First, I know there are tons of GPS tests, but all of them seem to focus on the extreme accuracy and less on the casual driving GPS experience. So I thought of making a small test and by doing this, I also discovered solutions to some existing unanswered questions. This is a subjective test, made by someone with some knowledge on the subject, but I am not an expert or anything close to that.
1. The test was made during an 800Km trip. 400km were done on the way "there" during the day and 400km on the way back in the evening. I used 2 GPS software packages: coPilot and iGo MyWay for Android. Both purchased. I also used 2 chargers, a cheap charger with 1x500mA and a more expensive one with 2x500mA USB ports. All the findings below were not influenced at all by the software used.
Now come the findings in a list:
a) Accuracy - I had absolutely no issues with accuracy. My position was fixed on the road even in dense urban areas with tall buildings. Initial fix took maybe 1 minute and there were 0 problems after that. Both coPilot and iGo performed really well, even at tight roundabouts.
b) Phone temperature while charging and using GPS - this is a bit more complicated to explain. First, I used a generic phone/PDA holder. For the first few KMs I drove with the phone held firmly in place. Outside temperature was 26-28 degrees and inside was 22 degrees. Clear skies with the sun shinning all day long.
Now, on my first few kilometers I encountered the all-to-common issue of overheating. My battery got to a temperature of about 54-56 degrees C and it would stop charging. The back of the phone was VERY hot all around the camera. So I started playing around to see how I can fix the issue and found a few "tricks":
- I tried to leave a small gap between the phone and the back of the holder (5mm). This lowered the temperature by A LOT! After doing this, the phone battery never went above 51 degrees.
-I then switched to Night Mode on the GPS software. This also lowered the temp by 2-3 degrees to around 48.
- After that I tried to place a piece of paper over it, protecting the phone from direct sunlight. Result, temperature never went above 46 degrees while charging.
- As another small note, I noticed that the battery gets hotter if it is fully charged or close to it. The difference was about 2 degrees between 90% charge and 50% charge.
Also, with the cheap charger I could not get the phone under 50 degrees, with the expensive charger I got at least 2 degrees lower on the temp display in similar conditions.
c) Loosing charge while charging - I used normal car USB chargers rated at 500mA per port. While the battery temperature was under 52 degrees, I never lost charge, it actually charged slowly (1% every 10 minutes or so). If the temperature goes above 52, I start to loose charge even though the phone still shows that it is charging. I think there is a self-protect mechanism that blocks the battery from charging when it is too hot.
Conclusions (after doing many combinations and seeing the difference in temperature): the phone is great for a GPS system if you follow a few pointers:
- Never cover the back of the phone. You should always have a small space there so the phone can cool itself. (very important, 3-5 degrees difference)
- try to protect the phone from direct sunlight... Being black it absorbs a lot of heat. (important, 4-5 degrees difference)
- use a good charger and not a cheap one. (important , 1-2 degrees difference)
- try to leave it on battery until your charge level reaches 50-60% and then plug it in. (less important , 1-2 degrees difference)
- use Night Mode, if possible (less important , 1-2 degrees difference)
On my way back, when the sun was down, I never got above 50 degrees no matter what I did.
Also, iGo seemed to use a lot more resources than coPilot. While on battery alone, I was loosing charge about 1.5 times faster.
* battery temperature was measured by "Battery Status" app. The readings were verified using the not-so-scientific method of touching the back side of the phone and "feeling" how hot it was
Great post. Kind of spooky how temperamental the phone gets when it's hot; especially because it gets hot so easily. I've got a Case-Mate double-layer Tough Case on mine. I was thinking while I was putting it on there could be issues with heat dissipation. Your test makes me wary. Thanks for providing so much detail.
Had my sat nav on for around 3hours none stop today and my phone never gets hot. I use official Samsung case and the gps in the phone is better than any phone I've tested. Very happy indeed.
Sent from my GT-I9100 using XDA App
Good post and info therein.. Thank you.
Thanks!
L.
vimto25 said:
Had my sat nav on for around 3hours none stop today and my phone never gets hot. I use official Samsung case and the gps in the phone is better than any phone I've tested. Very happy indeed.
Sent from my GT-I9100 using XDA App
Click to expand...
Click to collapse
Where did you get the original Samsung car holder? Cause I wanted to buy it too but it will only appear on June.
As another note, do not waste your time and money by buying Clingo holders for this phone. The sticky surface does not stick to the back of SGS2 properly due to the texture of the back-plate. Your phone will fall after a few mins at the slightest bump on the road.
Thanks for the info!
One thing to mention and I think it's CRUCIAL.
The gps is a sirf star4 I think and I presume it behaves similar to older sirf chipsets.
So, most important thing.
For walking it may not be ok. On old smartphones using sirf star3 chipsets you needed to disable static navigation inside the chipset. There were ceratin programs that did this, I have not found anything for android yet. The thing is if you'r moving very slowly it keeps the position in place. If you get an inital lock 20 meters from your actual position it will remain there unless you move more than 40m meters or smt. It's very good for driving so the position does not jump around but very bad for walking. I think there will be software available soon to correct this.
And second, as older sirf star chipsets it takes much longer o connect, but once connected the signal is strong and stable in most situation. On sgs 1 you get a much faster lock (if you fixed your gps antenna that is , it reports better accuracy (5 meters vs 10-20 on sirf) and even SNR on satelites seems better. However actually driving with it gives much worse results.
Another thing i noticed is that the gps drains the battery much faster than on sgs1
So all in all I am satisifed with the gps on sgs 2. It's not as fast in locking as the first (with internet connection off) but it gets a much more stable lock and more precise.
