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I've noticed that my battery life is draining somewhat faster than seems reasonable...
After 7 hours away from my charger I'm at 36% remaining, and frankly haven't used the phone much today. Two 5 minute calls and a bit of playing with email.
The battery status shows that 'Android OS' is using 43% of the battery at the moment. Next after that is the screen at 19%.
Is that normal? Or have I installed something that is draining away at it? What is the best app to identify the malevolent drainer?
Many thanks in advance!
my "Android OS" is always somewhere around 2-3%. You running stock build? mebby reboot the phone and check again?
Stock build.
Have rebooted and killed most of the apps that came along with the reboot. Will watch it over the rest of the day and see if the problem repeats.
Screen usually 70% Android 2-3%.
Mine was horrible then i saw an app G backup.that I had on auto eating up 40%... changed it to manual and eliminated that and an overheating issue... Wierd.
I have been having issues with battery life also. My cell standby was using 65-85% between charges. It would go down to 20-25% battery life after 7-8 hrs with little to no use. I did a factory reset and everything was great for one day, cell standby dropped to about 4%. I added some apps, recharged overnight, and in the morning after 1 hr battery was down to 80%, cell standby back up to 75%. not sure if it's an app i installed or not. At home i have been using a different micro usb charger, not the stock one. I'm wondering if that could be the cause. I did a 2nd factory wipe this morning and now cell standy is back to 4%. I'm going to only use the OEM charger and only add apps 1 at a time to try and narrow down the cause.
do you have the 3g problem?
my guess is ... if your phone keep switching between 3g/edge or umts/hsdpa
you keep using wireless radio and thus consumes much more power
no, I've never had any 3g problems, other than only getting a max download speed of about .8Mbps.
I called HTC about the high cell standby usage and they suggested - turning screen brightness all the way down, turn off GPS, turn off bluetooth, turn off wifi, etc... If I have to have everything turned off so my battery won't die then what's the point of having an otherwise awesome phone. It's been an hour now since unplugging and cell standby is at 20%, battery life at 98%. I guess we'll see...
Battery issues are almost always due to apps (or services) running, especially ones that are constantly using a data connection.
That's why Apple don't allow the iphone to run anything in the background ;-)
If it was fine after reset and then bad after you added some apps then you know one of them is to blame......
My nexus one has been unplugged for 24 hours now and is at 66% (fairly light use in that time to be fair).
it's possible that android synching could cause usage to spike to those levels, but that shouldn't be happening very often.
I leave syncing on all the time and my phone is easily 14 or 15 hours to get to 20% with what sounds like heavier usage than what konsta is reporting.
I read some guy solved most of the battery issues by turning off GPS. I'm now following this practise after a full charge from completely dead to see how it goes. I normally have to charge once per day, I do use the phone quite a lot, not much for phone calls though, twitter, facebook, sms, tech news etc!
I think that my "Android OS" drain must have been a one-time event (hope so, anyway). After my reboot I'm now up to cell standby as my primary usage. I've spent a fair bit of time in the last few hours in patchy signal areas, so seems fair.
Will see how long it lasts tomorrow.
I agree that the GPS seems to be the biggest battery killer. Completely drained my machine in next to no time when I was playing with Copilot live.
I am actually impressed with the battery life on the n1. I can keep GPS on and use it, playing games on the train and answering emails and calls all day long with seesmic constantly running and easily get through the entire day. If I don't charge it overnight I will be about 15-20% remainig in the morning. I have stock android os on an unlocked n1.
Power drain solved....
Hi every one.
My battery life to was abismal, that was until I read this over on Modaco.
GSM 2G+3G ("WCDMA preferred") drains battery over 5 times faster than exclusive 3G ("WCDMA Only")
Average battery drain / hour when phone is idle with screen off:
1-Standard shipping mode WCDMA prefered, i.e. both 2G and 3G enabled, Wifi off): 10% / hour
2-Alternate WCDMA Only mode, 3G exclusively, no Wifi: 1.7% / hour
So I tried changing the phone settings from WCDMA prefered to WCDMA only. WOW battery life instanly better!!! 3G still works and phone OK.
