yashsingh1/xdaforums huggingface dataset:
[Nexus 4 General] A-Squared:
Probably not...

Honestly I don't think so... that equates to 37.7*C which for me is quite comfortable, in the context of a phone call... I rarely ever hold the phone to my head though, I use a wired or wireless headset for almost all of my calls... But when I have had to hold it to my head for long calls I have noticed it gets warm... Phone radio, battery drain, and body heat from face...

I think others will agree that 100*F is acceptable for in-call temperature, especially if held against the face/head...

Still cooler than my phone while it's charging wirelessly LoL!!
[Nexus 4 General] A-Squared:
USB Charging

WIRELESS CHARGING

START

14:30 Wireless charging start at 26% and 31*C

14:50 38.3*C 38%

15:06 39.4*C 44%

15:32 39.9*C 52%

16:00 40.2*C 58%

16:32 39.8*C 68%

AFTER TWO HOURS. +42% Charge (pathetic).

17:00 40.6*C 75%

USB Charging

12:30 29.2*C 21%

13:00 30.6*C 49%

13:35 31.3*C 70%

14:04 30.3*C 88%

14:45 26.5*C 100%

Not only is wireless charging WAY slower than USB, it also causes my phone to "idle" about 10*C hotter...

WTF. Time for a new phone?? Especially given that there are other people that have reported charging their Nexus 4's (1) At the SAME speed, and (2) Without any crazy increase in temperature...
[Nexus 4 General] neb001:
I'm not seeing your low charging numbers...below is a full log of my recent charge from 8% to 99% via Energizer Qi Charger. As you can see for comparison, two hours worth of charge from 27% netted me a 92% battery level. I'll try to get an equivalent charge log using a usb connection for comparisons sake.

2012/12/08|20:41:20|208mA|8%|3756mV|35.2ºC|.616|16
2012/12/08|20:46:20|755mA|11%|3833mV|34.9ºC|.0|15
2012/12/08|20:51:20|710mA|14%|3864mV|35.3ºC|.0|15
2012/12/08|20:56:20|580mA|17%|3881mV|36.0ºC|.0|15
2012/12/08|21:01:20|681mA|20%|3889mV|36.7ºC|.0|15
2012/12/08|21:06:20|744mA|24%|3848mV|37.3ºC|.0|15
2012/12/08|21:11:20|755mA|27%|3900mV|37.7ºC|.0|15
2012/12/08|21:16:20|757mA|30%|3908mV|38.1ºC|.0|15
2012/12/08|21:21:20|670mA|33%|3918mV|38.5ºC|.0|15
2012/12/08|21:26:20|713mA|36%|3924mV|38.9ºC|.203|15
2012/12/08|21:31:20|659mA|39%|3893mV|39.4ºC|.0|15
2012/12/08|21:36:20|657mA|42%|3952mV|39.5ºC|.0|15
2012/12/08|21:41:20|564mA|45%|3966mV|40.2ºC|.240|15
2012/12/08|21:46:20|294mA|46%|3829mV|38.1ºC|.243|16
2012/12/08|21:51:20|636mA|49%|3990mV|39.0ºC|.286|16
2012/12/08|21:56:20|603mA|53%|4004mV|40.0ºC|.0|15
2012/12/08|22:01:20|664mA|56%|4023mV|40.7ºC|.0|15
2012/12/08|22:06:20|544mA|59%|3990mV|40.2ºC|.0|15
2012/12/08|22:11:20|316mA|60%|3998mV|38.8ºC|.0|15
2012/12/08|22:16:20|567mA|62%|4070mV|39.5ºC|.0|15
2012/12/08|22:21:20|628mA|65%|4094mV|40.5ºC|.0|15
2012/12/08|22:26:20|765mA|68%|4119mV|41.2ºC|.0|15
2012/12/08|22:31:20|575mA|70%|4131mV|41.0ºC|.246|16
2012/12/08|22:36:20|757mA|73%|4168mV|41.0ºC|.0|15
2012/12/08|22:41:20|666mA|76%|4196mV|41.1ºC|.0|15
2012/12/08|22:46:20|490mA|79%|4155mV|39.9ºC|.0|15
2012/12/08|22:51:20|400mA|80%|4227mV|38.8ºC|.0|15
2012/12/08|22:56:20|762mA|83%|4272mV|40.0ºC|.0|15
2012/12/08|23:01:20|553mA|85%|4285mV|40.2ºC|.0|15
2012/12/08|23:06:20|625mA|92%|4278mV|39.7ºC|.0|15
2012/12/08|23:11:20|506mA|92%|4313mV|38.8ºC|.0|15
2012/12/08|23:16:20|418mA|94%|4310mV|37.9ºC|.0|15
2012/12/08|23:21:20|339mA|94%|4323mV|37.0ºC|.0|15
2012/12/08|23:26:20|270mA|96%|4325mV|36.0ºC|.0|15
2012/12/08|23:31:20|221mA|97%|4329mV|35.2ºC|.0|15
2012/12/08|23:36:20|193mA|98%|4332mV|34.7ºC|.0|15
2012/12/08|23:41:20|152mA|99%|4333mV|34.5ºC|.0|15
[Nexus 4 General] abufaka:
You just discovered the first law of thermodynamics, congrats! You are just a little late for the nobel price ;)

