Funny battery values (nx6325)

[Joerg Wunsch]

Thanks for all the suggestions so far, I'm writing a mass-followup to
everyone.

As Dan Lukes wrote:

> And it's filled in C1AC() method. The Design/Last Full Capacity is
> filled here:

>   Store (C164, Local0)
>   Store (Local0, Index (DerefOf (Index (C1AF, Arg0)), 0x01))
>   Store (Local0, Index (DerefOf (Index (C1AF, Arg0)), 0x02))
> 
> It mean that both numbers are same and come from C164 variable.

Ah, that explains the observed behaviour, I think!  (See below.)


As Ian Smith wrote:

>  > Out of sheer curiosity... what does acpiconf -i1 say?
> 
> It should't be there, but .. I wondered about that too :)

It's available as an entry, but claimed to be "not present" (which is
correct).  I guess there's an option to stuff a second battery pack
into the DVD drive bay, I didn't check HP's website for that.  That
would at least explain the sheer existance of the second entry.

[About re-calibrating the battery pack]

> Yes, been through all that.  I drained it from the BIOS setup screen
> rather than with an OS running, until the power button won't respond
> at all.

I drained my TP600 battery with FreeBSD running single-user, until the
computer eventually turned off.  Pinging the ethernet IF remotely, I
could monitor by which time it stopped responding.  After all, I've
got a battery back to 1.5 h lifetime, which is plenty for that machine.

> Pretty sure it's done for .. possibly what Joerg experienced, with
> at least one cell shot.

In my case, the battery was so severely dead, it did not accept any
charge, and the TP600 could not run from that battery at all.

> I'm really hoping
> the charging circuit is ok; even at 8.6V charging 'present rate' is 0.

It might simply refuse to charge due to the too low pack voltage.  I
wouldn't assume you can kill the charging circuit that way.

What eventually surprised me is that it seems almost all laptops use
some kind of de-facto standard 18650 cylindrical cells, usually
arranged in N pairs of cells, with N being either 3 (10.8 V battery
pack) or 4 (14.8 V battery pack).  I bought 5 identical-type old
laptop battery packs in the bay, in order to just use the cells for my
ham radio transceiver.  This got me 40 18650 cells, and I've been
using 16 out of those for the transceiver (these were all in really
good shape).  One battery pack suffered from a dead cell pair, so this
left me with another 3x2 cells in good shape -- which did now populate
the old battery pack of that TP600E. ;-) The other 16 cells are also
still usable for tinkering, but cannot deliver the higher currents
needed for laptops or my ham radio rig, though they would still do
pretty well for low-current consumers (general electronics).  So
bottom line, the good news is that you can actually replace those
cells in dead battery packs. :)


As Alexandre Sunny Kovalenko wrote:

> But this is likely the check for the presence of the second battery:

Yes, apparently, as the second batter is always (correctly) announced as
being not present.


As Ian Smith wrote:

> Can you / anyone suggest a good basic tutorial for ASL/AML?  The last
> time I tried following it from the ACPI specs I nearly drowned :)

I guess I'm also in need for one... ;-)

>  > Still curious, though.

> Mmm.  It still seems to come down to the wrong Design Capacity
> (equals Lastfull Capacity) being reported either by the battery
> itself, or being miscalculated by the EC.  This value - still
> something like 1/18 of the expected capacity - is then propagated to
> the 5% and 1% values.

I've had a look at the battery pack now, it is declared as 10.8 V, 55
Wh.  This would correspond to 5093 mAh.  However, now that I know the
"design" and "last full" capacity are always set as identical by the
BIOS, I'm no longer *that* surprised about the reported value.  This
machine has been essentially running from mains power for years now,
so I don't know when it actually might have been able to calculate real
values for "last full capacity" for the last time.

> Joerg, so how long does it really run on battery?

I'll try that as soon as possible (the machine is the production-level
machine of my wife...), and I'll use the single-user method so the
battery can actually drain down until it's really empty.

Btw., as someone suggested to tinker with the ACPI OS name, I gave
that a try, too.  When using "Microsoft Windows", it claims I didn't
have a battery at all :-o, for all other values (like "Microsoft
Windows NT", or "Microsoft Windows 2006") it reports the same 279 mAh
as when not modifying the OS name at all.

-- 
cheers, J"org               .-.-.   --... ...--   -.. .  DL8DTL

http://www.sax.de/~joerg/                        NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)