To do this enter *#*#4636#*#* on phone dial pad, select phone information, then scroll down to selection box, change set preferred network type to WCDMA only. Switch phone to airplane mode, then switch airplane off and watch your battery performance increase by 300% plus...
gadjet said:
Hi every one.
My battery life to was abismal, that was until I read this over on Modaco.
GSM 2G+3G ("WCDMA preferred") drains battery over 5 times faster than exclusive 3G ("WCDMA Only")
Average battery drain / hour when phone is idle with screen off:
1-Standard shipping mode WCDMA prefered, i.e. both 2G and 3G enabled, Wifi off): 10% / hour
2-Alternate WCDMA Only mode, 3G exclusively, no Wifi: 1.7% / hour
So I tried changing the phone settings from WCDMA prefered to WCDMA only. WOW battery life instanly better!!! 3G still works and phone OK.
To do this enter *#*#4636#*#* on phone dial pad, select phone information, then scroll down to selection box, change set preferred network type to WCDMA only. Switch phone to airplane mode, then switch airplane off and watch your battery performance increase by 300% plus...
Click to expand...
Click to collapse
Are you on T-Mobile?
gadjet said:
Hi every one.
My battery life to was abismal, that was until I read this over on Modaco.
GSM 2G+3G ("WCDMA preferred") drains battery over 5 times faster than exclusive 3G ("WCDMA Only")
Average battery drain / hour when phone is idle with screen off:
1-Standard shipping mode WCDMA prefered, i.e. both 2G and 3G enabled, Wifi off): 10% / hour
2-Alternate WCDMA Only mode, 3G exclusively, no Wifi: 1.7% / hour
So I tried changing the phone settings from WCDMA prefered to WCDMA only. WOW battery life instanly better!!! 3G still works and phone OK.
To do this enter *#*#4636#*#* on phone dial pad, select phone information, then scroll down to selection box, change set preferred network type to WCDMA only. Switch phone to airplane mode, then switch airplane off and watch your battery performance increase by 300% plus...
Click to expand...
Click to collapse
Are you on T-Mobile? Do you have a fairly strong 3g. signal ? if one did have a fairly strong 3g signal would this still be advisable?
rockky said:
Are you on T-Mobile? Do you have a fairly strong 3g. signal ? if one did have a fairly strong 3g signal would this still be advisable?
Click to expand...
Click to collapse
Hi rockky.
No I am on Orange, I usually only get a full strength 3G at my works and not usually at home, however since getting a Nexus 1 i now get a limited 3G at home..
after uninstalling mobile defense and city caller id my bat went back to normal.
I noticed pretty good battery improvement when I turned off GPS (only turn it on when I need it).
I'd just like to share with everyone my findings with this setting. I had great battery life with my n1 one day, 16h 30m since charge at 22% wifi on all day and sipdroid running to receive calls over wifi.
Next day I enabled data services while roaming as an option and my battery was completely dead 6 hours in. I believe this was due to the fact that I don't get t-mobile service at work and it was trying to connect.
So I test it again the day after without this option, wifi, sipdroid, web browsing, regular calls. Again great battery life.
If anyone is getting poor battery life they may want to uncheck data services while roaming. in my area when I'm not in doors I get 3g signal like normal. I was wondering if this option is of any use to anyone or is just a battery killer for when you don't have signal.
I use the phone with my T-mobile data plan but also since I don't get service at work or in my basement I use wifi to get data and my normal calls with sipdroid, gizmo5 and GV.
Hmm interesting.
It would be awesome if someone could make an 1800 mah battery without requiring a bigger size case - for the N1. They got the 1600mah, can they do the 1800! I would buy that in a heartbeat.
