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Support This is why your battery drops 10-15% in the first 20 minutes.

Discussion in 'Android Devices' started by Jesse, Jun 17, 2010.

  1. NeoteriX

    NeoteriX Android Expert
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    Watch out for unintended consequences folks...

    I just want to toss out the possibility that the charging behavior exhibited may be by intentional design in an attempt to better condition the battery. I know my Thinkpad laptop has an option to 1) maintain a full charge, or (what is allegedly better for the battery) 2) to set specific charge thresholds that the battery will fluctuate between. In other words, it is better for the overall longevity of the battery not to maintain a constantly full charge, but to rather charge to full, and then wait until it drops to a certain % and then charge again.

    There is no correct answer to this question, but I would challenge everyone to ask themselves: Would you rather have a system that keep a battery always topped off (in other words, had the extra 5-10% battery every day) but where the battery only lasted 3/4th as long, versus a system that we have now, but that resulted in a longer lifespan?

    If we HTC to modify this behavior, that may be the question we'll have to face.
     

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  2. Rigmaster

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    From the last couple of posts, it looks like my guess that the issue is definitely software related is the most likely culprit. Def needs an HTC fix because charging outside the Evo isn't practical given the difficulty of the battery cover which isn't meant to be opened/closed that often.

    FYI, I charged from 3:30a-6:30a using a Gomadic charger with fully tested 1A charging, and I'm at 90% after removing from charger at now 2:30p which is an improvement at almost the 2-week mark. Not a big believer of break-in so much as I think it's taking that long for the phone-to-battery power calibration to sync better. My use has been moderate (calls for 3 mins, about 10 texts, 15 mins of SprintTV for World Cup viewing, 15 mins online and using Android Market, and 5 mins of making changes to my address book with 3G connection going all day). Not bad. I can definitely make it through a workday with no problem with normal use. I did the same thing with heavy use (3 hours SprintTV, 4 long calls, 1 hour internet/A.M., 15 mins adjusting pages/screens, and continuous 3G connection). Needed about an hour to recharge from 4p-5p but made it to bedtime from then.

    My wife regularly goes from 6:30a - 8pm with moderate use and still has 40-50% remaining. Her Evo seems better calibrated.

    That little software fix would be huge. Come on HTC and Sprint!
     
  3. bluehaze013

    bluehaze013 Well-Known Member
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    Charging the battery in the phone is a crap shoot because occasionally you will unplug the phone as it hits 100% and it will then not do the drop but othertimes you will unplug the phone long after it's hit 100% and it will have drained some of the battery. This is why there are so many random posts of "do this random thing and it will mysteriously fix your battery life"

    It works like this, the phone charges to 100% then shutsoff until around 90% before it will start recharging. This is to extend the life of the battery, if the phone constantly charged everytime it dropped to 99% it would severely shorten the lifespan of your battery and you would be replacing them every 6 months. So it's good that HTC does this.

    The problem lies somewhere in the softwares ability to determine how much charge the phone has on it after it's reached a full charge and remains plugged in. It always shows 100% after it's reached a full charge regardless if it has drained or not so when you remove the phone from the charger you think it's at 100% but it's actually not the software then over the next few minutes catches up and shows the real percentage.

    Your phone is not actually draining the battery that fast, the software is just catching up now and calibrating itself to show the battery is not 100% charged. This is why when you take the phone off charge for a couple minutes then hook it back up it lasts much longer because the software has a chance to recalibrate and recharge up to 100% at which time you promptly remove the phone and it really is at 100% charge because it didn't have time to sit there and drain without the software of the phone realizing it.

    This is the "HTC battery fix" they are aware of the problem and it will be fixed eventually. I think it is likely a problem with Android 2.1 software because I had the same problem on my Nexus One but once I got a spare battery and charger to charge the spares out of the phone the bad battery life disappeared.
     
  4. whatsitsname

    whatsitsname Android Enthusiast
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    You are stating this as though it is fact. How is it that you know the phone will need to be at 90% before it will charge up again? How do you explain that some of us don't have this particular problem. As far as I am concern its all just speculation now. Same with some reporting that formatting the SD card solves all their battery woes.
     
  5. as329

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    I think this is exactly right, but it is based on admittedly anecdotal evidence. I have three EVOs in the house, so I've been able to observe this on all three phones.

