01-08-12 08:47 PM
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  1. A1C-James's Avatar
    Hello friends,

    Intro:
    The information I'm about to post about your battery is universal to all lithium batteries and in no way is your case special as they're operation is complex but simple to break down for all of you to digest and decide if you are in fact having a problem or not. I will cover the various circumstances playbook users experience and what it actually means.

    FAQ:
    1.)"My playbook has a funny bump or bulge on the back and Its warm/hot around that area"

    *quick edit - it was pointed out to me that the battery is offset from the swollen area invalidating most of question #1. and a quick thanks to "SumthinNew" for pointing this out. Although unrelated to the battery i was looking at the teardown and it appears this is simply the result of the processor getting hot enough to disfigure the plastic. I would assume this would frequently occur with those who have cases for their playbooks as that would help insulate the heat increasing the internal temperature

    This is normal and likely an attribute of excellent design. "How can that be"? you ask, well you playbook uses a battery type called a Lithium Polymer. Its a rectangular tightly wrapped air free series of small lithium cells. When a battery is in use in the playbook; charging, On, being used; it build up heat through resistances which causes the battery to expand from pressure. "But why some and not others?" this happens because the battery pack has a tiny pocket of air inside some times and because of that the pressure builds up and the casing expands.

    So in a nutshell, your battery has a small air pocket in the battery which due to heat buildup from the battery being used, build pressure and revels a little swell after a good charge or using your playbook for a while. The reason I said this is the result of a good design is because RIM choose to make the playbook back plate flexible is accomidate the swelling to provide all end users a healthy long lived battery.

    2.)
    "My battery is not charging! Is it dying?"


    I will let you determine the answer to your question. There are only 3 things that ware down lithium batteries within reasonably controlled environments (being your playbook). The first is time, the second is usage, the third is heat. Infact they all stack against each other multiplying the ware.

    *Time - Simply speaking, all lithium batteries have and expiry date. Hypotheticly with some variables aside, even if it was never used it would still ware out within 5 years or so.

    *Usage - the more the battery operates the faster the decay. The amount of charges is irrelevant to popular belief within a batteries life. Infact the decay is simply measured in total Amp hours. Simply put, you cant measure a vehicles life time in gas station fill ups but rather the ware and tare of its usage right?

    *Heat - This is the only thing you can actually control. Heat builds pressure in the battery which produces ware and tare similar to my analogy above. Heat is also a product of energy transfer, that of which travels through the battery to power the tablet or charge the battery. The more energy involved, the more heat is produced which has diminished returns on chemical structure of the battery. simply put, if you have a piece of metal and don't want it to rust then you obviously would not expose it to water right? You can ultimately reduce the heat by lowering the power consumption or you can be nerdy like be and build a cooling station for it while it charges


    3.) "My battery dies very quickly whats going on!"

    If you have ready everything above then this should be quiet clear. There is 1 way to discharge a battery and that is through power consumption. Thinking in a way that your battery circumstances are changing is false but rather the truth its either your device sucking up the power through regular usage or a fault in the programming causing redundant processing or you have a physical power leak.
    A physical power leak will never occur over time by its self. These are subject to faulty circuitry and such symptoms can determined after a physical accident such as dropping it, water damage, or anything that could cause a circuit to be crossed to allow the energy to not flow the way intended.

    4.) AND THE MONEY QUESTION "How do I preserve my battery?"

    - Simple use less power where possible! know it sounds stupid but you have features on your device to reduce power consumption whiles its not being used or simply keeping the the screen lamp dim even while using it. Here are some more examples is excessive power usage; using the speakers on the device or the volume level, running multiple apps, WIFI, Bluetooth, physically charging your battery uses energy.

