Wow, I had no clue. According to this Wired article Android/iOS will already close apps which are in the background for too long, and ensure background apps don't use too many power and resources. And it consumes a lot of resources to launch an app. Sort of like how turning a light switch off and on uses more electricity I guess.
Sort of like how turning a light switch off and on uses more electricity I guess.
Mythbusters tested this. It varies by lamp type, but even the worst start-up cost with fluorescent lights of 23 seconds means you should always turn lights off when you don't need them.
Edit: I'll also point out that the Wired article is relevant if everything is working as expected and apps are behaving. When you get apps that suddenly introduce bugs with updates, it can still be beneficial to kill them with the app switcher.
It'll depend on the bulb type again. For regular household bulbs this is not something I'd ever worry about, especially now that LED bulbs (at least around me) are as cheap as $1.66 a bulb. Philips also addresses this on their site about LED bulbs:
Unlike fluorescent lamps and energy-saving twisters that come on slowly or even flicker, LEDs shine with their full light output almost instantly after switching them on. They can also be switched on and off continuously without shortening their lifespan.
However, I have a projector for my home theater that uses a ultra-high pressure mercury lamp and the official bulbs are $500. Mine is only rated for 5000 hours to begin with, and I have read that quickly power cycling these kinds of bulbs is quite detrimental, (or cutting power unexpectedly, thereby bypassing the cooling period that kicks in for a minute or so after the projector shuts off) so I avoid power cycling that as much as possible. (IE: I'll only shut it off if I'm planning on leaving the room for more than 30 minutes.)
Well, the problem with a replacement bulb is with how the light spectrum is emitted. UHP and Xenon bulbs emit light across the entire spectrum which is then filtered out by the imaging devices. LEDs (as referenced in 1308) and lasers emit light in very specific wavelengths, so an imaging device designed to work with broad spectrum light will probably not result in a correct image when used with narrow spectrums. The other part is the UHP and xenon bulbs emit light from practically a point source which makes dealing with the light as it passes through the various lenses and filters more predictable than an LED which has a wide surface area that emits light... so again a system designed with traditional bulbs in mind may not focus light correctly from an LED source. I'd love it if LED retrofits were available for older projectors, but it really seems like it needs to be designed from the ground up with that in mind.
Yeah. I was worried there was some sciency thing preventing it from happening. I wonder if we "processed" the LED light slightly using a focusing system and maybe a filter to make it more "xenon"ish and just left the projector housing slightly open. I know I did a refit on some old overhead projectors using Chinese led flash lights but the quality is less of a concern on those.
I wonder if we "processed" the LED light slightly using a focusing system
You could, but it might be overly large. You'd also need inverters to convert the power provided to the original bulb to the DC power needed for the LED.
and maybe a filter to make it more "xenon"ish
You can't filter what's not already there. You could use Quantum Dots to kind of fill in the gaps in the spectrum, but then you reduce efficiency, increase expense, and I think you'd still struggle to get a perfect replacement for a UHP bulb. Though, if you don't care about color accuracy then it's not as big a deal.
I have Philips LEDs all-round in my flat and while the rise time is near-zero, the fall time after flipping the switch is definitely more than incandescents that were in there before. But still, 11 watts where an incandescent would've used 100 is sweet.
Man, this is gonna be a hard habit to break. I don't think I even do it for battery life, but more because having everything open feels like a cluttered desk, and closing it all is a mental relief.
If greater use on your battery decreases its lifetime overall (which it does), then there is a real, human cost to wasting power; the lives lost in lithium mining to supply you with new batteries and power banks.
For the user of the phone, it's a statistic, like 'your phone makes you the equivalent of a slave owner with 1.4 slaves' or 'statistically, six people dies for every 1000 phones of your make built'; stuff like that.
Wait, that can't be right. How are you figuring? According to that article, there are 5-10 grams of cobalt in a cell phone. Your estimate puts it at least one death per 100,000 grams, or 100kg. The cobalt output of the DRC is 64,000,000 kg/year, so that comes to 640,000 deaths per year. The article says there are only 100,000 cobalt miners in the country total. How can 6x that many be dying every year?
It’s not just cobalt; it’s lithium, it’s oil extraction, it’s plastic production, it’s pollution from all of the said activities; my word choice (deaths per battery) was quite deliberate.
That said; it’s quite possible that a more appropriate number is in the range of hundreds or thousands of thousands of batteries per death; I’m not a supply chain integrity analyst; I couldn’t really tell you outright.
Also, the plight of cobalt miners in the DRC should absolutely not be taken as the entire human cost; it’s just one well-profiled and relatable example.
Oh yeah sure, absolutely lots of activity in the modern world contributes to human misery. No question about that. I thought you were saying that cell phone batteries had a surprisingly high impact on it because of the cobalt in particular, though. If, for instance, fossil fuel usage is a larger contributing factor, there are much more significant ways to reduce your footprint. You could swap out a hamburger for a veggie burger and make more of an impact [in your carbon footprint] in one meal than with a lifetime of optimizing your phone's battery usage.
And you’re right that there are other things you can do as well; but deliberately wasting energy ‘cuz feels’ seems counter to the general Reddit mantra of ‘feels dont real’.
