Re: Its not Wifi, but GPRS that is consuming most of the battery
 

I can make the N900 charge meter display 100% for 2 days :)

Re: Its not Wifi, but GPRS that is consuming most of the battery
 

Battery is 3.7V, 1.32Ah, so a full charge is abut 5 Wh; it's provided with a switching power supply, which are typically around 90% efficient, so let's be generous and say 6Wh. At the US average price of 12 cents/kWh, that means 0.072 cents to fully recharge the N900.

No, that's not "free" either, but there's no way to complain about such costs without sounding incredibly lame.

Re: Its not Wifi, but GPRS that is consuming most of the battery
 

Test 3)

Same characteristics but without IM enabled, I list them again

- Wifi disabled, 3G enabled, no IM accounts enabled, kernel ideal loaded, 2 desktops, widget of calendar, three contacts in desktop, two widgets-like indicating the internet IP and the battery percentage, brightness to the 1 position, display almost all the time disconnected. Mail autocheck each 30 min.
- A not so-constant slope seen in BatteryGraph app, like repetitive cycles of higher slope I guess coinciding with navigation

Well, last time with 3G and IM enabled (brightness 3), I had a battery decrease of a 42% in 2h 46min -> -0.253% / min

Now, this are the results, -66 % in 4h 15min -> 0.259% / min

(detailed)
- 7:55 90%
mail
casual navigation (< 5 min)
3 SMS sent
- 8:13 83%
nothing
- 9:02 74%
mail erase some messages
sms received
- 10:13 68%
mail erase some messages
navigation 5 min
- 11:03 48%
mail erase some messages
navigation 5 min
- 12:10 24%



So, conclusions, having the two IM accounts enabled has not implied a significant difference, has it? Or if not, perhaps I have had this time a little more activity, but since both IM were disabled I have kept the same battery decrease. In any case, the differences are minimum, in my opinion the price you pay to be connected is not huge, but rather acceptable.

What I think is not acceptable, is that with such a minimum activity, the n900 is so empty of energy.

This time we have moved from subjectivity to objectivity, then I have two questions:
a) Is this a normal behaviour of the n900?
b) Is this a reasonable behaviour of the n900, taking into account what the other devices offer? Just to decide which position the n900 deserves in an hypothetical top chart.

As a subjective note, I had the same battery-sensations with the n900 normal-clocked and without extra-devel enabled, two options that however I find absolutely necessary to have a decent n900 experience.

EDIT: No catorise or similar installed, since I read time ago that it had a bug that could induce a high and constant CPU usage

Re: Its not Wifi, but GPRS that is consuming most of the battery
 

If i did understand your test case then i would say that something fishy is going on. Only difference between test 1 and test 2 is that in test 2 you have IM accounts disabled. That alone should give you less drainage compared to test 1. Hmmm...btw. IIRC some people had problems with ip-widget and also battery %-widget. I do not know current sitsuation, but when we are speaking about widgets (constantly running on background) i would remove as many as possible to be sure.

Re: Its not Wifi, but GPRS that is consuming most of the battery
 

Yes this is not acceptable behaviour. And very very much thank you for providing detailed answers. This is how you can help yourself and other people here. Also you can export graph from batterygraph (from top menu) to make next time even detailed. This also helps to track battery drainage for yourself.

What i have seen here and from my own experiences with N900 i would say that you have some weird drainage going on. Do not know if it´s because of custome kernel or some application on background. I would also recommend to list applications by running in xterm
maemo-list-user-packages

As i said before I think that you are experiencing some sort of bug either from 3rd party app or from official maemo OS or app.

There is powertop named application in extras-devel which can help in finding out what is causing battery drainage on your phone.
http://maemo.org/packages/view/powertop/
minimize xterm and go to desktop, lock n900, leave it on table for couple of minutes, open it up and research powertop output. Most of time device should be in sleep.

Re: Its not Wifi, but GPRS that is consuming most of the battery
 

i installed powetop about two weeks ago but have not figured out how to use it. any suggestions?

Re: Its not Wifi, but GPRS that is consuming most of the battery
 

Did you manage to run it?
It´s shell application. It´s pretty geeky and i do not understand it+s ouput fully, but i do understand/see when something is not right. Hard to explain :)

http://maemo.org/packages/view/powertop/
http://www.lesswatts.org/projects/powertop/powertop.php
http://www.linuxpowertop.org/powertop.php

Use google and power search to learn more. And run it with different usage scenarios on your N900.

Re: Its not Wifi, but GPRS that is consuming most of the battery
 

I have not. I will look into the links you posted, thanks. The first i have already and it is useless as far as usage goes.

Re: Its not Wifi, but GPRS that is consuming most of the battery
 

Wiki seems to have some explanation about powertop output (see the Analysis tools section):

http://wiki.maemo.org/N900_Software_Power_management

Re: Its not Wifi, but GPRS that is consuming most of the battery
 

Um.. you oughta do something wrong. I let my n900 automatically switch to flight mode during night. It uses aprox 50mAh during that time.. About 8-10h that is. It means about 4% drain for 10 hours. Your iphone takes 3% on 2 hours. Do the math.... I am guessing you have configured your ideal profile wrong.. or not configured it at all.