Battery drain during T-Mobile Data Outage
I found that my battery, which normally lasts about 15-16 hours, drained completely in about three hours during this data outage. And I was not even using the device during this time!
In fact, the USB cable was insufficient in recharging the phone until T-Mobile finally got the data service running again.
Did anyone else notice this? Is this a 'feature' or something that we can expect to happen when out of a data source?
Did anyone try to compare battery life between no data connection and idle data connection?
I always turn data connection off after update, but I am asking how does idle data connection effects battery?
I know it drains it...but how much?
And the reason I don't know results from myself...
Sometimes my battery drops from 100 to 90 or less over the night, sometimes from 100 to 80 or even more, with the same usage or any usage at all...so I don't know how to compare it because it's so random...and this is without data connections, it is only device with phone on in sleep mode...
I once compared an over night-drain where no connection took 3% of the battery and with data connection 4%. Approx 8h sleep
It's hard for me to compare during normal use since my usage varies a lot from day to day. So I have nothing to contribute during daytime usage.
umiss said:
I once compared an over night-drain where no connection took 3% of the battery and with data connection 4%. Approx 8h sleep
It's hard for me to compare during normal use since my usage varies a lot from day to day. So I have nothing to contribute during daytime usage.
Click to expand...
Click to collapse
I was using wmlonglife for some time, however one time it stops to work - i have found that i had a permament data connection in idle, but didn't notice a thing, so technically it do not drains the phone dramatically
when you guys say "idle" data connection, is the phone not automatically checking for email accounts etc? If not have you disabled them overnight - how do you do that please?
From yesterday until today, until now, I left idle data connection and it dropped in 12h from 80 to 75.
When I tried to close connection and left it overnight it dropped from 100 to 93.
By my expirience there is difference in battery drain: 15% with idle data connectino and 7% without data connection.
But numbers change from day to day...but more or less is 2x more when i have data connection on idle
might have to do with the network.. most networks do their work at night because they seem to asume everybody is asleep.. it could be offline every now and then but keeps searching for updates..
Mine has 3g toggle turned off, but the 'data connection' toggle is always on, i have three email accounts that get checked over edge every 2 hours, and battery drops roughly 2% during 7 hours sleep.
yuo have 3g off permanently or just overnight?
What do you "lose" when using 2g vs 3g?
My options about 3g mode is set to auto, so I guess it switch to 3g or hsdpa when available...
wigwam12 said:
yuo have 3g off permanently or just overnight?
What do you "lose" when using 2g vs 3g?
Click to expand...
Click to collapse
yea 3g permanently off. I live right on the edge of my local 3g coverage, and with it on itchews through the battery as it switches on/off/on/off. I get full reception using edge which is easily fast enough for surfing low bandwidth sites(like xda dev! ) twitter and emails etc.
my HD2 drains battery VERY fast when i have idle connections. when i don't turn them off my phone battery is from 100% to empty in about 6 hours.. but maybe there is a problem with my device / rom.
i hate to use your thread for topic for this but maybe anyone can help me with my battery being empty so fast? i am using Dutch stock rom v1.66 with standard radio rom. i am going to try a newer radio rom tonight. but i dont think that is going to help mutch.. i dont mind flashing to a custom rom but i want the same user interface as i now have. i dont like the custom one's with their shiny buttons and stuff..
would really apreciate help / advise!
samsamuel said:
yea 3g permanently off. I live right on the edge of my local 3g coverage, and with it on itchews through the battery as it switches on/off/on/off. I get full reception using edge which is easily fast enough for surfing low bandwidth sites(like xda dev! ) twitter and emails etc.
Click to expand...
Click to collapse
Thanks. I think the most bandwidth site I would currently access is Facebook.
I will try 2G then. When I get more into using the phone as an internet device I guess I could turn it on.
