I have tried switching the n900 (and its plug) off/on when connected to the mains, but sometimes it just wont start charging-has anyone else had the same problem?

I used to fiddle with the lead just below where it plugs into my n900, as it would sometimes start charging thereafter if I did, leaving me to believe the cable might just be a poor one, but now im not so sure. The battery is now down to around 10 percent, and this battery problem was around before and after updating my phone. Ill try again tomorrow, but could it be another n900 bug, with the phone not knowing when to start charging, despite being plugged in?

I had something like this happen since around when I got my N900. I didn't get a direct outlet-to-micro-usb charger with mine (just a microusb-to-usb one) because I got it online, and I was using a mini-usb charger with a mini-to-micro usb adapter... I've had the adapter have it's casing fall apart before, but it still works, so that may have something to do with it in my case, but I think that sometimes the N900 just glitches and fails to recognize the fact that a charger has been inserted. That said, in my experience, taking the charger out and plugging it back in usually does the trick. Occasionally I have to try a couple of times before it works but mostly one attempt does it.

could the micro usb port on the n900 be loose?

droll, I have checked my port often since this started on my device (well, not often, but occasionally, inluding earlier today) and my microUSB port is fine, so this not-starting-to-charge thing isn't necessarily linked to it. And I think the OP would've noticed. But a valid inquiry nonetheless, assuming it's loose enough to be noticed upon close inspection but not lose enough to be blatantly obvious.

I have noticed this also. It is generally when I am using an old Nokia charger with the micro USB adaptor. If the power is on and I insert the cable it may or may not recognise it. However if the power is off, I then insert the cable and then switch the power on at the wall socket, the power is instantly recognised.

my phone eventually ran out of power.. but its a lie! as today (with no further charging) its now showing a fully charged phone. so it would seem that when I connected up to the mains in my first post, it WAS charging, but the phone simply didnt realise it, so refused to stay on. sounds like yet another bug

itt'll get worse and worse, ur micro usb is on its way out, mines just about gone.
backup now while u can, then u need to send it off to nokia repair.

I don't think your microUSB is on the way out just because you have a hit/miss ratio on the charger. I think you might find that your hit ratio drops if your CPU is running at 100%, which suggests it's not hardware related at all.

extent: that is interesting.

I realised that my phone was fully charged this morning as my phone was left plugged in overnight, so sometime during the night the phone eventually realised it had a mains adapter plugged into it, and decided to start charging!

I did some tests today, my adapter is fine-it does not have a weak lead or connection. When my phone states it has almost no power left, its telling the truth after all...Its simply the case of my n900 not knowing its plugged into the mains, so not charging up. As you say that may be because the cpu is running highly (or simply being used for any other activities when I plug it in) but thats very annoying. I usually stop all activities and charge then, just like yesterday-so it sounds like a bug..

perhaps its similar to windows when it tells me some programs or files wont close or be deleted, as they are "still in use", so I then have to use windows "unlocker" to correct the problem.. too bad there isnt a tool to force closure of all processes no longer in use, so it will actually begin charging on the n900 (or better yet a tool to safely realise that it actually needs to be charged-and list a reason as to why it wont start the process!)