    Last night, in a bout of insomnia, I decided to wait until my battery hit 100% and pull if off the charger precisely at that moment. At 1:00am it was at 100% and woke up at 7:30am with 97%. I leave wifi on all the time, as well as GPS. I have an airave so signal isn't an issue at home. I'm not rooted and have made *some* of the changes recommended for battery life without crippling the phone.

    I then drove to a meeting about an hour an a half away and left my phone on the charger the whole way. I had used my phone before I left and it reached 100% again about half way there. I put the phone in my glove box when I got there, (my meeting was at a prison, I can't take it in) did two hours of meetings. When I came out, the phone was at 91%. (similar use overnight and in the glove box, just a couple emails received)

    This is just an example of the many times I have tried similar "experiments" over the last week. It happens every time. FWIW

    As for "up time" battery life, I get much better battery life using wifi and airave at home than 3G at the office...
     
  6. bluehaze013

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    It's not a fact it is just an explanation based on my experience with a few phones running Android OS 2.0 with a few different batteries and a few different chargers. I can pretty much predict when my phone will quickly drop below 90% after taking it off the charger vs when it will stay at 100% so I feel my explanation is much more plausible than "format your sdcard and it will fix your battery life" type of explanations.

    In the end I always buy an external battery charger now not just because of this but mainly because its so much more convenient to just plug the charger in with a spare battery in it and continue to carry the phone with me and use it as much as I want with my other battery without worrying about it dying but for those days I will be away from a power source I can also just leave the battery in the external charger remove it in the morning pop it in the phone and always start the day with a full 100% charge which usually gets me through the day regardless of how much I use the phone.

    Charging the battery using the phone is fairly unpredictable, charging it using the external battery charger is fairly predictable.

    It works for me...

    Cheers.
     
  7. whatsitsname

    whatsitsname Android Enthusiast
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    What are the charging times for the battery (for like say it only has 10% left) to fully charge. I bought one of those combo 2 batteries and 1 charger from ebay and those take 3 to 5 hours to fully charge a battery.

    BTW, I agree you explanation is much more plausible than the sd card format scenario.:D
     
  8. Rose4uKy

    Rose4uKy Android Expert
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    I just went to Amazon to see about ordering this and I accidentally clicked the final step and now I am getting one too. I wasn't a 100% sure but I didn't mean to click on place order and I did.

    But I have an extra battery from my TP2. Usually I always have my charger with me at work and I bring it back home and I have a car charger. But if I am ever out of town and my battery dies and I don't have time to charge it the extra battery comes in handy. And it's nice to charge both at once. One in the phone and one in the charger. But some of you say the battery charges better outside of the phone and last longer so will see. It's a pain to take my case off and open up the back. Especially since my clarivue protector lifts when putting the case back on. But since there isn't a dock made yet with an extra battery slot this seemed good. Is this the one that was on Seidios site for like 35 40 bucks? I figured for 23 it wasn't bad. My TP2 battery has been just sitting in my purse since I sold my TP2 abotu a week before I got my EVO. So I am sure it could use a top off and is not at a 100 still from sitting in my purse for a couple weeks, I'm going out of town on Sunday so I hope I get this by then. So you really like it? There was only 2 reviews on it.

    My battery was completely dead in phone when I got home from work at 11:20 and at 12:40 I just noticed it was fully charged.

     
  9. bluehaze013

    bluehaze013 Well-Known Member
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    I don't know I never really timed it I would guess 2 hours maybe 3? Will try and check tonight when I get home from work.


    I like it, mainly because of the plates, won't have to buy a new charger everytime I switch phones, now I can just buy the battery plate for the charger. I believe it was 30 bucks on Seidio's site, not sure though I usually order everything from Amazon because I pay the 80 bucks a year to get the free 2nd day shipping on everything so have to take advantage of it :)
     
  10. Rose4uKy

    Rose4uKy Android Expert
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    Oh cause I ordered off Amazon it was 23 bucks over 30 at Seidio but there out of it. And I really wasn't even sure if I wanted it or not but had clicked on place order by mistake. But I could use it since I have an extra battery.. It said I could cancel though since there out so I'll decide. I have to call Sedio about something so I may order from them.

     
  11. Rigmaster

    Rigmaster Android Expert
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    Try Gomadic chargers - they're modular and you only change the tips for devices. I've replaced every handheld device charger I have with these as long as the devices can accept a 1A charge without problems (most can as 1A is hardly enough charge to burn out/damage most gadgets). They make tips that fit just about everything.
     
