Battery life on ICS great (zt280)

[jezebabe]

I only received my zt280 this week and it was running gingerbread when I got it.
I used it for a couple of days and was getting between 5 and 6 hours battery life on a full charge.

I decided to take the plunge on Wednesday and upgrade to the latest ICS.
Since then I have been getting fantastic battery life e.g. after 4 hours use 70% still remaining!
According to battery stats 70% of that usage is taken by 'mobile standby' which it doesn't seem possible to disable on this version. So this could potentially be improved on in later ICS versions! Can't wait.

Jez

Sent from my ZT ICS using Tapatalk

 

[criver]

Hi!
By mobile standby you mean the cell standby right - if that's it then there is a way in Gingerbread to disable it - you turn on airplane mode (btw, you can turn wireless on in airplane mode - so no problems there) - the same option should be available in ICS, no? Now I'm running ICS - but a rooted custom ROM which has cell standby disabled as a whole - so I get pretty much the same battery life without the annoying need to turn on airplane mode every time.

 

[J515OP]

I can't vouch for ICS since it is newly out but the cell standby has nothing to do with battery life on devices without a cell chip in pre-ICS versions of Android. It is simply a misreported stat.

 

[criver]

"cell standby has nothing to do with battery life on devices without a cell chip"
Yes, it has. I can assure you of that - my tablet (ZT-280 C91) doesn't have a cell chip, but when I had Gingerbread - if I didn't turn on Airplane mode I had a really nice graph in my battery stats, which showed how much of the battery went to "cell standby" - it was above all the other things - I don't know how the people form Zenithink or those who were in charge of the android version of Zenithink did this, but it is a fact... You can read a few articles on the net if you don't believe me - or try it yourself if you have a C91...

 

[J515OP]

Hi criver, maybe there is something different with the ZT tablet, but just because there is a graph saying where the battery life is going does not make it a drain on the actual battery life. The only way you can confirm it makes a difference is to do a run down test which is complicated by several factors making it difficult. Unless you have results of run down tests and the methodology used that you would like to provide I stand by my statement. I have read plenty on this topic and no evidence of improved battery life via a rundown test has ever been offered.

The removal of the information from the graph is simply a placebo effect. If you take this reporting metric out of the equation it simply gets reported elsewhere in the battery statistics. Rather than telling us how much of a difference you noticed in a graph why don't you tell us in terms of time how much longer your device runs since making the change? If it isn't a multiple of the current run time (i.e. x2, x3 etc.) than any savings in battery life are likely due to changes in use or other changes (i.e. you went from 8hrs to 9 hrs).


JP

 

[criver]

I didn't really measure how much my tablet ran etc. - but it surely isn't a placebo effect - why - because I don't need a clock to tell me the difference between a battery that dies after about three hours and a battery that lasts a whole day... I didn't notice this after installing ICS - it was long before that that I started dilligently turning on Airplane mode whenever I turned on my tablet... I don't really need any test when there are facts. Btw, nothing of this is intended to be offensive as I know that "my words could sound a little harsh".

P.S. From the things I've read there's some variable called nonphone in your system folder that's set to false - actually in the rooted ROM I have of ICS this variable is set ot true - so I don't need to turn on airplane mode anymore.

 

[J515OP]

No offense taken I am just looking for proof that the battery life was increased. Again, your battery life increase can be related to other factors. For instance, turning on Airplane mode disables cellular, wifi and bluetooth. Turning off either wifi or bluetooth when not in use can result in significant increases in battery life (and even more if you are using and turning off both at the same time). So more than likely all you were doing was turning off wifi.

Just to throw out an example from the numbers above if the cell standby was using 70% of the battery before ICS and it lasted 5 hours then getting rid of the cell standby should result in 3.333 times the battery life or 16.5+ hours! There are other problems when just looking at percents though. Say the graph reported 70% cell standby, 20% screen and 10% system. By removing the cell standby you just reallocate the other use as a portion of 100%. So you now have a graph reporting 66% screen and 33% system use of battery. This doesn't indicate any increase in battery life, just a reallocation of how the battery was used.

I would love to have a magic bullet way to improve battery life but to think you can simply turn cell standby off to get significantly more battery life (and all the corporate and hobby developers have somehow missed this) just doesn't make sense. Again, I welcome any methodical testing to prove otherwise as maybe for some devices it is possible there was an oversight in applying the code to that device.


JP

 

[criver]

First of all - there's no bluetooth on my tablet.
Second thing - I was saying that when you have Airplane mode on, it isn't necessary that your wi-fi is off - as I've been saying - I can use wifi with airplane mode on - and I use it. So your theory doesn't work here.

"and all the corporate and hobby developers have somehow missed this" - they haven't I've just been saying that one of my ROMs came with a nonphone=true - either they did it just as a joke or there was a reason for this...

"Just to throw out an example from the numbers above if the cell standby was using 70% of the battery before ICS and it lasted 5 hours then getting rid of the cell standby should result in 3.333 times the battery life or 16.5+ hours! " - To begin with, the thingy with the 70% - I never said that - jezebabe said it...I said 3 hours - 3x3=9 hours = pretty much the whole day...

