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Story - stupid thing i did at school

ok here it goes....i thought about sharing this story about what i done during a boring physics lesson at school, it sounds quite dangerous, but luckily i am still alive to tell your guyz out there.
I was bored during class when the teacher was explaining facts about an electric socket. The teacher told us many facts about an electrical socket that gives an output of 240 volts and 0.5 amps. And then he said that 0.1 amp can kill someone. Without realizing or caring about what he said, i was dared by my friends to shove a pair of scissors into the socket and turn it on. Once i did it, the whole classroom lights suddenly blew out, and all electrical appliances that run on mains switched off. Sparks then came out of the socket holes and I was laughing.
Luckilly the teacher didnt see me or anyone else appart from my friends. After the physics lesson, everyone said that the whole of the 4th floor had a blackout. And dats the point where i laughed hard
I still dont know why i did that in the first place, although i know it was a stupid thing to do and i could have got myself killed. But all i really know is that i blew up many fuse,

it's described at walking on the edge of committing a darvin

Well, I'm not sure if your teacher is mistaken or you've just remembered it wrongly, but a 0.5A on a 240V is not sufficient to power many things. E.g., the total power of a 240V 0.5A is 120W, that's slightly higher than an old fashion 100W lightbulb. The max plug in UK (which I believe is so in HK) is 13A, that is more than 3000W, which then can be used to power stuff like an iron/heater, which goes around 2000W.
Pluging in the scissors to the socket short circuit it and hence creating a flux high current, blowing/triggering any safety fuse along the way. Since you said the entire floor was blackout, it seems that it only blown/triggered 1 major fuse. Unlikely it will cause multiple blown/triggered fuses.
On the 0.1A killing a person issue, if you consider a person's resistance is 2MOhm (which I think is higher than that), it would take a relatively large 20MV (that is 2x10^7) voltage across, which you can't easily get (if not impossible, consider a high tension cable is probably around 1MV). If you were to get that kind of voltage, the power across would be 0.1x0.1x2MOhm = 20,000W, which would definitely kill someone. Consider the amount shown, I bet it takes less than 0.1A to kill someone. To put into perspective, a Taser gun has a peak (not constant) voltage of 50,000V, which is (consider the 2MOhm assumption) 0.025A.
FYI, in most cases of electric shock cases, the fatal part is usually the duration of the electric shock (i.e. small continuous current flowing, cooking you for 30 minutes) or hurting yourself after a shock (i.e. knock yourself onto the solid ground after a shock).
Anyone fall asleep yet? anyway, whatever you do, don't mess with electricity. Respect it.
p/s: Sorry for the lengthy lecture above.. "occupation sickness".

Alan Chan said:
I still dont know why i did that in the first place, although i know it was a stupid thing to do and i could have got myself killed. But all i really know is that i blew up many fuse,
Click to expand...
Click to collapse
You might want to lay off the pipe. As you can see, there is no good that can come from it.

16 Volts AC straight through the heart can be fatal.
AC requires about 60 mA to cause fibrillation, DC needs 500 mA for the same result. Fibrillation is not always fatal....

get new friends

mikechannon said:
Jees it'll be a merciful release.
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Click to collapse
I have a heart condition and I can assure you from personal experience that fibrillations are far from mercyful

wow, i never knew you guys would be so passionate about what i did. I thought u guyz would growl at me for my stupidity.
Hanmin, you can be my next physics teacher for giving me a very comprehensive lecture , your lecture was easilly understood compared to my crappy science teacher
and yes ultraprimeomega, i think i may need new friends for the sake of my safety and education

Anyone here watching "Myth busters"?
They did a whole episode on throwing electric appliances in to bathtub and measuring the current across the "heart" of a dummy to see if dropping a hairdryer or toaster in the bath can really kill you.

I didn't see that Mythbuster. I guess it should be confirmed? Although there are lost of circumstances influencing the outcome:
-use pure H2O, it hardly conducts
-use non-ionic bath oil (good for the skin too)
-a decent Residual-current device would cut off power before you can even notice it
-a decent low amp fast fuse could be a life saver
-high ionic bath salt makes the water much more conductive than your body
-place the tub on rubber, use PVC water supply and drain pipes

they had to mess with the fuses to get enough current to kill the gel doll before they went off

Rudegar said:
they had to mess with the fuses to get enough current to kill the gel doll before they went off
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Click to collapse
oh, right, a gel doll again... very nice material for ballistics, although I believe they should put bones in it for realistic results.
Arteries, veins and nerves are full of ions giving excellent conductive paths through our body, I doubt if they simulated those in the gel.

I got kicked out of woodwork when i was 13 for tying a pupils tie round a lathe and threatening to turn it on, because he had made a better baseball bat than me, unfortunatly, for him, my friend hit the power button and nearly killed him, we promptly got suspended and moved into sewing as a punishment, with a teacher from hell. My friend who i wont name decided to wire up some gold thread to the mains socket and complained to her(teacher) that the machine was faulty, needless to say when she touched the machine she was electrocuted along with my friend, who was promptly expelled, and i was giving a severe caning, in those days we had no trip switches so the only thing that saved them both was the thin gold thread that blew as well.
Moral of the story is dont mess with electrics, or hang around with nutcases

Maggy said:
oh, right, a gel doll again... very nice material for ballistics, although I believe they should put bones in it for realistic results.
Arteries, veins and nerves are full of ions giving excellent conductive paths through our body, I doubt if they simulated those in the gel.
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Click to collapse
With an heavy insulation on the outer body part (i.e. skin = not very good conductor), not even a gold wire inside the body matters. Further, I suspect that the water and the bathtub plays an important part as well.
First, consider that you throwing an electrical appliance into the water, chances are, the 'Neutral' line will be in the water (together with the dangerous 'Live'). Any current from the live line will eventually find the shortest path to the neutral line, leaving the rest (i.e. probably you) untouched.
Then, consider that the current is increased, hence requiring not only the shortest path to the neutral, but a lot of paths to the neutral as well. As with the Faraday cage theory, electric current will tend to go around an object (i.e. electrons repelling each other), especially a better conducting one (i.e. a car protecting the driver from a lighting strike). As such, in terms of choice, if the current require additional path to go to the neutral, chances are, it will rather go via the water (better conductor, I think) or the steel bath tub (i.e. like the body of a car), than your body.

