Fix idle battery time from under 7 hours to over 9 days!
 

Edit:
This bug seems to occur only when using static IP with Wi-Fi. There is also a potential devel level fix for the problem described in the most recent comments on bug thread https://bugs.maemo.org/show_bug.cgi?id=6615

If you can confirm the bug only occurs with static IP, please post it on comments of the bug. Also if you are knowledgeable enough to use devel level fix, do post the results.

---

Suffering from battery time of around 6 hours or less on low usage? Then you might benefit from the following info.

Some people have problem with N900 and Wi-Fi. For some reason N900 doesn't recover from having been connected to Wi-Fi and will keep eating loads of battery even after closing the connection. Only restart will help. Simply searching for Wi-Fi without making actual connection doesn't trigger the bug for me. (The phone searches for Wi-Fi whenever you manually start any internet connection.)

So, do not use Wi-Fi unless you want your battery to die fast. Or reboot after using it. This is until a real fix comes for the problem.

With this fix I managed to get my idle battery time to increase over 30 times! (From bellow 7 hours to over 9 days.)

Note: This is about IDLE usage. Everything you do will use battery of course and the real usage battery time will vary depending on what you do. This is just about the bottomline battery usage.


It seems some people do not have this problem with Wi-Fi usage on their N900. It may be related to encryption method used or the Wi-Fi router connected to. In any case, some circumstances trigger a bug in N900 causing excessive battery drainage even after having disconnected from Wi-Fi. And the issue is fully reproducible. So, if you get it once with given Wi-Fi connection saved, you will get it every time unless you change some settings elsewhere than on the phone. That is, until the real bug has been fixed.

There is also a bug report made about the problem. If you have the issue, do vote and add more info the the bug report:
https://bugs.maemo.org/show_bug.cgi?id=6615


I had first experimented with various other things and have found out that normally there is no battery drainage problem with following things: Calendar widget, media player widget, foreca weather widget (only manual update), location widget and alarm clock. Also keeping terminal window open on the back doesn't drain battery noticably.

Wi-Fi tests were done with following settings (no problems prior to activating Wi-Fi connection for first time after reboot):
- Ask when needing connection.
- Dual GSM mode (uses 3G here at all times, 3.5 G when there is data activity - signal is a bit weak but doesn't matter).
- Widgets: Calendar, media player, foreca weather (only manual update) and location widget (on other than the viewed virtual desktop)
- Software: X terminal on background; Custom programs installed: OpenSSH client.

I did some experiments about battery usage on different cases. Prior to testing I rebooted the phone and kept it at idle for 20 minutes to let the battery voltage stabilize after the booting load. Results:
Idle without having used Wi-Fi: 54 mAh usage in 9.3 hours -> 5.8 mA.
Idle with 3G internet connection idle: 32 mAh usage in 1.9 hours -> 16.8 mA.
Idle after connecting and manually disconnecting from Wi-Fi (10 mW): 183 mAh in 1.0 hours -> 183 mA.

The difference is huge. The fully charged new battery charge is 1267 mAh, so idle 5.8 mA usage gives about 9.1 days, idle with 3G internet connection idle 16.8 mA usage gives about 3.1 days and idle after connecting and manually disconnecting from Wi-Fi 183 mA usage gives 6.9 hours. That is over 30 times the increase from idle to Wi-Fi bug triggered idle. And still over 10 times the increase from idle with 3G internet connection idle to Wi-Fi bug triggered idle.

The test times are high enough for accurate results and as such, it can be safely said that the Wi-Fi bug makes a really huge difference to the battery time.

I also tried to test having the Wi-Fi connection on but idle at 10 mW for an hour, but the phone had automatically disconnected it at some point. The resulting usage from part idling Wi-Fi 10 mW connection and rest pure idle with battery drain bug activated was about same as the 183 mAh an hour from previous test. Thus, there is no way to avoid the bug opening a Wi-Fi connection triggers as of now. At least unless some other connection setting than ask when needed keeps the connection alive.

