So, as I had anticipated the battery in my n900 has now finally decided to start failing. How's everyone elses holding up after two years of use?

I know Li-Ion batteries will only last about 2 years or so, so it's not exactly a surprise. Though what was a little surprising was how sudden the battery death was. Literally it was pretty much as normal one day and then the next I would only get around 6 or 7 hours out of it on stand-by. Under use it would be as little as a couple of hours. Quite a dramatic shift really considering that just days previously it was lasting a good 48 hours in stand-by at the very least.

So far so good (fingers crossed). Using Kernel Power 49 and things are still better now than they were on stock kernel in the early days.
From a full charge this morning, I've made 4 calls (all about 5 - 10 mins in length); watched a few vids in CuteTube and browsed the web over 3G for 30 mins today. Still reading 60%+ in BatteryGraph.

I am actually considering purchasing a new/better battery over the next month or two, just in case.

Aaah yeah the power kernel is a great tool for helping out with battery life. Especially when running low on battery a heavy underclock (down to 125MHz) and loading the low voltage profile really does help scrape the last few miliamps out of the battery. You have to put up with sluggish performance doing that of course but it's allowed me to have the phone last a night out with very minimal charge on a number of occasions.

Oh, and BTW, doing a bit of reading I think I've discovered the cause of my rapid battery failure. Low temperature. I left the thing on a window sill that turned out to be very cold while visiting some family and it was afterwards that it couldn't hold charge properly anymore. I think it must have been outside of the normal operating temperature for Li-Ion batteries as being too cold and discharged is not something they like!

1. I replace the battery yearly. BL-5J are so cheap it would seem strange not to. Read the battery thread, get a 1500mAh scudd.
2. Underclocking to 125 does not save power. Using ondemand govener the CPU jumps to the max freq all the time. Also, race to idle thing where it uses 0 power.

This is not true, underclocking does save power. Wait till your device is at a low state of charge, somewhere around a level where you know it's going to shut off after an hour or two at stand-by, then under-volt and under-clock. You'll notice a significant increase in the remaining battery life. Doing this throttles the crap out of the cpu, and in turn reduces the amount of power it's consuming.

...so my cpu spends loads of time awake going slow instead of sleeping using 0 power?

vi_ is right. Our MPU is able to go into 0 mhz state, when it does'nt have anything to do - many times every second. During this state, You save power, not only on "undervolting/umderclocking", but also on power leakage (check how power leakage is calculated - there are many values, but * by mhz @ some point - multiplying by 0, You got zero, no matter what).

"Underclocking" to 125 mhz as way to save power is ages old myth, but to my surprise, it's still popular amongst low-activity members (of Maemo community as whole, or TMO particularly).

This description was short as it could be, cause it was written in details (many times, also by me...) in plentora threads. Interested people are encouraged to search for verbose description.

/Estel