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Posts: 3 | Thanked: 0 times | Joined on Jun 2008 @ Knoxville
#1
I've had my tablet a few days and have noticed that it will not operate from AC power... only from the battery. I'm accustomed to using my laptop at home while plugged into the AC outlet, thus conserving the battery life. Most laptops will charge the battery while being used from external power. But the n800 appears to be using the battery even while still plugged in to the AC.
Example: I charge the battery overnight until it says it's fully charged; turn the unit on while still plugged in; operate the n800 for a couple hours (plugged in); and upon turning off the unit, notice that it is now once again charging the battery!! This is after it had already told me that it had a full charge prior to operating while plugged in.
Does this mean that the n800 will only operate from the battery? Does this mean that if I were to remove the battery, the unit will not operate at all via AC cord? Will I never be able to operate the tablet for extended periods of time unless I purchase additional batteries? I am confused on this issue since it doesn't follow standard laptop operation.
 
IcelandDreams's Avatar
Posts: 228 | Thanked: 30 times | Joined on Mar 2008 @ Ontario & Iceland
#2
1st rule, don't turn it off! It goes to low power mode more efficiently than a laptop. It uses more when you cycle the power.
It will run forever plugged in to AC but I don't think I'd run without a battery even if it did work.

So don't worry.
 

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#3
Ok, I'll try and clear things up a little. In terms of software the N8x0 is closer to a desktop or laptop computer running linux, but in terms of hardware it's more similar to a cell phone. For the sake of miniaturization some of the flexibility of a laptop's power system is left out. On the tablet, the charging circuit charges the battery, and the system runs off the battery. Without a battery in it, it won't run.

As for your experience with it switching to "charging" after having already been charged, there are two possible explanations.
1) There are situations when the tablet can draw power from the battery, faster than the charger can add it. During the booting process is one such time, because of all the work it's doing starting up. In general, this isn't something to worry about.
2) Also, instead of constantly charging the battery, it's possible (likely?) that the hardware in your tablet lets the battery get down to 90-95% and then charges it back to 100%. However, if you plug in the charger when it's at 99% it will say charging for a second, before switching to charged. It's probably a similar case when the battery applet starts for the first time.

Executive summary: Don't worry about it. This is normal. You can use your tablet for as long as you want while it's plugged in. Also, it draws so little power while plugged in and turned on with the screen blank, that there is little reason to turn it off while it's plugged in.

-John
 

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Super Moderator | Posts: 5,335 | Thanked: 8,172 times | Joined on Mar 2007 @ Pennsylvania, USA
#4
Originally Posted by pphilipp View Post
Does this mean that the n800 will only operate from the battery?
Technically, yes, from what I understand, the Nokia Internet Tablets always pull energy from the battery for their operation--even while connected to a charger. So...

Does this mean that if I were to remove the battery, the unit will not operate at all via AC cord?
That's what I've read, though I haven't tested it. I'd test it for you now, but my N800 and I are temporarily geographically separated from both A/C and automotive chargers.

In any case--barring battery or charger problems--a tablet will, of course, charge its battery when connected to a charger. So, the power an operating tablet draws from the battery will continually be refreshed by power from the charger.

Does the water on a spillway come from the reservoir or the streams feeding the reservoir? And if inflow and outflow are equal, does it matter?

If inflow and outflow aren't equal...

...and upon turning off the unit, notice that it is now once again charging the battery!
Depending upon the charger used, and the work an operating tablet performs, it's possible to draw power from the battery faster than it is refreshed by the charger. For instance, setting the display to full brightness + "stay on while charging", playing streaming audio or video at full volume, and inserting and removing high capacity flash cards filled with media with media all on a tablet charging via a USB adapter connected to an older notebook computer would lead to "Low battery" warnings in no time.

Is that a problem? Well, yes, it is for you if that's how you intend to use your tablet. They're not designed for that; it's close to worse case scenario for them.

However, under more normal usage, the design works fine. Average web browsing, email checking, and even media playback won't deplete the battery faster than a good charger manage.

That's not to say the battery will stay at 100%. It'll be down a bit at the end of the activity, but not so much that the charger can't top the battery back off quickly.

Also, note I wrote "good charger" above. The A/C adapter that comes with a tablet supplies a fair amount of power. USB adapters generally supply less, and car adapters may be as good as the A/C adapter...or not.

As a bit of a side note in closing, the last version of Canola2 I played with (beta 8?) had (or triggered) a bug that caused tablets connected to chargers to animate the charging indicator in the status bar happily ever after. It wouldn't stop when the battery was full; it would only stop when the charger was disconnected.

EDIT: The mighty Johnx is both faster and more concise.

Last edited by sjgadsby; 2008-06-09 at 16:42. Reason: The mighty Johnx is both faster and more concise.
 

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Posts: 3 | Thanked: 0 times | Joined on Jun 2008 @ Knoxville
#5
If I understand right, the on/off switch is not normally needed... just leave it on all the time.

But if I use it to the point where I've exhausted the battery power, I assume that the unit will shut itself off at that point, or will it go into some kind of sleep mode until connected to power?

Thanks. After twenty years of using desktop/laptops and ten years of using Windows CE devices, I'm having to learn to use something different with the n800.
 
Super Moderator | Posts: 5,335 | Thanked: 8,172 times | Joined on Mar 2007 @ Pennsylvania, USA
#6
Originally Posted by pphilipp View Post
But if I use it to the point where I've exhausted the battery power, I assume that the unit will shut itself off at that point..
It will.

You'll want to avoid this though. While the power system in the tablets shuts the device down before the battery becomes dangerously (to the battery) low, hitting that point still isn't kind to the battery. Your tablet's battery will stay healthy longer if you can recharge well before you begin seeing "Low battery" warnings.
 

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#7
Iceland is right, your unit is opperating nomally. It would be more reasurring if our battery indicator showed a "100%" number rather than the icon.
 

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#8
Originally Posted by pphilipp View Post
If I understand right, the on/off switch is not normally needed... just leave it on all the time.
Yup, exactly. You only need to switch off if the tablet has to be restarted for some reason, but that's quite rare.

If you want some hints and tips on power saving I've done a tutorial all about it:

http://tabletschool.blogspot.com/200...e-battery.html



But if I use it to the point where I've exhausted the battery power, I assume that the unit will shut itself off at that point, or will it go into some kind of sleep mode until connected to power?
It will warn you several times before the battery runs out, both with dialogue boxes and an alarm tone. If you ignore the warnings it will eventually switch itself off.


Thanks. After twenty years of using desktop/laptops and ten years of using Windows CE devices, I'm having to learn to use something different with the n800.
This power saving aspect isn't actually any different in princple to other computers.

Computers always use more power starting up than when they're just switched on, because the process of starting up a computer involves much more intense processor activity than simply being switched on.

If a computer has no moving parts and no running apps, and it dims the screen automatically when not in use, it can remain in standby mode for a very long time before the battery runs out, as much as several days. That's what the internet tablets do.


Also, note I wrote "good charger" above. The A/C adapter that comes with a tablet supplies a fair amount of power.
The other important point to make is that the Nokia charger which comes with the tablets will load the battery much faster than most Nokia chargers.

All standard Nokia chargers will work in that they will load the tablet's battery, but they will do so at different rates depending on what current they're rated at.

The way to tell the difference between Nokia chargers (or any chargers) is to look at the specs printed on them, and look for the output current which will be in mA or milliamperes. The higher the output current, the faster the battery will charge.

Last edited by krisse; 2008-06-09 at 17:47.
 

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