Mind you in the middle of a major city and moving from Voda "excellent" to "very good" signal zones it should stay 3G most of the time not switch so often......
the rom i.m using makes it easy to manage data, left soft button on home screen brings up comm manager and all the toggles have been activated, takes moments to switch on/off 3g and wifi, the rest of the time the edge data just works fine.
incidentally, in terms of power use other things to look at that might get overlooked, block size on sd card, if its real small and you have lots of sd card access, such as progs installed there, browser cache there, can significantly increase the number of read writes to the card in any given time period, costing power.
Hi, I have been decorating my small bathroom today and I have had my N1 sat on a shelf busily streaming music from last.fm over a wifi connection.
I had the volume up full and was listening for a good 7 hours. The battery was at 95% when I started listening and I expected the phone to shut down by mid afternoon but it didn't.
At about 6.30pm I finished decorating (for the day!) and looked at the battery guage. It showed 64%. I couldn't believe it!
Battery use is shown as 26% cell standby (good 3G connection all day), phone idle 23%, mediaserver 2%, and wifi was just 10%.
I always thought wifi was a battery drainer but apparently not on the N1
i get steady drain when indoors @ the office where i only get Edge no 3G. Is the battery drain as bad when searching for 3G as it is searching for a signal in general?
aj
To my knowledge the screen uses the most battery (other than voice calling). So if you were not using either of them it should last you a long time.
andythefan said:
To my knowledge the screen uses the most battery (other than voice calling). So if you were not using either of them it should last you a long time.
Click to expand...
Click to collapse
Yea the brightness of the screen is to blame for most rapid battery drains.
I've found that forcing 2G when indoors is the best way to go (unless you still generally have solid 3G).
If you are in a solid 3G area, then just force 3G...
This gives you a much more stable network connection and means the phone doesn't have to work as hard, switching between EDGE and HSDPA.
gsvnet said:
I've found that forcing 2G when indoors is the best way to go (unless you still generally have solid 3G).
If you are in a solid 3G area, then just force 3G...
This gives you a much more stable network connection and means the phone doesn't have two work as hard, switching between EDGE and HSDPA.
Click to expand...
Click to collapse
how do you force a 2G connection?
aj
edit: network settings. got it.
ghostrida said:
how do you force a 2G connection?
aj
edit: network settings. got it.
Click to expand...
Click to collapse
Go to settings > wireless & networks > mobile networks and select only use 2g networks.
Edit: Nvm you ninja edited on me lol
gadgetgaz said:
I always thought wifi was a battery drainer but apparently not on the N1
Click to expand...
Click to collapse
FWIW, the specs on the Google page list 6.5 hours browsing the web on Wifi vs. 5 hours for 3G so it is at least better than 3G.
Also, streaming FM probably runs the Wifi in bursts with some buffering rather than continuously, wouldn't it?
Also, streaming FM probably runs the Wifi in bursts with some buffering rather than continuously, wouldn't it?
Click to expand...
Click to collapse
I'm sure you're right but the wifi radio is switched on all the time even if it just accessed data in bursts.
gadgetgaz said:
I'm sure you're right but the wifi radio is switched on all the time even if it just accessed data in bursts.
Click to expand...
Click to collapse
If it supports the WMM extension along with the router then it can request some low power support for maintaining the signal which drastically reduces the power needed when not actually sending/receiving data. It was created for things like WMA (which this phone doesn't have), but can be used more generally.
Last time I checked the screen display only used 4% at about half brightness ( maybe I'm wrong but I checked with bettercut shortcut )
ghostrida said:
i get steady drain when indoors @ the office where i only get Edge no 3G. Is the battery drain as bad when searching for 3G as it is searching for a signal in general?
aj
Click to expand...
Click to collapse
Your phone uses a lot of battery when searching for signal. Enabling Edge only should make that stop. My phone fluctuates at work because I'm in a big building so I just connect to the wifi and leave it.