Just tried to use a vent holder for the phone... temperature stayed at 32 degrees with AC set on 22 degrees auto. So vent holder is the way to go if you want to keep the phone cool.
Ive done a few tests with co pilot and my tracks and samsung really did nail the gps this time-it really is good. I find it strange that op said about a minuet to lock on-mines always 10 sec max cold start.
My initial cold start lock time is way more than 10 seconds ( never got under 20 seconds )... but that is influenced by a lot of factors: weather, objects around you like buildings or tall trees, the country you live in and the time you try to get a lock ( depending on how many satellites you have over you at a given time ). Still, lock time is less important, accuracy over a lengthy period of time is what I think is important.
Azra2k said:
First, I know there are tons of GPS tests, but all of them seem to focus on the extreme accuracy and less on the casual driving GPS experience. So I thought of making a small test and by doing this, I also discovered solutions to some existing unanswered questions. This is a subjective test, made by someone with some knowledge on the subject, but I am not an expert or anything close to that.
1. The test was made during an 800Km trip. 400km were done on the way "there" during the day and 400km on the way back in the evening. I used 2 GPS software packages: coPilot and iGo MyWay for Android. Both purchased. I also used 2 chargers, a cheap charger with 1x500mA and a more expensive one with 2x500mA USB ports. All the findings below were not influenced at all by the software used.
Now come the findings in a list:
a) Accuracy - I had absolutely no issues with accuracy. My position was fixed on the road even in dense urban areas with tall buildings. Initial fix took maybe 1 minute and there were 0 problems after that. Both coPilot and iGo performed really well, even at tight roundabouts.
b) Phone temperature while charging and using GPS - this is a bit more complicated to explain. First, I used a generic phone/PDA holder. For the first few KMs I drove with the phone held firmly in place. Outside temperature was 26-28 degrees and inside was 22 degrees. Clear skies with the sun shinning all day long.
Now, on my first few kilometers I encountered the all-to-common issue of overheating. My battery got to a temperature of about 54-56 degrees C and it would stop charging. The back of the phone was VERY hot all around the camera. So I started playing around to see how I can fix the issue and found a few "tricks":
- I tried to leave a small gap between the phone and the back of the holder (5mm). This lowered the temperature by A LOT! After doing this, the phone battery never went above 51 degrees.
-I then switched to Night Mode on the GPS software. This also lowered the temp by 2-3 degrees to around 48.
- After that I tried to place a piece of paper over it, protecting the phone from direct sunlight. Result, temperature never went above 46 degrees while charging.
- As another small note, I noticed that the battery gets hotter if it is fully charged or close to it. The difference was about 2 degrees between 90% charge and 50% charge.
Also, with the cheap charger I could not get the phone under 50 degrees, with the expensive charger I got at least 2 degrees lower on the temp display in similar conditions.
c) Loosing charge while charging - I used normal car USB chargers rated at 500mA per port. While the battery temperature was under 52 degrees, I never lost charge, it actually charged slowly (1% every 10 minutes or so). If the temperature goes above 52, I start to loose charge even though the phone still shows that it is charging. I think there is a self-protect mechanism that blocks the battery from charging when it is too hot.
Conclusions (after doing many combinations and seeing the difference in temperature): the phone is great for a GPS system if you follow a few pointers:
- Never cover the back of the phone. You should always have a small space there so the phone can cool itself. (very important, 3-5 degrees difference)
- try to protect the phone from direct sunlight... Being black it absorbs a lot of heat. (important, 4-5 degrees difference)
- use a good charger and not a cheap one. (important , 1-2 degrees difference)
- try to leave it on battery until your charge level reaches 50-60% and then plug it in. (less important , 1-2 degrees difference)
- use Night Mode, if possible (less important , 1-2 degrees difference)
On my way back, when the sun was down, I never got above 50 degrees no matter what I did.
Also, iGo seemed to use a lot more resources than coPilot. While on battery alone, I was loosing charge about 1.5 times faster.
* battery temperature was measured by "Battery Status" app. The readings were verified using the not-so-scientific method of touching the back side of the phone and "feeling" how hot it was
Click to expand...
Click to collapse
Great stuff! The given details are very clear and informative. Its really helpful information, thanks for sharing the valuable info.
New Brunswick practice test | PEI drivers test practice
Another method I am using to lower temp and Battery loss is to fix it to 800Mhz while navigating, depends of course on the navigation software but sometimes even 500Mhz is enough.
Everyone should try if its ok with his nav-software, I felt no stutters on 800Mhz^^
Related
I just had a couple of longish calls in a short period. Both averaged about 30 minutes or so.
The phone is HOT. It is hot on the screen and battery side. This is not the first time the phone as started to get warm after long use.
This has never happened on my Raphael. I had it happen the other day while I was using the GPS a lot too. This seems like a very bad thing to me as heat will destroy the battery and possibly chips.
Hmmm....supposedly from the HTC site:
Why does the phone heat up when I’m charging the battery or when I’m making long duration calls? more
It is normal for the device to heat up during charging. After charging, it will return to its normal temperature. It is normal for the device to heat up when you are using the same function for a long time, such as making long duration calls or recording a long video clip. Please rest assured that all HTC devices are factory tested before released. Was this helpful? Yes | No
(I say supposedly because only way to get it was using Google Cache...the page didn't pull up from the link.)
But this isn't 'warm' like I would expect from a battery...this feels hot, like when I tell someone not to put laptop on their lap because blocks vents...and then have them put hand on their laptop. That kind of hot.