If you want to test out these things yourself, here are some hints to use. On terminal, you can get good information about battery status with command "lshal|grep bat". It will include some unnecessary information as well. To only get current mAh remaining use the following alias:
alias b="lshal|g ng.c"

And then to check battery level I use "uptime;b" to get both current time as well as current mAh remaining. Then keep the terminal on background to see both old values as well as new values. Do note you can scroll the terminal text to see backlog.

Edit: I have moved advanced stuff about battery information into a separate guide. See it for more information:
http://talk.maemo.org/showthread.php?p=421349

Do post your own experiments to see how common this Wi-Fi bug is. And if there are any other significant bugs related to excessive battery usage.

--
Note to mods: I am aware my last posting with preliminary tests a day ago was moved into general battery time suggestions thread. But this about a critical bug that alone makes the battery to die very fast. As such I feel there really is the need for separate thread. I did send a message to the mod who moved my previous posting, but as there has been no reply and the matter critical, so I decided I just have to let people know about it now that my thorough tests are finished. I apologize for acting alone.

Re: Fix battery time from under 7 hours to over 9 days!
 

will test. sounds good

Re: Fix battery time from under 7 hours to over 9 days!
 

Well, as someone's signature said (sorry, i forget whose): "in theory practice and theory are the same. In practice they are not"
In theory, you have a point. However the 30-fold increase in battery life is hard to believe. If it turned out to be true, someone on nokia is going to at least get a pay cut (maybe a 100% one, if you get what i mean) for missing this
What is needed here is practical testing: don't use wi-fi at all and see how much the battery lasts. I'm betting no more than 3-4 days, since that's what my dumb sony ericsson gets (admittedly on a smaller battery, but not much)

Re: Fix battery time from under 7 hours to over 9 days!
 

I bet there's a way of just turning the wifi radio off. Be it a kill switch in /sys/bus/pci/drivers/ or somewhere. I doubt you need to reboot the device just to do this...

Re: Fix battery time from under 7 hours to over 9 days!
 

This 30-fold increase is about IDLE time. Ie. no usage at all whatsoever. That is just the base bottomline battery usage on which everything you do will pile up. So, yes on moderate usage it won't last more than few days.

This is about a clear bug that is triggered by using Wi-Fi. I have heard of some people who do use Wi-Fi with battery time of 2 days on low usage. So, the bug is not affecting everyone. But for those that it is affecting, it is a very critical extra drainage for the battery.

Re: Fix battery time from under 7 hours to over 9 days!
 

i took my n900 off charge at 8:30am, and connected to my company wifi at 9:30am.

i only have a 2G connection, but even so my battery is still at 80% by 14:30pm, despite being continuously connected to the wifi for five hours now.

Re: Fix battery time from under 7 hours to over 9 days!
 

From my one day of usage I have found WiFi has a nasty habit of crashing if you are getting a poor signal. It will still claiming to see the WiFi network (at least sometimes) but fail to connect to it.

This may be connected as its quite likely its crashed it will not enter power saving mode properly. Impossible for me to say from only a days use though, the battery is expected to only last 7 hours or so on its first couple of charges.

Re: Fix battery time from under 7 hours to over 9 days!
 

I'm constantly on wifi and my battery life is excellent. 3g is a killer mind you.

Re: Fix battery time from under 7 hours to over 9 days!
 

Lithium batteries shouldn't experience significant battery capacity changes during first few charges. There may be something small, but nothing significant.

As for Wi-Fi crashing, there may be partial crashing from the bug that causes the Wi-Fi not to be able to enter power saving state. But there isn't any complete crashing as I can make a new Wi-Fi connection and data will go just fine, even after triggering the Wi-Fi bug. And I did manual disconnection from the Wi-Fi and the drainage still existed, so something is clearly wrong on the phone side.

Re: Fix battery time from under 7 hours to over 9 days!
 

Yes, I know some people aren't experiencing the problems with Wi-Fi. As for 3G, yes it uses battery like there is no tomorrow if you do transfer a lot of data. But the usage is very low if nothing is being transferred.