---------- Post added at 01:21 AM ---------- Previous post was at 01:17 AM ----------

Sometimes in the Summer, when i go outside, it get's to like 36°C, should i be concerned?
[Nexus 4 General] 320flyboy320:
What app are you using to log the charge current and temperature?
[Nexus 4 General] neb001:
Can't link because I'm too much of a noob apparently :D The app's name is "Battery Monitor Widget" I have the pro version but both log the same way.
[Nexus 4 General] A-Squared:
Nice!!

VERY COOL!! Thanks for the data dude.

You're right, you're not seeing the slow charging rate, but the temperature is still high like mine...

I'm also participating in another thread that talks about the WCP-700 specifically. You might be interested:

http://xdaforums.com/showthread.php?p=35302923&posted=1#post35302923

I'm going to bring my Energizer charging pad to work so that I can gather data on Wireless charging using the Energizer.

---------- Post added at 08:24 AM ---------- Previous post was at 08:20 AM ----------

I'm using an App called "Battery Stats Pro".

I also have "Battery Monitor Widget Pro" installed. Battery Monitor Widget is a bit ridiculous in that it gathers data and displays graphs! Ridiculous in a good way LoL.
[Nexus 4 General] neb001:
I agree with you in that there is a noticeable heat increase with the wireless charging but I disagree that it's worrying. I have not had any of the issues that you seem to be having, perhaps you just have a bad phone? Given that the typical efficiency figure given for the WPC/Qi spec is 70%, is it really surprising that it gets warm?
[Nexus 4 General] CharmingCharlie:
Just adding my voice to the concern about this wireless charging. I was really looking forward to experiencing this feature but so far it has been hugely disappointing. I purchased a Maxell Qi charger and have barely used it because of the heat and slow charging rate.

I get the feeling there is a problem with some Nexus 4's but to be honest I can't be bothered to investigate things too much. I can still use USB charging so I will make do with that, but right now I am pretty hacked off with this wireless charging malarkey.

EDIT :-

I thought I would have another go with this thing, I really want to use wireless charging if I can. So I turned off Dream Scene (or whatever it is called) and left my phone on the charger next to me for 1hr. When I placed it on the charger my phone was at 44% charged and about 30c temperature. I looked at it exactly 1hour later and it had gone up to 89% and was 34c. So I get the feeling in my case the problem is the dream scene stuff. Perhaps it is a case that dream scene is so power intensive that any charge the pad is giving the phone automatically gets used by the Dream Scene program.

So I have a choice use Dream scene with USB charging or use wireless charging but with no dream scene. There is no question I am going with wireless charging :D
[Nexus 4 General] neb001:
Yeah, I had seen comments earlier that reflected the same issue that you were having with Dream Scene. That seems to be the culprit.
[Nexus 4 General] A-Squared:
Don't think so...

Look at my earlier posts... I charged Wireless and Wired with NO "Daydream" enabled, wireless still got the phone up to 40*C and took longer to charge.

