Re: power consumption after shutdown
On Mon, Feb 16, 2009 at 12:19:41AM -0500, Richard A. Smith wrote: qu...@laptop.org wrote: (If one discharges an XO battery outside the XO using a home lighting circuit, the displayed state of charge will be inconsistent. Persisting in this practice results in increasing inconsistency. Ceasing the practice results in decreasing inconsistency over several XO moderated charge and discharge cycles. The inconsistency results in forced power-down before the state of charge would suggest, manifesting as my XO stops too soon.) How far off is it? The EC actually tries to detect this. The ACR register will decrease when you use the battery outside the laptop. Last I checked, some months ago, it was no more than about 30% error. I didn't proceed with the test beyond about that point. Good to know it tries to do something about it. -- James Cameronmailto:qu...@us.netrek.org http://quozl.netrek.org/ ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
In a discussion thread like this, it would good to have a source code link for all to reference, now and in the future. Thanks for all the contributions! On Mon, Feb 16, 2009 at 3:36 AM, James Cameron qu...@laptop.org wrote: On Mon, Feb 16, 2009 at 12:19:41AM -0500, Richard A. Smith wrote: qu...@laptop.org wrote: (If one discharges an XO battery outside the XO using a home lighting circuit, the displayed state of charge will be inconsistent. Persisting in this practice results in increasing inconsistency. Ceasing the practice results in decreasing inconsistency over several XO moderated charge and discharge cycles. The inconsistency results in forced power-down before the state of charge would suggest, manifesting as my XO stops too soon.) How far off is it? The EC actually tries to detect this. The ACR register will decrease when you use the battery outside the laptop. Last I checked, some months ago, it was no more than about 30% error. I didn't proceed with the test beyond about that point. Good to know it tries to do something about it. -- James Cameronmailto:qu...@us.netrek.org http://quozl.netrek.org/ ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
frederick wrote: In a discussion thread like this, it would good to have a source code link for all to reference, now and in the future. Thanks for all the contributions! unfortunately, the code in question (i.e., the EC firmware) is one of the few small bodies of code on the XO which isn't open. paul On Mon, Feb 16, 2009 at 3:36 AM, James Cameron qu...@laptop.org wrote: On Mon, Feb 16, 2009 at 12:19:41AM -0500, Richard A. Smith wrote: qu...@laptop.org wrote: (If one discharges an XO battery outside the XO using a home lighting circuit, the displayed state of charge will be inconsistent. Persisting in this practice results in increasing inconsistency. Ceasing the practice results in decreasing inconsistency over several XO moderated charge and discharge cycles. The inconsistency results in forced power-down before the state of charge would suggest, manifesting as my XO stops too soon.) How far off is it? The EC actually tries to detect this. The ACR register will decrease when you use the battery outside the laptop. Last I checked, some months ago, it was no more than about 30% error. I didn't proceed with the test beyond about that point. Good to know it tries to do something about it. -- James Cameronmailto:qu...@us.netrek.org http://quozl.netrek.org/ ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel part 2 text/plain 129 ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel =- paul fox, p...@laptop.org ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
Richard A. Smith wrote: The instrumented setup only has a current measurement resolution down to about 1mA. So there's room for a lot of error in that measurement. Looking at the schematics I see that there are quite a few other parts that share the 3.3V rail with the EC so 1mA or so seems reasonable. I've started a long term measurement test using the ACR guage inside the battery. I'll check it on Monday. Based on a long term (44 hour) test I've measured that the average draw of the XO when powered off is 1.64 mA. Although this seems to match my previous measurement it actually does not. This is a measurement of the battery voltage rail. So 1.64 mA * 6.68V = 11mW. I was expecting a number half of that. The previous measurement was on the suspend 3.3V rail which would be 5.3mW so there's 5.7mW unaccounted for. Some of this is probably the switching regulator since I doubt its very efficient in this range. In any case Leaving the battery in the XO will cost you about 1.3%/day. -- Richard Smith rich...@laptop.org One Laptop Per Child ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
I made http://wiki.laptop.org/go/XO_Troubleshooting_Battery#Tips but you folks can do a much better edit. In q2e32 I've pulled in some of my batman.fth stuff. I noted this in the same page's batman.fth section. -- =S ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
