power a day in YOUR home”.
Wizard’s 7.5% a day is an excellent result and is slightly better than the ~9% of Universal, particularly taken into account the bigger battery size of the latter.
Standard power consumption test suite: now, for the Universal and the hx4700!
I’ve also re-run my standard test suite including the HTC Universal (a.k.a. i-mate JasJar, Qtek 9000, O2 XDA Exec, SPV M5000, MDA IV/Pro) and the HP iPAQ hx4700 (with WM5 version 2.01 – see FAQ here on this particular ROM version) now to find out how they behave.
The test suite I’ve tested:
Backlight tests: (all with no wireless units (GSM radio, Bluetooth, Wi-Fi, IrDA) switched on, no CPU usage. This finds out the absolute minimum power your device at least will consume when it’s switched on, runs at the default (automatic) CPU speed.)
No backlight at all (Note that in this scenario these devices are far from being usable, particularly the Axim x51v, which has an, in my opinion, slightly less visible screen in external light than the other three devices (which all have a screen using the same Sony technology and, therefore, behaving in a very similar fashion)
(Absolutely) minimal backlight
Maximal backlight (may be useful to know for example when watching videos on Sony screens because of the very high contrast and saturation of these screens (the x51v's not-really-saturated, not-contrasty screen has a definite advantage here) or in outdoor circumstances when you need to use the maximal backlight level available to see anything)
Wi-Fi searching for networks (also testing possible power saving modes to find out whether they’re of any help)
CPU usage vs. power consumption tests with Resco Audio Recorder (recording in q:3 32 kHz 19 kbps Speex mode (my favourite one with the best size/quality ratio but, unfortunately, with pretty high, about 60% CPU usage) - please see Everything you may need to know about sound recording on the Pocket PC for more information.)
Note that, this time, I’m also stating the original charge level at the start of the test. As is also stated for example in this pretty nice article by Brighthand forum member tanbam, there may be slight (not much) differences in power usage depending on the charge level of the battery because of the proportional Voltage level decrease as the battery is discharged. (Note that the Voltage decrease with Li-Ion batteries is in no way as visible as with other kinds of batteries. That is, a Li-Ion battery that only holds little charge will still have only a bit less Voltage than a battery full of charge. This is why there aren’t major differences in the low-charge and the fully-charged cases, Amperage-wise).
As can clearly be seen, what I’ve stated in my first battery consumption-related articles and tests is still topical:
when there is some remarkable CPU usage (see the Resco test), the power consumption figures skyrocket, particularly with the iPAQ and the x51v, particularly because both are 624 MHz devices, as opposed to the 520 MHz Universal and the PL720 (the latter consume decidedly less power in these cases). It’s, therefore, essential that you use some kind of CPU underclocking, especially on 624 MHz devices, when you run an application that constantly uses the CPU.
Fortunately, CPU underclocking is already supported by the x51v (in the Processor tab in the Settings/System/Power applet) but, unfortunately, not in the hx4700. Note that the Resco results are almost the same in the 624 and the 520 MHz modes; it’s only in a heavily (on the verge of usability underclocked) 208 MHz case that it’s visible decreasing. The case is a bit different with games – please see my former articles on the power consumption of the x51v and on my remark on what applications / games run OK when you (radically) underclock the device.
the Pocket Loox 720 is by far the best device, power consumption-wise
the lowest backlight level (with the – this is very important! – automatic backlight mode enabled as can be seen in here – it’s not enabled by default!) with the hx4700 consumes very little, as opposed to the other devices
when idling (without backlight – again, the hx4700’s backlight is far more battery-friendly than that of the other devices when used sparingly), the PL720 consumes the less; then comes the Universal, the x51v and, finally, the worst-behaving hx4700.
the various Wi-Fi power saving modes aren’t worth anything (at least when the device is actively searching for networks). In Wi-Fi, it’s again the PL720 that turns out the most power-saving (in my personal tests, it consumes about 25% an hour with BT enabled – connected to a StowAway BT keyboard -, in Web browsing mode, with the lowest backlight and connected to a Wi-Fi network).
BT and IrDA: Note that the chart doesn’t contain Bluetooth and IrDA beam activation power consumption data because I’ve already published them all. In a nutshell: you can freely activate and, with Bluetooth, actively use them (it’ll only result in an additional 1-2 mA power consumption, except on the PL720 in BT PAN mode, where you have taken into account what I’ve stated here), except for the hx4700, where it adds another 80-90 mA power consumption.)
finally, the Universal has turned out to be pretty good surprise: I’ve expected far worse, based on real-life usage. (Read: I need to recharge it on a daily basis with even moderate Web browsing – no hard-core gaming or stuff at all! – and mail reading while, using it in entirely the same way, the HTC Wizard doesn’t need recharging for days. Compared to the Wizard, it really sucks battery life-wise; compared to other VGA devices, it fares pretty well.) It fares decidedly better than the x51v and the hx4700 in almost every respect, particularly in the CPU usage and the Wi-Fi tests.
imho, given Menneisyys level of expertise and knowledge, i inherently value anything he posts be it original or (as you so inelegantly put it) copy/paste from another source.