    -A great way to preserve your battery and still enjoy the maximum benefits of your playbook is to mitigate the power consumption to other devices where possible. like using an seperately powered amplifier for sound rather than the built in speakers or head phones. Or taking advantage of the Mini HDMI port on your TV while running the lowest brightness on the tablet

    - Another great way to preserve the battery is to physically turn it off when ever your not going to be using it for a while instead of using standby mode all the time. This should be obvious but restarting the tablet fresh and restarting it will ensure any memory leaks invisible to you causing extra power consumption will be stopped temporarily.

    5.) And finally "how often should I charge my battery?" or "can I leave my charger in all the time?"

    First let me tell that lithium batteries do not diminish with memory like the old Nickel cadmium did that you would stick in your old camera, as a matter of a fact lithium batteries are nothing like any other battery what so ever aside from retaining power. The most notable difference is that it is the LAW everywhere that lithium batteries power levels and consumption must be regulated by circuitry. Why? well its because lithium batteries are extremely unstable unregulated and EXTREMELY dangerous without the proper measure set in place! Im not trying to rant but instead paint the picture of the complexity behind these batteries. This means that they charge much differently than any other battery. The battery charges very rapidly until it reaches a certain point close to its completion, after this stage the power slows down that is charging it eventually to a trickle charge. and then when fully charged the power automaticly stops. All of which is a good example of how these batteries are different.

    So leaving the charger in is good and bad. The good is that it doesn't have to so frequently endure the ware of a rapid charge which produces alot of heat BUT its bad to have a fully charged battery! WHATs THAT YOU SAY? BAD? yes a fully charged battery is not good at all! Lithium Batteries being made of chemicals actually expand with respect to the charge level. This is due to pressure from the preserved energy of which is stressful for the chemical structure of the battery. This leads me to what the most efficient charge level is. Keeping your battery around %50 is good. You still need to once in a while fully charge your battery and also fully discharge your battery (let it run out on its own). The reason why is because remember how i was mentioning the battery is electronically maintained? Well the electronics are actually smart enough to understand the batteries thresholds and adjust how it charges it. This is commonly referred to as Lithium Battery Conditioning.

    So in conclusion I'm very tired and im going to bed. Please read around the grammar and spelling since ill fix it up later should this topic grow.
    Last edited by A1C-James; 01-07-12 at 12:44 PM.
    malcerie, Nedmundo, CDM76 and 20 others like this.
    01-07-12 07:53 AM
  2. bbfan1040's Avatar
    Wow!

    I have 9 year old Prius. Lithium batteries are amazing!

    Your detailed explanations are excellent!

    I would suggest a second follow up topic on reducing power use - examples:

    Screen / brightness set to lowest adequate level.
    Backlight time out, Automatic backlight dimming, and standby time out should be used
    Don't run features you aren't needing

    Thanks again for excellent article.
    01-07-12 08:39 AM
  3. gladiatorofyale's Avatar
    great tread. im always checking my battery
    mariobastros likes this.
    01-07-12 08:58 AM
  4. SumthinNew's Avatar
    Nice write up, and not wanting to take anything away from your posts, but in regards to #1 (back bulge).
    This would make more sense if the battery is located directly behind the bulge, but in the PB case, the batt is to the right side of the device.
    mariobastros likes this.
    01-07-12 09:46 AM
  5. peter9477's Avatar
    I have 9 year old Prius. Lithium batteries are amazing
    They are amazing, but they weren't used in a 9 year old Prius. Prius has had NiMH (Nickel-Metal Hydride) batteries until very recent models, and is Lithium-ion only in some countries or in the new plug-in version. (I have a Prius too... six years old and a great car.)

    More erroneous facts above, from the OP: all the garbage about the "bulge".

    Anyone who's looked at the iFixit PlayBook teardown will have noticed that there are two batteries, not one, and they lie to either side of the motherboard, which fills the centre third (from camera to connectors) and lies behind the logo where the bulge is noticed. The heat comes from the main chips, not from the batteries, and the typical bulge is harmless.

    Unless you're seeing a bulge on either side where the batteries actually lie (and nobody has reported this), the bulge and heat have absolutely nothing to do with the battery.

