My N9 just turned off, after 6 days and 4 hours off charger. Powersaving mode was on, no lpm, no double-tap to unlock (don't know if it affects battery life), I didn't connect to wifi or 3G, I did about 20-30 minutes of calls, about 10 sms, and otherwise used it normally. I didn't hesitate to unlock it to check the time, I used the alarms once or twice a day with the snooze function ringing at least twice.

In general, I used my N9 as a dumbphone. It is new, has very few contacts and messages and no music or videos for tracker or smartsearch to index.

I don't advocate of using the N9 in this way, I just wanted to test it versus a dumbphone assuming similar use (mostly to have an argument against people who favor dumbphones because their battery lasts a lot).

The result is that with the N9 you have the choice. If the battery life is critical once in a while you can manage.

Well done!

Battery life on my crippled N900 is a day at most.

I have drained 2 N900 batteries and got the 3rd to half in just over 7 hours

I normally get a day or two out of the N9. With bunch of things running but without internet connection, i just turn it on when i need it. In general is ok but i wished it had more. Good to know that it can actually run several more days when needed.

Very well put! I actually use my N9 as a semi-dumbphone during travel when I know I may be away from the wall charger for unknown periods.

I basically disable internet connection- connect it only when I am going to need it. Exit wazapp etc. I have LPM on with double tap to wake screen, and network is set to use 2G only.

This mode gives me about 2 days plus a few hours, with 30mins of calling approx and few google address lookups per day.

Then I really need to order some Micro-USB ports and considering I don't have a credit card that's almost impossible.But almost.
Haven't ran NITDroid in 6 months now!
I'm now certain that I'm buying a second battery

Doesn't 2G use more power than 3G on N9?

[edit] Well. I guess that depends of signal strenght. Initially I thought that power saving features with 3g might be more efficient. Anyway I have both most of time off as I only switch on internet connection when using the internet/updating feeds.

I have similar experiences to qwazix with the battery life, when used like a dumb phone. ca. 4-8days with one charge. With no use at all it clocks about 10 days. BME predicts 15days (ca. 3-4mA), but often something manages to bump up consumption a bit so I end up with 5-8mA idle consumption.

rather then powering it off and on you may be better off putting it in Fly mode and power save.
starting up uses a tremendous amount of energy.
unless you are going to leave it OFF for days at end, of course...

So what are the low-hanging fruit? Low-power mode and flight mode?

Much of the time my phone just sits there

Qwazix clearly said... dumb phone
what do you get from a "dumb phone"???

• phone calls
• short messages
• address book
• calendar (sometimes)
• clock / alarm (dito)
• 

nota bene: flight mode was only an alternative to powering off / on the device on a regular basis...
if you want to be able to get / make calls, GSM is probably your best choice (assuming no net access).