i think i will just reflash it, can anyone suggest a detailed guide for a noob??

Just use flasher-3.5 and read the tutorial in the wiki.

Here you go:
http://wiki.maemo.org/Updating_the_firmware

It should be inthere about doing a Backup, but before you do so, do a bit of housekeeping and uninstall any apps you don't use. (Or you can edit the backup application list.) You could need a couple of hours or so to reinstall all your apps, so make sure you've got time to spare.

is your ssh server running all the time?
what about smscon?

i have same problem here, before i can use my phone more than one day whit the wifi on all day and now, even whit wifi off, no 3g and even dont using it can not use a full day, i installed it from a fresh reflash and i have exactly same things i had before and same use, but battery drains so fast

when i first flashed to 1.3 i installed power kernel as usual and my battery life was shocking, so i reduced the overclock from 850 to stock on the power kernel and it was still crap, finally i uninstalled power kernel and now my battery life is at least 40% better than it was before 1.3 at 600mhz.

In my case, I installed PR1.3 clean using flasher.

Now, checking it all using revserse ssh with my ubuntu server over 3g I see that the cpu usage went down to around 4-8% in total. What shows now at the top of the list is that ohmd daemon at around 2.8%, then the ssh and the top command itself. So I guess its not so bad, at least while the screen is off.

The hildon status menu consumes a little more than I want. Maybe it's that status menu application that extends the menu to show memory and cpu consumption (!) that increase the cpu consumption. (Don't remember its name right now).

Then again, I don't really know what's a typically normal 'idle' (or let's say average) consumption on the device.

Edit: Yes, I also run power kernel. Interesting....it might be contributing as well to the the drain.

Yes my SSH is running the whole time. Thx for the hint !
And what do you mean by " what about smscon" ? Is it draining much battery ?

I also had this problem, but even worse my SIM wasnt able to register! I took me almost a day with troubleshooting and googling before I figured out that it actually was the PR1.3 image that (in some way) was causing it.

By using flasher3.5, I degraded again to PR1.2 and everything works now.

had the same issue for about 2 days, cpu was running at 100% with hildon desktop being the cause

so searched around and deleted cpu mem aplet, removed all widgets from desktops( had only 2) removed CATORISE

been 20 hours and still 70% so i am hoping its sorted out other wise a reflash to PR1.3 is in order

hope this helps..
cheers