    Sorry, OP, but you're just making stuff up... try a few more posts with credible references if you want to actually help people.
    louzer, bbfan1040, m_rkus and 2 others like this.
    01-07-12 09:49 AM
  6. kennyliu's Avatar
    They are amazing, but they weren't used in a 9 year old Prius. Prius has had NiMH (Nickel-Metal Hydride) batteries until very recent models, and is Lithium-ion only in some countries or in the new plug-in version. (I have a Prius too... six years old and a great car.)

    More erroneous facts above, from the OP: all the garbage about the "bulge".

    Anyone who's looked at the iFixit PlayBook teardown will have noticed that there are two batteries, not one, and they lie to either side of the motherboard, which fills the centre third (from camera to connectors) and lies behind the logo where the bulge is noticed. The heat comes from the main chips, not from the batteries, and the typical bulge is harmless.

    Unless you're seeing a bulge on either side where the batteries actually lie (and nobody has reported this), the bulge and heat have absolutely nothing to do with the battery.

    Sorry, OP, but you're just making stuff up... try a few more posts with credible references if you want to actually help people.
    Yes, and the heat around the logo comes from the CPU, not the batteries.

    The bulge doesn't have anything to do with the batteries. It's a manufacturing (cosmetic) defect probably from too much force applied during logo stamping.
    Last edited by kennyliu; 01-07-12 at 10:53 AM.
    01-07-12 10:44 AM
  7. GlowingBlue's Avatar
    hmmm... keeping the battery at 50 doesn't seem to practical...
    01-07-12 11:00 AM
  8. kennyliu's Avatar
    Thanks for the guide nevertheless.

    To summarize, your LiIon batteries:
    - Do not have a memory effect (do not need to be fully discharged/charged all the time)
    - Fully discharging/charging only helps to recalibrate the OS battery meter (should only be done occasionally).
    - Battery health deteriorates more rapidly if the battery gets discharged too often (it's a good idea to start recharging your battery before it hits 0% (better start recharging at around 20%-50%). Similarly, having the battery at 100% all the time is also detrimental.
    - Temperature plays a significant role. Heat makes the batteries deteriorate faster.
    - To prolong the battery life (period between recharges), you can lower the display brightness, turn off unused connections (Wi-Fi, GPS, BT). The showcase mode can also decrease battery life.
    - Remember, the battery will not "die" all of a sudden. Battery deterioration is a continuous process.
    - Don't worry about battery deterioration too much. If you are not "abusing" your battery, it should last long enough and you will probably get a new tablet before it becomes unusable.

    Please, see Battery University's website for more resources (google "Battery University").
    Last edited by kennyliu; 01-08-12 at 12:00 AM.
    peter9477 and louzer like this.
    01-07-12 11:04 AM
  9. oilgeo10's Avatar
    I have noticed with my PB, if it is getting recharged by the standard charger or via usb, if I leave it charging for a bit after it reaches full (1/2 - 1hr @ 100%), then when using it portable the battery indicator will stay @ 100% for up to a couple of hours use until starting to indicate discharge. First time it did this I thought there could be a problem with the indicator, and was happy to see it finally start trickling down! My PB easily lasts for a full day of normal use when charged like this. Really like the standby feature as well, power use is minimal.
    My PB is only 10 days old since getting it last week, hopefully the battery performance remains this good for awhile.
    01-07-12 12:00 PM
  10. blackjack93117's Avatar
    The battery does seem to be off to the sides - though I have noticed the heat being concentrated in the center when charging and playbook is relatively inactive - especially in the charging cradle not so much when the PB is active (CPU heat) but when it is charging (battery heat) So which is it?

    Could battery heat be conducting through the case to the cradle (center) if it is acting as a heat sink? Thus causing it to warp in the center? If it is CPU heat why does it get hot when charging while the PB is in standby - well not sure actually when I've noticed this but I don't have the PB doing a heck of a lot while it is in the cradle. I will make more observations.