Re: Fix battery time from under 7 hours to over 9 days!
 

i havent used wifi since i got my device, about 2 weeks now and on moderate use, (some browsing, few calls, moderate text..etc) it lasts about 8-10 hrs.. on idle it lasts more.

Re: Fix battery time from under 7 hours to over 9 days!
 

You might have some widgets that eat quite a lot of CPU. Check general battery lifetime improvement tips from here:
http://talk.maemo.org/showthread.php?t=35907

Re: Fix battery time from under 7 hours to over 9 days!
 

Just repeat the mantra that people have been saying...

"3G is a power killer"

It's eats thru your power more than 3x faster compared to EDGE/GPRS/WIFI.

Re: Fix battery time from under 7 hours to over 9 days!
 

It is a bit like a double edged sword... Many older 3G devices eat power like hell just being on 3G without any active data connection etc. Just the normal being able to receive calls.

However, there is a very significant power saving in N900 there than on my old Nokia E70 for example. Not sure how well other modern 3G phones do than N900 though. N900 can handle 9.1 days of idle on 3G and 3.1 days of idle with 3G data connection on but idle.

It is true that data transfer on 3G eats power like there is no tomorrow. I suppose the worst efficiency on 3G is when there is some data going constantly but the amount of data is very small.

On other hand, while browsing for example, the time it takes to load a page on 3G is so much faster than on 2G that you might actually save power. Eg. 2 Mbps 3G and 0.2 Mbps 2G gives you 10 times the download time for a given page (assuming the server you download from is fast enough) on 2G. So, 10 times longer of moderate battery usage compares to short heavy battery usage. It would take more experimenting to know how it goes. And signal quality etc will matter of course.


Good old memories with E70 and 3G... When I had some problems with my normal connection, I used E70 as internet connection for my main comp and played Spring (open Total Annihilation remake sort of).. The transfer speed was low, but it was constantly transferring data on both directions, so I once even noticed the the charger was too slow to charge the phone so the battery died while being charged!

Re: Fix battery time from under 7 hours to over 9 days!
 

Hi, either all this information is misguided or 90% of n900 users have faulty units other than the wifi. I have had the 7 hour problem, since I have now tested it by doing the following-
uninstalled all apps
removed all widgets
deleted one desktop
disabled gps totally
not even tried to active any internet since switch on (so no wifi at all)
enabled gsm only, so 2g only
after this i have sent 40 sms, made one 15 minute call an thats all i did, it was totally idle an it still only lasted 16 hours, this is totally unacceptable (oh an have brand new sim card) and I want some-one to personally prove to me they are getting more than this cause i dont believe a word of it, that or like i said the majority are having problems so nokia have really screwed up an will receive alot comin back!!!! cause mine will be.

If I've offended anyone I apologise but after all the fuss of waiting three months for it I'm beside myself with it now that i dont believe that i have a device that it ment to be perminant 3g, perm gps an perm internet connection an theres just no chance at all less ye dont want a portable device ye just want a wire sticking out of it plaugged in all the time, whats the point?!?!?!?

Re: Fix battery time from under 7 hours to over 9 days!
 

About the WiFi bug, I rmmod/modprobe the WiFi drivers on Linux when the drivers crash, cant we do this on Maemo?

Re: Fix battery time from under 7 hours to over 9 days!
 

I have heard that some people have some problem with calendar widget using lots of battery. And some IM widgets also use much.

I myself have phone set to dual mode (stays on 3G at all times here), have bunch of widgets (calendar, media player, foreca weather and location) etc... GPS and GSM network location are enabled, but nothing should use those other than when I manually activate location widget or use some other program using location info. I do not have any IM widgets or anything that checks stuff from the net periodically. Foreca weather widget is set to update manually only (whenever data connection starts or I manually refresh it). I don't have much stuff on calendar though.

Anyway, other than the Wi-Fi bug, I do not experience any problems with battery life.

Re: Fix battery time from under 7 hours to over 9 days!
 

how long does your battery last????

