[maemo-users] What is Best practice for Battery Longevity on N8X0?

From: Igor Stoppa igor.stoppa at nokia.com
Date: Mon Feb 18 13:55:35 EET 2008
On Mon, 2008-02-18 at 12:47 +0200, Eero Tamminen wrote:
> Hi,
> ext Neil MacLeod wrote:
> > Igor Stoppa wrote:
> >>>>>> n800: 18 days
> >>>>>> n810: 27 days
> >>>>> Impressive, any details where the savings were done? Is this strictly HW 
> >>>>> related and the n800 has same OS2008 version as N810?
> >>>> it's both hw and sw; the sw part is about fixing wrong settings in muxing,
> >>>> pullup&pulldown and disabling voltage regulators when not in use or OMAP
> >>>> is in retention.
> >>> Just to confirm, these 18 days are already on N800 with OS2008 and with 
> >>> those sw issues fixed?
> >> I don't remember if i checked exactly the sw version that is public atm
> >> but if it wasn't then it was close enough.
> > 
> > I can't imagine those fixes are in the current software, or anything close
> > to them as a few weeks ago I performed an idle run-down test on an N800 with
> > 2.2007.50-2 (a freshly flashed device with no configuration changes whatsoever,
> I.e. you didn't restore a backup, configure a phone nor WLAN?
> > so essentially a factory fresh install with a fully charged battery).  After 12
> > days and 2 hours[1] the low battery alarm began to sound - that is just 2/3rds
> > of what you are saying is possible so why such a large discrepancy
> Igor, the 18 day number, is that until the device (is calculated to)
> shut itself down, or until there's the low battery warning?

heh, first of all i don't see much difference when we talk in terms of
days, considering that the notification itself with bells and whistles
would probably eat up a good deal of idling time.

Then, I intentionally let out all the magic used in battery prediction
and user management (what you see from the battery UI is not always what
you get, but rather what you _should_ think =)

It's a basic calculation done with battery capacity and average idle
current over a relatively short time (tens of minutes).

>  > could my 9 month old N800 battery really have lost 1/3rd of it's
>  > capacity?
> And you verified that it really was the original N800 battery and
> charger?  (I sometimes use the 770 ones, but I think its battery
> has smaller capacity)
> > Or can this  difference really be down to component variance (the tested N800
> > is from  March 2007)?
> > 
> > 1. https://bugs.maemo.org/show_bug.cgi?id=2602#c20
> 	- Eero

Cheers, Igor


Igor Stoppa
Next Generation Software
Nokia Devices R&D - Helsinki

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