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[Q] Nexus S Touchscreen not responding while charging

Hi everyone.
My Nexus S touchscreen has stopped working while charging. The charger is original, and I havent had any problems before this. The screen does work when charge it through my computer. Anyone have any idea what the problem might be? I updated to 2.3.4 around two week ago, but I've charged the phone after the update without the touchscreen dying.

I read about that problem a good number of times now, most often with third-party chargers, though. It seems, that the touch screen is very susceptible to interference on the power source (which is not really surprising, considering the touch sensor technology).
Maybe your wall adapter is just faulty or out of spec.
Something I just thought of: Do you have any power line communication devices? If so, try to unplug all of them and test again.
Try a few different power outlets, too, maybe even in different buildings.

If its not a real charger it won't work. Alot of these phones only will work with OEM charges from Samsung or Motorola chargers
Sent from my Nexus S using XDA App

I would love to know what you mean by "real charger".

One of my chargers is very slightly over voltage (5.2V) and my touchscreen becomes erratic when I use it - I try to keep using it to a bare minimum. Personally I'd stop using that charger. You never know what long term damage it may be causing.

I really don't mean to challenge your measurement, more so since I don't know how you got it, but I find it anything but trivial to measure voltages to any degree of accuracy.
Since I can't afford laboratory equipment with accuracy in the ppm range, I am stuck with a cheap hand multimeter that is rated at 1% plus a few counts, but only inside one year from manufacture when stored the whole time in defined conditions. The next best thing would have been a 150 Euro version with about 0.5%. That means, that the least significant number in the reading is all but useless.
And we are not even talking about ripple, interference and forward leakage. Try measuring your charger's +5V and 0V to earth. You will probably see significant readings.
Anyway, what I am trying to say is: The average user will have to trust the rating on the label.
And the 5.2V you measured are still inside the specification range, which is 5V plus minus 5%, so from 4.75V to 5.25V, if I remember correctly.
If I felt adventurous and had the problem I might try decoupling everything a bit with some big ultralowESR capacitors near the phone. That should give a lowpass together with the cable resistance.

Hi guys,
I have also come across this behavior - I was charging my Nexus S using the supplied USB cable and the screen hasn't been responding nearly at all.
In my case, this was caused by the notebook charger - when I unplugged it (ran on battery), everything was fine again. Therefore I blame my charger to be a source of some sort of interference.
If you are on a laptop, maybe you could try that. If this is a case of the outlet charger, maybe it is not working properly (to be replaced?)
Hope this helps

same here... wt*
okay im using some Chinese charger but what is doing with the display ...

[Nook HD/HD+ CM10.1] Charger control development

There were some requests into forcing the charger controller in the Nooks to allow higher rate charging from non-B&N chargers, I also was constantly annoyed by how my Nooks are always discharging when plugged into my computer with screen on because of only drawing about 500mA, where as the ports would happily provide 1A (development led by Apple).
The work here is experimental and if you decide to try anything, you bear the risk of stuff frying and catching on fire (granted, I did not burn anything here yet, but who knows, this is electricity we deal with here).
The "TRM" is here for anybody interested, sadly it does not match with what the hardware actually does in some important areas (also reflected in the driver comments). It looks like there is no real way to control the charging rate much, as soon as you write into draw rate register, it's two lowest bits are reset to 0 until D+/D- detection is performed, but then the detection resets draw rate back to appropriate defaults, huh? So this leaves us with two settints: 100mA or 1.2A
Plus there's something else going on, e.g. all of my iPhone chargers that I happen to have around only provide about 1.5 Watts of power and the controller refuses to draw more than 500mA from it anyway. All the Android stuff chargers I have on the other hand work out of the box and allow Nook to draw about 1.2A from them (even the native charger does not seem to draw more than this, about 7.5W according to my Kill-a-Watt display and also according to the battery current rate reported by the battery).
Anyway, I am providing two kernels, kernel for Nook HD+ and kernel for Nook HD
Flash the appropriate one for your device.
Then there's the control app: NookChargerControl.apk
Run the app, and it will present you with the main switch at the top (ignore the second switch, it's from the earlier experimentation and currently does not do anything).
If you flip the switch on, the charging is forced at 1.2A rate, no matter where you are connected (but see my earlier note about my iPhone chargers).
In addition to whatever physical measurements you are making, thee are two clues displayed about stuff:
The registers 00 and 08. When register 00 is 0x34 - that's indication of 1.2A, 0x32 = 0.5A, 0x30 = 0.1A, 0x37 should be 3A (When connected to power).
Also a battery-reported current is shown, this is your main clue about how much power does the battery really gets, negative values = discharging.
Tap anywhere on the screen to refresh the values, the battery rate reported sometimes takes several seconds to update, so do not panic if the values appear to be stuck for some time.
If you decide to try this, please report back in the thread with your findings.
In my testing, enabling the switch (while plugged into a computer) results in as much battery charging current as I am getting from B&N charger.