Re: Fix battery time from under 7 hours to over 9 days!
 

now been attached to the company wifi for eight hours, and the battery is still somewhere around 65%.

Re: Fix battery time from under 7 hours to over 9 days!
 

Yes, this seems to be the least efficient way to make use of the 3G 'race to idle' concept.

Yes, that's the right concept but unless 90% of your browsing activities are task oriented then most people will 'spend' the time savings anyway ("Oh, I have 15 minutes to kill while waiting for my appointment"). So in the same amount of time you'll drain the battery more as you plow thru more pages. Yes, you get more data-per-mAH spent, but you'll end up spending more power anyway unless you consciously control the power spending.

Re: Fix battery time from under 7 hours to over 9 days!
 

seems to be saving me a lot of power. some people dont have this problem?
faulty hardware? if so im bringing it back.

Re: Fix battery time from under 7 hours to over 9 days!
 

Here is some feedback from someone who is still on Nokia 6110 because the N900 is STILL not available in Switerzland.

When I first got my N6110 I was supriesed that my battery would not even last 2 days.

So here is what the problem was. At home I have a very poor GSM coverage and no 3G at all. My phone was set to dual mode.

I told the poor battery performance to my sales person and he showed me how to switch the phone to use GSM only.

He told me that the problem was that the phone was contantly searching for antenna coverage. And that draind it.

Setting it to GSM only allmost doubled my battery life back then.

I think if you life right under an antenna you will have longer battery time then if you are further away.

So maybe one should be looking for a good coverage and use the better GSM or 3G depending on needs.

Maybe a full coverage at 3G will drain the pattery less then a very bad coverage at GSM .

Just my two cents on this.

Regards Markus

Re: Fix battery time from under 7 hours to over 9 days!
 

At total idle 9.1 days with those widgets etc enabled and on 3G without data connection. At total idle with 3G data connection on but idle 3.1 days with otherwise same settings. Any usage on top of this will of course drain the battery more. I have only had few hours of time to play around with the device after I had found out a way to get out of the Wi-Fi bug and had finished tests relating to it. As such, I can't really say very much on the real usage time. But based on various usages I would estimate around 2-3 days on very moderate usage, full day on quite high usage and some 6-8 hours on continuous heavy usage.


Considering that you generally use a lot of time on the web reading text etc, the connection will be idle most of the time. You only gain the saved time on less waiting for page to open. So, if 10 % of your surfing time is waiting for pages to open and it goes down to 1 % (assuming ideal server speeds), you get 9 % more time to use. As such, 10 % of 2G usage doesn't go to 1 % of 3G usage but to 1.09 % of 3G usage. So, the difference is still huge on the time the moderate battery draining is in affect on 2G compared to heavy battery draining on 3G.

And whenever you are doing something real instead of just getting rid of excess time, you will finish the job faster. In case you have something better to do with the time, that is a bonus.

Re: Fix battery time from under 7 hours to over 9 days!
 

Yes, some people don't have it. The possible reasons are that the bug only gets triggered with certain Wi-Fi routers and/or encryptions used or a hardware bug. And even if it is a hardware bug, it might be able to be bypassed with software fix. In any case you can contact Nokia customer support about the problem and see what they tell you to do.

I myself will wait for the bug report to be processed and only then if the problem is found out to be a hardware problem that can't be bypassed with software fix, will I take the phone to servicing to get it fixed. At least here there is 24 months warranty on the phone.

Re: Fix battery time from under 7 hours to over 9 days!
 

this doesnt make sense unless you have a none faulty unit an alot of people like me have dodgy ones, i get 3/4 of a day without using anythin at all an u can average 3-5 days?!?!?!? just want advise as to send back or not, or ask for a refund if this is the norm for me. Thanks.

Re: Fix battery time from under 7 hours to over 9 days!
 

Yes, bad coverage may cause a lot more of battery usage. But generally 2G coverage is better than 3G coverage at any point. This is because 2G works fine with stations much further away. So, as such setting phone to GSM mode only will most often help in case of bad coverage.