Hanmin, your whole story sounds fair enough... for laymen.
First of all you're mixing up AC, DC and static behaviour.
Faraday created spectacular shows using extremely high static charges, indeed comparable to a car hit by lightning. If you want to conduct an experiment with a metal bath tub filled with nice warm water and any bath soap, salt or oil struck from the side by lightning, I volunteer to step in.
So, our PC's have metal housing, you'd say, so they're a Faraday cage? Right? Wrong. I've had a computer company near the Dutch coast where thunder and lightning are regular events. I could tell when repairs would come in the next day. Phone, Lan and power wires go straight into the metal cage without making contact with the cage itself. Lightning doesn't even have to strike these wires directly, induction can be fatal for your equipment.
Edison called AC "the killer current" and refused to sell AC. AC can not "flow away" to neutral, it wants to go to earth/ground. As long as the fuse doesn't blow, it delivers as much energy as it can. In a bath tub it will not behave like lightning trying to find the shortest way, but like a cloud, spearding as fast as it can. Remember electrons all have the same negative load so they push each other away. And they are LIGHTning fast.
That's why it's also not a good idea to use a standard vacuum cleaner to clean your PC on the inside: the motor will create a cloud of electrons trying to find a way to ground. The free electrons can move much faster through the cloud of static charged dust particles toward your PCB than the slow air stream moves to the vacuum.
The surface of the dry skin is indeed a bad conductor. But even good enough for ECG using leads with suction cups or stickers. And ECG measures very faint electrical pulses in the heart, even with leads on the hands or feet.
Most people believe that water is a good conductor. But in fact pure water is an almost perfect isolator. And even tap water in most Western societies is so pure that you can hardly split it into hydrogen and oxigen using a fairly safe 12 V DC set up, not without first adding a hand full of salt. Current needs ions to move through a liquid, our bodies are full of ions, tap water has much less.

Niiccceee.. good that my explaination has someone to read it in details. I'm so worried that my stuff will get everyone to sleep. Anyway...
You are right that the induction from a lighting can toast your phone, lan and power line. However, as these lines are not long and straight enough anywhere near the PC, the fatal induction is actually caused by somewhere along the way to your company (e.g. from the phone exchange, along the telephone pole/underground, to your company). Your PC will be safe from lightling if it is disconnection from possible external induction source (e.g. the phone line to the outside world). I'm happy to put myself inside the PC case (if it is big enough) for a lighting strike
Some history lesson for all. Edison called the AC the killer current mainly because of the business competition between the DC and AC business. As Edison has spent a lot of money and effort just to change the public point of view on the safety of electricity, and just as the business is getting some money... this Tesla (I think) guy made AC electricity and business is good (costrofit ratio), due to the fact that AC has a certain edge on long distance transfer (I'll omit the details on this). Hence, Edison is trying very very hard to make AC look dangerous, by killing innocent animals (in some cases, virtually just cook it), and eventually, co-invented the electric chair.
In the view of the danger of DC current, it is a false impression of most people thinking that DC current is safe, mainly because the DC current we normally exposed to are low voltage DC current (e.g. batteries and phone charger). However, in strict AC/DC defination, a lighting strike is a DC current. And, I think a Taser gun uses DC too (you would certainly need to use some form of capasitor to store enough voltage for a shock, using regular batteries), unless the battery use is exceptionally designed for it.
Anyone has a Taser to confirm this? Does it gives out a buzzing sound from low to high frequency when armed some AA batteries operated cameras with powerful flash will have the same buzzing noise, indicating that the capacitor is charging, ready for the flash).
As for your statement of "AC can not 'flow away' to neutral, it wants to go to
earth/ground.", I'm not sure if you really meant "can not", or "not only". Anyway, all AC electric stuff, electrons goes between live/neutral, and does not require the earth/ground to be functional (not safely, at least).
If you remember some electric circuit theory, if caes where you have two parallel line (AC or DC), with one line much lower resistance (i.e. shorter distance between live and neutral) compared to the other (longer distance to 'ground' where 'ground' is not designed to pair with live), majority of the current will go through the lower resistance route and hence current that goes through the high resistance route maybe very well harmless. HOWEVER, there are cases where the current in through the high resistance route is harmful, that are in the cases where the current going through the low resistance route is excessive high. Example, the low:high resistance current ratio may be 100:1. If it takes (say) 1A to be fatal, the other route will need to have 100A (which will have all fuses nuked - e.g. my house has a main fuse of about 80A for both the heater and the cooker). That's what mentioned on my post above around the "consider that the current is increased..." section. And, as for the case with extreme high current, apply the Faraday thing mentioned on your first paragraph.
Take the Taser gun for example. If you were read the user manual, there is a minimal distance requirement between you and the target, due the the fact that the probes triangular trajectory path. Being too close to the target, will cause the probes to be too closely attached, not giving enough muscle area to 'disable' the target. The electron will not spread around (like clouds) through all the muscle, just the shortest route to the other probe (there may be current through other muscles, but too small to be noticeable).
Where in the Western societies are you in now? US? Nice... in the UK, you are/not so lucky, as you dont get very much pure water over the tap. UK is on hardwater, which seemingly adding mineral to the diet, probably in such situation, protect us from electrocution? If you were to be 1+ hours around London, take a bit of tap water, leave it on any surface and leave it for it to evaporate. At the end of the day, you'll get a pile of white powder. Yes, it is this bad.
As for the ECG issue, it goes the same with the low-vs-high resistance route. I'm sure it wont work underwater (dirty water?). However, still, it is a better conductor than many things.