I too am extremely satisfied with the battery life, for as fast as the phone is I wouldn't expect so much. I'm amazed, seeing it with such a small battery, this phone sips power.
just as a note, have had the 2800mah battery now for the recommended 5 full charges...phone has been on for 3 days now and is at 40%...crazy
nmeofdst8 said:
just as a note, have had the 2800mah battery now for the recommended 5 full charges...phone has been on for 3 days now and is at 40%...crazy
Click to expand...
Click to collapse
Nice! How does the extended back affect your use?
wow, just 31% after 7 hours!!
I lose 10% just getting to work (1 hour) with very limited usage and edge only.
britoso said:
wow, just 31% after 7 hours!!
I lose 10% just getting to work (1 hour) with very limited usage and edge only.
Click to expand...
Click to collapse
bouncing between edge and 3g drains the battery also.
I would like to collect cell standby data from you. Cell standby is much too high, i have 1% per hour even under optimal conditions. Some users have much more and are satisfied when they reach 1% but i think this is too much. SGS1 and SGS2 are below 0,5%.
Can you post
time on battery,
remaing capacity in %,
cell standby in %
and calculate the consumption per hour:
(100 - "remaining capacity in %") * "cell standby in %" / 100 / "time on battery"
Sample:
time on battery = 5,5h
remaing capacity in % = 84
cell standby in % = 40
(100 - 84) * 40 / 100 / 5,5 = 1,16% per hour
//EDIT//
I build a google sheet where we can enter these information and which then calculates the average stanby drain:
https://docs.google.com/spreadsheet/ccc?key=0Ambt0PkdLr7BdEJ1alptQ2M1bFlLbm11aVdtNmtIY0E
Maybe that helps to identify those configurations without drain.
Hi,
I think this is a good idea, but it would be good to post your current ROM, Radio and Kernel plus the country and provider.
All these points could influence the cell standby. I am on 3G an have medium to good reception.
ROM Omega 5.2
Radio XLF2
Kernel Siyah 1.2.6
Country Germany
Provider O2
Standbydrain
time on battery = 4h
remaing capacity in % = 75
cell standby in % = 41
(100 - 75) * 41 / 100 / 4 = 2,56% per hour
Time on battery 6:30
stanby cell= 58%
remainig capacity=67%
ROM Foxhound 0.3
Radio XLF2
Kernel Siyah 1.2.6
Country Luxembourg
Provider Tango
(100 - 67) * 58 / 100 / 6.30 = 3,03% per hour
valerio.tosti said:
Time on battery 6:30
stanby cell= 58%
remainig capacity=67%
ROM Foxhound 0.3
Radio XLF2
Kernel Siyah 1.2.6
Country Luxembourg
Provider Tango
Click to expand...
Click to collapse
I added those values to the spreadsheet.
ok you can add
signal strenght 2-3Bars
Network type 3G/Hspda
wifi On, also when display off
---------- Post added at 04:20 PM ---------- Previous post was at 03:37 PM ----------
how is this possible that sellman makes 35 hours?
The next few days I will switch my Radio, to see if there is any considerable impact.
whaaat 42h???? Guys commeon you are killing me!!!!
valerio.tosti said:
whaaat 42h???? Guys commeon you are killing me!!!!
Click to expand...
Click to collapse
I thought the same
How unfair life can be
Cell standby seems to be
1) A modem firmware failure for those who actually have bad cell standby battery life. This seems to be caused by not entering low power mode on non active connections or switching to fast/often between the power modes.
2) The batteryprofiles.xml populates the cell idle entry with 33mA as power drain as opposed to 3mA for the S2 which has the older version of same type of hardware modem. This is absolutely retarded as the actual drain is not really that much and being reported much higher than it is.
I personally am running on 2G which is more than enough for chat, email and notifications and switch to 3G whenever I need to manually or am on Wifi. I am still on my first charge since I have gotten the phone, and I'm at around 40 hours lifetime with 4H screen time with 33% battery left. This is with around 20 reboots while flashing and testing my kernel, and playing with the phone. Over-night (8+ hours) I lose about 3%.
no cell standby issue in CM9 by the way guys
AndreiLux said:
Cell standby seems to be
1) A modem firmware failure for those who actually have bad cell standby battery life. This seems to be caused by not entering low power mode on non active connections or switching to fast/often between the power modes.
