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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. Jesse

    Jesse Well-Known Member
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    Plain and simple: When the Evo is fully charged, it begins running off its battery until you plug it back in. It DOES NOT trickle charge whatsoever after it reaches 100%. When you're using your Evo on the charger, and it's showing full 100% charge, it is running off the battery, not the AC plug. And then when you unplug it, well, we all know what happens next. The battery meter drops insanely fast to the actual charge of the battery, which could be very low, depending on how long it's been sitting idle at 100% on your charger.

    So all those times you've charged your Evo overnight, only to take it to work the next day and be at 80% within an hour? Your Evo was running off its battery for what I'm guessing was most of the night. It takes my Evo about an hour to two hours to fully charge back to 100%. Let's say you put your Evo on the charger at 11PM, it'll reach full charge by 1AM at the latest, and then run off its battery until whenever you take it off the charger in the morning.

    Workarounds?

    1) Turn your Evo off while it's charging.
    2) If you must leave it on for an alarm clock, put it in airplane mode and end all CPU intensive tasks to minimize battery drain.
    3) When you wake up, unplug it for 10-20 minutes (still experimenting with this number), and then plug it back in to top it off. Once it reaches 100%, take it off the charger, and go about your day.

    Try it out for yourself. When your Evo is 100% charged, take it off the charger immediately, and I highly doubt you will lose the 10%-15% within minutes.


    UPDATED 6-18-10
    So to help prove my theory, I've plugged my Evo into a Kill A Watt, and charged it to 100%. For those who don't know what a Kill A Watt is, it's a device you plug into your wall, and then plug your electronics into it, and it will tell you exactly how much electricity they're drawing. Coupled with the Battery Indicator app, I took readings on how much electricity my Evo was drawing as it charged.

    I started charging at 78%, and it was drawing 0.08 amps until it reached 90%. At 90%, it began drawing less and less, until around 50%, at which point it was drawing only 0.04 amps. It stayed steady at 0.04 amps until it reached 100%. Soon after Battery Indicator was reporting a 100% charge, the Kill A Watt also reported a draw of 0.00. Meaning the Evo was not drawing any electricity whatsoever, indicating that it was in fact running off its battery. Even when I turned the screen on, maxed out the brightness, and ran Linpack, the Kill A Watt reported no electrical draw.

    I kept my Evo plugged in for 15 more minutes, all while Battery Indicator reported a 100% charge, however, the Kill A Watt remained at a dead 0.00 draw. This doesn't necessarily mean that the Evo doesn't trickle charge, but it does mean it runs off its battery once it reaches a 100% charge. I have a feeling once the battery drops to a certain percentage (although still displaying a 100% charge), it will draw electricity until it reaches 100% again.

    Still a bit more testing to do. Will be back with results.
     

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  2. sh4o8kid

    sh4o8kid Well-Known Member
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  3. Jesse

    Jesse Well-Known Member
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    I dunno man. In the 2 weeks I've had my Evo, I can count on one hand how many times I've been able to take it off the charger, and have it maintain its 100% charge for at least an hour, and I've never tinkered with the MicroSD card. In retrospect, most of the times I've gotten the best battery life out of it were when I was in a hurry, and only had time to charge it to 100%. Then I took it off the charger and left. I'm fairly certain it's an issue with the Evo's lack of trickle charge.

    Just checked out your thread. Looks like you pulled the Evo off the charger right when it hit 100%, and then it maintained 100% for almost an hour, which kind of substantiates what I'm saying. Taking it off at 100% will yield the slowest drain.

    All you're doing is formatting the MicroSD card, which really has nothing to do with the core functions of Android. It's just a piece of flash memory used for storage. I've owned 3 Android phones, and I've never had to format my MicroSD card to improve battery life.
     