Here in Finland, there is 2G coverage generally anywhere, even in the forests etc. But 3G coverage is only in the places where there are lots of people nearby. That is both because 2G was there before 3G but also due to it being cheaper to fill given area with 2G coverage than with 3G coverage.

Re: Fix battery time from under 7 hours to over 9 days!
 

Well, hard to say. With the Wi-Fi bug triggered I get less than 7 hours of idle time. But as long as I don't trigger it, it works fine for me. And as such, I can't really help with other possible problems.

Either you have some problems with your phone or some of the programs you are using are causing excessive power drainage. Anyway, contact Nokia customer support if you can't fix the problems just by reading around the forums.

Re: Fix battery time from under 7 hours to over 9 days!
 

Thanks, I will tomoz, I have nothin else at all runnin i un-installed everythin, thats why i cant understand it an think its a hardware fault other than the known issue with the wifi cause i havent bin near it at all to trigger it off, but think theres a hell of alot of people in the same situation as me, anyway thanks for the help an hope the wifi's sorted soon :)

Re: Fix battery time from under 7 hours to over 9 days!
 

Isnt there any way to completely disable Wifi? So that it doesnt turn on unless I specifically activate it? I hardly use WiFi, so I dont really need it most times..

Re: Fix battery time from under 7 hours to over 9 days!
 

I have issue with WiFi too. I tried to connect to WPA/PEAP/MSCHAPv2 and fail because used wrong setting. After 2h battery was completely drain and phone was Hot....
Now when I am using same network but with correct parameters.

Phantasm: Could you like to tell how to determine Current from your script?

I have this result for battery:
battery.charge_level.capacity_state = 'ok' (string)
battery.charge_level.current = 2 (0x2) (int)
battery.charge_level.design = 8 (0x8) (int)
battery.charge_level.last_full = 0 (0x0) (int)
battery.charge_level.percentage = 22 (0x16) (int)
battery.remaining_time = 3600 (0xe10) (int)
battery.reporting.current = 285 (0x11d) (int)
battery.reporting.design = 1245 (0x4dd) (int)
battery.reporting.last_full = 0 (0x0) (int)
battery.voltage.current = 3737 (0xe99) (int)
battery.voltage.design = 4200 (0x1068) (int)

thanks

Re: Fix battery time from under 7 hours to over 9 days!
 

Are there any battery cases for the n900 yet?
Like this one for the iphone:
http://bit.ly/zS4iU
But since the phone is quite big, a case like this would make it less practical...

Re: Fix battery time from under 7 hours to over 9 days!
 

battery exploded :l

Re: Fix battery time from under 7 hours to over 9 days!
 

There is the current mAh remaining (285) and design capacity (1245). So, with new battery the full load will be that 1245 mAh. There was also a percentage mentioned in there, but you can also calculate it just from those two, so 23 % charge level.

Re: Fix battery time from under 7 hours to over 9 days!
 

care to elaborate?

Re: Fix battery time from under 7 hours to over 9 days!
 

exploded in my phace

Re: Fix battery time from under 7 hours to over 9 days!
 

Everytime I have used wifi I do ifconfig wlan0 down as root in xterm. I have gotten very nice battery time lately even with moderate use. Many phone calls, a few sms, listening to music for about an hour, web browsing, taking photos and a short video clip I got over 20h of battery time.

Many say that it takes about 5 cycles before the battery gives full power. In my case it seems that after 10 or more cycles I am getting max of it.

Re: Fix battery time from under 7 hours to over 9 days!
 

You can hook up to your company wifi on a non-issued device??? Security! ;)

Re: Fix battery time from under 7 hours to over 9 days!
 

Who was it?

Re: Fix battery time from under 7 hours to over 9 days!
 

The bateri exploded in my face >/

Re: Fix battery time from under 7 hours to over 9 days!
 

Ok guys, just to back up for a second, are you recommending that once I finsih with WiFi, to disconnect it, then shut off the phone? This will make sure it's not still searching for Wifi even if i don't have it connected?