Taser guns use electronics related to those modern tiny switched power adapters. The result in both cases is indeed DC. The physics of the lightning path are very complex, lightning can fork out to lots of places being hit by one strike but in general you're right that DC/static tries to find a short route.
In one of my first messages in this thread I mentioned what DC it takes to kill, so yes, I'm well aware that there is no such thing as "safe electricity".
If you short a capacitor or battery, current flows in one direction, from high potential to low potential till both potentials are equal.
AC doesn't come in batteries or capacitors, it comes from a generator constantly pulling the potential from above neutral to below neutral, 50 or 60 times a second. If you would short circuit the generator itself it would continue to produce electricity as long as it hasn't killed itself. There is no flowing away till both potentials are equal.
I'm a retired computer engineer, but I still do remember Ohm's law, thank you.
In case of the bath tub it means:
we have a fixed voltage (U) of 110 or 220V, depends where you live
we can measure resistance (I) from the device that drops into the water to the feet of the tub, to the tap, to the drain
U=I.R in this case U=I1.R1+I2.R2...InRn
With an 80A fuse, the radio falling on the feet, the tap behind the back and the drain and two tub feet straight under it it seems likely that about 2/3 of 80A, well lets say 50A will strike you, 50 x 110 = 5500W
That should boil the egg if not electrocute it

I WOULD SAY YOU WOULD GET A GREAT SHOCK FROM A TOASTER IN A BATH. If you took a mains plug and put two springs on the live and neutral and inserted this into a bath of water it would generate heat, i know i have boiled a cup of water for tea by this method. so if the electricity didnt kill you you will be boiled like an egg

yeah in some situations i see myth busters as more intertainment then real science
like when they had a rather small boat as an example of titanic pulling people down when it went down
a such a small raft cant compare to titanic in ways of down pull
but they are ok fun
but if they bust a myth dont mean a 100% bust in my book

Maggy said:
...
we have a fixed voltage (U) of 110 or 220V, depends where you live we can measure resistance (I) from the device that drops into the water to the feet of the tub, to the tap, to the drain
U=I.R in this case U=I1.R1+I2.R2...InRn
With an 80A fuse, the radio falling on the feet, the tap behind the back and the drain and two tub feet straight under it it seems likely that about 2/3 of 80A, well lets say 50A will strike you, 50 x 110 = 5500W That should boil the egg if not electrocute it
Click to expand...
Click to collapse
Equations, I like! For the case you've calculated above, you consider that the full 80A is flowing. And weirdly, you seemingly considering that 2/3 flowing through a human body. Lets look at this, at the 50A you mentioned (yes, you are right, 5500W will cook you very well). Consider the worst case of U at 240V, your body will have to have (U/I = R) a resistance of 4.8Ohm, which is weirdly small, dont you think?
As with scousemartin's boil an egg, you will have to consider the large amount of water in the bath tub as oppose to the amount of water you use in boiling the egg (e.g. it would take really long for the water to boil) And, even IF the water has similar rate in raise of temperature, I'm sure the person involved will be pretty quick to jump out of the water (when a toaster hit the tub) before it gets boiling.

[Solution] Nexus 4 overheating.

I just bought my Nexus 4 about 3 weeks ago, and noticed that it get considerably hot, and I mean, Reallyyyy hot, even when im not using.
So I've been trying out several roms and kernels and finally found the perfect solution and thought I should share it with everyone out there facing the same issue.
Just flash the latest stable version of CyanogenMod, and do not flash any extra kernels with it, leave it as it is, and notice the difference, it doesnt even heat up that much anymore, not even with extreme gaming.
Another tip, if u have touch control, or wave control installed, make sure they arnt working in the background as they keep the alot of sensors working even while the screen is off.
Just thought i'd share this.
Sent from my Nexus 4 using xda premium

problem is, threads like this keep continuing the falsity that the n4 has an overheating issue, when really it does not. its supposed to heat up with use, every similar device does, many even warmer then the n4. my question to you is, what temperatures did your nexus 4 reach that you are saying it "overheated"? cpu temp? battery temp? if it actually overheats, theres a safety mechanism in the device that will shut it down so it can cool off. plus, the n4 has that glass back, that makes it "feel" hotter than it actually is. if it had a plastic, carbon fiber, or metal back, you wouldnt really feel it.
also, very important, what is the air temperature around you?

simms22 said:
problem is, threads like this keep continuing the falsity that the n4 has an overheating issue, when really it does not. its supposed to heat up with use, every similar device does, many even warmer then the n4. my question to you is, what temperatures did your nexus 4 reach that you are saying it "overheated"? cpu temp? battery temp? if it actually overheats, theres a safety mechanism in the device that will shut it down so it can cool off. plus, the n4 has that glass back, that makes it "feel" hotter than it actually is. if it had a plastic, carbon fiber, or metal back, you wouldnt really feel it.
also, very important, what is the air temperature around you?
Click to expand...
Click to collapse
This.
Guys, just google any smartphone powered by dual+ core+overheating problem+xda and I assure you will find similar threads. The last device I didn't feel much heat on was galaxy r with tegra2 1ghz. Everything more powerful than that was noticeably warmer. But honestly I really don't think that N4 gets warmer than my old S2.
Yeah temperature around you is very important. Let's say you ride the bus on hot sunny day and check some websites. It's not browsing itself that causes overheating, but the combination of few factors. The device is actually already warmer than usual when you take it out of the pocket.

