Small Battery Power Drop on A2109!

WasteLandSavage

Senior Member
Dec 3, 2012
194
38
Well FloRider called it here's my first question.

I have a program that keeps an eye on my battery power mainly for when I'm running it on the battery.
Last night while I was setting up my new A2109 I noticed the power on the battery dropped to 99% and stayed there for a bit, then went back to 100% and stayed there the rest of the night.

Then tonight after I'd been on it for a bit it dropped to 99% again and stayed there for a bit again, and I had to get up for a bit so I thought I'd power it down and restart it to see what it said when it shut down and it said 99%.
I rebooted it and walked away and came back and it was at 100%.

My question is this has anyone else experenced this?

I thought it maybe because of the Quad Core Processor it has on it and I had been doing quite a lot with it?
But I would think that if this was so Lenovo would put a bit more powerful adapter to it.

Any thoughts on the matter, I've had this happen on Laptops but not during use only after it was sitting overnight.
 

Spider

Administrator
Staff member
Mar 24, 2011
15,785
1,813
Nothing to worry about Ricky, the circuitry in the tablet is turning the charge on and off to maintain it at around 100%. If it kept charging when the battery is at 100%, battery damage could occur so it shuts off. When it senses the charge has gone below 100% it turns back on. Your battery would naturally discharge even if nothing was connected to it.
 

WasteLandSavage

Senior Member
Dec 3, 2012
194
38
Nothing to worry about Ricky, the circuitry in the tablet is turning the charge on and off to maintain it at around 100%. If it kept charging when the battery is at 100%, battery damage could occur so it shuts off. When it senses the charge has gone below 100% it turns back on. Your battery would naturally discharge even if nothing was connected to it.

Thanks I didn't really figure it was much to worry about but I am a worry wort as my wife would say.
But I never noticed it on my Iconia that I know of but I hadn't had this program for long before I got my new one.
And this is only my second tablet, I started on desktops and haven't even been using laptops all that long.
But again Thanks much. Ricky :rolleyes:
 

tragidy

Junior Member
Jan 29, 2011
827
433
Thanks I didn't really figure it was much to worry about but I am a worry wort as my wife would say.
But I never noticed it on my Iconia that I know of but I hadn't had this program for long before I got my new one.
And this is only my second tablet, I started on desktops and haven't even been using laptops all that long.
But again Thanks much. Ricky :rolleyes:

If it keeps occurring or you decide to use it UN-powered for about 2-3hours and its still 99 or 100 pct, then let us know and we will help you reset your battery stats.
 

WasteLandSavage

Senior Member
Dec 3, 2012
194
38
If it keeps occurring or you decide to use it UN-powered for about 2-3hours and its still 99 or 100 pct, then let us know and we will help you reset your battery stats.

Hey Thanks for the reply.
As I said last night it had came back up on it's own to 100%
I decided to run it on battery to see if it's staying power was as bad as I've read in some of the reviews.
I don't think it's all that bad actually I had it running for right at 4hrs last night, and I've had it running now for another 30mins and it's just now at 44%.
It started dropping steadly after I unplugged it, With most of that playing games and a tad bit of web surfing and facebook.
So I'd say I ought to get about 7 or 8 hours out of it and that's about what my Iconia averaged and it was only a Dual Core Tegra 2.

I'll let ya know if I continue to have problems.
I take it to reset the battery stats on a tablet is just like doing it on a laptop?
You let it shut it self down due to running it completely out of juice and then recharge?

And while I'm here what if any good does it do to run it in a Balanced Power Mode?
I know what it is in Windows and I've always used it even when gaming, But I was just curious exactly how it acted in android?
In any event Thanks Again: Ricky
 

tragidy

Junior Member
Jan 29, 2011
827
433
Hey Thanks for the reply.
As I said last night it had came back up on it's own to 100%
I decided to run it on battery to see if it's staying power was as bad as I've read in some of the reviews.
I don't think it's all that bad actually I had it running for right at 4hrs last night, and I've had it running now for another 30mins and it's just now at 44%.
It started dropping steadly after I unplugged it, With most of that playing games and a tad bit of web surfing and facebook.
So I'd say I ought to get about 7 or 8 hours out of it and that's about what my Iconia averaged and it was only a Dual Core Tegra 2.

