Date: Sun, 1 May 2011 20:55:04 +0100 From: Anton Shterenlikht <mexas@bristol.ac.uk> To: Ian Smith <smithi@nimnet.asn.au> Cc: Bartosz Fabianowski <freebsd@chillt.de>, Anton Shterenlikht <mexas@bristol.ac.uk>, freebsd-mobile@freebsd.org Subject: Re: acpiconf shows 100%, but laptop switches off Message-ID: <20110501195504.GA39246@mech-cluster241.men.bris.ac.uk> In-Reply-To: <20110501144052.M85801@sola.nimnet.asn.au> References: <20110427221701.GA63285@mech-cluster241.men.bris.ac.uk> <4DB8A3D9.7000705@chillt.de> <20110430220055.GB31905@mech-cluster241.men.bris.ac.uk> <20110501144052.M85801@sola.nimnet.asn.au>
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On Sun, May 01, 2011 at 03:39:24PM +1000, Ian Smith wrote: > On Sat, 30 Apr 2011, Anton Shterenlikht wrote: > > On Thu, Apr 28, 2011 at 01:16:41AM +0200, Bartosz Fabianowski wrote: > > > >Design capacity: 1 mAh > > > >Last full capacity: 1 mAh > > > > > > Those are obviously bogus values. Your battery quite likely is actually > > > dead and provides 20 minutes of run-time only. But since its capacity is > > > not being reported properly via ACPI for some reason, FreeBSD has no way > > > of knowing that. > > > > > > - Bartosz > > > > Thanks. I wonder whether ACPI is working correctly > > at all. What other things can I check? > > If there were problems with ACPI, you would most likely see some ACPI > messages in dmesg regarding battery status, or problems showing the EC > (embedded controller) having trouble communicating with the battery. > > This seems more likely a battery failure than a problem with ACPI, both > from misreporting its capacity and the actual behaviour of the battery > under load. The best course would be to replace the battery, preferably > with a genuine or at least fully compatible one, and see how that goes. > > The little chips on the battery that record charge in and out, voltage > and estimated capacity can get well out of synch with the real situation > especially when there isn't regular use of the laptop on battery, which > is why many manufacturers recommend 'conditioning' cycles - where the > battery is run down to total exhaustion without shutting down (best done > from eg the BIOS setup screen, where no filesystems are at risk), then > fully charging the battery - sometimes repeating that twice or thrice. > > 'Conditioning' can a) raise 'Last full capacity' to a greater fraction > of the original 'Design capacity' (likely in the range 3,000 - 5,000mAh) > and b) improve the battery's estimate of capacity and/or time remaining. > > That said, I've not seen a battery misreport 'Design capacity' before, > nor show silly values (also 1mAh) for 'warn' and 'low' capacities which > are usually about 2-3% and 1% of full capacity, respectively. But then, > what's 1%, or even 100%, of (the misreported) 1mAh remaining capacity? > > Only one cell needs to die, either short or high internal resistance, to > render a battery pack useless, unless you're prepared to open the pack > to replace single cells. At 4 years old, I wouldn't bother trying. > > It should be useful to compare acpiconf -i0 data with your new battery. > > cheers, Ian Many thanks Anton -- Anton Shterenlikht Room 2.6, Queen's Building Mech Eng Dept Bristol University University Walk, Bristol BS8 1TR, UK Tel: +44 (0)117 331 5944 Fax: +44 (0)117 929 4423
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