BlackBerry® PlayBook™

[knottyrope]

the current OS version of the playbook allows it to charge while powered off, but previous versions need to have it with power on.

[shortz]

omg wow i have charged my playbook while it was of since i have opened it out of the box so allllllll you guys are on drugs lol srry to burst all your bubbles but fact. i have been since i got the playbook

[shortz]

sorry forgot to mention there is a led indicator that flashes while the playbook power is OFF! just took it off 20 mins turned it ON than started checkin out more formes

[walcom]

when i plug in my playbook when it is off, i see a blinking green light that tells me it is charging. is it still true that you cant charge a PB when it is off cos thats not my experience

[knottyrope]

PlayBook can be charged when off with latest software release 1.0.6

[Xandrex]

hello,

for Peter :

the Battery University website states that it is not recommended to have a full voltage charge when reaching 100% of charge. It simply means that the battery is supposed to tell the charger to lower the voltage until reaching the "top charge" voltage (much lower voltage that is used to keep the battery fully charged, when already charged).

On the other hand, and though it seems contradictory but it is not, it is recommended that a lithium battery is always charged, that is the reason why the docks/cradles that appeared first with the Apple iPod and the first HTC smartphones are not harmful in any way to the battery.

And same goes for the datasync docks/cradles.

*****

Now the question that was often raised by JerryG is that the nominal voltage for a battery to be charged depends on the battery itself. Usually, the battery contains an inner controller that can stop the charge in case the voltage is too high or too low (granted a too low voltage should not be harmful for the battery). For your information, this inner controller is usually what is missing in fake batteries (the ones that made the iPhones explode).

*****

From what has happened in the recent OS releases (1.0.5 or 1.0.6 I can't remember), it seems that for the PlayBook, the battery inner controller is software and not hardware, since:

• at first the PlayBook could not be charged when turned off
• now the PlayBook can refuse to be charged when the voltage is too low, with an explicit error message (especially some laptop USB port that do not deliver enough).

I am quite surprised by that (going the opposite way as everyone else : from hardware to software controller), maybe RIM is several steps ahead.

[peter9477]

It's going to take me a while to parse your meaning with that, since the term "100% of charge" is meaningless other than when interpreted as "at full voltage". There is no "%" in a battery... there's the voltage. If you don't charge to the full voltage, you're not at "100%". I'll reread your post a few times and see if I can figure it out.

Also note that it's a near certainty the batteries do have integrated/embedded microcontrollers (what you're calling the "inner controller") but I think those are unlikely to be directly involved in the charging process, at least other than as having a "veto" on whether the battery can continue to supply power (at very low voltages) and, possibly, whether it can continue to accept a charge at high voltages. The fact there's an embedded controller in there doesn't preclude them also having software running in the PlayBook to manage the charging process more intelligently and effectively.

[Xandrex]

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peter9477 wrote:
It's going to take me a while to parse your meaning with that, since the term "100% of charge" is meaningless other than when interpreted as "at full voltage". There is no "%" in a battery...

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Battery is an energy container, my "100%" means "battery is fully charged".

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peter9477 wrote:
Also note that it's a near certainty the batteries do have integrated/embedded microcontrollers (what you're calling the "inner controller") but I think those are unlikely to be directly involved in the charging process, at least other than as having a "veto" on whether the battery can continue to supply power (at very low voltages) and, possibly, whether it can continue to accept a charge at high voltages.

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well a battery charger does modify its voltage to match the quantity of voltage the battery wants to receive, given its state of charge. So one way of the other, the battery does say "I'm half charged" or "I'm nearly full, don't push too hard on me".

Here is the time diagram that is available on battery university:

http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries

[peter9477]

Okay, that helps. So we could say that when the battery has reached the maximum voltage (during charging), it's not "fully charged", and the controllers have to monitor the current to determine when they've shoved enough extra energy in that they can stop charging.

I'll note, however, that in the curve shown, the voltage has reached the "full voltage" way back at the first dashed vertical line, long before this point is reached. That doesn't fit in my head with the suggestion that you shouldn't "have a full voltage charge when reaching 100% of charge".

Which part of that page, or other page, makes the recommendation to keep the battery "always charged"? (I've read the page a half dozen times, but would prefer not having to read it again just to find that! :-) )