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maemo.org - Talk (https://talk.maemo.org/index.php)
-   Nokia N9 / N950 (https://talk.maemo.org/forumdisplay.php?f=51)
-   -   N9 battery goes straight from 100% to 94% coming off charge (https://talk.maemo.org/showthread.php?t=85801)

waspy 2012-07-31 21:10
N9 battery goes straight from 100% to 94% coming off charge
 
Hi there,

Just wondered if anyone else has had similar problems to me; it concerns a brand new 16Gb N9. I did a full charge from new (well, I charged it at work to about 70%, turned it off and then continued the charge later on when I got home to 100%) and thought I'd imagined the battery meter jumping straight down to 93%. Well I didn't imagine it, draining the battery today (to cycle the charges before I top the battery up normally) it jumped straight down to 94%. Is this nomal? Idling along with 3G on and push mail I watched it and it only seemed to be losing 2-3% an hour, which is what I'd expect, but it seems either I'm missing full capacity or my calibration is wrong. Actually, I should probably mention that the N9 shut down at around 10% too.

Anyone else experienced this? Will this iron itself out after a few more power cycles?

slashd0t 2012-07-31 21:19
Re: 9 battery goes straight from 100& to 94% coming off charge
 
mine always charges right to 94% if that makes you feel any better..

Maemomd 2012-07-31 21:21
Re: 9 battery goes straight from 100& to 94% coming off charge
 
Similar deal, once it is fully charged, it automatically kicks off the charger, and starts trickle drain. I've found a slower charger is the way to keep it at a higher charge state, use your data cable instead to a usb charger, if you charge overnight, higher battery percent in the morning, but again, slower charge rate.

waspy 2012-07-31 21:22
Re: 9 battery goes straight from 100& to 94% coming off charge
 
Well, don't know if it makes me feel better but relieved perhaps :-)

Is there a way a la Android to erase the battery stats? Sorry if that's a stupid question, I'm still getting to grips with Inception and root rights for MeeGo etc etc

waspy 2012-07-31 21:23
Re: 9 battery goes straight from 100& to 94% coming off charge
 
Quote:
Originally Posted by Maemomd (Post 1245608)
Similar deal, once it is fully charged, it automatically kicks off the charger, and starts trickle drain. I've found a slower charger is the way to keep it at a higher charge state, use your data cable instead to a usb charger, if you charge overnight, higher battery percent in the morning, but again, slower charge rate.
data cable to a USB socket on a computer rather than a high mAh wall charger? I think I read that somewhere else too

dr_frost_dk 2012-07-31 21:45
Re: 9 battery goes straight from 100& to 94% coming off charge
 
we talked about this for the N900.

Quick explaining:
Voltage curve for Li-ion/LiPo battery's is not linear, and the voltage drop from goes pretty fast from 100% to 90% compared to 80%-50%.
^^ - just some info on battery voltage

But main thing is your charger almost never goes to 100% because this actually let your battery live longer, it charges normally to 4.15V-4.20V and 4.23V is 100%.

Hope this helps, else there are plenty of battery pages on the net or go through some pages in my battery thread or other thread's for the N900 about the same "problem"

so again nothing wrong here, just a good practice for letting you battery's last abit longer, + you will not get much out of the last few % anyway.

conred 2012-07-31 21:46
Re: 9 battery goes straight from 100& to 94% coming off charge
 
Just read a nice posting about charging lithium batteries some days ago.

http://talk.maemo.org/showpost.php?p=821755&postcount=4

Quote:
Originally Posted by woody14619 (Post 821755)
Lithium batteries don't ever want to be totally charged or discharged. The effort involved in either is futile.

On the charging side, picture a wall of small boxes about 20 inches cubed. Now randomly throw a bunch of balls (just under 10" diameter) at the wall and try to fill all the cubes up perfectly. That's how a lithium battery charges... Getting it up to 75% is easy, beyond that takes a lot of extra throwing, which builds up heat and wastes energy.

On the other side, discharging it is like pumping water out of a well with a submersible pump. You can get all but that last couple percent out pretty easy. But below that, your pump has to work extra hard, the flow is irregular, and it quickly builds up heat and eventually the pump will fail.

Most devices never tell you a percent. They show you "4 bars" or some such. In that case the break down is usually about 17% per bar, with bars representing >75%, 74%-57%, 56%-39%, 40-23%, and 22-5% being NO bars. If the battery only charges to 92%, the first bar lasts just as long as the others. And as long as its over 75% the user thinks it's "at max".

waspy 2012-07-31 21:51
Re: 9 battery goes straight from 100& to 94% coming off charge
 
Quote:
Originally Posted by dr_frost_dk (Post 1245627)
we talked about this for the N900.

Quick explaining:
Voltage curve for Li-ion/LiPo battery's is not linear, and the voltage drop from goes pretty fast from 100% to 90% compared to 80%-50%.
^^ - just some info on battery voltage

But main thing is your charger almost never goes to 100% because this actually let your battery live longer, it charges normally to 4.15V-4.20V and 4.23V is 100%.

Hope this helps, else there are plenty of battery pages on the net or go through some pages in my battery thread or other thread's for the N900 about the same "problem"

so again nothing wrong here, just a good practice for letting you battery's last abit longer, + you will not get much out of the last few % anyway.
Good to know, thanks dr_frost_dk, I suspected it may be something like that but thanks for explaining it. I wonder though why perhaps the software doesn't simply recalibrate itself to show the top whack as 100%, just avoid general consumer confusion?

Also, my HP Pre 3 (yeah I have a thing for commercially dead platforms) seems to stay for a long time at 100%. Is that just the way webOS has been designed and is actually not a true reflection of the battery level?

dr_frost_dk 2012-08-01 06:32
Re: 9 battery goes straight from 100& to 94% coming off charge
 
Well it could calibrate but i like to have the REAL % instead, i made my meter a long time ago to really get the real %, it is not perfect but fits, im thinking about doing the same on my ASUS EEE 1015PN since i doubled the cells from 6 to 12, (from 11.1V 4400mAh to 11.1V 8800mAh) it is a big battery but it does mean i can go all out for some 4 hours+ of full CPU/GPU usage, i have not tested how long it will go in a close to idle mode, but my problem here is that the damm battery will not calibrate to show the new Wh the battery has, i made a script to calculate how much there is left, a simple update every 20secs and add current discharge.rate and it showed the battery had 85Wh instead of the 47Wh it is showing, long story short this results in the first 50% of the total discharge it goes from 100% to 0% and then remains at 0% until it dies or i turn it of/start charging when i can see battery voltage getting to the REAL 0%.

Win7Mac 2013-05-17 16:36
Battery jumps from 93% to 100% while charging
 
Holy crap, now I do not only have the draeded drop to 4% everytime when battery gets stressed below ~20%, but also just saw the battery-status jump from 93% to 100% while on the charger. :eek:
Next time I recharge I'll try to force a calibration and see if it's any help.
Anybody else experienced this?


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