  12. Rose4uKy

    Rose4uKy Android Expert
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    Yesterday I had a full charge when I got up and then I let it drain some and then fully charged it. I didn't plug it back into a charger till it was completely dead. I talked on it on my way to work. Texted and surfed the web some and checked emails. I did keep it on airplane mode alot at work cause I am in a basement and don't get a good signal and I think it drains while searching but not as bad as my TP2 I don't think. But anyway I closed out everything that was checked in the Sprint Zone and that and airplane mode helped me out. I always have my charger with me but I got a little over 16 hours of being unplugged which was the best I've had so far since I've had this phone. I don't think that was too bad.

    I charge it full every night then unplug it for a bit then charge it full again. And today I may skip the airplane mode and just see for the heck of it how long it last. But I like the idea of if I am out of town and battery dies I can swap out and put in my TP2 one which I haven't used yet on my EVO. Then let the other charge while I still use the phone. So I think this battery chager will come in handy. Even if I had a docking cradle that held the extra battery this little battery charger is would be easier to take with you when traveling.
     
  13. cabbie

    cabbie Android Expert
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    Observation I've made that has happened twice:

    I charge the phone overnight so the LED is green. I pull it off the charger (computer USB) and let it sink like the titanic to 85% in just a few moments, then put it back on the charger back up to 100%. Then I turn the phone off, it shows amber for a couple minutes then turns green.

    Then when I pull it off the charger, the LED remains green for no less than 20 seconds, as if it were still on the charger. As I put it on and off the charger back up to green, the time it takes for the LED to shut off shortens.

    Odd.
     
  14. mike.s

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    i got this tip from the htc evo website itself.. it was a question about why does charging through a computer usb cable takes longer to charge than through the wall socket.. htc's responce is this


    "Why does it take so long to charge my device using the USB?
    The USB cable acts as a trickle charger so it will take longer than if you were using an AC charger. While the USB will work, it is recommended to use the AC charger, especially if the battery level reaches 10% or below."


    so if the usb acts like a trickle charger mabey we should charge the phone through the usb and mabey we will bypass the whole cutoff at 100%. im going to try it tonight, ill let you know what happens
     
  15. toomuchgame441

    toomuchgame441 Android Expert
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    I will be interested to see those results, I've been experiencing batter battery life with my Evo within the past few weeks, but I never actually tried charging my Evo using a usb attached to my PC
     
  16. R1_Rydah

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    Fwiw... I charge via usb every night, and I get the same results...
     
  17. Oddball

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    There's a problem with that. You can NOT exceed 100% on a Li battery or else you risk immediate damage, i.e. anything over 4.2 volts. The internal circuitry specifically prevents this. Same holds true for under voltage. Both are very detrimental to Li batteries.

    I've known for quite some time the USB port on a PC/Laptop won't charge nearly as quickly as an A/C wall charger or even the lighter charger.

    It seems like the battery is behaving correctly. The handset charges to 100%, stops charging, draws down to around 90% then does a topping charge (much lower current charge) and we may be catching this handset at the point (delta) where the charge has already reached it's peak and it's now drawing off the battery. Take it off the charge and bang, 5-10% loss in rated capacity.

    Remember though, the handset can't control the battery. It simply provides a means to recharge it and that's it. It's either reading the battery's internal circuitry or calculating the % remaining based on the input voltage. And there is NO way to condition an Li battery but you could just run it down until the warning appears at or around 40% and then do a full recharge on a wall charger. That merely refreshes the metering of the battery itself. It's recommended on my company laptop. The Lenovo hardware allows a full discharge/recharge cycle to calibrate the power meter.


    At least this handset recharges when I am using it. My test Windows phone a year or so ago couldn't charge it on my laptop if I was using it!
     
  18. aburgthing

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    Since this thread has resurfaced, I found that charging your battery out of the phone via a separate battery charger for a spare battery will give you 100% battery life with no drop off when you put the spare battery in the phone. Furthermore, I always keep a spare battery in my pocket at work. Most times I do not use it. The last time I had charged the spare was two weeks ago. I needed it last night and swapped out and to my surprise it was still 100% after two weeks off the charger and did not have the battery drop seen when taking it off the charger as I normally do before work. For the Evo, 2 spares and charger (on Ebay) are the best $10.00 I have spent on the phone.
     