  4. sh4o8kid

    sh4o8kid Well-Known Member
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    Yeah a lot of people seem to have these problems with the dropped battery life. I tried a lot of things to have it be maintained. The only way I had to working was the HTC tip where we turn off the evo and keep recharging it over and over. Thankfully I tried this micro sd thing and now it seems that I can just charge it to 100% and take it off without having to turn it off and recharging it 10 times. Hopefully both our methods work. :cool:

    edit: Just saw your edit. Well right now, we're not even 100% sure why there is a drop in battery life at 100%. Almost every charge that i hit at 100%, the battery life would drop quickly. Since then, i relied on the htc fix but very annoying as i don't want to sit next to the evo and recharge it over and over. Since the format of the micro sd, i can easily charge it to 100% and take it off.
     
  5. BetterMost

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    Im sure it has to do with trying not to over heat the Li-ion battery while charging. I do think this was one of the causes of battery melting and battery fires a few years ago.
     
  6. horadin

    horadin Well-Known Member
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    Ummmm, I think the Evo is likely about like any other phone I have had and it charges to 100% percent, then runs off the battery until it drops to ~95%. (This number could be 90% who knows?) When this happens it will again charge it to 100%. Therefore if you happen to unplug it while the battery is at 95%, or whatever charge it may drop to before kicking the charger on again, it will appear that the battery is draining rapidly.

    If what you were saying was true, then I could plug my phone into the charger and leave it on the charger for a week and the phone would be dead. So I say you are wrong. Sorry.


    EDIT: To add on to that, another reason I believe people are seeing the large drop is due to the battery monitoring software not being properly calibrated. Haven't any of you noticed how the last 20% seems to discharge extremely slow? That has to do with the monitoring software, or maybe you guys are using your phone a lot when you first turn them on? Who knows, but it isn't because it is running off the battery for eternity once it hits 100% on the charger.
     
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  7. acp

    acp Android Expert
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    I don't fully understand either, if there was battery drain occuring while charging after the phone reaches 100%, then why doesn't the percentage change? I remember this exact same problem with the Samsung Moment and your solution is similar except we were all "topping" off the battery with a USB charge.
     
  8. pokerjv

    pokerjv Member
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    I agree with this
     
  9. MrX8503

    MrX8503 Android Enthusiast
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    I think what is happening is that the phone charges quite fast and the software indicates that its at 100%, when in actuality its probably at 90%.

    But since the software is telling the phone that it is at 100%, it stops charging it. So when you unplug the phone, it reveals its true capacity.

    At the end of the day, the EVO seems to not support trickle charge and thats a darn shame. As trickle charge promotes battery lifespan and ensures that your battery is at 100% capacity.

    Quite frankly jumping through all these hoops to get it to 100% is not worth it. I'm just gonna do the SD card trick and call it a day. I'm not gonna sit by my charger unplugging it and plugging it back in.

    After owning this phone since launch, I cannot believe the laundry list of problems ranging from something little to something major. The EVO is like a diamond in the rough.
     
  10. SprintFun

    SprintFun Android Expert
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    @Jesse, I respectfully disagree with your theory. I have mine on the charger and watch the World Cup on Sprint TV. If your theory was correct, then after my battery was full it would absolutely destroy the battery once I took it off the charger, because Sprint TV is quite battery intensive. But that's not the case...
     
  11. apocalypse_later

    apocalypse_later Well-Known Member
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    Too much snake oil in these forums. Seriously, most of the battery tips are bunk. Honestly, if you don't understand the technology and can't test multiple phones then you're just exhibiting confirmation bias.
     
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  12. Rigmaster

    Rigmaster Android Expert
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    Agreed. Would be nice if someone actually tested the phone and would publish the exact cause. A lot of these tips are based on speculation.

    I don't have a spare battery or charger, but it would be very informative if someone could:
    1. Charge Evo with battery to full and then time it's battery drain.
    2. Charge a spare battery outside the Evo until full, then put it in the Evo and time it's drain using the exact same settings as in step 1.
    That would give a reasonable idea whether the issue is tied to how the phone is controlling charge. If there's significantly less operational time in step 1, then something about the phone's firmware or software is the likely culprit. If there's not much difference, then it's more likely that the phone simply uses power at a high rate and a lot of our perceptions aren't accurate.