S Page wrote: I made http://wiki.laptop.org/go/XO_Troubleshooting_Battery#Tips but you folks can do a much better edit. In q2e32 I've pulled in some of my batman.fth stuff. I noted this in the same page's batman.fth section. I don't see it. In q2e32 i've changed the names of some of the functions a bit and re-did some things. There's a lot of cruft in batman.fth that I don't need to carry over. The existing batman.fth on the wiki will probably complain when loaded on q2e32. I've got a new one that I need to push up. I'll go do that now. Currently none of the functions that use the data formatting functions like 'bat-recover' are pulled in. So you still need batman.fth for charge balance issues. -- Richard Smith rich...@laptop.org One Laptop Per Child ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
On 15 Feb 2009, at 05:36, Mikus Grinbergs wrote: My apologies for not being clear. I'll try again: I want to feel that the battery that I just put into the XO I'm walking out the door with is as charged up as it normally can be. 1) If that battery came from an XO that was plugged into the AC 24/7 for the past week -- I *think* it is fully charged up. 2) If that battery came from an XO that had been shut down for 48 hours; but then that XO had been plugged into the AC until the 'power' light went green -- I *think* it is well charged up. 3) If that battery had been sitting on the shelf (not in an XO) for a month -- what did I need to do to make it topped off ? What I am now interested in is understanding a correct state of charge value after having my battery out of the XO for one month. Not possible without discharging the battery fully to determine the state of charge it had. The test is charge destructive; once it is completed there is no usable charge in the battery. Sorry - I did not mean that I cared exactly how charged up it was -- what I want to know is how to ensure to myself, without going to extremes, that the battery was well charged up. [Is 94% reported by the pop-up for an on-the-shelf battery believable, or is the 'true' value half that? And if do I see 94%, do I need to worry that this is a battery that requires some more charging?] the software pop-up says 94%. But I notice that after an hour, the software pop-up *still* says 94%. I hope you aren't surprised. No reason it should change. Battery is not being used. I was under the impression that when the battery charge went somewhere below about 97%, the XO would charge it some more. So I was surprised to have it stay at 94%. [If 94% being shown on the pop-up is not low enough for charging some more, then how can I initiate charging being performed by the XO ?] But when the software pop-up is between 90-96% (for a previously out-of-case battery), and despite the AC adapter being plugged in that value does not increase in an hour -- what ought I to do to find the state of charge ? No possible way except a full discharge while measuring the power provided. Apologies for being unclear. I'm not particularly interested in the precision of the state of charge. What I am interested in is is the battery as 'well charged up' as I can make it be by using the XO's 'built-in' charger - I will want to get the most minutes of use of my XO when carried to a place that does not have electricity ? Have you tried either of the tools/procedures at: http://wiki.laptop.org/go/XO_LiFePO4_Recovery_Procedure Either olpc-pwr-log (download and run in terminal) or bat-recover (download a batman.fth file and use from Open Firmware), display actual charge going into (or out of) the battery, so you could use either of them to charge and see when your battery stops getting any more juice. Of course, without testing full discharge/charge cycles occasionally, you could never be quite sure where a batteries max is/ was (but that just takes us back to the email loop on precision). --Gary And if it is not 'well charged up', what do I need to do to make it so? In particular -- if it *were* 90% charged up when I took it off the shelf, would I have to fully discharge it in order to then charge it up (using the XO as the 'charger') closer to 97-99% ? mikus ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
On Sun, Feb 15, 2009 at 6:36 PM, Mikus Grinbergs mi...@bga.com wrote: I was under the impression that when the battery charge went somewhere below about 97%, the XO would charge it some more. So I was surprised to have it stay at 94%. [If 94% being shown on the pop-up is not low enough for charging some more, then how can I initiate charging being performed by the XO ?] It probably is trying to charge it, but batteries are chemical mixes, so - there is no real 100% or 0% - the software is handwaving to some extent... - the charge and performance of the battery changes with many variables, and generally degrades with use so I have many batteries that after some use I only see reported as 95% charged. Even if they get more charge, the battery doesn't hold it. Or perhaps the software estimated the capacity a bit too high. In short, the % you see is a fiction, a bad simplification. This is increasingly apparent as you use older batteries, and in general as you gain experience with different batteries... m ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
