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  1.    #1  
    My TP takes about 3.5 hours to charge from 2% to 100%. The touchstone is taking about 6 hours to charge from 2% to 100%. Is this normal ?
  2. #2  
    No idea but it's not good to let your TP drop to 2% power too often, it will affect your battery life.

    I tend to leave mine on the Touchstone overnight and/or when I'm not using it so it's topped up as much as possible.
  3. Semma2's Avatar
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    #3  
    That's a bit long. HP says it should take about 50% longer, and I found the charging time on the Touchstone consistent with that. Are you leaving it turned on in Exhibition mode? If so, charging will take longer because you're using some extra current.

    Other than that, are you sure your TP is properly centered on the stand? Not in a case that increases the separation? Using the HP 2-amp charger?
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    #4  
    I've never timed it but it seems reasonable to me. Do you leave it on presentation mode?

    Battery life is good so I just leave mine on the touchstone overnight when needed.
  5.    #5  
    Quote Originally Posted by kenmitch View Post
    I've never timed it but it seems reasonable to me. Do you leave it on presentation mode?

    Battery life is good so I just leave mine on the touchstone overnight when needed.
    I don't leave it on presentation mode. I'll try a few more times to see if it gets better. (My touchpad is naked - ie: no case or covers on it.)
  6. #6  
    same thing with me.
  7.    #7  
    Quote Originally Posted by Steep View Post
    No idea but it's not good to let your TP drop to 2% power too often, it will affect your battery life.

    I tend to leave mine on the Touchstone overnight and/or when I'm not using it so it's topped up as much as possible.
    I thought we had to run the battery down as far as possible, then give it a good 100% top up ?

    At what percentage level should I charge my TP ? I don't like the idea of leaving my TP charging all day or all night as I thought that would cause my battery life span to shorten quicker ? I prefer to charge up to 100% and then immediately remove it from the charger. I also thought frequent charging (ie: using the TP for 10 minutes, then throwing it back on the charger) would shorten the life span of the battery ?
  8. #8  
    I have noticed that it does take about twice as long on the touchstone. And I also read that you are not supposed to drain it that much.... ive charged it on usb twice and touchstone three times. Once at work where i took it off as soon as it hit 100% and twice overnight but i always get up to go to bathroom mid night so if it was at 100% i took it off. I too im afraid to leave it on the TS all the time.
  9. daonei's Avatar
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    #9  
    Quote Originally Posted by sylvestor1234 View Post
    I thought we had to run the battery down as far as possible, then give it a good 100% top up ?

    At what percentage level should I charge my TP ? I don't like the idea of leaving my TP charging all day or all night as I thought that would cause my battery life span to shorten quicker ? I prefer to charge up to 100% and then immediately remove it from the charger. I also thought frequent charging (ie: using the TP for 10 minutes, then throwing it back on the charger) would shorten the life span of the battery ?
    I think you're right. It's better to use up your battery and charge when necessary rather than constantly charging at random intervals.

    BTW, completely turning off the Touchpad also helps to charge more quickly. You won't know when it's charged, but I noticed that it charges much faster that way.
  10. #10  
    Quote Originally Posted by Semma2 View Post
    That's a bit long. HP says it should take about 50% longer, and I found the charging time on the Touchstone consistent with that.
    Where does HP say it should take 50% longer? Here is what I'm seeing on the HP site:


    HP Touchstone Charging Dock

    4.8 out of 5 stars (59 reviews)
    • Simple and elegant inductive charging dock

    • Easily adjustable, charges in portrait or landscape, no cables

    Same charge time as with standard AC power adapter
    HP TouchPad chargers, Touchpad | HP® Official Store

    Just curious where you saw something different. This wouldn't be the first time the HP site specs were wrong.
  11. #11  
    This has been posted several times before but the old adage about letting your batteries fully discharge before charging applies to older battery technology, like NiCd, not newer ones like Lithium ion, like the ones in the TouchPad.