Install System info widget and check the temperature of your battery, should be at 98F - 106F
I've had mine get too hot a few times. I'm assuming that's what this means, but when the phone is hot, I see the led indicator light alternate flash between green and Orange. I've taken out the battery and let it cool down and then everything was normal again. I'm beginning to agree with other people that I don't like this phone. I never had this problem, or any problem, with my Samsung moment. If this crap continues with this phone, I am giving the Samsung epic some serious thought. People have ranted and raved HTC phones. The Evo being my first one, I'm not very impressed with it once I played with it for awhile. Yeah, the specs looked impressive on paper but in real life, I don't care too much for it. I guess I will wait and see what happens.
Sent from my PC36100 using XDA App
Any idea why the phone would get warm when screen is off and you have no background apps running? I get this at work amd im sure its not caused by signal searching Im outside all night
My phone shut down from heat today.
I got into my car, turned on gps and bluetooth, put the phone into the mount, and started navigation. Sure enough, the thing shut down in about a min. The car and the mount were kinda hot too.
I had to take off the silicone case and point 1 air vent at the phone, to get the temperature to a pretty cool 31C (with charging at the same time).
On its own, I haven't seen the battery heat up, especially when the screen is off.
Perhaps that batter is defective, or you have a rogue process that's running the battery down.
How fast does your battery drain when it heats up, and normally?
The normal speed for draining the battery with the screen off is about 1% per 1 hour.
Covers, cases, holsters, in your pocket, being in a hot car (even not in direct sunlight), etc. Pretty much anything that can keep the heat from escaping the phone or add to the phone's temperature.
I hope cyanogen can be a miracle maker with the custom rom he's making, because this phone's quirks are getting on my nerves. Yeah, it's past the 30 day return deadline.
Sent from my PC36100 using XDA App
herbthehammer said:
Covers, cases, holsters, in your pocket, being in a hot car (even not in direct sunlight), etc. Pretty much anything that can keep the heat from escaping the phone or add to the phone's temperature.
I hope cyanogen can be a miracle maker with the custom rom he's making, because this phone's quirks are getting on my nerves. Yeah, it's past the 30 day return deadline.
Sent from my PC36100 using XDA App
Click to expand...
Click to collapse
Which other phone can run 1Ghz processors and not overheat under full load and inside a case?
I think common sense tells me I should have expected that.
I get pretty good battery life from my evo. 20 hours of moderate/high usage took me to 30-40% but I work in a pretty well air-conditioned ambulance and drive around with my phone in my lap most of the time or in my pocket on occasion and when I pick it up sometimes the screen and back cover are warm. I look at battery temp and its like 32-36 degree celsius idling like that
Edit: phones naked btw no screen protector or case for now
After a couple hectic days of ebook reading and killing my battery my phone was getting hot like really randomly and when I had the screen on for like 10 mins or more, or when I charged it or pretty much if I even looked at it wrong! On a side note I have it in the body glove case from Sprint. Also my battery life was horrible. I was going down to like 30% in like 7 hour of practically no use.
Now I was running completely stock and unrooted( I hadn't felt the need to root yet) My solution was I rooted, installed DC rom then and I believe this is what fixed it cleared my battery stats from the recovery menu. Bam my phone hasn't even gotten warm since. Also it's been a week since I did this, and I'm getting crazy battery life now( like I'm down to 70-80% in 7 hours now with light use)
I'm curious what are the standard operating temperatures people experience with their X10s, especially under heavy use?
I'm wondering, because I've noticed that my X10 tends to hover in the 42-46°C often under use (most commonly at work while running Barnacle WiFi Tether while connected to my X10 charger). This while using SetCPU to to run at 384MHz max with "Screen Off" and 576MHz max with "Temp > 42.3°C" ("Screen Off" has the higher priority of the two).
I understand that while running Barnacle, the phone has both the 3G and WiFi radios in operation, so a temperature increase makes sense. Charging on top of that will further increase temps. I just want to make sure I'm within "expected" ranges when doing this.
It should be noted that my 3G signal is pretty crappy (-94 to -102dbm) where my cubicle is, so that likely doesn't help).
Totally within normal mate... Mine usually is about 39 degrees but I don't tether, and usually charge when I'm not using it at all..
35- When Idle, around 35 when using, 40+ when charging
Sounds about right mate, i only experence very high battery heat when running Navigon whilst plugged into my car charger and its hit 50 degrees +, thats when i know i need to turn it off for a bit.
Yeah, I hit 50°C once or twice. Not sure what is what that pushed it that high either time, but in both cases I simply unplugged, shut down Barnacle, and switched to "GSM only", and it cooled down quite quickly. Then I re-enabled stuff and all was back to normal.
Good to hear I'm seeing typical temps.
Are there any ways to cool it down other than shutting down whatever you are doing. I get to about 44 gaming and the phone feels pretty warm. (No WiFi, 3G, GPS etc)
xGary said:
Are there any ways to cool it down other than shutting down whatever you are doing. I get to about 44 gaming and the phone feels pretty warm. (No WiFi, 3G, GPS etc)
Click to expand...
Click to collapse
44°C is fine. It can be warm to the touch, but no more so than a laptop.
To cool it down: you could take off the back cover. That should help it dissipate heat a bit better. Of course, then you also don't have any insulation so it'll likely also feel a bit hotter to the touch.
I have a cheap rubber skin I keep the phone in most of the time (for a bit of bump protection). I bought it on eBay from Hong Kong for like $1.00. It probably contributes a bit to the heat build-up, but it does make it a bit easier to hold while warm.
Im a wireless technician and when I need to climb a tower I tend to leave my phones in the truck (work phone is a S2). After a couple of hours of the phones being in sub zero temperatures, the Atrix loses about 60 to 80 percent of battery. Well, thats what the OS is telling me. It will continue to work throughout the day at 1 percent. If I charge it from that point forward it wont charge past 70 to 90 percent. Depending on how long I used it at 1 percent. Only way to fix it is remove the batter after it has been in the charger all night and put it back on once the question mark is there. And I need to do this almost every night. If I leave the phone for 30 minutes it might drop 10 to 20 percent. But just enough to mess up.