On Sun, Feb 15, 2009 at 12:36:36AM -0500, Mikus Grinbergs wrote: My apologies for not being clear. I'll try again: I want to feel that the battery that I just put into the XO I'm walking out the door with is as charged up as it normally can be. 1) If that battery came from an XO that was plugged into the AC 24/7 for the past week -- I *think* it is fully charged up. Yes, 95% likely. 2) If that battery came from an XO that had been shut down for 48 hours; but then that XO had been plugged into the AC until the 'power' light went green -- I *think* it is well charged up. Yes, 95% likely. 3) If that battery had been sitting on the shelf (not in an XO) for a month -- what did I need to do to make it topped off ? Discharge it to 90% capacity, then charge it. (You can do this manually in OFW using the watch-battery command ... or you can periodically attach the AC adaptor until you get an orange LED instead of green.) Sorry - I did not mean that I cared exactly how charged up it was -- what I want to know is how to ensure to myself, without going to extremes, that the battery was well charged up. [Is 94% reported by the pop-up for an on-the-shelf battery believable, or is the 'true' value half that? And if do I see 94%, do I need to worry that this is a battery that requires some more charging?] Given a battery with an unknown history, it is not practical to predict the state of charge. I was under the impression that when the battery charge went somewhere below about 97%, the XO would charge it some more. So I was surprised to have it stay at 94%. [If 94% being shown on the pop-up is not low enough for charging some more, then how can I initiate charging being performed by the XO ?] Discharge it some more. (There is no facility for boost charging ... one reason is that this would shorten the life of the battery.) But when the software pop-up is between 90-96% (for a previously out-of-case battery), and despite the AC adapter being plugged in that value does not increase in an hour -- what ought I to do to find the state of charge ? No possible way except a full discharge while measuring the power provided. Apologies for being unclear. I'm not particularly interested in the precision of the state of charge. My explanation of this precision was so that you would understand why you cannot get what you want. I had tried explaining that you cannot get what you want but you persisted, so I thought you were interested. What I am interested in is is the battery as 'well charged up' as I can make it be by using the XO's 'built-in' charger - I will want to get the most minutes of use of my XO when carried to a place that does not have electricity ? Discharge to 90% and then charge to completion. Power off, then remove the battery. Travel as fast as possible to the place that does not have electricity, do not delay by a month. Insert the battery and power on. You will have the most minutes of use. And if it is not 'well charged up', what do I need to do to make it so? In particular -- if it *were* 90% charged up when I took it off the shelf, would I have to fully discharge it in order to then charge it up (using the XO as the 'charger') closer to 97-99% ? No. Assuming a battery that has only been used in the XO, you need only complete one charge cycle, from orange LED to green LED. Since you cannot cause this cycle unless the state of charge value was low enough, you need to manipulate the state of charge value down, and the only way to do this in the design is to discharge for a short time. Usually about five minutes, but it depends on how busy the XO is. -- James Cameronmailto:qu...@us.netrek.org http://quozl.netrek.org/ ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
qu...@laptop.org wrote: 3) If that battery had been sitting on the shelf (not in an XO) for a month -- what did I need to do to make it topped off ? Discharge it to 90% capacity, then charge it. q2e32 can help you out. In q2e32 I've pulled in some of my batman.fth stuff. As James mentions the EC won't try to charge if it thinks the battery is full because the battery full flag is set. I've added some commands that let you reset that flag. ok batman-start ok bg-clr-full-flag ok ec-reboot The EC should then charge your battery. -- Richard Smith rich...@laptop.org One Laptop Per Child ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