    Thanks for taking the time to write this up - I'd like to copy this to the Tips for Newbies sticky with OP's permission, but want to be sure it is accurate.
    .
    Stating sources would be helpful.
    Last edited by blackjack93117; 01-07-12 at 12:32 PM.
    01-07-12 12:21 PM
  11. blackjack93117's Avatar
    ^^Can anyone tell where the audio power amp is? That seems to be quite a heat generator as well.
    01-07-12 01:15 PM
  12. peter9477's Avatar
    Thus causing it to warp in the center? If it is CPU heat why does it get hot when charging while the PB is in standby - well not sure actually when I've noticed this but I don't have the PB doing a heck of a lot while it is in the cradle. I will make more observations.

    Thanks for taking the time to write this up - I'd like to copy this to the Tips for Newbies sticky with OP's permission, but want to be sure it is accurate.
    When you're charging with the cradle, you're pumping almost 10W of power through the connector at the bottom, and across some of the motherboard. Maybe 13-15W if you've got the thing turned on... that's more than enough power to explain the heat without involving the batteries. In fact, the batteries rarely report a temperature above 30C while the CPU can often get to 40C.

    There's zero evidence that "battery heat" is involved in any bulges, or that there's any "warping" going on... that would imply that the bulge gets worse over time. Has anyone claimed that yet? I've seen lots of reports of the bulge, but kennyliu's speculation is one of the most reasonable I've seen so far: a simple manufacturing defect. I think it might actually be the RF shield behind the logo (seen in the photos as covering the main chip area) rather than the logo or the case itself, but I don't know why anyone points to the batteries as a possible cause without any evidence to back up that theory.

    I think only kennyliu's excellent follow-up summary merits being in a Tips and Tricks list, but even then I'd caution against telling people not to discharge below any particular value, or not to leave it on the charger. I wouldn't even mention heat since it's only going to scare people unnecessarily and get us even more "mine gets pretty warm, is it okay?" threads...

    Here's a summary for Tips and Tricks: there is no certain way for any pattern of use to do any significant damage to your PlayBook, so you can simply forget about the battery and have confidence you're not damaging it. Never store your PlayBook after fully discharging the battery, as that can over a long period of time damage the battery.

    (Then mention a list of things you can do to maximize the life from one charge.)
    louzer likes this.
    01-07-12 01:48 PM
  13. dugggggg's Avatar
    WRT to bulging, there are two independent issues.

    First, heat. The center of the back of the case, where the logo is, is the only place where the metal heat sink is exposed---the rest is covered by rubberized plastic. So it's not too surprising that this area will feel the warmest. Heat is generated from the batteries both charging and discharging, and from the CPU and other chips.

    Second, the bulge itself. We honestly don't know the root cause. Perhaps RIM does, but they're not telling. It could be due simply to a sizing error in the back of the case. Or overstamping or misalignment as some have suggested.

    But it could certainly be due to swelling of one or both of the Lithium Polymer cells---even though the cells are not located in the center. This is because the center is considerably less constrained than near the edges---and that's where the expansion will be the greatest and most noticeable.

    Lithium ion battery chemistry is tricky, and proper construction is critical. Even minor contamination (even by simple humidity) of the materials could result in trapped moisture, leading to liberated hydrogen and oxygen, causing swelling of the otherwise solid battery pack.

    As an engineer, I'm well cognizant that heat causes expansion. But the operating temperature range here is really quite small---and it's unrealistic IMHO to suggest that the noticeable case expansion is due only to heat.

    Until PB owners are willing to void their perfectly good warranties, disassemble both a normal and a bulging PB, and carefully compare the battery dimensions---the true cause of the bulge will likely remain just pure conjecture.

    That said, a swelling battery is potentially dangerous. I would think that if someone notices a visible increase in the bulging, that they should avail themself to a free replacement tout de suite.
    Last edited by dugggggg; 01-07-12 at 02:28 PM.
    peter9477 likes this.
    01-07-12 02:09 PM
  14. blackjack93117's Avatar
    ^^^ thanks for the info peter, duggggg Plus I suppose the bulge is there on day one with little use so that blows my theory... manufacturing and quality control thing I guess. Mine doesn't bulge so I don't have anything to look at.

