Date: Tue, 16 Mar 2010 17:02:23 +1100 (EST) From: Ian Smith <smithi@nimnet.asn.au> To: Joerg Wunsch <joerg_wunsch@uriah.heep.sax.de> Cc: freebsd-acpi@freebsd.org Subject: Re: Funny battery values (nx6325) Message-ID: <20100316155931.A85436@sola.nimnet.asn.au> In-Reply-To: <20100315212026.GH52442@uriah.heep.sax.de> References: <20100315062028.GC52442@uriah.heep.sax.de> <4B9E912E.4000409@root.org> <20100315201216.GF52442@uriah.heep.sax.de> <7d6fde3d1003151400t7af423e9h3a5af79f7c77e293@mail.gmail.com> <20100315212026.GH52442@uriah.heep.sax.de>
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On Mon, 15 Mar 2010, Joerg Wunsch wrote: > As Garrett Cooper wrote: > > > > I think the 2 A are realistic. With a 5100 mAh capacity, it should > > > result in somewhat more than 2 hours of run time (maybe more if the > > > laptop eventually goes idle, and reduces CPU speed). > > > If you were pulling 2 A, that's be the same approximate amount as > > many 2 x 1U servers. > > Remember, this is measured at 10.8 V (or whatever the actual value is) > battery voltage... The laptop is running on batteries here, how > should it be able to measure the mains voltage/current? (Despite, the > mains part of the supply is completely decoupled by the PSU.) That's right, 2A * 11V = ~22W which sounds perfectly reasonable. My T23 on battery draws about 24W @1133MHz idle, about 12W @733MHz, which I've verified as my house supply is 12V, and on AC these draw metered 3.0 and 1.5A respectively, ie 36W and 18W @12V, allowing inverter inefficiency. > This is what I'm getting on an old TP600E machine: > > dhcp208# acpiconf -i 0 > Design capacity: 34560 mWh > Last full capacity: 14080 mWh > Technology: secondary (rechargeable) > Design voltage: 10800 mV > Capacity (warn): 1728 mWh > Capacity (low): 345 mWh Which are 5% and 1% of nominal capacity, commonly used values. > Low/warn granularity: 1 mWh > Warn/full granularity: 1 mWh Same on my T23. cf below to your nx6325 values. > Model number: ThinkPad Battery > Serial number: > Type: LION > OEM info: IBM Corporation > State: discharging > Remaining capacity: 99% > Remaining time: 1:18 > Present rate: 10641 mW > Voltage: 11850 mV > > 10.6 W / 11.85 V = 0.9 A (the machine was idle here) Looks about right to me. > No idea why the Thinkpad is returning Watts instead of Amperes, as > most other ACPI BIOSes do. Same on the T23. Likely depends on both the EC and the in-battery chip, but there must be an order of magnitude miscalculation 'somewhere'? Requoting your original: > The battery is declared as 55 Wh, which would correspond to 5.1 Ah > (probably 3 x 2 x 18650 cells). Sounds right. My T23 battery is rated at 43200mWh design capacity. > When unplugging the AC supply, I get: > > remi# acpiconf -i 0 > Design capacity: 279 mAh > Last full capacity: 279 mAh These are obviously completely silly, and should be more like 5100mAh as you observed. ie, they're something like 1/18 of their proper value, perhaps 1/20? > Technology: secondary (rechargeable) > Design voltage: 10800 mV > Capacity (warn): 14 mAh > Capacity (low): 3 mAh These are 5% and 1% of the silly value above. > Low/warn granularity: 100 mAh > Warn/full granularity: 100 mAh About 9mWh, further showing how crook the capacity values are. > Model number: Primary > Serial number: 00784 2006/10/04 > Type: LIon > OEM info: Hewlett-Packard > State: discharging > Remaining capacity: 98% > Remaining time: 0:08 > Present rate: 2064 mA > Voltage: 11870 mV This shows the remaining time calculation using these wrong capacity values. 0:08 times ~18 = 146m = 2:26 which sounds much more likely. What happens if you let it discharge; how long do you really get? cheers, Ian
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