Chris Ball and Paul Fox responded: I take this to mean that *something* was draining some power for the two days the XO was sitting in its shut down state. The embedded controller was. Something needs to be watching for a power button press in order to know when to turn on. Thank you. I guess it's simpler to do it that way, than to add two extra latches to the package. [2 latches might work as follows: One latch would be turned on when sent electricity through the power button. This first latch would turn on the second latch if that second latch was off. The software could test the first latch state, and could turn that state off when it wanted to be watching for a power button press. The second latch would connect the battery to the motherboard proper. It would be turned off by the software for zero power drain mode.] Benjamin Schwartz wrote: All rechargeable batteries lose stored energy over time. This phenomenon is called self-discharge. True. I have found the XO-1 batteries (mfg by BYD Company Ltd) to be very stingy with energy loss. When I put one back in after a month out of the case, the XO software told me it was still 94% charged. James Cameron mentioned measuring a current draw of 24mA. I suspect this was *not* on a thoroughly shut-down G1G1. In my experience, after two days in a shut-down state the XO software shows the battery charge % to be somewhere in the mid-90's. James wrote: If you wish to avoid this draining by the EC, and instead rely only on draining by self-discharge of the battery pack, then remove the pack from the XO. Self-discharge rate has a dependency on storage temperature as well. Thanks, mikus ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
On Fri, Feb 13, 2009 at 8:38 PM, Chris Ball c...@laptop.org wrote: Hi, by default the wireless card remains alive to participate in a potential mesh network, disabling wireless should give you a lot more time. You're thinking of sleep mode, not the full shutdown that Mikus is doing. That's not how I learned it. The wireless was designed to remain active when everything else was off, in order to support mesh networking throughout a community. However, I don't see any measurements for that, although the wireless chip draws less than a watt. Perhaps someone would be willing to add it to http://wiki.laptop.org/go/XO_power_draw - Chris. -- Chris Ball c...@laptop.org ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel -- Silent Thunder (默雷/धर्ममेघशब्दगर्ज/دھرممیگھشبدگر ج) is my name And Children are my nation. The Cosmos is my dwelling place, The Truth my destination. http://wiki.sugarlabs.org/go/User:Mokurai (Ed Cherlin) ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
da...@lang.hm wrote: The embedded controller was. Something needs to be watching for a power button press in order to know when to turn on. by default the wireless card remains alive to participate in a potential mesh network, disabling wireless should give you a lot more time. In power off the the WLAN is not powered up. Only the EC remains powered. from the XO. Self-discharge rate has a dependency on storage temperature as well. The self discharge of LiFePO4 is quite low. The numbers thrown about in the marketing docs are between 3-5%/month. Based on the values in the datasheet I calculate ours to be 3.8%/month at 25 degC. However, its highly temperature dependent. The datasheet suggests that at temps = 45 degC its 33%/month and at 60 degC 100%/month. This has be somewhat experimentally verified. There were a few boxes of laptops stored in a temp controlled environment for at least a year and when I examined those batteries they still had plenty of life but, batteries sent to Jordan that were stored in a hot warehouse arrived completely discharged. I did this just now, on a unit running Q2E27, and another running Q2E30, the current is 24mA at 12.9V powered from a large sealed lead acid battery with nothing else attached. Two days of this would be 1.15 amp hours (Ah). Three days would be 1.73 Ah. While running on eternal power the EC does not attempt to enter a low power mode. This is because its monitoring the battery. This is sub-optimal while on things like solar power so at some point this may roll up on the Fixme: list but theres a lot of conditions that have to be dealt with. For now Ext power == EC on full. When powered off and on battery power only the EC attempts to to go into the STOP state where power consumption is much less. Not as low as it should be (see below) but much less. days later I insert the AC adapter into the (still closed) XO, after the 'power' light comes on, it goes yellow. [I've seen this both when I was running 'joyride' on the XO, and when I was running 'staging'.] I take this to mean that *something* was draining some power for the two days the XO was sitting in its shut down state. As mentioned above the EC attempts to go into STOP mode when the power is off and not plugged up to external power. The data sheet indicates that STOP mode is supposed to be in the 10s of uA range. Measurements taken (this morning against my EC dev tree) via instrumented XO indicate that its 4mA. Studying the datasheet that suggests that rather then going into STOP mode the EC is only going into IDEL mode. In IDEL the instruction fetch is turned off but the clocks and timers still run. 4mA is listed as the nominal draw in that mode. Looking at the EC code the go-into-STOP-mode rather than the go-into-IDEL-mode bit is getting set. So the code is _trying_ to go into STOP mode but its power draw suggests otherwise. I'll have to study it deeper. In anycase @ a 4mA draw the EC will see the net ACR diff at about 3.1%/24hours so across 2 days you would have probably discharged enough for the EC to enable the charger to top up the battery. -- Richard Smith rich...@laptop.org One Laptop Per Child ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