  19. cirehawk

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    Whoa!!! $10.00 for 2 spare batteries and a charger? That will be one for me and one for my wife (who will be getting her EVO in the next few days). I think I'll be heading to Ebay when I get home.
     
  20. cabbie

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    i get a drop-off to around 84% despite external charging, wiping battery stats, everything. dont know what to say.
     
  21. wodin

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    I don't have any fancy theories or inline milli-watt meters, just empirical anecdotal data. When I plug my EVO in overnight, and just let the screen time out, it will usually drop to 90% or less in just a half hour or so of taking it off charge; but if I leave the screen turned on, either by disabling the screen timeout, or running an app that keeps the screen on, it will go for several hours without dropping below 90%.

    I have since written a Tasker profile to disable screen timeout while power is applied. Works for me!
     
  22. Droid_Genius

    Droid_Genius Android Enthusiast
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    Yea this is crazy cause I have a Seidio battery and I get same results, charge it and then....BAM down to like 85% but it will hold there for a looooong time with use of browsing, 4G, etc.....weird, not sure if there is a true fix for it. Or it could just be operating correctly.
     
  23. PGR

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    First, my "qualifications" to comment on the subject: I've been an electronics hobbyist for my entire life and a model (R/C) aviator for years and I've been powering my electronic projects and electric airplanes with LiPo (Lithium Polymer) battery packs since we had to build our own packs from individual cells and design/build our own chargers. That, I should add, was back when rechargeable consumer electronics devices including laptop computers and cell phones were still powered by NiMH and even NiCd cells.

    Back then, LiPo cells were real expensive and (like today) they have this nasty habit of "venting with flame" when they're misused so I found it prudent to learn everything there was to know about the use and care of LiPo cells. That said, let's look at a very typical discharge voltage curve for a single LiPo cell:

    [​IMG]

    This particular discharge voltage curve is for a 6C discharge rate which means that if it was a 1500mAh cell then the discharge rate was around 9000 mA or 9A. Of course a cell phone would draw just a fraction of that which would change the curve as follows:

    The starting voltage would be more like 4.2V which is the "fresh-off-the-charger" resting voltage of a fully-charged LiPo cell. Once the external power (charger) is removed the cell voltage would quickly drop to the nominal "loaded" voltage which is roughly 3.7V.

    Now does this sound familiar to any of you so far? :rolleyes:

    Anyway, the rest of the discharge curve would be relatively flat until the cell was around 80% discharged. At that point the cell voltage would be around 3.4V, so for all practical purposes there's only a 0.3V difference between a fully-charged cell running at nominal "loaded" voltage and the same cell after an 80% discharge.

    From there the voltage will drop off pretty quickly, and it's important to understand that a LiPo cell is depleated once it reaches 3.0V and discharging it below 3V typically results in irreversible damage to the cell chemistry.

    So in summary, a fully charged cell will have a resting voltage of ~4.2V but this will drop to the nominal "loaded" voltage of 3.7V very quickly once a load is put on the cell. But despite this initial 0.5V drop in cell voltage, the cell still contains nearly 100% of it's stored energy.

    The bottom line is what you people are seeing is what LiPo cells do under normal use. The mistake(?) HTC has apparently made is their battery "meter" is showing "Full" at the ~4.2V LiPo "resting" voltage instead of the ~3.7V LiPo nominal "loaded" voltage. To correct it they would simply have to re-index the displayed discharge curve.

    This whole thread reminds me of one just like it which ran it's course in the Garmin (the GPS company) forums. When the "Oregon" series of handheld GPS units were first released, everyone just pitched a fit about what a battery hog those units were until Garmin "fixed" the problem with a firmware upgrade. The truth of the matter is they did virtually nothing to improve battery life but they did re-index the battery indicator to reflect usable energy instead of merely showing a linear display of the battery voltage.

    And everyone was happy, and that's really what it's all about, isn't it?

    And now for your viewing pleasure, here's your's truly committing some LiPo-powered model aviation:

    http://www.youtube.com/watch?v=mpBFSMPHu4E

    Pete
     
    FLEMTP, willisJ and cabbie like this.
  24. FestoKGB

    FestoKGB Android Enthusiast
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    No SD card format voodoo or anything wacky. Simply charged my battery in an external charger. Popped in the battery, got dressed, ate breakfast and drove to work. Took this screenshot when I got to work.

    100% after just over 1.5 hours.

    [​IMG]
     
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