If the phone was overheating, it would turn off. Yes, it gets warm, but not as warm as you think. You only notice it because it has a glass back. Mine isn't getting any hotter than my old nexus s. Under heavy use, it doesn't go above 45C, which is an OK temp.
From a Nexus 4 bathing in Jelly Beans

To all three responses above me:
Fine it might not overheat to the point of melting or burning or even getting damaged but it does reach throttle temps and get uncomfortable to touch at times. Both of these are issues. Your phone should not be too hot to keep on your ear during a conversation, nor make your palm sweat excessively from holding it. It would also be ideal if your quad phone 1.5GHz phone stayed at 1.5GHz when under load. If it is forced to go below that, there is a good reason for threads like these.
Sent from my Nexus 4 using xda app-developers app

My nexus 4 reached up to 77C. It never shut off or anything. I called Google and they said as long as everything still works its fine. I thought it was a lame answer but we will see. Battery got up to 56C.

younix258 said:
To all three responses above me:
Fine it might not overheat to the point of melting or burning or even getting damaged but it does reach throttle temps and get uncomfortable to touch at times. Both of these are issues. Your phone should not be too hot to keep on your ear during a conversation, nor make your palm sweat excessively from holding it. It would also be ideal if your quad phone 1.5GHz phone stayed at 1.5GHz when under load. If it is forced to go below that, there is a good reason for threads like these.
Sent from my Nexus 4 using xda app-developers app
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Click to collapse
1. Throttle temps are actual very low.
2. It's glass. Glass absorbs hest from the ambient air very easily ( it is summer for many) and from the inside of the device.
3. The phone shouldn't get to hot to hold to ear. I have never felt the display to be hot. Unless it was in direct sunlight.
4. All modern smartphone phones will throttle. Yes this one is more aggressive than most but they all do it. The amount of power all the modern high end chips can draw under load is the highest it has ever been. So they get hotter than ever. Since they are passively cooled, even the best designed phone under full load will throttle.
5. The only good reason for threads like this is to inform the user there isn't a problem. There are no issues.

younix258 said:
To all three responses above me:
Fine it might not overheat to the point of melting or burning or even getting damaged but it does reach throttle temps and get uncomfortable to touch at times. Both of these are issues. Your phone should not be too hot to keep on your ear during a conversation, nor make your palm sweat excessively from holding it. It would also be ideal if your quad phone 1.5GHz phone stayed at 1.5GHz when under load. If it is forced to go below that, there is a good reason for threads like these.
Sent from my Nexus 4 using xda app-developers app
Click to expand...
Click to collapse
thats the thing, its not a phone. its much much more than that. you ever feel how hot a laptop could get? anyways, i do agree with you with one point, that lg, or google, chose to set the cpu throttle temperature too low as a default. having root, i choose to disable thermal throttle, so i never have an issue with with my cpu being throttled down. i sympathize there with non rooted users. but thats only a software fix(the difference is changing a Y to a N in a file), thats not an issue with the n4 overheating.
---------- Post added at 02:07 AM ---------- Previous post was at 02:03 AM ----------
albundy2010 said:
1. Throttle temps are actual very low.
2. It's glass. Glass absorbs hest from the ambient air very easily ( it is summer for many) and from the inside of the device.
3. The phone shouldn't get to hot to hold to ear. I have never felt the display to be hot. Unless it was in direct sunlight.
4. All modern smartphone phones will throttle. Yes this one is more aggressive than most but they all do it. The amount of power all the modern high end chips can draw under load is the highest it has ever been. So they get hotter than ever. Since they are passively cooled, even the best designed phone under full load will throttle.
5. The only good reason for threads like this is to inform the user there isn't a problem. There are no issues.
Click to expand...
Click to collapse
you look familiar to me, where have i seen you..

Waiting for you to post the solution on how to use the volume buttons on the side of the phone.

What do you expect with no laptop class ventilation?
Sent from my Nexus 4 using xda app-developers app

youssef.sala7 said:
I just bought my Nexus 4 about 3 weeks ago, and noticed that it get considerably hot, and I mean, Reallyyyy hot, even when im not using.
So I've been trying out several roms and kernels and finally found the perfect solution and thought I should share it with everyone out there facing the same issue.
Just flash the latest stable version of CyanogenMod, and do not flash any extra kernels with it, leave it as it is, and notice the difference, it doesnt even heat up that much anymore, not even with extreme gaming.
Another tip, if u have touch control, or wave control installed, make sure they arnt working in the background as they keep the alot of sensors working even while the screen is off.
Just thought i'd share this.
Sent from my Nexus 4 using xda premium
Click to expand...
Click to collapse
My N4 get realy hot too, when i'm outside (38C-42C) i can't talk because it burns my years but i see MIUI and 4.3 the heatting issue is gone, i mean it's still hot sometimes but not burning.
I've got a Optimus Black when it first appeard and i got even hotter...

Actually, the Nexus 4 is more prone to overheating than, say, the almost identical Optimus G. Something about a small space in the Nexus 4 somewhere that doesn't conduct heat as efficiently away from the SoC, unlike the Optimus G.
However, like said before, it is summer for most people and it got hot in the UK, so your phone will be warmer than usual if left in the pocket or in the sunshine, but you can't expect to use a phone that's running at 55C-60C by only browsing, can you? Have you guys noticed the drastic temperature difference between wifi usage (low temps) vs data usage (high temps)? This pattern is present in most if not all phones but not as drastic as this, no way.
Then again, sometimes Franco's app is reporting 40-45 C and the phone feels really cool to the touch, and another moment, it's reporting 38 C and the back feels hot, so there's lots of factors that play in this.
Make sure you keep the phone out of the sun, and use Wakelock Detector to see if any rogue apps are holding a dirty wakelock doing lots of syncing especially over data (recent Whatsapp versions have been producing fullsync wakelocks with me everyday).
Disclaimer: other than hot weather and normal heating of the phone, i have not experienced any abnormal overheating, but have a friend who has. My normal temps are 34 C - 38 C, even in hot weather with most of my usage on wifi. Outside in hot weather gets to 42 C - 44 C but that's understandable.