This doesnt happen with the S2. It does drain faster but it is not noticeable. Anyone else notice this? Oh and my Atrix messes up big time in the humidity so I have something to look forward to this summer.. I doubt the phone will last long enough to get ICS.
And something else I noticed. After I pick up the phone after it has been in the cold for a couple hours I will check SetCPU to see what my cpu temperature is at. I have never seen it below 18 C. Makes me wonder how accurate it actually is. If the phone is room temperature at idle, my CPU temp will be 39C. I bet it is actually only at 25 to 30 C.
I first saw this behavior when I took my Atrix camping in December. The phone was at 95% when I turned it off at night, and in the morning when I turned it on, it was at 40%. Another guy camping with us had an iPhone with a similar drop, but I don't know what his percentages were.
This weekend I was in Utah skiing and fully experienced what you are talking about...the phone was on the charger all night and it would only go to 70%. I pulled the battery and after the restart it was at 99%. This was in my heated hotel room and not outside.
I think the cold weather in general causes batteries to go crazy. Have a read:
http://batteryuniversity.com/learn/article/discharging_at_high_and_low_temperatures
I have the exact same thing happen to me as the OP and it has been happening for a long time even after i got a refurbished atrix so it is definatly something to do with the battery and not the phone itself. Damn cold Canadian winters
Sent from my MB860 using xda premium
Ratchet556 said:
I have the exact same thing happen to me as the OP and it has been happening for a long time even after i got a refurbished atrix so it is definatly something to do with the battery and not the phone itself. Damn cold Canadian winters
Sent from my MB860 using xda premium
Click to expand...
Click to collapse
Hey we can't complain. Its very mild, well here anyways. And I love wasaga. Best may long weekend place to go!
And as far as the issue.. I have noticed it with my iPhone but once charged it was always go to 100 percent. Sucks that ours really messes up.
There is a wealth of information about lithium ion batteries if you look for it. They perform better in colder temperatures. They self-discharge slower in colder temperatures. Their lifecycle degrades slower in cold temperatures.The only real drawback is that the need to be warm to pass full current, so an extremely cold battery might not power your device properly until it warms slightly. If you let your battery discharge all the time it will severely decrease it's lifecycle, as lithium ion does not cope well with this.
NASA requires that their lithium ion batteries perform to -80C.
Remember that the batteries also have protection circuitry for safety. This may be set up in the Atrix batteries to discharge rapidly under certain circumstances.
I believe you can get a rapid discharge though if you go from an extreme cold temperature to a very warm temperature quickly, which could be the case if a phone sits in a truck all day at sub-zero temps, then you jump in, start it up, and start cranking the heat.
http://batteryuniversity.com/
Never had that happen.
Had the temp down to 12 C on the phone.
It did get a little hot during the summer months.
g2tegg said:
Hey we can't complain. Its very mild, well here anyways. And I love wasaga. Best may long weekend place to go!
And as far as the issue.. I have noticed it with my iPhone but once charged it was always go to 100 percent. Sucks that ours really messes up.
Click to expand...
Click to collapse
Living here you come to know that May long weekend is the WORST time of year because the majority of tourists are jerks! Fun to watch them get arrested though Right now its cold as hell. And yea it kinda of sucks, no matter what i do i can't make it read 100% it just goes up to that on its own sometimes. One time i had my battery last 3 hours sitting at 1%.
Sent from my MB860 using xda premium
I've had my atrix shut off on me while skiing a few times. Get home and plug it in and it has plenty of juice...just cant push out enough current to power the phone properly.
My phone sits in my work truck all day (since its not intrinsically safe) and even when the temp is well below zero it never fails to come off the vehicle dock without a full charge just that sometimes it thinks 40% or 70% is a full charge fixed it pretty much the same way as you guys described. Other than that in low temps the touch screen responsiveness is sometimes an issue and ocassionally the external sd card wont show up until it warms up. but overall a reliable phone considering the abuse it takes. wonderfull build quality from motorola as usual.
However... I think heat is a bigger issue as I managed to melt my first vehicle dock this summer when it hit 34C in Calgary. The suction cup and part of the stem remained on the windshield but luckly the phone fell to the floor in the shade.
Really surprised I haven't seen any pix of melted atrix on the internet unlike the S2 & Iphone4
I am new to this forum
Just wanna ask if i switch on my nexus7 wifi 24*7 then will it affect its wifi??
Just curious to know becoz i rarely switch off my wifi and i am scared will itt damage it after sometime??
Heat accelerates almost all aging & failure mechanisms.
Temperature cycling accelerates some types of failure mechanisms (fracture/rupture type failures)
So leave it on or turn it off every night, which is worse?
So long as you aren't streaming data at full bore 24x7 you will probably be fine leaving it on.
Note I said *probably*. That's because I certainly do not have accelerated life-test data for the N7 sitting in front of me; but even if I did, those statistics would only predict what fraction of units would fail over yeah-many hours/years of service... not which individual units will fail.
So unless someone from Asus comes in here and divulges what their MTBF design goal for the N7 was, or what the first 18 months of the repair stream has indicated about their reliability models, you're not going to get much of an answer to your inquiry.
FWIW, I leave mine on the charger & with the WiFi on when I am not using it, and I have the expectation of using it for a couple more years to come.
bftb0 said:
Heat accelerates almost all aging & failure mechanisms.
Temperature cycling accelerates some types of failure mechanisms (fracture/rupture type failures)
So leave it on or turn it off every night, which is worse?