    It appears the battle of the bulge is nothing to be concerned about - only cosmetic.
    Last edited by blackjack93117; 01-07-12 at 02:55 PM.
    01-07-12 02:44 PM
  15. bluezone1's Avatar
    very nice write-up. good info. but may i ask to add that 100% discharge of Lithium batteries is not good for them either. the high current draw at full discharge is what caused battery problems with early Lithium batteries. things have changed with the charging practices in regard to this. infact if a Lithium battery is so low in charge that a high current draw is nessary to recharge it. it will not charge to prevent over-heating of the battery. so try to not let it get too low in charge level. my android phone warns if the charge is nearing 15% that immeadate charging is nessary.

    i enjoyed your post keep up the good work.

    cheers
    sam81 likes this.
    01-07-12 02:47 PM
  16. peter9477's Avatar
    But it could certainly be due to swelling of one or both of the Lithium Polymer cells---even though the cells are not located in the center. This is because the center is considerably less constrained than near the edges---and that's where the expansion will be the greatest and most noticeable.
    ...
    That said, a swelling battery is potentially dangerous. I would think that if someone notices a visible increase in the bulging, that they should avail themself to a free replacement tout de suite.
    Valid point about the bulge being centered.

    Totally agree on the potential danger -- until we really know the cause -- and the advice to definitely get a replacement if the bulge increases, as we've now heard at least two users say theirs did (in another active thread).

    (There could be two unrelated things here: bulge existing in shipped units, and bulge forming after use in other units, so no reason so far to assume merely having a small bulge is more than a minor and largely cosmetic flaw.)
    01-07-12 02:51 PM
  17. peter9477's Avatar
    ... but may i ask to add that 100% discharge of Lithium batteries is not good for them either. the high current draw at full discharge is what caused battery problems with early Lithium batteries. things have changed with the charging practices in regard to this. infact if a Lithium battery is so low in charge that a high current draw is nessary to recharge it. it will not charge to prevent over-heating of the battery. so try to not let it get too low in charge level.
    Please get the full picture before scaring people with this sort of thing, or before being scared by it.

    "Full" discharge... "high current draw"... care to quantify those so we can apply the information in context?

    The PlayBook is designed never to discharge the batteries "fully". In fact it shuts itself off when the batteries reach 3.4V, which is well above any level generally considered to be "not good" for the batteries. The charging subsystem is design never to overcharge the batteries, either in terms of voltage or current.

    You can discharge the PlayBook to 0% without concern for the battery, as far as all my research indicates. I'd be more than happy for someone to prove me wrong about that, provided they can offer references and hard facts, rather than merely repeating phrases out of context in ways that simply scare regular users into doing silly things that unnecessarily limits their PlayBook experience.

    Sorry to jump on you bluezone1, but while what you say is technically true, I think you'll agree that it simply doesn't apply when the product's design prevents anyone from getting their battery to the state you're talking about. If you can show that 3.4V is a level at which these batteries will be significantly damaged, or that the batteries can ever take a "high current draw" from the charger, I'll eat my hat (and that's a figure of speech: I hate the taste of wool!).
    bluezone1 and wellard like this.
    01-07-12 03:00 PM
  18. nogutsnoglory's Avatar
    BUT its bad to have a fully charged battery! WHATs THAT YOU SAY? BAD? yes a fully charged battery is not good at all! Lithium Batteries being made of chemicals actually expand with respect to the charge level. This is due to pressure from the preserved energy of which is stressful for the chemical structure of the battery.
    First, thanks for the thread. I enjoyed reading it.

    I am a little confused though. It sounds as if you are saying that the battery can be damaged if kept in a fully charged state such as if one were to keep the PB in a charger for a good part of its life.