    Anyone with a spare battery and charger able to try this? Should be simple to do, and just leaving on SprintTV or something battery-intensive would be the best way to do the battery drain.
     
  13. swatpup102

    swatpup102 Well-Known Member
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    This is incorrect, and I'm pretty sure the memory card thing actually had something to do with it. I wiped mine and restored everything back on it, and now with 1 hour clocked on the phone since last charge, I am at 98% charge, where before it'd be at 90 pretty quickly.
     
  14. Jesse

    Jesse Well-Known Member
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    It's a wild theory, I admit, but, it seems to be working for me. I charged my Evo all night last night, and then when I woke up, I took it off the charger. Within 4 minutes it had dropped to 91%. I placed it back on the charger for a good 20 minutes and took it off right when the LED turned green. I've been doing some texting, and the battery has only dropped 1% in an hour.

    What Horadin said makes sense though. Seems like the phone will charge to 100%, run off its own battery until it drops below some arbitrary percentage, and then charge back to 100%.

    I'm definitely seeing MUCH slower drain when charging this way. The initial 10% dip is non existent when charging this way. This method/theory might need some tweaking, but I think it's a step in the right direction.
     
  15. Jesse

    Jesse Well-Known Member
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    That's interesting, for sure, and definitely worth trying. How long was the phone at 100% before you took it off the charger?
     
  16. SolApathy

    SolApathy Just another robot
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    Going to start my own battery improvement thread. "How I kept it at 100% for 29 hours" and simply post in the thread..."I never turned it on"


    Pretty soon we are going to need a sticky with a link to all the battery improvement threads to keep this stuff organized & get reliable real-time reports from multiple users to guage the actual effectiveness of each method that is being used.
     
  17. neoshi

    neoshi Android Enthusiast
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    So is this SD card wipe and restore a one time deal or are we going to have to repeat it to prevent that drop every time we charge it?
     
  18. Jesse

    Jesse Well-Known Member
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    I haven't done any SD card wipe, nor will I, as I don't believe it's causing any issue with the battery life.
     
  19. darweth

    darweth Member
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    If this is true, why is the battery drop identical when I charge the phone while turned off?
     
  20. swatpup102

    swatpup102 Well-Known Member
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    I have just done it one time, logically if this actually continued to work, it would be because after the update it was searching in a directory way based on how the card was originally formated. Once you format it again and restore it, the phone has to basically re-register it and I assume at that point it would see things the proper way, kinda like having trouble with a card in a card reader and doing a format on it where it works again. Just a guess though.
     
  21. Vincent Law

    Vincent Law Android Enthusiast
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    Sorry, this thread is incorrect. The EVO does indeed "float charge" (it's not called trickle charging). It will always attempt to keep the battery between 95 and 100%. It does this using the mV rating from the battery itself, not any percentages on the UI.

    If the EVO worked as the OP described, one could kill their EVO by simply letting it play movies all day when it is plugged in. This is obviously, easily tested false.
     
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  22. swatpup102

    swatpup102 Well-Known Member
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    It was charged overnight, then i tried erasing the card immediately after I unplugged it and took it to my computer, so if your theory is correct, there is no way it would have charged back up to 100% again that quick after charging all night. I'll know tomorrow when i take it off in the morning again.
     
  23. Yankees368

    Yankees368 Android Enthusiast
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    I dunno, I'm conflicted on this one. I am ROUTINELY seeing that if I take my evo off the charger from an overnight charge, the battery will drop VERY quickly. However, if I put it back on the the charger for a few minutes, the % does not drop nearly as fast. Something weird is happening here.
     
  24. darweth

    darweth Member
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    I also didn't use the included SD card. I formatted the Class 6 card from my G1 before transferring it fresh to the EVO. Never even booted up with the Sandisk.
     
  25. horadin

    horadin Well-Known Member
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    Thank you, this is exactly what I was trying to describe in my post earlier I just couldn't think of the correct term for it.
     
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