I have time/charge%/temp data in a previous post.
[Nexus 4 General] neb001:
Yeah, but imho your phone is suspect in my eyes. Your charge rate is ridiculously slow compared to what I'm seeing.
[Nexus 4 General] goldfingerfif:
Here is the temp of my charge from roughly 1% to 100%, screen off, put on the charger before I went to sleep. Charger used is the Oregon Scientific QW201.

I did an overlay of 3 graphs during that same time. Hope this helps.
[Nexus 4 General] CharmingCharlie:
It's curious a few weeks ago I tweeted to LGUK asking when the Wireless Orb would be available. I was surprised they answered me back and said that there was a "delay" in the Orb. I am wondering if they might be having a problem getting Daydream working properly with the Orb. After all one of the key features of this orb is the fact it is slanted in such away you can see the screen and what is "on" the screen during charging.

Ah well I can live without daydream, I am normally asleep when I have my phone on charge anyway :silly: . Since getting to the root of the problem with wireless charging I have to say I love the convenience of it.
[Nexus 4 General] A-Squared:
Nice!!

WOW, very impressive. I was actually putting my data in an Excel spreadsheet yesterday! I'll see if I can't get it uploaded today.

Thanks for the data!! It's a bit strange eh?

Blue line: Almost perfectly linear rate of charging until 90%, and it's at ~40*C.

Red: More "typical" charging rate (at least in my experience), and 42.3*C !!!

Yellow: Huge ramp up, then a sawtooth-like run up to 100% and ~42*C...

DUDE... the YELLOW line seems to represent something I have observed on the Energizer charger --> When I put the phone on the plate, the light comes on, then goes off, then comes on, then goes off... As if it's connecting/disconnecting/reconnecting... It doesn't happen always, but it does happen sometimes...

Weird dude... I would assume that your data (and for that matter anyone else's) should be CONSISTENT given the same conditions right??? Night time, same charger, full charging...

Pisses me off that this doesn't just "work" you know?

Personally I am NOT comfortable with my phone sitting for what will amount to hundreds of hours (over a few years) at 42*C... Say we charge once per day for 1 hour... that's 365 hours/year... 42*C is really high for charging, and batteries LOATHE heat... And why be happy with temperatures that exceed USB charging temperatures by 8-14*C???? (I have USB-charged at 28*C at work... other times at 32*C)...

Thanks so much for the data, it gives us all more insight to the issues some of us are experiencing...
[Nexus 4 General] InvalidUsername:
I get that on/off thing with my Energizer as well sometimes. I've noticed that unplugging the charger and plugging it backs helps. I've also noticed that wireless charging (whether the phone or Energizer is to blame, I'm not sure) is not reliable at all. Yesterday, I had the phone on the charger with the blue light on and the phone indicating "charging" on the lock screen. A while later, I check the phone's charge whiles it's on the charger still and it says "charging - 0%" and as soon as I took it off the charger, it died. I was really pissed off as I had to go out for a while, and I just ended up plugging it in. It was charged when I came back. I charged it wirelessly again since then with no issues. Weird.

On a side note, Facebook had used 60% of my battery in that last cycle! I restarted the phone, and it is now back to not showing up in the battery usage, since I rarely ever open the app and I have 4 hour sync. Looking at the reviews on Google play, it seems that other people are also seeing this issue. Might be worthwhile to look into for anyone having really bad battery life.
[Nexus 4 General] neb001:
Looking at the chart it looks like color of the the label on the vertical axis that matches the color of the line. They don't all reflect a temperature value.
[Nexus 4 General] Rod3:
This. The yellow line represents the mV's to the battery as it charges from zero. The red line is the temperature associated with the linear charge from zero (blue line). The lines are overlayed, but do not represent the same things.
[Nexus 4 General] Nexus-Six-:
Frankly, I think you are being slightly unreasonable in your expectations for wireless charging. You need to bear in mind the laws of physics. Inductive charging cannot be as efficient as USB. The lost energy will manifest as heat and result in a warmer phone and charger. It cannot charge as fast as USB either, for the same reason (technically, it probably could but the generated heat would be unacceptable).

If we were seeing big variations between chargers or phones then I would believe there is a problem. However, the data collected seems to indicate that they all warm the phone to about 40c and they all charge at about the same rate (providing around 100ma less than USB charging). I think manufacturers have probably set this charging level on purpose to achieve the maximum power delivery while remaining within acceptable temperatures.