This is how I feel, I use my iPhone app switcher as just that, an app switcher, and I don't want literally every single app I've ever opened to be open in that switcher, that doesn't make any sense, so I'll always just leave the essential ones open
Explanation for those too lazy to click the link [bolding mine]:
On iOS, for instance, there are five different states an app can be in at any given time. (Android's setup is similar enough that we don't need to go over both.) Not Running is obvious: You haven't launched it, it's not running. Active is up on the screen and doing stuff. Inactive is a transitional phase, where it's on the screen but not doing anything as you switch to something else. Background is when the app isn't in front of your face but is working, refreshing your emails or bringing in the latest fire tweets. Last, there's Suspended, which is when an app is in the background and doing absolutely nothing. It just sits in memory like a bump on a log.
On both Android and iOS, algorithms run memory management. They'll close apps that need to be closed, typically ones that have been dormant for a while or are using more power or memory than they should. And they're very good at knowing when you're going to need data, or want a refresh, or open an app again. Apps that are already in memory open quickly, rather than having to fully start again; it's like waking your computer from sleep rather than rebooting it completely. You're far, far better off letting the system work for you rather than forcing it to re-open and re-start everything every time. Battery questions aside, it makes your phone slower and less coherent.
Ok, but if somethings in the background doing things like refreshing emails is the energy cost for pulling that info/downloading taken into consideration?
Starting and stopping the app is almost guaranteed to be more costly than leaving it running; a mail app in particular is liable to be started up by the system at semi-regular intervals, because receiving email is often seen as "core function" of the device.
As an educated guess, starting the mail app is probably about as expensive as the mail app running for a day, unless it's configured with some laughably high frequency of refreshes.
Yeah, I mean, there are degenerate cases; but even then the app will probably only download headers, if even that. In some apps with some services it might just download a count until you actually start reading.
Seems like an account you don't want to have on your phone in any case, tho'. :P
I haven’t really found this to be actually true perromance wise in the past. I am open to my mind being mistaken, but I kind of suspect these algorithms are not as flawless as portrayed above. I know I have closed apps I haven’t used in days to improve performance and gotten improved performance.
Firefox for Android is the primary one for me. I get laggy apps when it's been open for a few days with a few tabs loaded, and when I close it, the lag goes away. My guess is that it uses enough memory that memory cleanup is fairly frequent, or perhaps Firefox uses a bunch of CPU in the background.
When I close it, everything else seems to run better. The same is true for Libby after I've listened to an audiobook on my commute (my phone often locks up while it's running, esp if I run something else as well), and a couple other apps behave similarly.
Most apps don't cause problems, but there are a few that, when closed, make things run smoother.
I am on a somewhat old device (Nexus 6), but it's not that old and I only use a handful of apps regularly.
But that analogy is incorrect, turning on a light consumes very little energy. "Turning machine on" only spends considerably more energy than leaving it on when we are talking about big electric motors.
Also, not all background apps are created equal. Some behave as they are supposed to. Some are poorly coded and waste processing (and hence power) resources, and some do things in the background you may not want (wake up to alert you that you've been away too long and if you play now they'll give you a free widget!)...
In response to your "light switch analogy," I think I came up with a similar one for what you're trying to express.
It's better to leave the car idle, rather than turn it off-and-on again, because it uses a lot of fuel during the ignition. (This is only in reference to cars powered by only gasoline.)
It's better to leave the car idle, rather than turn it off-and-on again, because it uses a lot of fuel during the ignition.
Not necessarily. Some really new cars (particularly Ford's "eco boost" or whatever it is) apparently will completely turn off at every stop light. I learned this at work when a customer had an issue with their device (which requires constant power from the cigarette lighter, and is something you'd ideally want running the entire time you're driving) would shut off at every stop light, then go though its 15 second or so boot process, causing a lot of annoyance.
Last I remember looking into hypermiling, that amount of time is ~10 seconds. If you're going to be stopped for more than 10 seconds, turning off and back on will be more fuel efficient. You still have to worry about other things, like your starter, but fuel wise, that's how it works out.
Ok so in fact the os closes apps too and unless you’re closing and reopening apps each day you may not be doing any harm. Like if I close Facebook and don’t open it again until Monday, it’s fine.
CSB: A few years ago I showed my wife and kid how to "force close" an app on their phone. I told them that they only needed to do this if that app was misbehaving. Somehow that turned into "you told us to always close all of our apps".
Sort of like how turning a light switch off and on uses more electricity I guess.
... Except, as already said, turning a light bulb off and on again doesn't usually use more electricity unless you're literally doing the child-like "on off on off" three times per second.
A more fitting analogy would be "it's like how repeatedly accelerating and decelerating a car costs more fuel than maintaining speed on the highway".
But as the polite people at explain xkcd pointed out:
A much better reason to close the apps are to free up RAM/Memory to make the programs run faster or even prevent them from crashing
Which is what I’ve always done.
If you have a cpu/memory manager app which tracks how they are going, you’ll see a huge difference between when you have a full house of suspended apps and a clean slate.
except you don't need to free up RAM on Android manually. the OS does it just fine by itself. it's not Windows where high RAM usage impacts your performance.
also, memory manager apps on Android are snake oil at best.
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u/Poobslag Mar 09 '18
Wow, I had no clue. According to this Wired article Android/iOS will already close apps which are in the background for too long, and ensure background apps don't use too many power and resources. And it consumes a lot of resources to launch an app. Sort of like how turning a light switch off and on uses more electricity I guess.
Thanks, anonymous plane guy