Evo 4G Battery drops by 9% after full charge on standby

[Nightcrawler2]

HTC Evo 4G

I don't mean for this to be another pesky battery thread, but I'm getting extremely frustrated and don't know what else to do. I promise I've read damn near every thread on battery life and tweaked the hell out of my Evo 4G and I still think it could do better. I keep reading these threads of people getting between 24-60 hours of moderate usage. I feel like I'm running the bare basics with very light usage and dropping to 30% in about 12 hours.

After charging all night long (9 hours) I pulled it off the charger and one hour later my battery was at 91% after sending one text message. The rest of that time it was on standby. (I have "calibrated" the battery as well.)

1. I'm rooted, stock sense, removed as much bloatware I thought was safe to do so (still a lot on it.)
2. SetCPU: Screen off max: 384. All other time max is set to 576 or less. (perflock disabled)
3. Bluetooth, GPS, 4G, Background data, hotspot all OFF. ALL accounts strictly manual update.
4. Wi-Fi is on all the time as I'm in range of it and locked on one of two networks - and uses less battery than 3G but as I said before - all my background data, etc is off.
5. Vibrate profile, all haptic feedback and everything else is OFF. Notifications off.
6. No live wallpapers, screen timeout 15sec (I usually shut it off before this), screen brightness ~15%.
7. I do not use a task killer as I pretty much have everything off. My list of running services is only 9 long and they're mostly labeled things that I don't understand (PVWmdrmService, -Proxy, HTC DM, etc)
8. No widgets running in the background (besides the clock?)
9. I've wiped all caches, data, battery stats, etc. in between flashing other ROM's.


I've attached some screenshots too. Please, if anyone has any suggestions on how I can even get about 20 hours or so under normal use (texting, checking email a few times, facebook, maybe a bit more?), I would greatly appreciate it. I've read a lot of people saying to flash a new kernel, but I have no idea what's compatible with the stock sense or even how to do that (and if I'm already underclocking the hell out of my CPU is it going to matter?). Do I do it the same way I flash a ROM? Where do I even get kernels?

 

[ccano8]

I'm not an expert on batteries and how they function, but I will do my best to explain what I have learned. Mine will also drop quickly if you charge it too long/overnight. Once the battery reaches 100%, it will actually start to discharge in order to keep the battery from overheating, that is why you will see a steep drop when you take it off the charger. I have gotten into the habit of not charging the phone overnight and instead charging when I have a chance during the day. If I do charge overnight, I usually take it off the charger when I wake up, unplug it and let the battery sit and calibrate to it's actual %, then reconnect and fully charge. I'm sure someone else can chime in with a better explanation, but this may ease your mind that there is most likely nothing wrong with your phone/battery.

 

[Azwizzard]

From what I have read / learned, the EVO will charge to 100%. Once the battery reaches 100% it actaully quits charging (I assume to help save the battery). Once the battery drops 9% it will start to charge again.

When you unplug your phone, it is luck of the draw on your battery. It could be anywhere between 91% - 100% charged depending on where it was when you unplug it.

I have seen my battery at 100% all the way down to 92% (and everwhere in between) when I unplug it. I usually just plug mine in overnight when I am sleeping.

If I plug it in during the day to top it off, as soon as I notice it is "green" I unplug it and I have always been at 100-99%.

Although I could be wrong...

 

[moritzes]

Nice bug tracing and documentation! Makes it much easier to give you suggestions.

I think you might simply have a poorly performing battery. I think it's a fairly common issue, and worth eliminating as the cause. Your battery management strategy looks excellent.

Other things you might try (that have worked for me):

Are you wedded to a Sense rom? I'm running CM7 with good success.
I use CM7 built-in underclocking. Conservative governor with a max 768 speed.
I also used viperMOD to undervolt by 50. No performance issues from either underclock or undervolt.

I'm using Tiamat v4.0.6 sbc kernel. The sbc allows for "top up" charging, which also might help you. I know there is a debate over whether sbc is ultimately harmful to the battery, but I'm convinced that any harm will only manifest in 2-3 years, minimum. I'll will have moved on from the Evo by then, likely.

I used Spare Parts app to identify a program or two that were causing "partial wake locks." FlightView and one of the weather programs, if I recall. Might be worth a look. I was getting a warm Evo w/o any use, which is a sure sign. Evo is always cool now, unless I've been watching video.

I do have push email for both gmail and exchange, and frequently read when I get a notification. I don't run widgets, but I use Plume (Twitter) and check my RSS feeds frequently throughout the day. Google Voice for SMS, generally auto-brightness for the screen, but I will manually turn it down if I think about it indoors. WiFi, GPS, 3G always on. Notifications, haptic feedback always on. Screen timeout 1 minute. Relatively poor phone reception at work and home, which negatively affects battery life, but what can I do?

I'm getting v. good battery life, after getting really poor (10 hrs w/ moderate use) on the unrooted phone. For example, 20.5 hours with moderate use and WiFi always on and still 49% remaining battery. 38 hours with 30% remaining and moderate/light use. (I happen to know these numbers b/c I took pictures, but they are fairly representative -- I did milk it a bit for the 38 hour run...) Right now, 5 hours with 87% remaining.

(Incidentally, Nexus One with similar settings just crushes -- I get 70 hours with light use.)

Good luck. Report back if you have any success with further techniques!

 

[Nightcrawler2]

Hey everyone, thanks for all of the suggestions/advice.

I have read a little bit about SBC and I'm pretty convinced that it doesn't do any damage. I have a lot of rechargeable devices with the same types of batteries that trickle charge to top-off and they work perfectly fine. I'll start looking for an SBC mod...

As for the Sense ROM. I'm not attached to it, I have flashed CM7 a few times (might flash it before I leave on a trip soon and spend the ride customizing it.) and like it and would also like to try out MIUI but it keeps getting stuck in a boot-loop and I have to start all over. I have several friends running CM7 but I haven't had enough time to really sit-down and customize it the way I want because I'm juggling medschool along with a few other life speedbumps at the moment.

I'll also check out the Spare Parts app too. That seemed to help someone else identify a rogue app as well.

I'm still open to other suggestions of course.

 

[Nightcrawler2]

Oh! I almost forgot.

I did noticed when I pulled the battery that the water damage tag has a red net design on it. In my previous experience with battery water tags, they turn red after being wet. Now my phone is only 2 weeks old and I am 100% positive this phone hasn't been anywhere near any source of water. Hmmmm... I wonder if they did give me a bad battery.

 

[moritzes]

Red net design is correct. When it gets wet, the background turns pink (i.e. the "net" bleeds a bit). I'd prefer not to say how I know this (*washing machine*).