These are the tradeoffs you have to accept with wireless charging, and probably always will be thanks to that pesky first law of thermodynamics.

Personally, I'm not worried about it because I think the convenience will mean I'm more likely to do smaller charges at different times of day rather than let it drain completely and then leave it plugged in all night at 100% (letting Li Ion batteries drain below 20% and charging them above 80% also stresses them quite a bit). So the stress caused by a bit of extra heat for the odd hour during the day will probably be offset by the benefit of not fully discharging and fully charging the battery as often.
[Nexus 4 General] 320flyboy320:
You know what would be great, if there was a way to limit the amount of charge, say to 80%. Maybe custom roms can do this, I don't know.
[Nexus 4 General] [hfm]:
Enough induction power to charge the battery is going to generate heat on both transfer coils. Since these devices are touching it's perhaps slightly intensified. It is by law always going to be less efficient than direct contact through a conductor such as the micro USB connection. This is physics, this is fact.
[Nexus 4 General] neb001:
Thanks for typing that up, as it sums up my own thoughts as well. I was responding to his request for data mainly because I was curious as to what the exact charge curve looked like using the wireless charge and just how hot the temp sensor got during the charge. I'll put up comparison graphs once I'm allowed to link outside this forum, I have a google doc made up for it.

I am curious if there'll be any difference in temp if I put an aluminum plate between the charger and phone to act as a lightweight heat spreader. I have a few different sheets of different thicknesses so I'll give that a try just to see if it has any effect at all for curiosities sake (not expecting any difference, really...but why not?)
[Nexus 4 General] A-Squared:
LoL!!

LoL you're absolutely correct... I'm a moron. When I read "3 graphs overlaid" I thought he meant 3 charging runs!! I'm an idiot...

But still, it remains that 40-42*C is waaay too warm for my comfort... Sustained heat like that certainly cannot be good for the battery, let alone the device...

If I charge wirelessly once per day then my phone is going to be sitting at 38-42*C for an hour every day... I don't like that idea. I can't think of any other device (laptop, cell phone, USB power pack, that gets anywhere near that hot while charging...)

And I'm not satisfied with those temperatures either because I've read other posts from users that indicate that their wireless charging experiences reveal NO major difference in temperature from USB, and with no noticeable degradation in charging speed...

I would love to get to the bottom of why different Nexus 4 devices are behaving differently on the same chargers...!!

Thanks again for correcting me ;)
[Nexus 4 General] 320flyboy320:
I can't see any wireless charger not charging at the temps we're seeing in the above charts, that is around 40C, it's the nature of the beast. Those that are saying theirs doesn't heat up with a wireless charger are probably checking it a few hours later when it's fully charged, but still sitting on the charger when its nice and cool.
[Nexus 4 General] A-Squared:
:-/

I don't know dude... What you're suggesting is entirely possible, I agree... but then what about user phermey's post in the other thread:

http://xdaforums.com/showpost.php?p=35275866&postcount=57

Hey says "if you are having heat issues... my phone went from hot the first two days to barely warm from the third day on. rooting and installing aokp fixed this for me. it doesnt seem to take any longer to charge either. i think the difference is the governor. my reasoning may be incorrect, but the outcome is most certainly true."

(I believe you replied to his post LoL).

IF what he is saying is true, then there is something more to what we're seeing... If he rooted and (more significantly) installed aokp, and he's seeing "normal" temperatures while charging wirelessly... then what's the deal?? How can that be explained? How is phermey charging wirelessly without problems but others get up to freaking 42*C? I don't know what to think...

I'm running 4.2.1 right now, and I have the suspicion that I did not see this until I upgraded... I'm really tempted to perform a full backup and reformat back to "out of the box" settings to see what impact it has on my wireless charging performance.
[Nexus 4 General] 320flyboy320:
Ya maybe there's something to him flashing AOKP Mako. I might try this next week and see. I was also thinking of trying Matr1x kernel since it seems to improve battery life (undervolted to 100 mV).
[Nexus 4 General] goldfingerfif:
Glad some people liked the overlaid graph I made.

