Recently my n810 looses charge when idle. I need to fully charge it in the evening to even hear the alarm in the mornig. And then it is at like 50%. It won't survive 24 idle hours. That's about 1/10 of what it should be.

I have kernel 2.6.21-omap1 #3

I used to have ASUI installed and it reported drain rates around 5%, which is also 10 times of what it should be. However, ASUI showed the CPU lowering the frequency when idle and a cpu load around 5%, all nice and dandy. ASUI is now uninstalled.

I tried with two different batteries and saw comparable drains.

As far as I can tell the battery drain is normal when the device is busy, i.e. I get a few hours busy time and not 1/10 of that.

I dual booted into a pretty much vanilla installation and there I have the same problem. So I wonder what these two installations have in common. Well there is

• The harware
• The initfs and the kernel
• The swap

Did I miss anything?

As for the swap, I just recreated it, but I don't yet have results.

I monitored the loadaverage overnight every 5 minutes along with the battery voltage and percentage. Load average was close to 0.00, occasionally 0.05 and very rarely in the 0.10 area. Still the battery lost both "voltage.current" and "percentage".

Two other strange observations:

• After a reboot the battery indicator reported 5 days/3 hours. After another reboot it showed 10 days/4 hours
• In my usual installation the battery indicator shows no animation when charging. In the vanilla installation it does.

Is there a possibility, that the battery is just okay and my n810 only thinks it is draining?

Can you think of any hardware related issues, which could cause this drain.?

Or can you think of any other reason

Its opera browser perhaps, i have the same issue with my n9

No, opera wasn't running

A big battery drain for me is Modest, but that's because I have it constantly scanning for any new messages every minute.

If you have a huge collection of music, you might want to disable metacrawler.

root
update-rc.d metalayer-crawler remove

Also, in your Control panel --> Connectivity, remove the search intervals.

To me though, you might want to purchase another battery.

The wifi stack has a bug that causes it to poll when disconnected. My device drains at 14%/hr when this happens, but it can be prevented by always entering flight mode when not using wifi. ASUI has a hack that quickly enters and exits flight mode when wifi disconnects to prevent the problem but it isn't a 100% solution and sometimes it still drains.

You could also have an old battery that can't keep its charge.

Thanks Addison and auouymous.

However I don't use modest, metalayer-crawler is disabled and the drain also happened in flight mode (when ASUI was still installed).

So the battery itselft really seems to be the culprit. I had ruled out this option because

• It happens with two different batteries. None of them is new. One is a 2 year old Mugen, the other is an even older original Nokia
• Battery life is unsuspicious when the device is busy

But a bad battery is consistent with the observations that

• It started happening all of a sudden
• It happens with the vanilla installation too

So tonight a removed the battery and left it outside. In the morning I reinserted the battery, rebooted and the battery indicator had dropped from 7 hrs when idle to 5 hrs when idle. These numbers are not really consistent with the observations when the battery is in the device, but they indicate that the battery might discharge itself somewhat.

So I'll buy a new battery.

As a side note: with ASUI I did not manage to swich USB from HOST to OTG. It insisted on HOST. Does this ring any bells?

I've had the battery in my N900 drain on idle in just 8 hours once when it normally takes about 2 days. The reason was that I had an SSH session open that I did not close properly. A reboot fixed it. (I know a reboot wasn't strictly necessary but one was planned anyway for another reason.)

Unlikely to be the OP's problem though as (s)he has tried two batteries which involves a restart.

Battery level can be higher or lower after a reboot, just the way lithium ion works. The level is only partially reliable after the device has been charged and not rebooted after the charge.


Did you press and hold for 1 second?

Yes. I then get a yellow frame around the USB button and when I relase the pen, the frame turns blue. But is keeps displaying "Host". I also tried writing "otg" into that /sys/... file, but when I "cat" that file I don't see any difference.

Meanwhile I have a new Battery, but it does not make any difference. Can hardly use the alarm anymore, becuase the "low battery" signal wakes me up before the alarm goes off.

Ideally I would now reflash and see if the problem persists. But I don't know how to restore everything once the culprit is found. I boot from internal mmc. Would that survive the reflashing? So I only had to reinstall bootmenu?

If that fails, I have a hardware issue. If I buy another n810 I would like to restore everything there. I assume I could just tar my internal mmc partition and untar it on the target device and reinstall bootmenu?

Or how would you do such a transplantation?

I can't resist to post my progress.

Once again I tried to find modern replacement for the n810, but my three hard requirements (must run emacs, must have a hw keyboard, must run a week when idle) could not be satisfied. So I bought a used n810 on ebay for the price of two mugen batteries. Sometimes it is good that the n810 is a niche product.

I cloned my internal memory card's boot partition to the new device, using tar called from ssh from my desktop computer, so the big tar file would end up on my desktop machine. Then I did the inverse operation on the new device, re-installed bootmenu and the Diablo Turbo kernel, eh voila, the device looks and feels exactly like the old one. Even my debian chroot worked, once I inserted the external card. That was pretty painless.

I don't have any hard numbers concerning the battery life yet, things look promising though. ASUI reports 0.5% drain in the last hour, which looks fine to mee. Also ASUI allows switching USB from host to OTG and back, which was not possible on my old device. So I really suspect a hardware issue somewhere around the USB circuitry.

Thanks to all for trying to help.