    He is where my confusion comes in. My 2-3 year old lap top has a lithium battery. I use the lap top for work 8-10 hours a day during the week and occasionally on the weekend. For the past 2-3 years, I have always docked my laptop at work to keep it in a constantly full charge state. At home it is always plugged in. After 2-3 years of this practice, I would think that my battery would have fairly excessive wear under the above theory. According to a battery monitoring program I have my laptop battery has only 6% wear in this period. I would have thought it would be more.

    Anyone know why this is?
    01-07-12 05:43 PM
  19. peter9477's Avatar
    I am a little confused though. It sounds as if you are saying that the battery can be damaged if kept in a fully charged state such as if one were to keep the PB in a charger for a good part of its life.

    Here is where my confusion comes in. [describes how his laptop is fine after doing this for years]

    Anyone know why this is?
    Every time you see someone telling you that the battery "can be damaged" by leaving it fully charged, ask them for references and quantifiable data as to what they mean. You'll generally find they have nothing and are merely reporting stuff they "read or heard somewhere", or perhaps have an anecdote to share about a friend's cousin's battery that died because he did X to it (or didn't).

    If they actually have a link, or produce some data, it will probably be generic info dealing with Lithium-Ion battery theory. It won't take into account anything to do with your particular product (laptop, tablet, etc) and all the things the designers and engineers will already have done to the hardware and software to ensure that, under typical patterns of use, it largely avoids the potentially damaging conditions and ensures a long life for the battery.

    Those saying "leaving it fully charged" or "discharging it fully" can "damage" the battery are defining neither "full" nor "damage". Without numbers, it's FUD. With numbers, we could actually demonstrate that the PlayBook, and probably your laptop, are not in any danger of getting into the extremes where this matters.

    (I'm thinking if I can be blunt enough about this, maybe it will inspire someone to make the effort to find some actual data that can refute what I'm saying in some small degree. Then we'd be making progress...)
    BuzzStarField likes this.
    01-07-12 07:32 PM
  20. bluezone1's Avatar
    Please get the full picture before scaring people with this sort of thing, or before being scared by it.

    "Full" discharge... "high current draw"... care to quantify those so we can apply the information in context?

    The PlayBook is designed never to discharge the batteries "fully". In fact it shuts itself off when the batteries reach 3.4V, which is well above any level generally considered to be "not good" for the batteries. The charging subsystem is design never to overcharge the batteries, either in terms of voltage or current.

    You can discharge the PlayBook to 0% without concern for the battery, as far as all my research indicates. I'd be more than happy for someone to prove me wrong about that, provided they can offer references and hard facts, rather than merely repeating phrases out of context in ways that simply scare regular users into doing silly things that unnecessarily limits their PlayBook experience.

    Sorry to jump on you bluezone1, but while what you say is technically true, I think you'll agree that it simply doesn't apply when the product's design prevents anyone from getting their battery to the state you're talking about. If you can show that 3.4V is a level at which these batteries will be significantly damaged, or that the batteries can ever take a "high current draw" from the charger, I'll eat my hat (and that's a figure of speech: I hate the taste of wool!).
    i am not offended by what u are saying nor do i feel jumped on at all. communication is always good. no hat eating will be needed.
    i will explain myself if u would like to private message me.i understand the point about not scaring people.
    01-07-12 08:51 PM
  21. Chaddface's Avatar
    Please explain here
    [YT]http://www.youtube.com/watch?v=Pj-qBUWOYfE&feature=related[/YT]
    01-07-12 09:11 PM
  22. bluezone1's Avatar
    Every time you see someone telling you that the battery "can be damaged" by leaving it fully charged, ask them for references and quantifiable data as to what they mean. You'll generally find they have nothing and are merely reporting stuff they "read or heard somewhere", or perhaps have an anecdote to share about a friend's cousin's battery that died because he did X to it (or didn't).