So long as you aren't streaming data at full bore 24x7 you will probably be fine leaving it on.
Note I said *probably*. That's because I certainly do not have accelerated life-test data for the N7 sitting in front of me; but even if I did, those statistics would only predict what fraction of units would fail over yeah-many hours/years of service... not which individual units will fail.
So unless someone from Asus comes in here and divulges what their MTBF design goal for the N7 was, or what the first 18 months of the repair stream has indicated about their reliability models, you're not going to get much of an answer to your inquiry.
FWIW, I leave mine on the charger & with the WiFi on when I am not using it, and I have the expectation of using it for a couple more years to come.
Click to expand...
Click to collapse
recently i played hd movie on my nexus 7
(Movie-300 blue ray version
Frame width-1280
Frame height- 544
frame rate - 23 frames per sec )
and found playback time of 5hrs only
I didn't played entire movie jst calculated in the form that my battery level reduced from 93 to 92 in exact 3 min
Like this i calculate entire playback time ,....
But on internet it says nexus 7 support 9 hrs of hd playback
Plz tell 5 hrs playback is fine for bluray version or I'm having some sought of a battery issue
And if it's a battery issue then what shall i do for its replacement because its been only 1 months
Plz do reply asap.
Regards.
nitu12345 said:
recently i played hd movie on my nexus 7
(Movie-300 blue ray version
Frame width-1280
Frame height- 544
frame rate - 23 frames per sec )
and found playback time of 5hrs only
I didn't played entire movie jst calculated in the form that my battery level reduced from 93 to 92 in exact 3 min
Like this i calculate entire playback time ,....
But on internet it says nexus 7 support 9 hrs of hd playback
Plz tell 5 hrs playback is fine for bluray version or I'm having some sought of a battery issue
And if it's a battery issue then what shall i do for its replacement because its been only 1 months
Plz do reply asap.
Regards.
Click to expand...
Click to collapse
Three minutes (or a 1% change) in battery "percent charge state" is way way too small of an interval to extrapolate from - the sampled data is just way too noisy to be meaningful. A 10% change would be a better measurement. And, those types of measurements should be made in the "middle" of the battery charge state (in the 30% - 70% range, not near the ends).
But - to answer your question - quite a long time ago, @bcvictory ran many battery drain tests - using a video loop test - with a bunch of different kernels, and most of the results tended to be between 5 and 7 hours or so.
I made some very detailed battery drain measurements playing a video loop about 4 weeks ago on my N7 (MX Player), and without tweaking anything (stock kernel, KitKat 4.4.2) I got about 6.25 hrs for a full discharge (100% - 4%).
So, I guess that means that if you saw an Asus/Google claim of 9 hours, that would probably be a significant exaggeration.
(BTW, keep in mind that for *movies* the GPU isn't doing all that much work, as the scenes are not being rendered from a model - they are just being decompressed from a file (or byte stream). So... that means that you should probably expect even worse battery drain times for playing video games continuously).
.
nexus 7 overcharging
bftb0 said:
Three minutes (or a 1% change) in battery "percent charge state" is way way too small of an interval to extrapolate from - the sampled data is just way too noisy to be meaningful. A 10% change would be a better measurement. And, those types of measurements should be made in the "middle" of the battery charge state (in the 30% - 70% range, not near the ends).
But - to answer your question - quite a long time ago, @bcvictory ran many battery drain tests - using a video loop test - with a bunch of different kernels, and most of the results tended to be between 5 and 7 hours or so.
I made some very detailed battery drain measurements playing a video loop about 4 weeks ago on my N7 (MX Player), and without tweaking anything (stock kernel, KitKat 4.4.2) I got about 6.25 hrs for a full discharge (100% - 4%).
So, I guess that means that if you saw an Asus/Google claim of 9 hours, that would probably be a significant exaggeration.
(BTW, keep in mind that for *movies* the GPU isn't doing all that much work, as the scenes are not being rendered from a model - they are just being decompressed from a file (or byte stream). So... that means that you should probably expect even worse battery drain times for playing video games continuously).
.
Click to expand...
Click to collapse
Sir by mistake i overcharged nexus7 tablet for 1 hour and found out that
That it didn't get discharged for next 1 hour ( in which i surf web , watch youtube videos,and played temple run )
Don't you think it get overcharged for i hour because last time i removed the charger at exact 100 % and it started draining within that i hour
And plz do tell even if tablet gets overcharged
Is it safe ?
Becoz i usually charge my tablet at night.
nitu12345 said:
Sir by mistake i overcharged nexus7 tablet for 1 hour and found out that
That it didn't get discharged for next 1 hour ( in which i surf web , watch youtube videos,and played temple run )
Don't you think it get overcharged for i hour because last time i removed the charger at exact 100 % and it started draining within that i hour
And plz do tell even if tablet gets overcharged
Is it safe ?
Becoz i usually charge my tablet at night.
Click to expand...
Click to collapse
I wrote a script to "watch" the battery current and voltage in my N7 once per minute (while it was charging from about 4% - 100%) and log the output to a file. (see attached image). So, I think I know exactly why you saw the results you did.
So here is what happens: as the battery voltage rises during charging, the current slowly gets smaller and smaller. Somewhere around 90% the current suddenly starts to slow down much faster in time, and the battery voltage only rises a tiny bit over the 90% - 100% interval.
Here was the surprise though: when the "% charge" got to 100%, the battery continued to charge (slowly) for another 20 minutes. Over that 20 minutes the battery charging current eventually went to zero.