Richard A. Smith wrote: going into STOP mode the EC is only going into IDEL mode. In IDEL the instruction fetch is turned off but the clocks and timers still run. 4mA is listed as the nominal draw in that mode. /s/IDEL/IDLE -- Richard Smith rich...@laptop.org One Laptop Per Child ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
Richard A. Smith wrote: into STOP mode but its power draw suggests otherwise. I'll have to study it deeper. After deeper study I have verified that the EC is going into stop mode. I have also found the (biggest) source of the additional power draw I measured. The tinder box XO has the EC serial port connector loaded and has a TTL-USB adapter connected. The 3.3V EC rail is ORed in with the 3.3V regulator from the 5V USB since the device can be powered by either side. Disconnecting the EC serial port drops the power draw to 1.6mA. This also tells me that the reading listed as EC is not just the EC but all the devices connected to that rail. The instrumented setup only has a current measurement resolution down to about 1mA. So there's room for a lot of error in that measurement. Looking at the schematics I see that there are quite a few other parts that share the 3.3V rail with the EC so 1mA or so seems reasonable. I've started a long term measurement test using the ACR guage inside the battery. I'll check it on Monday. -- Richard Smith rich...@laptop.org One Laptop Per Child ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
On Sat, Feb 14, 2009 at 01:56:22PM -0500, Mikus Grinbergs wrote: I have found the XO-1 batteries (mfg by BYD Company Ltd) to be very stingy with energy loss. When I put one back in after a month out of the case, the XO software told me it was still 94% charged. The displayed state of charge is stored in the chip in the battery, and is maintained by the EC. The battery does not change it's own state of charge value. I don't think that batteries outside the XO will have their state of charge value changed by the chemical self-discharge process. But once the terminal voltage becomes significantly inconsistent with the state of charge value, I imagine that the terminal voltage is trusted more. (If one discharges an XO battery outside the XO using a home lighting circuit, the displayed state of charge will be inconsistent. Persisting in this practice results in increasing inconsistency. Ceasing the practice results in decreasing inconsistency over several XO moderated charge and discharge cycles. The inconsistency results in forced power-down before the state of charge would suggest, manifesting as my XO stops too soon.) James Cameron mentioned measuring a current draw of 24mA. I suspect this was *not* on a thoroughly shut-down G1G1. Wrong. It was on a thoroughly shutdown mass production unit. The unit was shutdown using the Sugar shutdown option, then the DC cable and the battery were removed, 30 seconds were allowed to elapse, and then the DC cable was reinserted. The measurement was after this reinsertion. In my experience, after two days in a shut-down state the XO software shows the battery charge % to be somewhere in the mid-90's. You observe a difference between my measurements and yours. I knew the technique was inadequate, but I was providing it as a maximum. I had already said that I thought the external DC supply path to contain additional losses. Richard has explained that the difference was due to the EC not stopped, because it knows it is on external DC supply. -- James Cameronmailto:qu...@us.netrek.org http://quozl.netrek.org/ ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