    Battery life span for the TouchPad is determined by the cumulative discharge. The less you discharge your battery the longer it will live. Keep it on your Touchstone when not in use.

    If you want more information, look up "memory" for NiCd versus Li-ion.
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  12. Invid's Avatar
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    #12  
    Quote Originally Posted by tasogare View Post
    This has been posted several times before but the old adage about letting your batteries fully discharge before charging applies to older battery technology, like NiCd, not newer ones like Lithium ion, like the ones in the TouchPad.

    Battery life span for the TouchPad is determined by the cumulative discharge. The less you discharge your battery the longer it will live. Keep it on your Touchstone when not in use.

    If you want more information, look up "memory" for NiCd versus Li-ion.
    This is correct. Excessively discharging a lithium ion or lithium polymer (Li-ion or LiPo) battery will shorten its service life. Top up the Touchpad when you're not using it - don't get me wrong, use it if you need it, but deliberate full discharges are not a good idea.

    There is actually circuitry inside the cell to prevent the battery from discharging too deeply (~3.0 volts per cell vs. ~3.7 volts fully charged), as such a deep discharge can destroy the battery in one charge cycle. The tips you remember about fully discharging nickel cadmium (NiCd) cells from the '80s and early '90s don't apply to this battery chemistry.
    Last edited by Invid; 09/26/2011 at 08:04 PM.
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  13. #13  
    My TP takes about 3.5 hours to charge from 2% to 100%. The touchstone is taking about 6 hours to charge from 2% to 100%. Is this normal ?
    I find that Touchstone charging is much slower than the standard method. Oh well, the price for coolness :-)


    -- Sent from my HP TouchPad using Communities
  14. #14  
    Quote Originally Posted by tasogare View Post
    This has been posted several times before but the old adage about letting your batteries fully discharge before charging applies to older battery technology, like NiCd, not newer ones like Lithium ion, like the ones in the TouchPad.

    Battery life span for the TouchPad is determined by the cumulative discharge. The less you discharge your battery the longer it will live. Keep it on your Touchstone when not in use.

    If you want more information, look up "memory" for NiCd versus Li-ion.
    Quote Originally Posted by Invid View Post
    This is correct. Excessively discharging a lithium ion or lithium polymer (Li-ion or LiPo) battery will shorten its service life. Top up the Touchpad when you're not using it - don't get me wrong, use it if you need it, but deliberate full discharges are not a good idea.

    There is actually circuitry inside the cell to prevent the battery from discharging too deeply (~3.0 volts per cell vs. ~3.7 volts fully charged), as such a deep discharge can destroy the battery in one charge cycle. The tips you remember about fully discharging nickel cadmium (NiCd) cells from the '80s and early '90s don't apply to this battery chemistry.
    Exactly and well said. Anyone who is skeptical can read up on Li-ion and LiPo battery technologies, and charging practices versus more conventional battery tech used in the past
  15. #15  
    Actually, it's not correct. Invid's assertion that charging circuitry prevents full discharging is correct, but not the point that discharging one's battery fully harms batteries. While that sounds counter-intutitive, consider that the circuity Invit writes about *prevents* actual full discharging. When a person sees his or her battery discharged to 1-2% that is not an actual full discharge but merely what the OS is indicating a low battery state to be.

    These modern lithium ion batteries can not be fully discharged by an end-user nor can they be overcharged. The main reason companies recommend monthly "full" discharge and recharge cycles (as apple's official documentation does, for example) is to ensure proper calibration of the battery gauge.

    Also, maintaining a full charge at all times will eventually reduce battery longevity because it's important to move the electrons around inside the battery (again, according to apple's official literature). For long term storage, however, batteries should be kept around half to 2/3 charge--no more and no less.

    Li-Ion batteries count lifespan in complete cycles not partial cycles. If you charge your battery from 1-100 then it's the same as if you charge from 50 to 100 twice. There are no other guidelines I'm aware of other than these.

