Hi,
Just recently my N9 has started (4 months old) to have a battery level fluctuation where the battery level drops off suddenlyunder constant heavy use for couple of hours (e.g. maps, playing a game, browsing the web). When i stop using it the battery level comes back (e.g. from 3% to 32% today, other times less depending on the height of the original battery level) after about 30 mins. I know my avg active current is in the high 300mA (~375) but shouldnt there be some safegaurd against battery fluctuations? The hardware should be designed to have a battery that supports max draw for extended periods (usually max draw is a function of total battery capacity).
I read another poster saying this but i couldnt find the thread, it might have been buried.

After heavy usage, the battery can recover a bit again. But 30% seems to be far to much.
I sugest you have a look on the batterygraph app (see my signature) which shows the history of the battery.

well, i cant wait til we have a 32nm processor. even those qualcomm wp7 approved processors are on 45nm. Nokia is too loyal to TI, they should ask for more from them.
how about a dualcore armv6 processor (like the ones used for symbian)? no one has that. a cheap dualcore. i would buy that in an e7.
Everyone keeps making complex (armv7-cortex-A\M) dual cores. some that suck too much power (like the TI in the Fire). But the nvidia tegra2 on 32nm in my asus transformer running on a 3300mah battery and a 10in screen can easily give 9 hours of internet wifi usage and never sucks on the battery enough to droop. now imagine a armv6 dualcore built on the same feature size. that ll be great to see.

@balisingh,

It's (probably) not the battery, but how the phone estimates the current charge level.

The N900 has the same issue. You start with, say, 40% and turn on the flashlight for 20min. If you then look at the battery level (using battery-eye), you see it's dropped a lot, but then after a while it goes up again.

The reason for this is BME (battery management entity), which does not report the actual battery percentage, but an "estimation", meaning that if you draw a lot of current for a while, it will *assume* that the battery has gone down by a certain amount.

No idea if N9 uses BME though.

thats pretty lame.

If you dig a bit into how to detect/measure a batteries fill state, you will realise that it is very difficult. One way is to measure the used charge, but this is very difficult and you will have to know exactly how much capacity the battery has.
The other, more common way, is to measure the voltage.
Its a simple fact that the voltage will raise again, after the load dropped.
So its not only BMEs fault, its simply a physical imitation.
How ever, as I said, it shouldn’t be more than some percents.

I've a similar problem. It goes down from 20+% to 4%. On a reboot it gains back to 19% and then the reading is accurate till the battery discharges.