So - it is safe to let your tablet sit on the charger. It is not the charger that determines how much current the battery receives, it is the SMB347 chip in the N7. There is no such thing as "overcharging" so long as the hardware in the tablet is operating correctly. I leave my tablet on the charger all the time when I am not using it, and don't worry about that one bit.
bftb0 said:
I wrote a script to "watch" the battery current and voltage in my N7 once per minute (while it was charging from about 4% - 100%) and log the output to a file. (see attached image). So, I think I know exactly why you saw the results you did.
So here is what happens: as the battery voltage rises during charging, the current slowly gets smaller and smaller. Somewhere around 90% the current suddenly starts to slow down much faster in time, and the battery voltage only rises a tiny bit over the 90% - 100% interval.
Here was the surprise though: when the "% charge" got to 100%, the battery continued to charge (slowly) for another 20 minutes. Over that 20 minutes the battery charging current eventually went to zero.
So - it is safe to let your tablet sit on the charger. It is not the charger that determines how much current the battery receives, it is the SMB347 chip in the N7. There is no such thing as "overcharging" so long as the hardware in the tablet is operating correctly. I leave my tablet on the charger all the time when I am not using it, and don't worry about that one bit.
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That means my battery's working fine..na??
Can u suggest me a gud free app to scan battery's performance?
Hws BetterBatteryStats_xdaedition_1.15.0.0 ?
And thanks a lot for clearing my doubts
U r bst
What does "Battery Charge %" Mean?
nitu12345 said:
That means my battery's working fine..na??
Can u suggest me a gud free app to scan battery's performance?
Hws BetterBatteryStats_xdaedition_1.15.0.0 ?
And thanks a lot for clearing my doubts
U r bst
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Click to collapse
@nitu12345 - I don't use battery monitoring apps. I'm not really sure what value they have except in deciding whether or not your battery is sort of "normal". Some of them try to "estimate" current rather than actually take measurements from hardware (which depends on the availability of both system hardware and kernel software, so it makes sense why a generic Android battery app might not even look at current measurements even when they are available on a particular handset/tablet) , so: garbage-in = garbage-out. Basically though, I can't make a recommendation as I haven't used them.
TL;DR - see attached plots at end of post.
I want to take this opportunity to show some more data that I measured in the hopes that it can add to folk's understanding. I made a bunch of measurements of my tablet under both discharge and charging conditions, Originally I was going to make a big long post, but it was simply too much effort to do a good job of it with all the data I had. So here is a mini-report about charging. In particular, it asks and answers the question:
"What exactly does charge percentage mean"?
Is it the measurement of Amp-hours pumped into the battery?
Or is it somehow proportional to battery voltage?
Something else?
Before I begin I should point out just a few key observations. The 2012 N7 has a TI (Texas Instruments) chip - the BQ27541 (iirc), that has the sole purpose of observing the battery - the amount of current going into or out of the battery, and the battery voltage. It does NOT CONTROL ANYTHING - it is just an observer. For that reason, TI calls it a "fuel gauge" chip. It is connected to the processor via an I^2C bus, and the N7's kernel reads the "% charge" directly from this chip. There is no system "battery software" or "calibration software" which alters this number in the N7 - it comes directly from that BQ27541 chip. No doubt there is a tiny amount of firmware in that chip, and the datasheet for that chip indicates it can be factory programmed with different battery curves. But for our purposes it is a black box that we can't easily change - the kernel interface on the N7 does none of that "factory programming", it just reads values from the "black box".
From that chip several things can be read - "% charge", "battery current", "voltage", etc.
Attached at the bottom of this post you will find a curious graph. It shows the behavior of five measurements versus time. "Potential", "Charge", "Current", "Energy", and "Percent". The reason that I said "curious" is that all the raw data were re-scaled so that the min-to-max range of each variable are "normalized" to the range 0.0 to 1.0 (except for the "Percent" variable, since charging here started at 6%).
for any given variable this is done by subtracting the minimum value from the dataset, and then dividing by (max - min), as in:
x' = [ x - min(x) ] / [ max(x) - min(x) ]
Why do things this way? Well, for one, so that all the different variables may be plotted on a single graph running from 0.0 to 1.0.
But more importantly, observing the "shape" of each curve in comparison to others gives you very good physical insight into what is happening under the hood.
A little background in physics:
I Current == Charge/second
Q Charge == Integrate[Current(t), dt] (note this is effectively the same thing as "Amp-hours")
P Power == Voltage*Current
E Energy == Integrate[Power(t), dt]
V Potential (= Battery Voltage)
So from measurements of I(t) and V(t) only - current and voltage, we can use numerical integration to figure out approximate values of Q (charge), and E (energy, or "work" that we put into the battery), starting from only the I(t) and V(t) measurements.
So finally - look at the first JPG image carefully. ("nexus7-2012-Normalized_ChargeCurrentVoltageEnergyPct_vs_Time.jpg")
What you will notice is that three variables: Charge (Q), Energy (E), and Percent all rise quite smoothly in a nearly straight line from 6% to 90% charge state, (or from 0 secs to 9000 secs). So this says that - even though the battery voltage is not smoothly increasing, nor is the current into the battery smoothly decreasing - the charging discipline enforced by the other important chip in the N7 (the SMB347 USB Interface Chip) tries to perform a "constant power input" charging scheme.
A quick diversion: why is the shape of the Energy (E) curve almost identical to the Charge (Q) (or Amp-Hours) curve? It is because of the (apparent) "constant power input" scheme the charger uses: as the battery voltage rises, the amount of current used for charging is adjusted downward. Notice in the graph that even though the "Percent" variable is steadily rising in a straight line, neither the current nor voltage are behaving that way - they are almost inverses of each other so that I(t) * V(t) = Constant.
