Talk:Suspend and resume: Difference between revisions
(what about those weird units, anyway...) |
(→Testing Suspensions: added ruminating over accum_current) |
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==Testing Suspensions== |
==Testing Suspensions== |
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The "weird" units of accum_current seem to be joules*10 (or kilojoules/100; that would be consistent with the temperature units degreesC/100). Anyway, I ran /usr/bin/olpc-logbat into a spreadsheet and compared the accum_current values with a prediction based on accumulating current_avg * voltage_avg. they were pretty close, a small error that grows linearly over time. this is to be expected, i guess, since the current and voltage are 10-second averages and not the actual instantaneous numbers that accumulate into accum_current. |
The "weird" units of accum_current seem to be joules*10 (or kilojoules/100; that would be consistent with the temperature units degreesC/100). Anyway, I ran /usr/bin/olpc-logbat into a spreadsheet and compared the accum_current values with a prediction based on accumulating current_avg * voltage_avg. they were pretty close, a small error that grows linearly over time. this is to be expected, i guess, since the current and voltage are 10-second averages and not the actual instantaneous numbers that accumulate into accum_current. |
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Other weirdness: accum_current will drop below zero before the battery dies. Also, 16 watt-hours is 57.60 kJ. My battery seems to range from about -550 to 6850. does my battery store 74.00 kJ? that's 20.55 watt-hours! well, it ''is'' new... |
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instead of joules, the units could be volt-coulombs. but joule = watt * second = volt * amp * second = volt * coulomb. whatever... [[User:Co149|Co149]] 02:45, 18 January 2008 (EST) |
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Revision as of 07:45, 18 January 2008
Testing Suspensions
The "weird" units of accum_current seem to be joules*10 (or kilojoules/100; that would be consistent with the temperature units degreesC/100). Anyway, I ran /usr/bin/olpc-logbat into a spreadsheet and compared the accum_current values with a prediction based on accumulating current_avg * voltage_avg. they were pretty close, a small error that grows linearly over time. this is to be expected, i guess, since the current and voltage are 10-second averages and not the actual instantaneous numbers that accumulate into accum_current.
Other weirdness: accum_current will drop below zero before the battery dies. Also, 16 watt-hours is 57.60 kJ. My battery seems to range from about -550 to 6850. does my battery store 74.00 kJ? that's 20.55 watt-hours! well, it is new...
instead of joules, the units could be volt-coulombs. but joule = watt * second = volt * amp * second = volt * coulomb. whatever... Co149 02:45, 18 January 2008 (EST)