2) The batteryprofiles.xml populates the cell idle entry with 33mA as power drain as opposed to 3mA for the S2 which has the older version of same type of hardware modem. This is absolutely retarded as the actual drain is not really that much and being reported much higher than it is.
I personally am running on 2G which is more than enough for chat, email and notifications and switch to 3G whenever I need to manually or am on Wifi. I am still on my first charge since I have gotten the phone, and I'm at around 40 hours lifetime with 4H screen time with 33% battery left. This is with around 20 reboots while flashing and testing my kernel, and playing with the phone. Over-night (8+ hours) I lose about 3%.
Click to expand...
Click to collapse
So what you are saying is that it is just a miscalculation? Then the voltage would still show up correct.
Any idea where to find the battery voltage?
Sent from my GT-I9300 using XDA
mc-paulo said:
So what you are saying is that it is just a miscalculation? Then the voltage would still show up correct.
Any idea where to find the battery voltage?
Sent from my GT-I9300 using XDA
Click to expand...
Click to collapse
Yes that's what I'm saying. The whole battery statistics page in terms of percentages is absolutely useless. Not only are the modem values completely ****ed but the CPU accounting is dead wrong, the values are the same for 1400-900MHz as the Galaxy S2 values for 1200-200, with all the steps below 900MHz being reported as the S2's 200MHz current consumption (55mA). You can absolutely not rely on any of that data for now as it is absolute hogwash.
What does the voltage have anything to do with it? You can't do anything with the voltage value alone, other than maybe estimate battery charge level. Use Battery Monitor Widget if you still want to see statistics.
The Voltage would show if the battery really discharges that fast or if it just is a miscalculation, as you are stating.
My phone is dead after 20hours, no matter how I am using it. The only thing that helps is Airplane mode, but that way a phone is kind off useless.
No wifi, no app and not even the screen are killing my battery. There has to be a culprit and I am guessing, as maby others are, that it's a bug in the radio.
Sent from my GT-I9300 using XDA
mc-paulo said:
The Voltage would show if the battery really discharges that fast or if it just is a miscalculation, as you are stating.
My phone is dead after 20hours, no matter how I am using it. The only thing that helps is Airplane mode, but that way a phone is kind off useless.
No wifi, no app and not even the screen are killing my battery. There has to be a culprit and I am guessing, as maby others are, that it's a bug in the radio.
Sent from my GT-I9300 using XDA
Click to expand...
Click to collapse
Battery discharge of course it correct, I'm just claiming that the battery statistics and break-down is absolute nonsense. I suspect that it is fast-dormancy, try idling it on 2G/EDGE and see if it's the same.
Ah, now I am getting you.
If it was Fast Dormancy that would explain why two identical setups in two different countries, with different providers are having such different runtimes.
In 2g mode fd is disabled, if I read you right? As I am wifi areas most of the time, 3g is not that important to me. Worth the try.
Sent from my GT-I9300 using XDA
mc-paulo said:
Ah, now I am getting you.
If it was Fast Dormancy that would explain why two identical setups in two different countries, with different providers are having such different runtimes.
In 2g mode fd is disabled, if I read you right? As I am wifi areas most of the time, 3g is not that important to me. Worth the try.
Sent from my GT-I9300 using XDA
Click to expand...
Click to collapse
FD doesn't exist for 2G. So yea, basically disabled.
Added my actual data and i'm surprised. No one has an acceptable power consumption for cell standy. I hope Samsung fixes the problem.
The last hours I was running on 2g only and it didn't do any good.
Experienced nearly the same amount of battery drain than before.
I will switch to another Radio, and will keep an eye on that drain.