coolnow said:
Then again, sometimes Franco's app is reporting 40-45 C and the phone feels really cool to the touch, and another moment, it's reporting 38 C and the back feels hot, so there's lots of factors that play in this.
Click to expand...
Click to collapse
this thought that coolnow just had..
feel doesnt report a temperature, feel only shows that something is warmer than/cooler than whatever body part you are touching it with. its all relative to your body temperature. try this experiment.. get 3 glasses of water, one hot water, one ice water, one room temperature water. at the same time, stick one hand into the hot water and the other in the ice water. keep them in there for a minute. now pull both of your hands out and stick them both in the same glass of room temperature water at the same time. this will mess with your senses, so be warned! the hand that was in the hot water, will feel the room temperature water to be cold, the hand that was in the ice water will feel the room temperature water to be very warm, while they are both in the same glass of water. so you see, reporting how something feels is very inaccurate and unreliable.

As simms22 point out about the feel, that is a terrible way to judge it.
Also so is the actual number from franco's app. His app measures the cpu (Soc) temp. It doesn't also include the battery temp. The higher battery temp will make the phone feel hotter even if the cpu temp is basically the same. Example when changing from the wall. It's also much larger than the SoC so it warms up a gesture surface area more quickly than just the SoC.
It's also located on the middle to lower part of the phone where it is more common to have your hand. Compared to the near the top / camera location for the SoC
Another thing that is obvious but I never mentioned. Is the phone is black. A black glass phone in summer sunlight ( on a call holding the phone up to your ear) will get hot. Even if the thing was turned off.

simms22 said:
this thought that coolnow just had..
feel doesnt report a temperature, feel only shows that something is warmer than/cooler than whatever body part you are touching it with. its all relative to your body temperature. try this experiment.. get 3 glasses of water, one hot water, one ice water, one room temperature water. at the same time, stick one hand into the hot water and the other in the ice water. keep them in there for a minute. now pull both of your hands out and stick them both in the same glass of room temperature water at the same time. this will mess with your senses, so be warned! the hand that was in the hot water, will feel the room temperature water to be cold, the hand that was in the ice water will feel the room temperature water to be very warm, while they are both in the same glass of water. so you see, reporting how something feels is very inaccurate and unreliable.
Click to expand...
Click to collapse
That's exactly what i'm saying, reporting what you feel, especially on a glass backing that the Nexus 4 has, is inaccurate (and everyone who went through highschool biology knows our sense of temperature is just a measure of temperature difference).

coolnow said:
Wow, it took you 158 words to get to my point? That's exactly what i'm saying, reporting what you feel, especially on a glass backing that the Nexus 4 has, is inaccurate (and everyone who went through highschool biology knows our sense of temperature is just a measure of temperature difference). But thanks anyway for your useless post :good:
Click to expand...
Click to collapse
In case you didn't notice, Simms22 was not arguing against you but supplementing your arguments instead. In layman's term, you are both playing for the same team. So stop fighting amongst yourselves.
At this point I think we can all agree that in terms of actual temperature the Nexus 4 is not (much) hotter than other phones with similar specs. However, there is probably something about the design and/or materials used that causes people to worry (and complain) about the phone overheating. Now if you good folks want to figure out what actually causes the phone to "feel" hotter in comparison to other phones, feel free to proceed. I have no doubt that it will become an interesting topic.

snapper.fishes said:
In case you didn't notice, Simms22 was not arguing against you but supplementing your arguments instead. In layman's term, you are both playing for the same team. So stop fighting amongst yourselves.
At this point I think we can all agree that in terms of actual temperature the Nexus 4 is not (much) hotter than other phones with similar specs. However, there is probably something about the design and/or materials used that causes people to worry (and complain) about the phone overheating. Now if you good folks want to figure out what actually causes the phone to "feel" hotter in comparison to other phones, feel free to proceed. I have no doubt that it will become an interesting topic.
Click to expand...
Click to collapse
Somehow, i took his post as heavy sarcasm. I've edited my post.

coolnow said:
Wow, it took you 158 words to get to my point? That's exactly what i'm saying, reporting what you feel, especially on a glass backing that the Nexus 4 has, is inaccurate (and everyone who went through highschool biology knows our sense of temperature is just a measure of temperature difference). But thanks anyway for your useless post :good:
Click to expand...
Click to collapse
snapper.fishes said:
In case you didn't notice, Simms22 was not arguing against you but supplementing your arguments instead. In layman's term, you are both playing for the same team. So stop fighting amongst yourselves.
At this point I think we can all agree that in terms of actual temperature the Nexus 4 is not (much) hotter than other phones with similar specs. However, there is probably something about the design and/or materials used that causes people to worry (and complain) about the phone overheating. Now if you good folks want to figure out what actually causes the phone to "feel" hotter in comparison to other phones, feel free to proceed. I have no doubt that it will become an interesting topic.
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really, i wasnt arguing with you, i was backing you up, explaining, because unfortunately most people dont know that feel is just a measure of temperature difference.
what i think the issue is, is that lg(or google) had the cpu throttle temp set too low on stock devices, giving people a noticeable reduction in performance within a normal temperature range, plus the whole glass back thing, therefore freaking out many. enjoying the freedoms of root access, i disable thermal throttle, so i dont notice any of the affects that the throttle would cause.
---------- Post added at 04:30 AM ---------- Previous post was at 04:29 AM ----------
coolnow said:
Somehow, i took his post as heavy sarcasm. I've edited my post.
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and im out of thanks, but thanks

It is true that the Nexus 4 is heating more that other devices, it has been know even before its release. I had them too at first, when using heavy apps or games. But some roms and kernels make it heat more than normal because they are putting the cpu freq constantly at the max (1.5 GHz), that's why some users have problems constantly. I use the Paranoid Android rom, which is pretty light speaking of cpu usage, and franko kernel putting the max cpu freq at 1Ghz, also lowering the voltages. It helps a lot.