I'll let ya know if I continue to have problems.
I take it to reset the battery stats on a tablet is just like doing it on a laptop?
You let it shut it self down due to running it completely out of juice and then recharge?

And while I'm here what if any good does it do to run it in a Balanced Power Mode?
I know what it is in Windows and I've always used it even when gaming, But I was just curious exactly how it acted in android?
In any event Thanks Again: Ricky

To reset the battery yes it is ideal to drain it totally then charge it powered off, then afterward run an app like battery calibration to reset your androids battery tracker.

The above requires you to have Super User aka a rooted device, as does changing any power management in the android which can be done with the app CPU Master.

If you want to root your tablet I could certainly try and help you as you will gain full admin rights past that point where you can change the power govener to be conservative or ondemand etc, to save power in long term use.


A good example is my 7" it used to only get 3-4hours then dead, I modified the power schemes deeply and now that very power scheme is giving that smaller device 6-7 straight gaming hours with no performance hit that is noticeable to the human eye.
 

arbarnhart

Senior Member
Jan 1, 2013
178
38
To reset the battery yes it is ideal to drain it totally then charge it powered off, then afterward run an app like battery calibration to reset your androids battery tracker.
By "drain it totally" I think/hope you mean by using the tablet or other device with some power management baked in. Most devices will shut off around 10%. That's because draining a lithium battery completely will kill it.
 

WasteLandSavage

Senior Member
Dec 3, 2012
194
38
By "drain it totally" I think/hope you mean by using the tablet or other device with some power management baked in. Most devices will shut off around 10%. That's because draining a lithium battery completely will kill it.

I found out last night that on the A2109 an automatic shutoff happens at 6%.
 

WasteLandSavage

Senior Member
Dec 3, 2012
194
38
I posted this on he Lenovo Forums about my ongoing problems with the slight Power Drop that I have/had with my A2109.
Any Advice?
I know you guys are the BEST!
Hi all: I've had my A2109 for right at a week now.And for all pourposes I love it, But I have a slight problem that I don't quite understand. I'll be using my tablet while on power Lenovo Adapter it will be running at 100% for a couple of hours or so.Then it will drop to 99% this happened the first night and after an hour or so it came back up to 100% I thought OK no big deal.Followiing night I ran it on battery to 6% where it shut off, Ran it for awhile while on charger It charged up OK but I let it charge over night because it was only at about 29% charged when I went to bed. It was charged the following morning 100%, That night I again ran it on battery until it was at about 70% then charged it back up to 100% in the matter of a couple of hours.Next night it was finebstayed at 100%. Tonight after a couple of hours again it dropped to 99% I thought well no big deal it will go back to 100% here in a few.It didn't it stayed at 99% for approx 4hrs.I was getting ready to shut down when I noticed it was at 98%? The Power Adapter was warm but not overly, So I got out another Power Adapter that I have plugged it up and all of a sudden it popped up Fully Charged at 100% and this was all in a time frame of about 5mins from the time I switched Adapters. Does ayone here have an Idea Whats going on?I'd really hate to have to return my tablet for repacement where I bought it because I got it from newegg.com, If it is only an Adapter problem as I feel it is. But if it isn't and it is a problem wwith the tablet itself?I know dealing with newegg will be a lot quicker then dealing with Lenovo. Please advise with any opinions as to what I should do.Or what can be done to fix this.Or if this is normal? I have an Acer Iconia A500 and have never had this problem.But then again they didn't have a Switching Power Adapter. I'm ost grateful for any advice that you can give me: Ricky
 

vampirefo.

Senior Member
Developer
Nov 8, 2011
3,836
1,394
Hard to say, I honestly don't pay that much attention to my tablet's charging. I leave it plugged into a powered hub 24/7 when I need it, the tablet is 100% charged.
 

arbarnhart

Senior Member
Jan 1, 2013
178
38
Another consideration is how battery level is measured - voltage. If you have a 7.2v battery, it might be at 7.3v fully charged and 7v discharged. Those numbers may not be exactly right, but work for purposes of discussion. A percent of charge is likely only a few hundredths of a volt. Lots of things can cause the voltage and/or reading to vary that much. Sometimes I think the simpler approach of having 3 or 4 bars is a better idea.
 
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