Sent from my GT-I9300 using XDA
At night i have only 2G because in my home where the phone "sleeps" no 3G signal is available. The signal is much more worse, only 1-2 bars, but the battery consumption is even better than with 3G. In 8 hours of Standby only 2-3% battery like it was before with my SGS1. Seems to be only a 3G problem. I checked logcat, but i don't have the fast dormancy problem. I think with 1% per hour with 3G i have a very good performance but in comparison to SGS1 its worse.
Your phone has to run a whole setup, authentication and connection procedure with the antenna each time data network is cut. However when the data network is open (especially on HSPA frequencies) it drains the battery.
So FD is a 3G feature (HSPA-Versions being different extension levels) which basically tells the antenna that your phone will now disconnect the data connection but the antenna should remember him and the state of all TCP connections.
Periodically your phone will power up the data network through a very short and speedy handshake procedure which resumes the old data connection and ask the network whether any new packets have arrived. If so, it will accept and process them and keep the data connection open for new incoming/outgoing packets until it goes back to Fast Dormancy (IDLE) mode.
The network/antenna of course has to store any incoming data packets until the phone polls it so there is a measurable multi-second delay until the data is effectively received by your phone.
The exact polling frequency is defined by your phone's internal database of network operators and is e.g. for all luxembourgish network operators 5 seconds. Therere is no single 'good' value since:
- the network has to store the data. If your phone polls too slowly it might drop the data packets or even close the connection, forcing the phone to run through the full procedure again which causes huge battery drain. (This is also true if the network _SHOULD_ support FD but in reality does not)
- the incoming data packets are delayed by up to X seconds, X being the polling frequency. So you might e.g. only see incoming chat messages several seconds after them having been sent if the phone is in IDLE mode.
- too high polling frequencies put a high strain on the network (to the extend that they might refuse your mobile to reconnect for a certain timespan) and kills your battery fairly quickly.
Furthermore FD only works for incoming data packets, not outgoing ones.
If your phone sends a message, it will directly go to fully-awake 3G network until fast dormancy kicks in again after a certain idle period.
Now, basically FD is a very good solution to 3G's battery drain, however it only works if your phone does not send data and does not constanctly receive data. (Additionally of course, the FD network setup must be correctly configured with sane values... I've seen carrier-provided setups of 1 second Fast-Dormancy interval)
If you have apps which keep data connections open and constantly send/receive small amounts of data (e.g. Skype, ICQ, Msn, Facebook, ...) FD is more or less worthless for your setup and might only cause a huge battery drain.
Furthermore at least my provider (Tango, Luxembourg) sometimes shows bad cases of antenna hopping when waking up from FD which drains the battery even more.
(Antenna hopping is if the antenna tells your mobile phone to connect to an other antenna because it's overloaded or it knows that the other one has significantly more capacity available. However if not properly managed by a supervising instance, this may cause several antennas to play ping-pong with you and keep moving you to other antennas)
2G on the other hand doesn't know what FD is for a very simple reason; it uses the same frequencies for data network and voice. The latter has to be connected at all times anyway, so keeping the network connection open only causes insignificant battery drain. (As long as the device is actively sending/receiving data the battery usage will of course get higher)
So if you want your phone to be connected at all times (Chat, Push notifications, Emails, ...) you'd keep it in 2G. But due to 3G having a better KB/W ratio and being MUCH faster, you should switch when browsing the net.
There is a (paid) app for automated 3G/2G switching when the phone is idle which additionally can enable/disable Wifi when you're in range of a configured network based on it learning your exact location from signal changes of the coarse network-based location.
That app is called Juice Defender Beta (you need the 'Ultimate' donation key to unlock all the features) and so far works flawlessly on my phone.
(Additionally it can automatically dim the display below the minimum-brightness which is cool at night )
If the phone has a very high network drain in 2G too you most likely are either constantly receiving/sending data (e.g. Skype, I recommend using IM+ Pro and configuring it with Push notifications when in the background) or using an Exchange account which seems to have a battery-drain issue in Samsung stock firmwares.