Every device I've ever had, htc desire, archos 70it, galaxy s2, galaxy s3, galaxy tab 10.1, nexus 7, nexus 4 and nexus 10 all have a new thread like this every week, just because the device "feels" hot. All our SoC are so powerful these days do have a high TDP and that's made worse by our SoC's relying on passive cooling. We won't have cool CPU's anytime soon, unless you want a fan or any other active cooling mechanism. Anything under ~80C is fairly safe for modern SoC's and isn't really anything to worry about. When you CPU get's too hot it will aid passively cooling by thermal throttling the CPU to a lower Frequency and if it carries on going up, then it will shut down before any damage is done. With all my devices I've done the same test, Undervolt, turn stress test on when SoC is at ideal temp and time how long it take to reach a certain temp. Repeat the experiment several times. I found that my nexus 10 heats up by far the fastest, thanks 32nm A15's and the nexus 4 was one of the coolest, only being beaten by my galaxy tab 10.1, 40nm dual core A9. To be fair, I do have a faster binned chip. Even my 1.4ghz exynos 4412 s3's core temp was higher than the n4's, you just couldn't feel it as much through the plastic. The nexus 4's heat dissipation even with the minor fault compared to the optimus G is reasonably good.

Keep phone cool while charging (wireless/wired)

Hey everyone. I'm new to the Nexus 5 community, got my phone a week ago and so far it feels like ive had it for ever. Great device and so worth my limited money.
Anyways. I have been doing these methods on all my phones and so far i haven't seen anyone else trying this.
1. Speed cool your phone
If you have a heat sink from an old pc laying around (unless its one of those huge gaming computer heat sinks) it can now have a purpose again. If your phone gets hot, simply put the heatsink copper side up and put your phone on it. about 2 minutes later your phone should be as cool as it can get without using a freezer.
2. Keep phone cool while wireless charging.
I got a wireless charger recently, and sometimes the phone doesn't get hot at all, and other times it gets VERY hot (about 115 degrees F). So instead of finding the 'perfect' position for my phone to stay cool, i found that using simple cup stands or what ever they are called, helps.
You know those things at restaurants that you put your cup on? those things. For best effect, use 2 or 3 of these, put them under your phone while your phone is on the wireless charger. I think it helps because the cardboard isn't very dense and absorbs and quickly lets off most of the heat and my phone never got over 101 degrees F yet.
3. The first method can also be used while charging your phone though a wire.
Sometimes i want to watch a movie or something while charging my phone on a wire, i simply put it ontop of the heatsink and watch the movie. Might be a bit uncomfortable, so try to found a way for it to be comfortable.
Hope this helps anyone, im still working on a way to make a home made (thin) heat sink for wireless charging.

heat sink testing
So far ive built the heatsink, its about 6 - 7 mm thick using those cardboard cup stand things mentioned above, coper wire, and silicone, and some superglue. i thought tape (specifically the adhesive) would melt under heat.
So far, i have charged my phone all the way up from 20%, temeprature hit 118 degrees F (note this is wireless charging).
Currently testing the heat sink. Charging it up from 85 %. So far at 92% and max temperature is 97F but has gone down to 96F. The heat sink is pretty warm compared to the phone (the phone is actually quite cool).
If you would like to mess around with the design this is how i built it.
Took one cardboard cup plate and put a copper coil on it. I just took about 10 inches of copper wire (thin kind) and made it into a wide coil (ill post pictures later), and then hammered it to be more or less flat. Put small amounts of superglue to hold it in place. Took the second cardboard plate, and put it on top. Used silicone to seal the edge to hold. Also add some super glue to the top of the coil to glue it to the top cardboard piece.
Simply put the heatsink under the phone while wireless charging.

Pictures of heatsink
Here are the pictures.
Ill post screenshots later of the test.

I do the same thing for wireless charging. Instead of making one, I bought a set of ceramic/porcelain/granite (I don't really know) coasters. I used one coaster for wireless charging, and four more under my laptop for when it is on the counter or table (keeps it cool and above any drinks that may spill).

upndwn4par said:
I do the same thing for wireless charging. Instead of making one, I bought a set of ceramic/porcelain/granite (I don't really know) coasters. I used one coaster for wireless charging, and four more under my laptop for when it is on the counter or table (keeps it cool and above any drinks that may spill).
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link to the materials? Sounds like good idea.
I have this huge granite/porcelain slab my mom uses to beak bread. i wish it wasn't a 2 foot x 2 foot size, maybe i could have used that instead.
ALSO
so far the temperatures would go up to about 99F and then go back down to around 96...i think what happens is the phone heats up, then the heatsink takes the heat, and cools down while the phone heats up again...cycle

russian392 said:
link to the materials? Sounds like good idea.
I have this huge granite/porcelain slab my mom uses to beak bread. i wish it wasn't a 2 foot x 2 foot size, maybe i could have used that instead.
ALSO
so far the temperatures would go up to about 99F and then go back down to around 96...i think what happens is the phone heats up, then the heatsink takes the heat, and cools down while the phone heats up again...cycle
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As I mentioned, I am not exactly sure what the material is. My guess is ceramic. I had the idea when I saw them in a store.
You can find them just about anywhere, and decorated any way you like (mine are plain). Link to Amazon
The granite slab you mentioned should work just fine. I never precisely monitored the temperature, but I know its a lot cooler.