So - the conclusion, specifically for the N7 hardware - is that "battery percentage" is supposed to represent either Amp-hours input to the battery (charge), or Energy dumped into the battery during charging. For this specific device with it's specific hardware, they happen to be equivalent because of the constant power charging scheme.
Note there are a couple of other interesting tidbits in this graph. The charging cycle spends nearly 25% of the total time charging in the final 90-100% charging range. So if you are carefully watching your tablet charge, it will seem to "slow down" dramatically during that last 10% of charging. (I should also point out that my tablet charges quite a bit faster under normal circumstances - about 2.5 hours instead of 3.5 hours; I believe the script I used prevented the tablet from ever entering deep sleep during charging. A N7 tablet that isn't being held awake with wakelocks should charge in a little over 2.5 hours)
You will also notice that the battery is continuing to charge for about 20 minutes after it reached the "100%" charge state. That's because "100%" doesn't really mean that the battery has stopped charging. In this particular observation, the SMB347 chip was still pushing ~400 mA into the battery after the 100% mark had been reached.
Phew. Finally, I have attached another image ("nexus7-2012-BatteryVoltage_vs_ChargePct.jpg") that shows a display of battery voltage versus percentage charge for two charging cycles and one discharge cycle. Note that when the SMB chip needs to force current into the battery to charge it, it must raise the voltage in order to do that. So it is clear that battery voltage alone can not be used as a proxy for "charge percent", nor can you figure out what the charge is by only looking at battery voltage alone. Not only that, but look at the shape of the curve - it is not a straight line. There is very rapid voltage changes going on at the low end of "% charged" range during charging, very little voltage change occurring in the 90-100% range, and during discharge (red curve) there are are at least 3 different ranges where the slope of the battery voltages change relative to the "% charge" data that the TI chip emits. This is why I suspect that battery apps that only observe voltages probably are not capable of accurately predicting anything other than the ageing algorithms of the BQ27541 chip, and are probably absolutely useless for telling you anything from day to day.
OK, a couple more trivia observations:
- That BQ27541 chip is squirrelly (or perhaps it is the kernel interface, dunno.) There were many sampled data points where the "% charge" reading from the chip suddenly dropped from wherever it had been to *ZERO*. I was sampling the value once every 60 seconds for the data displayed here, but I have also sampled the sysfs (kernel interface) for that chip at much higher speeds, and it frequently produces garbage data. Additionally, the same chip would frequently report *zero current* during discharge condtion - an impossibility. On their website, TI says "Not recommended for new designs". (Usually that is weasel-words that mean "we are aware of some buggy behavior that we are not going to tell you about") Note for instance in the second graph that the battery percentage values 26, 47, 58, 69, 79, and 84% never appear in ANY data set. That means that a battery app - or even an OS "low battery emergency shutdown" trap - could exhibit odd, buggy behavior if they do not use defensive techniques that assume that the data they are getting is partly corrupted. (multiple sample averaging and outlier detection).
- I believe the "sudden steps" in current that I observed during charging (prior post) were real - the tablet had it's WiFi shut off, and the tablet was not in use at all. So while it is certainly possible that random app behavior could have caused some fluctuation in current available to the battery, that would have been much more short lived. Is it possible that the SMB347 chip also has some bugs?
OK, here's the graphs folks. Have fun and good luck with your tablet.
bftb0
Recently i reseted my nexus tablet and found that there was no google earth installed so I downloaded an apk file frm external source and installed google earth from it
but now when i try to uninstall it
There no such button as it shows only disable button
But since it wasn't there before how come now its not uninstalling
N r u using magnetic case .? Is it safe for nexus7?
Like i have heard that it messes with magnetic compass
Plz clear my query.
Seems the Nexus 6p has a cold bug. First phone i seen this in.
So i been doing some overclocking and bench marking on a few devices. The Nexus 6p has shown some strange behavior. When i had the phone chilled and ran some benchmarks the battery would drop drastically. Restart and all that did nothing. The batt. stayed at 39% for about 2 hours with some heavy use. Charged it back up no issues. Did it again and it did the same thing. Took my turbo 2 to an even lower temp and that was fine it did not have this.
Something you have to worry about? Nope not unless you are out in Alaska or taking a trip to the artic circle. However if you do this could cause you some issues.
Tested on a stock room and kernel. As well as a purenexus and elemental x combo. Same outcome.
Again not really an issue. And the Nexus camera visor and display survived the -40c freeze and back to room temp test. Attached is a pic of the massive drop
Not sure why the Droid Turbo didn't demonstrate this same behavior, but extreme cold temperatures definitely have an impact on lithium ion batteries. Perhaps the material of the Droid Turbo insulates the battery a bit better than the aluminum on the 6P?(pure speculation there - science geeks, feel free to rip that one apart)
I've experienced the same thing with my DSLR (Nikon D80) when shooting in the cold.
Sent from my Nexus 6P using Tapatalk
Devhux said:
Not sure why the Droid Turbo didn't demonstrate this same behavior, but extreme cold temperatures definitely have an impact on lithium ion batteries. Perhaps the material of the Droid Turbo insulates the battery a bit better than the aluminum on the 6P?(pure speculation there - science geeks, feel free to rip that one apart)
I've experienced the same thing with my DSLR (Nikon D80) when shooting in the cold.
Sent from my Nexus 6P using Tapatalk
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Yeah the turbo 2 was even exposed to cooler temps longer. And its not that the capacity was lost. After the bench it would stay at that + for a few hours before it started going back down. So when i started at about 74% after it still had 74% less just android was saying that it was lower. I still managed to get a full charge out of it. Not an issues just a omg my batt is almost dead. Fallowed by omg my battery has been at this % for a few hours.