Great writeup! Thanks.
Just wondering about your test setup - how were you able to measure current consumption? Did you use dummy batteries in place of the originals so that you could make an external current measurement?
Be as technical as you like - i've worked with electronics for 45 years now (Started with tubes and 'live' chassis!) so I'll understand anything you've got to throw my way.
Excuse me? This article has been written & all the measurements have done by myself. Or, do you happen to know it better? ;)
Take it as a compliment Werner. Just goes to show the authority behind your reviews.
I have a question regarding one (of your) article(s) I've read. How much power can be saved using Odyssey client compared to connecting using the WLAN utility? (Referring to the Wireless Zero Configuration). Or is the difference negligible?
Great writeup! Thanks.
Just wondering about your test setup - how were you able to measure current consumption? Did you use dummy batteries in place of the originals so that you could make an external current measurement?
Be as technical as you like - i've worked with electronics for 45 years now (Started with tubes and 'live' chassis!) so I'll understand anything you've got to throw my way.
I use acbPowerMeter. I've also thought of a dummy battery-based solution, but it would have involved a lot of additional work (as I do these tests on several Pocket PC's - making a dummy battery for all of them would have been a major undertaking).
I have a question regarding one (of your) article(s) I've read. How much power can be saved using Odyssey client compared to connecting using the WLAN utility? (Referring to the Wireless Zero Configuration). Or is the difference negligible?
I'd say nothing (without explicitly testing it - that is, I may turn out to be wrong), but I will certainly test it as soon as I have some free time.
I'd say nothing (without explicitly testing it - that is, I may turn out to be wrong), but I will certainly test it as soon as I have some free time.
I was referring to one of your posts in this thread http://www.pocketpcmag.com/forum/top...TOPIC_ID=15393 wherin you mentioned about the WZC disabler and doing the same using the Odyssey client to prevent wifi from actively searching for networks. If you have the time, I would appreciate it if you can test this theory out.
I use acbPowerMeter. I've also thought of a dummy battery-based solution, but it would have involved a lot of additional work (as I do these tests on several Pocket PC's - making a dummy battery for all of them would have been a major undertaking).
Thanks, I've grabbed a copy and will have a look at it.
So essentially, you use the internal power sensing circuits of the PDAs to determine current draw. I would imagine it should be fairly accurate when comparing all PDAs from the same manuf as they may use a similar power control environment. However, there may be internal design differences between manufacturers that may cause actual or real current draw to be measured differently, causing some inaccuracies in your posted measurements.
What do you think? - you've played with more toys than any of us here will ever dream of!
Thanks, I've grabbed a copy and will have a look at it.
So essentially, you use the internal power sensing circuits of the PDAs to determine current draw. I would imagine it should be fairly accurate when comparing all PDAs from the same manuf as they may use a similar power control environment. However, there may be internal design differences between manufacturers that may cause actual or real current draw to be measured differently, causing some inaccuracies in your posted measurements.
What do you think? - you've played with more toys than any of us here will ever dream of!
Well, so far, the measurements I've done highly correlated with the real-world battery life of these devices as reported by most users (and my experience). For example, I've measured some 300-350 mA current draw with the PL720 with Wi-Fi enabled; this pretty much correlates with the 1640 mAh battery's decrease 25% an hour while actively using Wi-Fi and browsing the Net, if you also take into account the "safety margin" all pre-WM5 operating systems use (to be able to power the RAM memory even when the battery level is stated to be 0%) and the "the given battery capacity is only a best-case one" rule of thumb.
for god sakes well people please leave the bitchy comments about Menneisyys at the door.Geez alot of people on here dont give this guy enough credit for the info his put himself out to share!.Thanks Menneisyys ive been intrigued myself as to what the battery comsumption is on my x51v.
Well, so far, the measurements I've done highly correlated with the real-world battery life of these devices as reported by most users (and my experience). For example, I've measured some 300-350 mA current draw with the PL720 with Wi-Fi enabled; this pretty much correlates with the 1640 mAh battery's decrease 25% an hour while actively using Wi-Fi and browsing the Net, if you also take into account the "safety margin" all pre-WM5 operating systems use (to be able to power the RAM memory even when the battery level is stated to be 0%) and the "the given battery capacity is only a best-case one" rule of thumb.
That's good to know and thanks again for the heads-up on the utility.
Unfortunately, when I run the utility it reads 0 mA and I can't seem to figure out how to get it to read current. Any suggestions? I have an X50v running A05.
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