This gets more and more bizarre !! James wrote: The displayed state of charge is stored in the chip in the battery, and is maintained by the EC. The battery does not change it's own state of charge value. and (If one discharges an XO battery outside the XO using a home lighting circuit, the displayed state of charge will be inconsistent. Persisting in this practice results in increasing inconsistency. Ceasing the practice results in decreasing inconsistency over several XO moderated charge and discharge cycles. The inconsistency results in forced power-down before the state of charge would suggest, manifesting as my XO stops too soon.) What I am now interested in is understanding a correct state of charge value after having my battery out of the XO for one month. [When I insert that battery and plug in the AC adapter, the 'power' light is green, and the software pop-up says 94%. But I notice that after an hour, the software pop-up *still* says 94%.] I presume that when I merely shut down the XO, and leave it sitting for two days with the battery still in the case: Then when I again connect the XO to the AC adapter (and let it charge until the 'power' light goes from yellow to green), I should be able to trust that what the software pop-up says is accurate. But when the software pop-up is between 90-96% (for a previously out-of-case battery), and despite the AC adapter being plugged in that value does not increase in an hour -- what ought I to do to find the state of charge ? mikus ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
On Sat, Feb 14, 2009 at 08:26:13PM -0500, Mikus Grinbergs wrote: This gets more and more bizarre !! No, it's just physics and chemistry, constrained by engineering. Please, if you think it is bizarre, explain why you think so, and I'll happily explain the physics that I know. What I am now interested in is understanding a correct state of charge value after having my battery out of the XO for one month. Not possible without discharging the battery fully to determine the state of charge it had. The test is charge destructive; once it is completed there is no usable charge in the battery. [When I insert that battery and plug in the AC adapter, the 'power' light is green, and the software pop-up says 94%. But I notice that after an hour, the software pop-up *still* says 94%.] I hope you aren't surprised. No reason it should change. Battery is not being used. I presume that when I merely shut down the XO, and leave it sitting for two days with the battery still in the case: Then when I again connect the XO to the AC adapter (and let it charge until the 'power' light goes from yellow to green), I should be able to trust that what the software pop-up says is accurate. No. It will be close to the true value most of the time, unless there is damage. By close I mean within 20% or so, 90% of the time, assuming no external use of the battery. I'm just giving you personal estimates there, I don't have all the data. But when the software pop-up is between 90-96% (for a previously out-of-case battery), and despite the AC adapter being plugged in that value does not increase in an hour -- what ought I to do to find the state of charge ? No possible way except a full discharge while measuring the power provided. The state of charge value that you refer to is calculated. It is an estimate. It often represents reality. The calculation is done by the EC based on a measurement of current flowing into or out of the battery, since the battery was manufactured. The measurement is over time, so it is called accumulation. Measurement is done by the EC using the battery support chip in the battery pack. The results are stored in the chip. Measurement does not occur of either chemical self-discharge, or external discharge by some other means. -- James Cameronmailto:qu...@us.netrek.org http://quozl.netrek.org/ ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
My apologies for not being clear. I'll try again: I want to feel that the battery that I just put into the XO I'm walking out the door with is as charged up as it normally can be. 1) If that battery came from an XO that was plugged into the AC 24/7 for the past week -- I *think* it is fully charged up. 2) If that battery came from an XO that had been shut down for 48 hours; but then that XO had been plugged into the AC until the 'power' light went green -- I *think* it is well charged up. 3) If that battery had been sitting on the shelf (not in an XO) for a month -- what did I need to do to make it topped off ? What I am now interested in is understanding a correct state of charge value after having my battery out of the XO for one month. Not possible without discharging the battery fully to determine the state of charge it had. The test is charge destructive; once it is completed there is no usable charge in the battery. Sorry - I did not mean that I cared exactly how charged up it was -- what I want to know is how to ensure to myself, without going to extremes, that the battery was well charged up. [Is 94% reported by the pop-up for an on-the-shelf battery believable, or is the 'true' value half that? And if do I see 94%, do I need to worry that this is a battery that requires some more charging?] the software pop-up says 94%. But I notice that after an hour, the software pop-up *still* says 94%. I hope you aren't surprised. No reason it should change. Battery is not being used. I was under the impression that when the battery charge went somewhere below about 97%, the XO would charge it some more. So I was surprised to have it stay at 94%. [If 