What I mean by:

Stand by = idle = not completely shut down = not powered down - Why? So I can have instant on and instant access to all programs.

off line = wifi off, internet off, bluetooth off, gps off (which I don't have (n800))

I understand that even if the browser is off you can still be connected to the internet and some programs can still be accessing the internet for various things which drains the battery. Various programs can check the internet for various things with the browser off. Such as looking for new emails, looking for various updates, news updates, and just checking for any new data that it may need to act on, etc. Also the wifi hardware it self uses power to broadcast and receive data wirelessly over the air, even with the browser off. That's why I make sure I'm off line when I don't want to be using the internet.

You can powering down (shut off) the Nokia by holding down the on/off button until it shuts off. or Briefly press on/off button and selecting "Switch off!" and OK from the Device Mode selections.

You can put the Nokia in idle mode (stand by mode) by briefly pressing on/off button and selecting "Lock touch screen and keys" and OK from the Device Mode selections.

You can put the Nokia in "Off line" mode by by briefly pressing on/off button and selecting "Offline mode" and OK from the Device Mode selections. To go back "On Line" briefly pressing on/off button and selecting "Normal mode" and OK from the Device Mode selections".

Ptaffs: On another thread someone claimed they changed their home wifi box settings an improved their battery life. But for wifi use, 8 hours sounds good to me.

I now know my battery life is not normal for "idle" mode, still not sure why. Think it's the OS2008. Oh well guess I'll keep charging.

Thanks for all the replies.

My N800 have OS 2008 too, Diablo. I'm pretty happy with battery life.

Actually, as stated somewhere else, battery life is better if you don't shut the unit off. Don't know why but it seems that booting drains a lot of power. I noticed that the battery was less impacted by a full night of standby offline than by a power down and a power up ...

Some corrections:

1. A few hours (or a day) when connected to wifi is not a good battery performance for N800/N810. Those devices can usually stay online in standby mode for a few days (at least 4 days for my 2 years old N800). The problem is that some wireless access points prevent using a good power save mode. If you use such a WAP (or wireless router), then indeed the battery will quickly drain while connected, even if not using the device.

2. Turning on/off does not eat that much time. If a 1500mAH suffices for 10 days of standby, then the device uses about 6mA on standby. If the device uses 1A for booting (and it actually uses less), and takes 1 minute for off/on cycle, then it makes sense (power wise) to turn it off if you know you won't use it more that 2.5 hours. This is a worst case scenario calculation. in actual numbers, it is closer to 1 hour.

Thanks for these corrections & precise informations !!!
I looked everywhere to find precise answers, thankyou again !

So, really, our N810 have an amazing battery life managment !!!
Ii will try again to shut down the unit for the night !

I reflashed to the latest OS2008 image last night, on a fully charged battery. The only configuration I performed was to connect to my WAP, and the battery was dead by the morning. The battery is moderately new, maybe three months old, it's my third battery. At a friend's house at the weekend, I was connected for 24 hours with minimal impact on battery, as I would expect.

My router is an SMC Barricade, SMCWBR14S-N2 wireless-n. I will resurrect my Linksys for the Nokia and see if it performs better.

I consider standby mode to be connected to the access point, signed-in to IM and periodically updating RSS and IMAP, but unused, idle, ie the screen goes black.

That's it, SMC is pure s***, I know, I have one myself
It's one of the few cheap routers manufacturers that insist in using a crappy propietary os instead of Linux.
In fact I'm eagerly awaiting for my router to be supported by openwrt so I can wipe out the factory installed crap.

Hi Luca, I don't disagree. What's your battery life like? Can you stay on-line, idle, and not drain the battery?

I had no clue WAP had that kind of impact on battery life. Why is that? My N800 bought when it dropped in 2007 still has the original battery. I can go all day if I don't hit a video on the net, modest doesn't barf or Mauku doesn't go crazy trying to reach twitter. I used to have the rss applet running and scrolling but discovered that it was sucking battery badly. I increased the time interval for e-mail checking and RSS updates, which also helped with battery life.

But at this point a single YouTube video can kill my battery and now I'm getting random power downs which I suspect are caused by some kind of overdraw on the old battery.

Also I'm not sure about how much the impact it's having on m battery life, but I boot from a class 4 SD card rather than the internal memory which can have a varied effect on battery life.

No, I get a couple of hours of usage or not even a day of standby.

UPDATE! UPDATE!

SD cards seems to be the problem for my battery drain in idle/standby (offline) mode. I removed all of my user installed programs. This had no affect on saving battery power. Nokia N800 would only last 2 days in idle/standby (offline) mode, even with no user programs installed. I then removed both of my SD cards and there was basically NO battery drain for 7 days. Battery lasted 16 days and probably could have gone another day for 17 days in idle/standby (offline) mode. Using two Kingston Elite Pro 2GB 50X SD Cards. I've seen other threads that say Kingston are good cards for battery usage.