-40°C isn't really common weather and is definitely out of normal range of temperatures. I live in a area where it gets cold (-30°C) during wintertime, I don't really use phone in a such coldness (my fingers would freeze pretty fast anyway.)
I once answered phone in -25°C (current phone at the moment was Sony Ericsson W910i) I talked for 15 minutes and my battery went from 100% to 21% and shut down moment after the call ended.
Don't all batteries exhibit fluctuations in total output in extreme situations high or low? I use an iphone in a work truck that is left outside in 20f to 30f temps and that thing is crazy swinging from 100% charged when I leave it in truck to dead in one night in cold temps.
Sent from my Nexus 9 using Tapatalk
is there a particular reason you guys do this stuff?
Soulfly3 said:
is there a particular reason you guys do this stuff?
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So we don't have to.
As an aside, the phones operating temp range.
http://imgur.com/aR9JMk7
JoshuaMh said:
So we don't have to.
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Why would we 'have to'?
Stbrightman said:
Why would we 'have to'?
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Perhaps gives an endurance threshold for those of us hiking in Alaska, or climbing an icy peak, ect.
Stbrightman said:
Why would we 'have to'?
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I think it was a funny
Sent from my Nexus 6P using Tapatalk
My nexus 6P sorta died on me today, it was stored in my GF's bag, we were outside, 0F, for like an hour. When I go to take my phone, won't turn on, tried plugging it in, nothing.. could the cold weather (not so cold) have killed my nexus 6P ? Anyone has had this problem ?
I live in northern Finland and I have experienced this kind of behavior with my 6P lately. The battery dies suddenly under -10 C degrees if I keep it in my pants pocket. This is daily problem so have to wear my phone in wool mitten and then pocket it.
I think this started right after 7.1 update. My phone is 12 months old so it might be the battery losing its best edge or simply software feature/bug.
The battery model uses inputs from current flowing in/out in the battery, outter voltage and battery temperature sensors and calculates Open Circuit Voltage leading to the estimated State Of Charge (by use of a 3 degrees polynom)
As any resistor, the internal battery resistance will vary depending on temperature. So will the OCV calculation.
All these parameters are linked non linearly and the models are done within temperature ranges (different coefficients for say different temperatures). If temperature exceeds thresholds ( /sys/class/power_supply/bms shows a nominal range of [10 degC, 45 degC] ), the SoC will not be computed.
If temperature exceeds thresholds or SoC varies too widely, the battery current will be downlimited, meaning it won't charge as expected or could shutdown for safety reasons.
If battery temperature goes under 5 degC, the SoC is considered invalid.
As such when starting again the device within this range the SoC will be calculated again correctly and the device will stay on.
There are also high/low safety thresholds which will instantaneously shut off the device (I think they are stored in the Qualcomm IC so I can't see these values).
So while the battery can probably work fine under 5 degres C, the SoC won't be calculated properly. You can also get some feedback from the known battery health in /sys/class/power_supply/battery/health (Good, Dead, Warm, Cool, Cold, Overheat, ...)
I've gathered this information from the Qualcomm IC driver source
Sound like a Overclocking CPU with Liquid nitrogen haha.
This just happened to me today. I was out skiing and temps were -10 f. Phone shut off in less than an hour after starting from 100%. Went back inside, warmed up the phone and the battery was stuck at 39%. I moved my phone to an interior pocket closer to my body and didn't have a problem for the rest of the day.
As a avid skier, I can say I've always had extreme cold weather issues with phones, but the Nexus 6p is definitely the most severe.
FYI I'm on 7.1.1
This happened to my Nexus 6 today. I was in the garage (non heated) working on my car and had my phone sitting on a box next to me. It was about 30°F and I grabbed my phone to send a picture of something to my friend. As soon as I launched the camera it shut down. It booted instantly after pressing the power button, but after being on for about 15 seconds the battery percentage displayed in the status bar suddenly went from 51% to 0% and it shut down again. After bringing it inside to warm up my battery was back to 50%.
I've also taken my phone snowboarding in much colder temperatures and never had this issue. Even while using it on the chair lift where it's directly exposed to the cold and wind it's never shut down.
The only thing that has changed between past usage in cold weather and today is the version of Android I'm using. Unfortunately I'm too lazy to revert to 6.0.1 to see if that solves the issue since I just did a clean install of 7.1.1 about 2 days ago...
What count is the battery temperature not the ambiant one. You can use "cool tool" or wharever app to display that. If you're rooted you can even check the health file I mentionned (to see if it's Cool or even Cold from the model perspective).
The are linked by discharge rate.
The theorical unusable capacity will increase at low and high temperature but also with discharge rate. So if you are at these extreme temperatures, you could try to lower the discharge rate as much as you can by disabling all what you don't need (sync, lte).
Anyway at -23 degres ambiant your battery was maybe at -10 which is outside of its theorical range. We don't know the practical performance at these temps. I'll have to check again to confirm the low temp threshold at which the SOC is not calculated (think 5 degres that is ambiant 0 or -5). Could be that the battery is ok but the software lacks a lookup table at these ranges. There could be a reason. Anyway, I would try to preserve the battery from these temp if you can.
I have the same issue - but in +3 or +4C degrees. The battery went from 60% to zero in 15 min.
NotEnoughTECH said:
I have the same issue - but in +3 or +4C degrees. The battery went from 60% to zero in 15 min.
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Ambiant or battery temperature? If the former, you'll need to know what the battery temperature was. That's the only thing that matters here. I guess you were talking about ambiant so the device once switched on could be at like 8 degrees so I'm surprised about your results.
I use Cool Tool but you can also use any other app like... Battery. What's relevant is battery temp AND battery health (Good, Cool, Cold ).
I've just put my phone in the fridge for some testing. Should be around 4 degrees also