94% being shown on the pop-up is not low enough for charging some more, then how can I initiate charging being performed by the XO ?] But when the software pop-up is between 90-96% (for a previously out-of-case battery), and despite the AC adapter being plugged in that value does not increase in an hour -- what ought I to do to find the state of charge ? No possible way except a full discharge while measuring the power provided. Apologies for being unclear. I'm not particularly interested in the precision of the state of charge. What I am interested in is is the battery as 'well charged up' as I can make it be by using the XO's 'built-in' charger - I will want to get the most minutes of use of my XO when carried to a place that does not have electricity ? And if it is not 'well charged up', what do I need to do to make it so? In particular -- if it *were* 90% charged up when I took it off the shelf, would I have to fully discharge it in order to then charge it up (using the XO as the 'charger') closer to 97-99% ? mikus ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
power consumption after shutdown
As far as I can tell, the battery in the XO-1 retains its charge quite well when taken out of the case. But in my experience, when I specify 'Shutdown' to the software, and close the XO lid after all its lights (including 'power') are extinguished -- then when two days later I insert the AC adapter into the (still closed) XO, after the 'power' light comes on, it goes yellow. [I've seen this both when I was running 'joyride' on the XO, and when I was running 'staging'.] I take this to mean that *something* was draining some power for the two days the XO was sitting in its shut down state. If I want to prolong the shelf life electricity of my shut-down XO, do I need to turn off some facilities before I click on the 'Shutdown' entry in the palette of the central icon in Home View ? mikus ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Mikus Grinbergs wrote: I take this to mean that *something* was draining some power for the two days the XO was sitting in its shut down state. All rechargeable batteries lose stored energy over time. The phenomenon is called self-discharge. It is sometimes modeled as a large (but not infinite) resistance in parallel with the battery. Just be glad the batteries aren't Li-Ion. Those can self-discharge totally in a month or less. - --Ben -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.9 (GNU/Linux) iEYEARECAAYFAkmWRtUACgkQUJT6e6HFtqRK1QCgnMJ2bhK9AXQ3/NAvlXMINRsB aMEAn1hr7kDpxwy6LoA+UYd4EXXUyP0T =hc5N -END PGP SIGNATURE- ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
Hi, I take this to mean that *something* was draining some power for the two days the XO was sitting in its shut down state. The embedded controller was. Something needs to be watching for a power button press in order to know when to turn on. - Chris. -- Chris Ball c...@laptop.org ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
On Fri, 13 Feb 2009, Chris Ball wrote: Hi, I take this to mean that *something* was draining some power for the two days the XO was sitting in its shut down state. The embedded controller was. Something needs to be watching for a power button press in order to know when to turn on. by default the wireless card remains alive to participate in a potential mesh network, disabling wireless should give you a lot more time. David Lang ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: power consumption after shutdown
Long ago I did some early measurements of the EC and it was consuming current while operating. The operating current has varied slightly according to the firmware version. There have been improvements, but I've not measured it recently. The symptom you describe is quite normal ... the battery has discharged, and the state of charge evaluated by the EC shows that charging would be of benefit. So it goes yellow. If you wish to avoid this draining by the EC, and instead rely only on draining by self-discharge of the battery pack, then remove the pack from the XO. Self-discharge rate has a dependency on storage temperature as well. If you wish to measure the EC current, a simple way to do it is to remove the battery pack, and place a current measuring device in series with the DC cable to the XO. This gives you a maximum. The actual current is smaller, because the DC socket path to the EC has more losses than the DC battery path. I did this just now, on a unit running Q2E27, and another running Q2E30, the current is 24mA at 12.9V powered from a large sealed lead acid battery with nothing else attached. Two days of this would be 1.15 amp hours (Ah). Three days would be 1.73 Ah. Assuming 3.1 Ah OLPC CL1 Li-Fe battery, two days should be enough to bring the state of charge down to about 63%, certainly time for a charge. -- James Cameronmailto:qu...@us.netrek.org http://quozl.netrek.org/ ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