    If they actually have a link, or produce some data, it will probably be generic info dealing with Lithium-Ion battery theory. It won't take into account anything to do with your particular product (laptop, tablet, etc) and all the things the designers and engineers will already have done to the hardware and software to ensure that, under typical patterns of use, it largely avoids the potentially damaging conditions and ensures a long life for the battery.

    Those saying "leaving it fully charged" or "discharging it fully" can "damage" the battery are defining neither "full" nor "damage". Without numbers, it's FUD. With numbers, we could actually demonstrate that the PlayBook, and probably your laptop, are not in any danger of getting into the extremes where this matters.

    (I'm thinking if I can be blunt enough about this, maybe it will inspire someone to make the effort to find some actual data that can refute what I'm saying in some small degree. Then we'd be making progress...)
    will this help?

    Basic to Advanced Battery Information from Battery University
    01-07-12 09:20 PM
  23. peter9477's Avatar
    Nope...

    Seriously, I've read that. Many times now, starting last April or so when I first started researching to develop Battery Guru.

    If you want to pull out something specific with numbers that we can apply to the PlayBook, I'm happy to discuss it. Generic terms like "full" or "empty" are useless concepts with these batteries, however, especially if the PlayBook's design is such that it effectively prevents those conditions (assuming some concrete definition of them) from even being possible.

    Let me try a simple example. Let's pretend that "fully discharged" was defined somewhere as being 2.8V. If the PlayBook shuts itself off as soon as the batteries give a 3.4V reading or less, for more than two minutes, would you agree that these batteries can never be "fully discharged", even if you run the PlayBook until it shows 0% and shuts itself off?

    The case with "fully charged" is a bit more complicated, since it depends on a measurement of current as well, but if you can provide a clear definition with some numbers, let's look at whether the PlayBook "fully charges" according to that definition and, if so, whether there's any possibility of damage because of it being left on the charger indefinitely. We'd need to define "damage" as well. I'd start by pointing out that it's unreasonable to define damage as any decrease in the battery life relative to it sitting at 40% and never being used.
    01-07-12 10:01 PM
  24. bluezone1's Avatar
    quote peter9477
    "Let me try a simple example. Let's pretend that "fully discharged" was defined somewhere as being 2.8V. If the PlayBook shuts itself off as soon as the batteries give a 3.4V reading or less, for more than two minutes, would you agree that these batteries can never be "fully discharged", even if you run the PlayBook until it shows 0% and shuts itself off?"

    under normal conditions i have to agree. but no battery storage system is static.
    things wear out or dischage over time. the idea i was trying to put across without getting in a protracted answer was. that beyond a certain point dischage of a battery is bad. to make things simple. worst case. someone puts their playbook away at the shut down point. 3.4 volts. then weeks later decides to recharge the playbook. if the battery has self discharged beyond a certain point. (lithium batteries discharge over time even without use). the safety system in the playbook may not allow the recharge of the battery. this would be to prevent damage.
    i have actually experienced the bad results of charging an overly discharged lithium battery(not in the playbook). battery bulge and ruined battery cell. lots of heat.
    so what i am saying with 100% discharge of the battery (not quoting some other indeterminate charge level and possibly changing cut-off point) is 100% discharge. not the playbook shutdown point.

    i'm not trying to be difficult. it's just the battery changes over time.

    i have been known to tear my tech apart 1st chance i get just to see what makes it tick. but i've grown out of this habit. plus it sounds like you have done alot of the leg work required to nail down information about the playbook charging system.
    Last edited by bluezone1; 01-07-12 at 11:40 PM.
    01-07-12 11:29 PM
  25. louzer's Avatar
    And, of course, to track the useage, drain, and overall health of the battery, you should not be without Peter's excellent Battery Guru app. If the Playbook had a 'startup' folder, I'd have his app in there. I know that there are some people who'd rather spend their money on Angry Birds, but this app actually serves a practical purpose on the Playbook. Disclosure - I also like the SSH app better than Angry Birds too.
    peter9477, wellard and kennyliu like this.
    01-07-12 11:55 PM
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