" Say the graph reported 70% cell standby, 20% screen and 10% system. By removing the cell standby you just reallocate the other use as a portion of 100%." - that still doesn't change the fact that I get more work time when I enable airplane mode - so realistically speaking these calculations don't hold any ground...

 

[J515OP]

criver, I'm not trying to say anything specific against you or your specific situation, just offering some general explanations about this feature of Android. If you don't have a cell chip what exactly in cell standby is sucking up all that power? Please let me know since I have no idea in that case.

First of all - there's no bluetooth on my tablet.

Never said there was bluetooth on your tablet or that you were using it. I only said Airplane mode shuts down those three features any of which can drain battery life and having all three going will really suck down the juice.

Second thing - I was saying that when you have Airplane mode on, it isn't necessary that your wi-fi is off - as I've been saying - I can use wifi with airplane mode on - and I use it. So your theory doesn't work here.

Yes, you can be in Airplane mode and turn on wifi. Each time you turn on Airplane mode or turn off wifi mode you save battery because wifi is off. You can see if there is a difference is in battery life between using Airplane mode and wifi on/off and just turning wifi on/off the way you do under Airplane mode. I suspect you will have no difference in battery life between the two other than what is attributable to use differences.

"and all the corporate and hobby developers have somehow missed this" - they haven't I've just been saying that one of my ROMs came with a nonphone=true - either they did it just as a joke or there was a reason for this...

You are missing the point of the flag. Android through Gingerbread is a phone OS, Honeycomb is tablet only and ICS is tablet/phone. That flag is for ICS to differentiate between the device it is on. It isn't to improve battery life on a non-cellular tablet by turning off cell standby. If it made a significant difference it would be edited out of the code (not difficult to do with root permission) by custom ROM developers and tablet manufactures on all makes of Android.

"Just to throw out an example from the numbers above if the cell standby was using 70% of the battery before ICS and it lasted 5 hours then getting rid of the cell standby should result in 3.333 times the battery life or 16.5+ hours! " - To begin with, the thingy with the 70% - I never said that - jezebabe said it...I said 3 hours - 3x3=9 hours = pretty much the whole day...

In your case if you were getting 3 hours and now get 9, great! Please don't say it was due to eliminating cell standby unless you have some sort of proof though. I openly invite such proof and would be glad to see it made available. I'm just suggesting that you may have made other use changes to achieve those results such as turning wifi on and off.

" Say the graph reported 70% cell standby, 20% screen and 10% system. By removing the cell standby you just reallocate the other use as a portion of 100%." - that still doesn't change the fact that I get more work time when I enable airplane mode - so realistically speaking these calculations don't hold any ground...

My point is this doesn't really mean anything. It doesn't help determine battery life and people shouldn't put too much stock into these stats. They are not the be all end all. Just a method (and a flawed one) of Android trying to report battery information.

If you feel that eliminating cell standby makes a difference for you, you can do all you want to eliminate it. I'm just letting people know that they probably won't see any improvement from this.

JP

 

[jezebabe]

Thanks for all the info criver and JP.

I have now downloaded a free airplane mode app, enabled it & then turned wifi back on. After doing this my battery stats still show around 70% used by 'mobile standby' which is strange.

Jez

Sent from my ZT ICS using Tapatalk

 

[criver]

@jezebabe: Maybe the free airplane mode app doesn't work - normally a person should have airplane mode in their settings (I had int on Gingerbread but not anymore)...Shouldn't it be "cell standby"?

@J515OP: You could be right about the fact that my battery's life didn't go up because of the airplane mode - cause I always had some problems with android.process.media (which was making my CPU run at 100% and so it was eating my battery) - I don't really remember when but after I noticed that it was doing this to my processor I managed to stop it from running (sometimes I had to kill it several times - I've tried many things to resolve it, but the problem still isn't completely solved), so my battery life improving could be due to this... However, you don't believe that somehow "all the corporate and hobby developers have somehow missed" the bug in the battery graph, do you? (so maybe it is not false information)

 

[J515OP]

However, you don't believe that somehow "all the corporate and hobby developers have somehow missed" the bug in the battery graph, do you? (so maybe it is not false information)

I think you are on the right track with the android.process.media or some other rouge process draining your battery life. As to the cell standby "bug" in the graph, it isn't a bug in the sense that Android through Gingerbread is strictly a phone OS. As you noted there is a flag to account for this in ICS, so they have taken care of it for an OS that supports tablets

JP

 

[jezebabe]

@criver It could be a faulty airplane mode app although when I switch it on it does correctly disable wifi which I then have to re-enable. ICS battery stats shows 'mobile standby' see attached.

Sent from my ZT ICS using Tapatalk

 

[guitarman]

hi guys. I read this post this morning and decided to test my c91 using 2.3.4, used it normally two times both ways and sorry, Criver, the times were roughly the same. I saw basically zero difference in my C91 usage time when Airplane mode was on. battery was consistent in time running down on both settings