upndwn4par said:
As I mentioned, I am not exactly sure what the material is. My guess is ceramic. I had the idea when I saw them in a store.
You can find them just about anywhere, and decorated any way you like (mine are plain). Link to Amazon
The granite slab you mentioned should work just fine. I never precisely monitored the temperature, but I know its a lot cooler.
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Haha like I said that slab is huge for an oven made to bake on. So if I had something to cut me a slice I would.
I was just sitting at my PC and I saw the little cardboard things and though why not try it. I tried with two and it seemed to work okay-ish so like I used my copper heat sink I thought of putting copper in between. Took me 5 minutes to make.
But I'll definitely give the porcelain a try.
Sent from my Nexus 5 using XDA Premium 4 mobile app

I don't recommend putting anything between the phone and the wireless charger, increased distance means less power into the phone and more wasted into the air. Also I don't think the plastic case of the phone will interface well with a metal heatsink but I admire your tenacity.
Maybe log your temps with and without and compare, though you would have to adjust values for ambient room temps otherwise a warmer day could throw off all your results.

bblzd said:
I don't recommend putting anything between the phone and the wireless charger, increased distance means less power into the phone and more wasted into the air. Also I don't think the plastic case of the phone will interface well with a metal heatsink but I admire your tenacity.
Maybe log your temps with and without and compare, though you would have to adjust values for ambient room temps otherwise a warmer day could throw off all your results.
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Yeah I noticed it takes a bit longer to charge but wireless charging is never actually fast as cord charging. I get about 1% ever minute with screen off and 1% every 2 minutes with screen on.
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Also I think its worth a try, maybe someone can come up with something more effective.
Sent from my Nexus 5 using XDA Premium 4 mobile app

just out of curiosity, completely. whats the point of this? heat is normal, especially while charging, and does not hurt the device. for the fun of it, i reach cpu temp shutdown purposefully all the time(105C), on all my devices, for years. heat has never ever caused any kind of damage to any of my devices. as the safety temps for battery and cpu shutdown are actually below the temps that our devices can handle before it can cause any damage.

simms22 said:
just out of curiosity, completely. whats the point of this? heat is normal, especially while charging, and does not hurt the device. for the fun of it, i reach cpu temp shutdown purposefully all the time(105C), on all my devices, for years. heat has never ever caused any kind of damage to any of my devices. as the safety temps for battery and cpu shutdown are actually below the temps that our devices can handle before it can cause any damage.
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Well looks like I have the exact opposite experience than you. All the phones I've had eventually had degraded battery's because of over heating. I had phones that would last 4 hours on an old battery and 12 on a new one. And that's just from gaming and such. Now charging is pretty much directly heating a battery. Also some people don't like picking up a piece if lava.
If you think its pointless then don't do it.
Sent from my Nexus 5 using XDA Premium 4 mobile app

russian392 said:
Well looks like I have the exact opposite experience than you. All the phones I've had eventually had degraded battery's because of over heating. I had phones that would last 4 hours on an old battery and 12 on a new one. And that's just from gaming and such. Now charging is pretty much directly heating a battery. Also some people don't like picking up a piece if lava.
If you think its pointless then don't do it.
Sent from my Nexus 5 using XDA Premium 4 mobile app
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Battery degradation occurs on all Li-ion batteries. Heat has very little effect on the overall lifespan of the battery. You can expect about a 30% loss in capacity every year no matter your usage patterns.

russian392 said:
Well looks like I have the exact opposite experience than you. All the phones I've had eventually had degraded battery's because of over heating. I had phones that would last 4 hours on an old battery and 12 on a new one. And that's just from gaming and such. Now charging is pretty much directly heating a battery. Also some people don't like picking up a piece if lava.
If you think its pointless then don't do it.
Sent from my Nexus 5 using XDA Premium 4 mobile app
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im not planning on it. as i said the very first thing, out of curiosity.
now degraded batteries that early can happen, but its mostly because of manufacturing defects. the chances of that happening more than once in a row is fairly low. but you said multiple times. which leads me to believe that theres either something wrong with your phone physically, or maybe you are doing something wrong. as i said, on my g1(s), ion, og droid, nexus one, nexus s, galaxy nexus, nexus 4, nexus 7, and nexus 7, ive never had any issues because of heat or because of battery. i do all the testing for trinity kernel, while testing i try to "break" the kernel. part of that testing is keeping the temps right under the thermal shutdown temp for long periods of time. i have yet to see any kind of damage because of this(except for me "breaking" any test kernels).

raptir said:
Battery degradation occurs on all Li-ion batteries. Heat has very little effect on the overall lifespan of the battery. You can expect about a 30% loss in capacity every year no matter your usage patterns.
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True that too. But there is enough research to support that heat does slowly degrade the battery.
Sent from my Nexus 5 using XDA Premium 4 mobile app

simms22 said:
im not planning on it. as i said the very first thing, out of curiosity.
now degraded batteries that early can happen, but its mostly because of manufacturing defects. the chances of that happening more than once in a row is fairly low. but you said multiple times. which leads me to believe that theres either something wrong with your phone physically, or maybe you are doing something wrong. as i said, on my g1(s), ion, og droid, nexus one, nexus s, galaxy nexus, nexus 4, nexus 7, and nexus 7, ive never had any issues because of heat or because of battery. i do all the testing for trinity kernel, while testing i try to "break" the kernel. part of that testing is keeping the temps right under the thermal shutdown temp for long periods of time. i have yet to see any kind of damage because of this(except for me "breaking" any test kernels).
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Interesting. But I'll stay on the safe side.
Sent from my Nexus 5 using XDA Premium 4 mobile app

russian392 said:
Interesting. But I'll stay on the safe side.
Sent from my Nexus 5 using XDA Premium 4 mobile app
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cool.
as everything is different depending on everyone else's experiences in life.. most important is that you are satisfied by doing it