I'm going to record a set of data from USB charger and lg wcp700. I'll try and get 3 sets total of each over the next couple days.
[Nexus 4 General] neb001:
What are you using to generate those graphs? For what it's worth I graphed out the differences in a google docs document here

I'm skeptical of the claim that flashing a different rom will suddenly take away the heat, but I'm willing to give it a try. I'd be a bit less skeptical if there was a charge log rather than just a claim that it ran cooler after flashing a rom.
[Nexus 4 General] Nexus-Six-:
All the actual data that has been posted indicates temperatures around 40c. A couple of people have claimed no heat issues (which is pretty vague already), but we've had no actual data to back this up. They may only be looking at the phone when it is already charged etc. etc.

Basically, charging log data or it didn't happen ;)
[Nexus 4 General] mrbkkt1:
Honestly, I've been using the lg wireless charger for a few days now, nothing excessively hot. Warm, but not hot.
[Nexus 4 General] shilent:
Any battery experts here? Isn't lithium polymer rated up to 45c charge temp, and 60c discharge temp?
[Nexus 4 General] Russ.Dill:
Read the datasheets if you like, 40°C is well, well, well, within operating specs. Most chips are rated to 85°C or 100°C for operating conditions. Hell, in many places it gets up to 50°C *ambient*. And as another poster said, the 20% or 25% you are throwing around is a completely meaningless number. In F, your calculation would give 16%.

For a proper measurement, you'd want to measure power consumption of the device, for every N units of power consumption, the temperature of the device will raise 1°C in temperature. So if the power loss during charging is 500mW on AC, and 550mW on Qi, then that would really be a 10% difference.
[Nexus 4 General] goldfingerfif:
I use battery monitor widget pro by 3c. I just found out I can have i can view the graph as full screen so next screenshot will be better.
[Nexus 4 General] neb001:
Ah, so you're just overlaying the images manually? I was wondering because I have the same app and thought that was what it was but haven't seen a multiple graph mode :)
[Nexus 4 General] Solutions Etcetera:
Popped mine (naked) on the LG charger at 35%...

2012/12/13|05:17:42 PM|-245mA|35%|3719mV|21.5ºC|.795|0

2012/12/13|05:27:42 PM|488mA|39%|3935mV|25.6ºC|.243|16

2012/12/13|05:37:42 PM|674mA|45%|3906mV|29.8ºC|.0|15

2012/12/13|05:47:42 PM|733mA|51%|3988mV|32.2ºC|.0|15

2012/12/13|05:57:42 PM|673mA|57%|4033mV|34.0ºC|.0|15

2012/12/13|06:07:42 PM|768mA|64%|4026mV|34.8ºC|.0|15

2012/12/13|06:17:42 PM|748mA|70%|4120mV|35.5ºC|.0|15

2012/12/13|06:27:42 PM|717mA|76%|4182mV|36.0ºC|.0|15

2012/12/13|06:37:42 PM|698mA|83%|4242mV|36.5ºC|.0|15

2012/12/13|06:47:42 PM|728mA|88%|4285mV|35.7ºC|.0|15

2012/12/13|06:57:42 PM|452mA|95%|4299mV|34.0ºC|.0|15

2012/12/13|07:07:42 PM|344mA|96%|4311mV|32.5ºC|.0|15

2012/12/13|07:17:42 PM|240mA|98%|4319mV|31.1ºC|.0|15

2012/12/13|07:27:42 PM|161mA|99%|4323mV|31.0ºC|.0|15

2012/12/13|07:37:43 PM|23mA|100%|4291mV|29.1ºC|.0|16

2012/12/13|07:47:44 PM|-36mA|100%|4278mV|23.4ºC|.0|0
[Nexus 4 General] A-Squared:
"Basically, charging log data or it didn't happen ;)"

LoL!! Awesome and hilarious. I agree entirely!!

