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  1.    #1  
    Hello,

    I have only had my Centro for about 4 days now, and when I first got my phone, I charged it fully before the first use. I've noticed that each morning after being on the charger overnight, my battery is 99% full instead of the full 100%. I'm not worried about not being able to use the last 1%, but only that this might be part of a bigger problem. Battery life throughout the day seems to be normal. I've ended each of the last 4 days with about 35% battery life remaining after typical usage.

    Is this common, or should I be concerned? Is there anything I can do without having to take the phone in for service?


    PS - I tried searching the forum, and thought it best to start a new thread rather than hijack an existing 'battery' thread.


    sleepy
    Lovin' my Centro...keeping an eye on the Pre.

    The road of life is rocky, and you may stumble too. So while you point your finger, someone else is judging you. -- Bob Marley
  2. tlphipps's Avatar
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    #2  
    I have this issue on my Centro as well and have seen others reference this. FWIW, I also had this on my Treo 700p (with standard and extended battery). I think it's just how the OS interprets the battery level.

    Personally, I wouldn't be concerned.
  3.    #3  
    Thanks for the reply!

    I had a feeling this was the case since my forum search didn't turn up any results, but I figured I'd post just to be safe.


    sleepy
    Lovin' my Centro...keeping an eye on the Pre.

    The road of life is rocky, and you may stumble too. So while you point your finger, someone else is judging you. -- Bob Marley
  4. #4  
    It has been pretty well established that the 755P also only charges to 99% or even less at times. Not likely anything to worry about. Apparently the 680 is the same way as well.
  5. #5  
    When I use the wall charger each night, the battery is at 99% in the morning. The few times I saw it at 100% was when I was charging at my PC via the hotsync USB cable.
  6. #6  
    Quote Originally Posted by chimmer View Post
    When I use the wall charger each night, the battery is at 99% in the morning. The few times I saw it at 100% was when I was charging at my PC via the hotsync USB cable.
    Thats like watching a Turtle race.
    at&t iPhone3G
  7. #7  
    Quote Originally Posted by KStewart View Post
    Thats like watching a Turtle race.
    How so? I wasn't sitting there watching it. I hot synced, and left the phone connected. When I went to remove it, I noticed it was at 100%. This happened at least twice.

    I've never seen it at 100% when I charge it overnight via the wall outlet. It's always 99% no matter how long I leave it charging there.
  8. #8  
    Quote Originally Posted by chimmer View Post
    How so? I wasn't sitting there watching it. I hot synced, and left the phone connected. When I went to remove it, I noticed it was at 100%. This happened at least twice.

    I've never seen it at 100% when I charge it overnight via the wall outlet. It's always 99% no matter how long I leave it charging there.
    I am talking of how long it takes to charge compared to your off the wall charger.
    at&t iPhone3G
  9. #9  
    mine charges to 100% when it is charged overnight. the minute i pull off the cable it registers 99%. Nothing to worry about just the palm os

    Fred
  10. #10  
    Quote Originally Posted by fkpalm View Post
    mine charges to 100% when it is charged overnight. the minute i pull off the cable it registers 99%. Nothing to worry about just the palm os

    Fred
    The initial problem is reaching less than 100% when plugged in charging i.e. 97%,or 99%, not how it changes to 99% after you unplug it which is standard.
    at&t iPhone3G
  11. #11  
    If you read the technical literature, LiIon batteries should not be left on constant charge all the time. Doing so will seriously reduce their life. When the battery hits some 100% threshold, the charger should be turned off. The battery should be allowed to discharge to some high threshold like 95% and then the charger can be turned back on to repeat the cycle. So a plugged in device should be cycling somewhere between 95% and 100% all the time.

    Because manufacturers know that most consumers don't know this and consumers like to see 100% all the time, manufacturers will sometimes "cheat" and report 95% charge as 100%. You'll see devices reporting 100% charge for a while even though they are off the charger and draining current. Apparently Palm doesn't hide the true battery charge from you so that is why you are seeing what you are seeing. I wouldn't worry about it.
  12. #12  
    KWarner --

    I tend to agree with your logic regarding the LiIon Batteries, I've read similiar issues many times HOWEVER . . . I've had a Vx -> m515 -> T3 -> 650 -> Centro and ONLY the Centro has had this 99% bs 100% issue. Explanations???
  13. #13  
    Quote Originally Posted by kwarner View Post
    If you read the technical literature, LiIon batteries should not be left on constant charge all the time.
    Don't today's "smart chargers" take care of that? Automatically charge to full, then shut down and "trickle" charge every so often to top off? Maybe the batteries also have some type of circuitry to assist in that (temp sensor?)

    I had a Sanyo VI-2300 for a couple years with 2 batteries. I would always leave one on the charger and swap out as needed. Sometimes each battery would remain on the charger for a few days. Never had any issues with battery life.

    Edit: I've also read where every month or so it's a good idea to let the battery drain down to shutoff, mainly to help re-calibrate the phone's battery meter as opposed to maintenance on the battery itself.
    Last edited by Trekker; 12/10/2007 at 07:27 AM.
  14.    #14  
    Quote Originally Posted by fkpalm View Post
    mine charges to 100% when it is charged overnight. the minute i pull off the cable it registers 99%. Nothing to worry about just the palm os

    Fred
    Heh...mine did this yesterday morning. I thought it was odd until I read this. Thanks!


    sleepy
    Lovin' my Centro...keeping an eye on the Pre.

    The road of life is rocky, and you may stumble too. So while you point your finger, someone else is judging you. -- Bob Marley
  15. #15  
    Don't today's "smart chargers" take care of that? Automatically charge to full, then shut down and "trickle" charge every so often to top off? Maybe the batteries also have some type of circuitry to assist in that (temp sensor?)
    Yes, LiIon should be charged with a "smart" charger. A mode called constant voltage is used to "top off" the battery. But the voltage should not be left on forever to "trickle" charge the battery. That technique is used for battery chemistries such as nicad and NiMh. Once a LiIon battery is fully charged, the charger should be shut off and the battery allowed to relax and self discharge. Temperature is used only for an emergency shutoff in case of charger failure. Again, other chemistries may have used a temperature spike to determine full charge but that is not used with LiIon.

    I've also read where every month or so it's a good idea to let the battery drain down to shutoff, mainly to help re-calibrate the phone's battery meter as opposed to maintenance on the battery itself.
    Yes, that is correct. One of the hardest things to estimate with LiIon batteries is battery capacity as the battery ages. Running down to shutoff allows the capacity estimating algorithm to measure how much real capacity the battery has. You'll see the advice to run to shutdown even with laptop computers.

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