1. kretch's Avatar
    Last week I purchased a new 64gb Playbook that had a May 2011 box date.

    When I first turned on the PlayBook it was showing 18% battery power so I plugged in my charger and set it up.

    After setup I installed Battery Guru, it reported 6 charges and a battery health of 90%.

    After the 1st week of use Battery Guru is reporting 9 charges and my health is 89%.

    I had also purchased a Playbook late Feb.-2012 with a box date of 6-2011, it has seen plenty of use over the last 6 months with daily charging. Its current battery status is 87 charges and a battery health of 89%.

    With these numbers do you think that the Playbooks battery heath decline is more age related than it is to use.

    I hope with a little more use my 64gb Playbooks battery health goes up a few % or do you think that will not happen and do you think 90% is to low for a device?


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    08-27-12 07:36 PM
  2. lavrishevo's Avatar
    Li-ion batteries deteriorate based on "charges" or cycles. The less cycles the better. Shelf life is a factor but should not be that much. As li-ion batteries do not have a memory like the older nicad batteries did it is best to charge them often rather then let them drain.

    http://batteryuniversity.com/learn/a...ased_batteries

    On my quad core MBP I am at 18 months old, 108 cycles, 94% health.
    Last edited by lavrishevo; 08-27-12 at 07:51 PM.
    08-27-12 07:45 PM
  3. kretch's Avatar
    So why would I have a health rate of only 89% with 9 charges?
    08-27-12 07:50 PM
  4. lavrishevo's Avatar
    Good question. I don't know if i would trust the app. Is there any other battery apps to try to compare with?
    08-27-12 07:52 PM
  5. ralfyguy's Avatar
    Good question. I don't know if i would trust the app. Is there any other battery apps to try to compare with?
    Battery Guru only displays what the OS reports to it. Basically whatever DVD you play, the TV will show it. Nothing added, nothing left out.
    peter9477 likes this.
    08-27-12 08:24 PM
  6. peter9477's Avatar
    So why would I have a health rate of only 89% with 9 charges?
    Possibly because at only 9 charges, it's unlikely the health reading has stabilized. Check again after you've got closer to 30 or 40 cycles and you can start to trust that the number is going to be pretty stable.

    Also, not all batteries are identical... these aren't precision devices (the batteries, that is) so there's a range of "normal" values. I'd call anything from about 87% to 95% pretty normal for relatively new PlayBooks, and few have reported values much below 85%, even after several hundred recharges.

    Might be time for another round of "What's your battery health?" so we can see if the last year of usage has started showing any significant downward trend for the oldsters among us...
    08-27-12 08:35 PM
  7. jpash549's Avatar
    Apparently based on pictures shown in another recent thread batteries from different sources have been used in the Playbook. The health or state of health (SOH) is apparently estimated using an algorithm including such factors as charge acceptance, internal resistance, voltage and self discharge. This is provided by an algorithm in the playbook software. As I understand it the details of this algorithm that is used in the PB are not available. I would assume that it does not provide an absolute measure of the quality of a new battery and the comfort feeling I get from having my SOH reported at 99% with 116 charges does not assure me that my battery is better than one which is reported to be at 90% with relatively few charges. I got my 64GB BBPB in January.

    Please comment.
    08-27-12 09:20 PM
  8. dugggggg's Avatar
    Simply put, the PB has a "nominal" 5400mAh battery---and the health calculation likely uses that particular value. But suppose your PB happens to be endowed with a 5500mAh battery---its health figure would then average several percentage points higher than one with a 5300mAh battery.
    08-27-12 09:53 PM
  9. peter9477's Avatar
    The health or state of health (SOH) is apparently estimated using an algorithm including such factors as charge acceptance, internal resistance, voltage and self discharge. This is provided by an algorithm in the playbook software. As I understand it the details of this algorithm that is used in the PB are not available.
    From what I can tell it's probably simpler than that, since there's no indication internal resistance or self-discharge is measured or considered at all. As you say, however, the details are not known, and probably change from version to version, and it doesn't really profit us to discuss it much.

    I would assume that it does not provide an absolute measure of the quality of a new battery and the comfort feeling I get from having my SOH reported at 99% with 116 charges does not assure me that my battery is better than one which is reported to be at 90% with relatively few charges. I got my 64GB BBPB in January.
    Although I would agree that "90% on relative few charges" would mean you shouldn't (yet) compare that particular battery with anything else (since the health reading won't necessarily have stabilized), note that it is quite possible to perform an independent measurement of battery health and confirm or refute the OS' own estimate, to within a few percent.

    With my "drain test" (http://forums.crackberry.com/blackbe...6/#post6931987), you can use the resulting data (as collected by Battery Guru) to determine the actual capacity of the battery. Divide by the nominal value and you'll get the "health". If you use the CSV export file to calculate the average drain during the test, times the duration of the test, you'll get a result in watt-hours. (You could also just check the power reading several times during the test and average those, for an even rougher check.)

    The nominal value is 19.98Wh, so if (for example) you found the average drain to be 1.800W, and the battery lasted exactly 10h, you'd have a capacity of 18Wh or a health of 90.09%. If the value reported by the OS is within a few percent of that, I'd consider it to be a match.
    08-28-12 03:51 PM
  10. ralfyguy's Avatar
    Mine has 141 recharges and still is at 92% health like the day I got it back in November last year.
    peter9477 likes this.
    08-28-12 05:57 PM
  11. axllebeer's Avatar
    Here is where I sit on health. Had mine since day 1.
    peter9477 likes this.
    08-28-12 06:06 PM
  12. dugggggg's Avatar
    After 9 months and 184 recharge cycles, health is now at 88%, down from a high of 95%.

    This correlates well with a drain test I conducted last night, which lasted almost exactly 10.4 hours. Using Battery Guru's CSV file, I used 42 sample points at 15-minute intervals to calculate average power and current. Average power was 1.76W---91.6% of 19.98Wh. Average current was 467mA---89.9% of 5400mAh.
    peter9477 likes this.
    08-29-12 12:39 PM
  13. peter9477's Avatar
    Checked my original unit, with a drain test using max brightness. (I've only ever done minimum brightness tests before but this seemed to work fine.)

    It averaged 3.2W and shut down after 5.4h, for a health of 86%. The OS is currently reporting 87%, so a good match.

    This unit has 212 recharge cycles on it and was received in late April last year.
    08-30-12 05:03 PM
  14. DerKane's Avatar
    Do you have it connected to a Live/Hotmail account?

    These have know battery draining effects, if removed all will be okay.
    08-30-12 05:12 PM
  15. peter9477's Avatar
    Do you have it connected to a Live/Hotmail account?

    These have know battery draining effects, if removed all will be okay.
    We're talking about the "health" of the battery, which is its actual charge capacity relative to the nominal capacity (19.98Wh).

    This has nothing to do with excessive battery draining, or Hotmail accounts...
    08-30-12 06:11 PM
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