Battery issues

Discussion in 'Hardware & software issues' started by MeetYourMaker, Aug 12, 2011.

  1. MeetYourMaker

    MeetYourMaker Administrator

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    Trying to fix a laptop for someone, its an Acer 5920 and so far in the last 6 months Ive replaced battery, screen, keyboard, upper and lower case, led and button board, PSU x2, led and button board, yes it would have been cheaper to buy a new laptop!

    Problem Ive got now is Ive replaced screen for the 2nd time, and the internal power cable, did that and laptop was fine. As it hasnt been charged properly I decided to cycle the battery a couple of times, (discharge/recharge) its done this 3 times and now on the 4th time the battery is at 0% and wont charge. Windows says laptop is plugged in and charging, led on laptop says battery is charging, tried uninstalling the battery from device manager to reset the power software as well as starting laptop without battery and plugging it in after windows loads, all result in the same, charging: 0%

    Any ideas?
     
  2. yako

    yako ♂Niko®

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    most ptobably the battery is broken, for what ever reason. Looks like you will need a new battery!
     
  3. doh

    doh hodlike

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    I've seen macbooks completely reject old batteries before. (i know its not a macbook)
    Batteries these days have electronics built into the battery along with the charging circuit in the laptop itself. Usually the laptop or the battery will also keep a history file which helps it calculate how long a full charge will last, so that the percentages are displayed properly. Other information like last full charge capacity, current charge in mV and design capacity is also available to the OS via ACPI. Sadly Windows is pretty useless when it comes to displaying this kind of information.

    Here's the output of my old honky IBM T40 via linux:

    cat /proc/acpi/battery/BAT0/info
    present: yes
    design capacity: 47520 mWh
    last full capacity: 11140 mWh
    battery technology: rechargeable
    design voltage: 10800 mV
    design capacity warning: 557 mWh
    design capacity low: 200 mWh
    cycle count: 0
    capacity granularity 1: 1 mWh
    capacity granularity 2: 1 mWh
    model number: IBM-08K8193
    serial number: 5655
    battery type: LION
    OEM info: SANYO

    cat /proc/acpi/battery/BAT0/state
    present: yes
    capacity state: ok
    charging state: charged
    present rate: 0 mW
    remaining capacity: 11140 mWh
    present voltage: 12386 mV


    As i see it, one of the following things could have gone wrong:
    1: The battery history file has been corrupted, meaning the the laptop actually have no idea how many percent the battery really has been charged, and just displays 0% instead. This is pretty easy to check, unplug the powercord, and see if it'll run on the battery after its been charging for a while. Resetting the history file could prove tricky, i really can't help with that.
    2: Battery charging circuitry is defective. For an example a temperature sensor in the battery could have stopped working, making the battery think that it is overheated, halting the charging. I'm unsure weather an ACPI message of overheating would make it to Windows, and weather Windows would display it if this was the issue.
    3: Battery cells are dead. This one seems unlikely though, that they all would fry at the same time.
    4: Laptop charging circuit is defective. Perhaps it is simply not getting any current. (you say internal power cable has been changed?!)

    All this doesn't really help you a lot, but without more information its hard to help. I would suggest that you boot a linux live cd, and see what it says about the battery. You should pretty more be able to fire off the 2 commands above if you get a live cd with acpi support, and your laptop supports it. You might both gain more information from the battery status, and you rule out that Windows could be the problem.


    And then a bit of information about Li-ion batteries found in all laptops these days for those interested.
    There are still some old myths floating around about batteries from earlier days. Like the memory-effect, which supposedly meant that if you didn't discharge your battery completely, your battery would keep a smaller charge.

    These are the facts about Li-ion batteries:
    Does more or less not wear out due to usage, they wear out due to age instead. The wear over time depends on a number of factors described below.
    Topping up the battery often does not damage the battery or create a memory effect.
    Li-ion batteries does not like having a low charge on them. The longer they remain with a low charge, the faster they wear out. They also loose a bit of charge over time, so make sure you charge them once in a while. The charge amount at which they degrade the slowest is around 40%-60%. The colder the batteries are kept, the less they degrade. Batteries can be kept usable for very long (10+ years) if kept cold at like 5-10C, and at a 40% charge.
    The degrading over time also makes it very important to check the manufacturing date on new batteries for laptops and phones etc. The longer since they were manufactured, the more they have already degraded.

    There is one reason why you would want to completely discharge the battery, and that is if the battery has been laying unused for a long time. When used again, the history file will then say that the battery has a specific charge, but in reality, the battery has degraded a lot, making the history file state wrong information. Completely discharging and fully charging the battery once will help the laptop determine the correct full charge capacity.
     
    Last edited: Aug 12, 2011
  4. MeetYourMaker

    MeetYourMaker Administrator

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    Yeh I had looked at that already, its showing 44000wah max new and 32000 max now and current 0wah.
    Its also showing right info as in what state it should be, ie currently charging and shows input voltage
    The laptop was charging and discharging fine yesterday, it hasnt moved so I cant understand what has changed.

    The battery is 4 months old, or at least was bought 4 months ago. Its showing charging 0% but isnt charging at all, if I remove power lead it will just shut off.
    Windows and laptop is saying its charging the battery but is doing bugger all, battery has no voltage in it and windows/laptop confirm this.
    I would guess either something wrong with charging circuit or the battery is knackered :(
     
  5. doh

    doh hodlike

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    Perhaps its time to stop spending any more money on it then? ;)
     
  6. sneez

    sneez Well-Known Member

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    [​IMG]
    solved.
     
  7. MeetYourMaker

    MeetYourMaker Administrator

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    Unfortunately its not my laptop otherwise this would have been gone a long time ago by now
     
  8. MeetYourMaker

    MeetYourMaker Administrator

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    :lol: I've spent two days trying to get this thing to charge, finally gave up and bought a new battery and what happens, come back to the laptop and its fully charged the battery. Stupid bloody thing!!!!
     
  9. Riv

    Riv TonTon

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    maybe im the one who should give you computer help next time.
     
  10. WaYnOs

    WaYnOs [Nil]

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    OWNED! :rofl:
     
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