posted by wap, platform: GoogleChrome

While this is a bit uncommon, we will be talking about a post in a particular thread rather than the whole thread itself. This post reminded us about the proper way of providing feedback on things as important as battery life. A sole post saying “battery life on rom xyz sucks” isn’t really going to help the developer (or anyone) determine the cause and provide a fix or a solution for the problem. XDA member frankpreyes decided to post a review on Myn’s Warm TwoPointTwo ROM thread for the EVO 4G. The comparison is carried out by keeping as many variables constant (no flashing other nighties, keeping radios, etc) and only focused on the kernels themselves as there were conflicting reports of many users claiming that battery life was better/worse with one or another. The report was done from an engineering perspective, so we are positive that many of you will agree with the approach.
Please leave feedback in this article since feedback in the thread will cause nothing more than make that monster thread even longer. And that is why the whole post will be featured in this article
I decided to see, so far, the difference between the HTC 15 and the older, HTC 17 kernel, as provided by Myn. Testing involved heavy usage, and light usage. Although the dataset is small, (From 1/3/2011 to 1/5/2011), there is definitely a quantitative difference between the two kernels.
For this comparison, I ran the same nightly, provided by Myn. I have a 0002 hardware. When I was running the HTC 15 kernel, I was using all the latest radios, wimax, NV (What the heck is an NV anyway). When I switched back to HTC 17, from Myns first post, I downgraded my radio. I decided not to downgrade my PRI (so far), to the previous revision, to see if I can quantitatively assess the impact, once I had baseline (HTC 15), and had modified as few variables as possible. Also, I started out with a fully charged seidio big battery, charged with the phone completely off, and cleared battery stats before using my evo. I also waited 1 hour after turning my evo on, before I used the % battery data, so as to allow the battery to stabilize.
Morning usage is light, typically reading emails, keeping up with this forum, looking stuff up, while afternoon usage is what I consider heavy, as I am using my Evo as a Wifi station (Sprint Hotspot, 3G), when I use my CR-48 netbook. U-Tube, This forum, Google reader, etc.
Using the battery monitor widget, I plotted %battery remaining per hour of use.
Here are the test results so far:
______________HTC 15_________HTC 17______% Difference
Light Usage:____-7.23%___________-4.3%_________40.5%
Heavy Usage:___-12.94%__________-9.3%_________28.1%
What I am reporting is the slope of a regression line drawn through the data for each day. The slope is the rate of change. In each case, the regression line matched very well with the data (R-squared = 0.96 to 0.99). The closer this number gets to 1, the more accurate the fit of the regression line to the data.
This provides some evidence that the HTC 15 kernel (Flashed on the first nightly) consumes more battery per hour than the HTC 17 kernel.
Todays data appears to be even better in favor of the HTC 17 kernel. This is proof, as some were saying that the #17 kernel gets better with use.
I will probably revert back to the previous PRI, to see what changes this makes to battery drain per hour. Once that is done, if there is any interest, I can post the graph I created that shows battery drain.
From a subjective standpoint, HTC 17 appears faster, and does not result in the morning sluggishness I was experiencing with HTC 15. . On HTC 15, I would get a force close in Launcher Pro Paid edition (Myns version) after first boot in the morning. After that, no other problems. With HTC 17, this no longer occurs. No programs were added or updated during this test.
You can find the full comparison in this post.

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XDA的文章，其实我也觉得的确如此，例如MIUI的ROM就非常省电（G7/N1的），MS的最近也蛮不错了，一般能用一天以上，省一点甚至能用两天。而XDA这篇文章测试结果大概也是如此，不同的ROM，使用起来甚至有40%的差异。如果再配合一些省电软件（JuiceDefender系列等），效果还是蛮不错的，感觉很好。

正常啊。所以有省电rom

posted by wap, platform: UC

我一向都是持怀疑意见的

A rom我每晚睡觉9小时掉电3%，最近刷了B rom，相同情况要掉8%左右，感觉略微耗电点:D

都不开飞行

[ 本帖最后由 bsgb666 于 2011-1-8 16:44 编辑 ]

官方ROM一般省点吧？

睡觉的话，如果用飞行模式，也会比较省的

装很多软件和刚刷完的初始状态耗电量也差很多。。。

posted by wap, platform: Android

感觉官方rom比较快和省电。。另外装得后台软件的多少绝对会影响耗电的。。

电源管理策略不一样吧。

posted by wap, platform: iPad

电源管理策略肯定是相同的，差别只是后台跑了多少\什么程序？

posted by wap, platform: Firefox

这话题在WM时代就讨论老了去了.. Android又翻起来炒

现在的智能机都是不动不耗电，一动大耗电
我的PP待机不动四天都能剩下70%
开个屏幕看了五分钟照片，立马60%。。。。。。

屏幕是耗电大户啊