    While I haven't researched HP's position on battery care, I did so for my macbook (hence the apple references). I choose to abide by apple's instructions because they are the leader in battery longevity and they warranty their batteries.

    my suggestion is to use the touchpad as you normally would and not worry about the battery. I don't have any suggestion as to the touchstone though, sorry.
  16.    #16  
    thanks to all for the comments. Great advise here..
  17. Invid's Avatar
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    #17  
    Quote Originally Posted by sm007h View Post
    While that sounds counter-intutitive, consider that the circuity Invit writes about *prevents* actual full discharging. When a person sees his or her battery discharged to 1-2% that is not an actual full discharge but merely what the OS is indicating a low battery state to be.

    These modern lithium ion batteries can not be fully discharged by an end-user nor can they be overcharged. The main reason companies recommend monthly "full" discharge and recharge cycles (as apple's official documentation does, for example) is to ensure proper calibration of the battery gauge.
    No it's not a full discharge, because of the preventative circuitry I mentioned in my earlier post. The charge circuit prevents the cells discharging below ~3V because doing so will destroy them in short order. The point I was trying to get across was that the chemistry of lithium batteries is not the same as the older NiCd or Nickel Metal Hydride (NiMH) cells and the same rules of thumb don't apply. The newer charge circuits don't require monthly calibration cycles anymore either. An occasional full discharge will suffice.

    You did mention a good point about storage though. Lithium batteries last longer in storage if they are put away with around a 50% charge and stored chilled (in the refrigerator, not the freezer). Even if you don't use them, their capacity will steadily degrade after manufacture, but that degradation can be minimized by storing them at low(ish) temperatures with a partial charge. Never freeze a lithium battery as the ice crystals will damage the electrolyte.

    A nice, plain-language article on the care and feeding of lithium chemistry batteries can be found here.

    Cheers!
  18. #18  
    To be clear, the calibration I was referring to was in regard to the OS gauge that is displayed to the user not the battery charge circuits themselves.

    I was on my touchpad earlier so didn't post the link, but as I wrote I prefer Apple's advice to lithium ion battery maintenance over a random internet source since they warranty their batteries and are the leaders in battery longevity (with the added caveat of "in my opinion" although I'm not aware of any rival portable devices).

    Apple - Batteries - Notebooks
    Standard Maintenance
    For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Apple does not recommend leaving your portable plugged in all the time. An ideal use would be a commuter who uses her notebook on the train, then plugs it in at the office to charge. This keeps the battery juices flowing. If on the other hand, you use a desktop computer at work, and save a notebook for infrequent travel, Apple recommends charging and discharging its battery at least once per month.
  19. #19  
    Very nice thread about batteries, which play a key role in almost everyone's life today, and still are overlooked. In my original Pre I used Dr. Battery to care for its calibration, and I prefer fewer and longer charge cycles (letting it drop near zero on purpose) instead of frequent short charges. After reading this thread, perhaps I won't change this habit, but also I won't worry as much when forced to do a short charge cycle.

    About the Touchstone charge times, well, I guess induction has important power losses that direct cable hasn't. Is there any literature about this subject?

    I couldn't help but giggle at reading that "keep the electrons in it moving" statement. So Apple's electrons are able to stand completely still?
  20. Invid's Avatar
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    #20  
    Another resource is available at batteryuniversity.com where they plot test data of depth of discharge vs. number of charge cycles before the battery is "exhausted" (only retains 70% of design capacity).

    The shallower the discharge, the longer the life and greater the number of charge cycles. Over its life, a battery that is shallowly discharged will provide more power than one that is discharged to the cell protection cutoff point on every cycle. Read the test data for yourself.

    They even cover the effect of charge voltage on capacity degradation, but that's largely out of our hands for consumer devices.

    It's also written in plain language, but it's more data driven than the more topical link I posted earlier.

    Cheers.
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