---------- Post added at 02:02 PM ---------- Previous post was at 01:57 PM ----------

What version of Android are you running? Stock JB 4.2, 4.2.1? Custom ROM? Just curious.
[Nexus 4 General] Solutions Etcetera:
Stock 4.2.1
[Nexus 4 General] Nexus-Six-:
Here's my log for completeness:

2012/12/14|16:48:16|133mA|30%|3799mV|26.3ºC|.196|16

2012/12/14|16:56:18|568mA|35%|3861mV|29.0ºC|.401|15

2012/12/14|17:06:18|670mA|41%|3936mV|31.2ºC|.106|15

2012/12/14|17:16:18|678mA|47%|3944mV|32.9ºC|.0|15

2012/12/14|17:26:18|731mA|54%|3998mV|34.3ºC|.0|15

2012/12/14|17:36:18|760mA|60%|4035mV|35.3ºC|.0|15

2012/12/14|17:46:18|759mA|66%|4017mV|36.0ºC|.0|15

2012/12/14|17:56:18|766mA|73%|4082mV|36.5ºC|.0|15

2012/12/14|18:06:18|706mA|79%|4187mV|36.8ºC|.0|15

2012/12/14|18:16:18|689mA|85%|4248mV|37.0ºC|.0|15

2012/12/14|18:26:18|564mA|91%|4288mV|37.0ºC|.216|15

2012/12/14|18:36:18|490mA|95%|4303mV|34.8ºC|.0|15

2012/12/14|18:46:18|324mA|96%|4313mV|33.0ºC|.0|15

2012/12/14|18:56:18|227mA|98%|4314mV|31.6ºC|.0|15

2012/12/14|19:06:18|152mA|99%|4322mV|31.5ºC|.0|15

2012/12/14|19:16:18|108mA|100%|4318mV|31.4ºC|.60|15

2012/12/14|19:23:18|0mA|100%|4264mV|30.7ºC|.291|16

Pretty consistent with other logs. The maximum temperature reached will depend on the starting temp and how long it charges for before reaching 90% when it begins to cool I guess.
[Nexus 4 General] A-Squared:
Thanks!

THANKS!!

And interesting... :confused:

I'm going to have to put mine back to stock, pre 4.2.1 and try wireless charging again... :)
[Nexus 4 General] neb001:
Thanks for posting the log!

There's also ambient temperature to consider, but I don't think that has as large an effect as the starting temp. I've graphed out both your and Solutions Etcetera's logs into a spreadsheet and they match up for the most part, though it seems mine is a bit of an outlier. I wonder if it's different because I started with a warm phone and I was doing a full 8%-100% charge, allowing more time for heat soak to settle in. I will have to do another full charge but starting with a completely cool phone to test that theory. It's actually quite interesting seeing the temp plots:

I do have to say I'm using an Energizer charger. My LG should show up today and I will be able to do a comparison charge with an identical charger later this weekend.
[Nexus 4 General] Makaijin:
I read a few people complaining about the heat in relation to the phone temperature tolerances in reference to the CPU specs and such. Personally my concern for heat is not to do with CPU or other component damage, but rather the life of the battery. Exposing the battery at 40 °c every day isn't really doing the long term battery life any wonders. Although getting to the battery is easy enough, but it isn't really supposed to be user replaceable. I really do like the convenience the qi chargers provide, but I also value my battery life.

What would be nice if the charging current can be adjusted. For example my sonicare toothbrush is charged via inductive charging, it never gets warm at all but the trade off is it can take over 10 hours to fully charge. As currently the qi charges the phone in about 3 hours or so. I can live with a 6-8 hour charge time if it meant less heat. But then again these my thoughts and won't happen anyway.
[Nexus 4 General] boggie1688:
I don't think it is the inductive charger. I'm going to second the dreamscape theory.

Here is a screenshot of my n4 charging and streaming a video from my server. I was using vplayer to playback the mkv file and HP touchpad charger.

The use of the GPU while charging pushes the phone to ~53C, and you can see it all starts to stop charging around 45C and only continues to charge after the temps drop.

I highly doubt induction alone can push the temperature that high.
[Nexus 4 General] aureum:
Hi,

I've found this thread as i was looking for some help with issue with hot phone while wireless charging.

I don't have a N4 but S3 with QI charger upgrade...

So... When i charge wireless only with screen off, WIFI off phone battery shows 33 C

But when i use Allshare Cast (wireless connected to dongle and stream phone screen to TV via WIFI) and wireless charging my phone shows 50 C!!!

Phone getting hot only when i turn WIFI and charging with QI... Is any posibility that WIFI have some interference with inductive magnetic filed from charger??