simms22 said:
cool.
as everything is different depending on everyone else's experiences in life.. most important is that you are satisfied by doing it
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You can say that again ?
Also...I notice that charging the phone bellow 80% (like even if I start charging at 75%) temps get to about 103° with my heat sink. But when it goes over 80% it starts to cool down. Still doing lots of testing and logging though.
Edit:
Here is something to read
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
Sent from my Nexus 5 using XDA Premium 4 mobile app

russian392 said:
You can say that again ?
Also...I notice that charging the phone bellow 80% (like even if I start charging at 75%) temps get to about 103° with my heat sink. But when it goes over 80% it starts to cool down. Still doing lots of testing and logging though.
Edit:
Here is something to read
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
Sent from my Nexus 5 using XDA Premium 4 mobile app
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Click to collapse
yea, it charges "faster" before 80%, then slows down. then slows down again around 92%. oh, and that article is outdated. our batteries are a newer tech than when that article was written(2010).

Using a Wireless charger doesn't generate that much heat lol.
I don't use my device while charging it either.

A little worried about my device...

Hey there, i just recently bought an lg g6, and ive been rlly enjoying it. Recently i had to leave my phone in the glovebox of my car ( it was turned off) and the weather outside was 64c outside, and im guessing even hotter in my glovebox (my car was parked in the sun), so should i be worried about any damage to my phone, and can i keep putting it there because its the only place i can put it cus of where i work..

I don't think you have to worry. The internals of the phone itself can withstand high temperatures, with processor temperatures/battery creating a lot of extra heat, so that is factored in. As long as the screen, etc is not in direct sunlight, you shouldn't worry.
Ideally though you'd not want it to get too hot to preserve the life of the battery... but with it being "off", that may not effect anything.
An easy enough solution though would be to get to a sun visor and point the reflective side out. This will reduce cabin temperature and protect not only your electronics, but will keep your interior in good condition as well (especially if the rest of your car is tinted). Just buy a decently thick one. I use one with a nice matte on the other side. Once you get used to using one, it takes only a few seconds to remove/replace.
You can reverse it in winter to keep your car cabin from getting too cold as it will allow some extra heat in.

maruichan said:
I don't think you have to worry. The internals of the phone itself can withstand high temperatures, with processor temperatures/battery creating a lot of extra heat, so that is factored in. As long as the screen, etc is not in direct sunlight, you shouldn't worry.
Ideally though you'd not want it to get too hot to preserve the life of the battery... but with it being "off", that may not effect anything.
An easy enough solution though would be to get to a sun visor and point the reflective side out. This will reduce cabin temperature and protect not only your electronics, but will keep your interior in good condition as well (especially if the rest of your car is tinted). Just buy a decently thick one. I use one with a nice matte on the other side. Once you get used to using one, it takes only a few seconds to remove/replace.
You can reverse it in winter to keep your car cabin from getting too cold as it will allow some extra heat in.
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Yeah thank you i will definitely do that, i was a little worried about the battery and screen but it seems like i shouldnt be worried, thanks alot i appreciate it!

I would also be careful because people have reported with change of temperature the camera glass have cracked. Example is going from air conditioning into the heat or vice versa.

Question Which battery temperature is normal?

My phone happens to stay around 37-43 degrees even if i am not doing anything. This makes it uncomfortable to hold in my hand. I am using the default case between.
Does anyone else have this issue?
Note: It´s currently 25 degrees here in germany and my phone is not cooling down at all, staying at 39 degrees while all apps are closed and I am not charging.

Pretty normal. Mine is between 31 and 40 degrees - depends what is the room temp of course and what im doing. Snap 888 is a hot processor .
Currently it has 32 degrees - phone is cool.
Btw. The temps improved a lot on A.19 and A.20 version. On A.15 and A.16 my phone was getting hot easily.

I live in the desert... I know a lot about heat and fried electronics
It's running hot because of services running in the background. It's in the 90's (°F) here and my 10+ is running at 97F; a couple degrees F above ambient. If it was running like the OP's I would need to turn it off or cool it! Not acceptable.
Google Backup Transport, Framework, Firebase, Google play Services and all cloud apps are prime suspects.
Trashware like FB, WhatsApp etc.
Hunt down the perpetrators and deal with them directly.
Power management can also cause excessive battery usage by interfering with needed dependencies. Turn off all power management and go from there.
Clear system cache.
Try a network reset.
Disable wifi unless you need it.
Cool or stop using phone once it reaches 100°F*.
*37.7778°C
The Fahrenheit scale is geared much better to real life usage than the Celsius system. It's range is scaled better for the temperature you live in.
43°C or 109.4°F is too hot. Max is 103°F for me and then I shut it down.
Don't expect auto thermal shutdown to save your device! The temp can rise faster than the sensors can detect it in critical areas like the AMOLED display with it's millions of temperature sensitive semiconductor junctions... and little heat sinking capacity. It's also helping to sink heat from the mobo and battery. Worse, glass is an effective insulator but you can feel how warm the display gets as it helps to sink the heat.
A case can also contribute to the problem. Some cases sink the rear cover heat better. I'm not advocating running the phone bare though as one drop is all it takes. Just be aware of this.
Using a damp microfiber cloth to cool it works well. I wrap one around the whole phone when charging.
Even now it will keep it way below 100F when fast charging.
Airflow should also be used... got a fan on me and the phone this minute.

How do you guys measure the temperature? Built-in menu or an app?

Mostly the temperature should be around the range of 40 to 45 degrees.

latino147 said:
How do you guys measure the temperature? Built-in menu or an app?
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In the weather section (just kidding)

latino147 said:
How do you guys measure the temperature? Built-in menu or an app?
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I watch the battery temp in Accubattery.
At 103F it's turn off time, regardless.