Post 982374 by halfcutskeleton@cybre.space
(DIR) More posts by halfcutskeleton@cybre.space
(DIR) Post #982120 by ky0ko@cybre.space
2018-11-05T05:58:02Z
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i'm sshed to my kindle, over wifi, doin stuff on it, and it's justsitting there, consuming a whopping grand total of 0.15 watts, as i'm un-tar.gz-ing files and compiling things on it
(DIR) Post #982129 by ky0ko@cybre.space
2018-11-05T05:58:26Z
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sorry, 0.015 watts, i miscalculated
(DIR) Post #982133 by ky0ko@cybre.space
2018-11-05T05:58:59Z
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i don't know how a device running linux, downloading things over wifi, and compiling stuff, can use that little power
(DIR) Post #982147 by tidux@mastodon.sdf.org
2018-11-05T06:00:53Z
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@ky0ko ARM Cortex M chips are like that. The max wattage/frequency is set stupidly low, so you won't ever be able to use it for a desktop, but at the same time, the chip stays low power no matter what it's doing.
(DIR) Post #982165 by halfcutskeleton@cybre.space
2018-11-05T06:03:44Z
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@ky0ko how are you calculating power usage? Powertop? You're right that it seems waaaay too low. That sounds like an inaccurate read to me. Possible that the battery isn't reporting to the kernel correctly.
(DIR) Post #982187 by ky0ko@cybre.space
2018-11-05T06:05:24Z
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@halfcutskeleton i have it hooked into a high end benchtop power supply from extech, which has built in ampmeter~$320 piece of equipment, i trust it's reasonably accurate
(DIR) Post #982215 by ky0ko@cybre.space
2018-11-05T06:08:41Z
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@halfcutskeleton
(DIR) Post #982261 by halfcutskeleton@cybre.space
2018-11-05T06:13:47Z
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@ky0ko ahhhhh...What I know about phone/tablet power is that they take the power directly from the battery at all times. If the device is plugged in, the actual power for the device is still coming from the battery, it just activates the charging circuit as well. Modern laptops and battery backup systems do the same thing.So you're measuring the charging circuit draw, not the device's draw from the battery.
(DIR) Post #982293 by halfcutskeleton@cybre.space
2018-11-05T06:15:21Z
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@ky0ko not sure if the Kindle does true pass through, but I doubt it. Most battery/hardwire devices don't. Especially low cost ones.
(DIR) Post #982294 by ky0ko@cybre.space
2018-11-05T06:18:10Z
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@halfcutskeleton just unplugged the battery, it's still runningdoes take more power though, so it seems you're at least partly correctbetween 0.38a and 0.150a now, depending on what it's doingso, between ~0.19w and ~0.75w, which is a bit less ridiculous
(DIR) Post #982340 by halfcutskeleton@cybre.space
2018-11-05T06:23:00Z
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@ky0ko yeah, my guess is that you're getting weird reading because you're not hooked directly to a power supply and the battery is throwing off the readings. That said, ARM chips are also designed for low performance, low power draw. If you're running it with powersave, conservative, or some other inefficient-but-low-power scheduler, that could be pretty accurate!TBH, I'm a network guy and most of my experience with battery power is with 1.5k 120w and 10k 208w UPS systems.
(DIR) Post #982345 by ky0ko@cybre.space
2018-11-05T06:24:00Z
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@halfcutskeleton do you mean 120v/208v?
(DIR) Post #982374 by halfcutskeleton@cybre.space
2018-11-05T06:28:05Z
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@ky0ko yep. That's exactly what I meant. Totally not really a power guy, and I've been drinking tonight. Thanks for the correction.
(DIR) Post #983676 by kalium@xkcd.network
2018-11-05T08:14:48Z
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@ky0ko arm truly was a gift from Demigod Sophie Wilson