verygreen said:
There were some requests into forcing the charger controller in the Nooks to allow higher rate charging from non-B&N chargers.... If you decide to try this, please report back in the thread with your findings.
Click to expand...
Click to collapse
Flashed new kernel and installed charger app. When I first turned on the charger app, I'm pretty sure it said "Reg00: 0x37". After turning on the "Force USB charger mode", Reg00 went to 0x34, and stays there whether I turn USB charger mode off or on. The "Battery current" started at 476000 and is now at 358000, but I'm pretty sure that's because it was already almost completely charged, and now it says it's at 100%, though the LED is still orange. All of these measurements are on the Nook charger. Haven't tried anything else yet.

dbrickg said:
Flashed new kernel and installed charger app. When I first turned on the charger app, I'm pretty sure it said "Reg00: 0x37". After turning on the "Force USB charger mode", Reg00 went to 0x34, and stays there whether I turn USB charger mode off or on. The "Battery current" started at 476000 and is now at 358000, but I'm pretty sure that's because it was already almost completely charged, and now it says it's at 100%, though the LED is still orange. All of these measurements are on the Nook charger. Haven't tried anything else yet.
Click to expand...
Click to collapse
Thanks.
Using nook charger with this app is pointless, as it's already working (as are a bunch of other chargers from android devices).
So I guess it's being targeted at people who want to draw more power from their host computer or with incompatible chargers.

Tried with a 1amp Samsung charger. It Is showing 1092000 on an HD+
Force power 2
Reg 00 0x34
Reg 08 0xac

is this for cm10.1 or nook original os or both of them?

verygreen said:
Thanks.
Using nook charger with this app is pointless, as it's already working (as are a bunch of other chargers from android devices).
So I guess it's being targeted at people who want to draw more power from their host computer or with incompatible chargers.
Click to expand...
Click to collapse
Now if you could just write a kernel to make the nook compatible with normal USB cables... heh.

loverppc said:
is this for cm10.1 or nook original os or both of them?
Click to expand...
Click to collapse
That's just for CM10.1

dbrickg said:
Flashed new kernel and installed charger app. When I first turned on the charger app, I'm pretty sure it said "Reg00: 0x37". After turning on the "Force USB charger mode", Reg00 went to 0x34, and stays there whether I turn USB charger mode off or on. The "Battery current" started at 476000....
Click to expand...
Click to collapse
I wasn't sure if the Reg00 was originally 0x37 or not, so I reinstalled everything, and yes, it was. And for a better benchmark, when I first started charging it, with the battery at about 70%, using the nook charger, the "Battery current" was around 1670000.

Tried with this charger and neither port seems to work. Shows right around 0 for the charge amount on both ports so no charge or discharge. http://www.amazon.com/gp/product/B0088U4YAG/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1
On my nexus 4 and 7 it shows USB charging from apple port and ac from the other.
Also shows this for both ports
Reg00 0x32
Reg08 0x4c
Hope this info is useful.

paaco said:
Tried with this charger and neither port seems to work. Shows right around 0 for the charge amount on both ports so no charge or discharge. http://www.amazon.com/gp/product/B0088U4YAG/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1
On my nexus 4 and 7 it shows USB charging from apple port and ac from the other.
Also shows this for both ports
Reg00 0x32
Reg08 0x4c
Hope this info is useful.
Click to expand...
Click to collapse
0x32 is 500mAh, so it tries to draw this much, but if charge current in the battery is 0, that means there's not enough power left after what's used by tablet itself with screen on.
I have this problem with my iPhone chargers, not sure how the charger controller differentiates.
Big win for me is with a computer port, where with the app and a new kernel I can draw much more current and keep battery charging even with the screen on

verygreen said:
0x32 is 500mAh, so it tries to draw this much, but if charge current in the battery is 0, that means there's not enough power left after what's used by tablet itself with screen on.
I have this problem with my iPhone chargers, not sure how the charger controller differentiates.
Big win for me is with a computer port, where with the app and a new kernel I can draw much more current and keep battery charging even with the screen on
Click to expand...
Click to collapse
Ahh, I got you. It is nice having it charge from computer. Didn't know if your ultimate goal was to get it to work with as many chargers as possible so was trying to give you more info.
Either way, thanks for all the work you are doing and sharing to make our Nooks more enjoyable.

paaco said:
Ahh, I got you. It is nice having it charge from computer. Didn't know if your ultimate goal was to get it to work with as many chargers as possible so was trying to give you more info.
Click to expand...
Click to collapse
Yes, that was the original goal, but sadly doc does not match with the controller behavior, so current state is the best I could achieve at the moment.

Verygreen: I'm having a really hard time understanding what's happening with Nook charging.
When I plug into the original nook charger (and SOME other charges), the little light is YELLOW and the lightening bolt shows up in Android to indicate it's charging. However, it clearly charges slower in my portable charger (Monster cable charger) than with the nook charger.
It I plug it into apple compatible chargers (including my battery) the little light is GREEN rather than yellow. This is true even if I plug the nook cable into one of these a shorted cable (which will cause my Nexus 7 to go into high power charging mode).
http://www.ebay.com/itm/POWER-ONLY-...67?pt=Camera_Cables_Cords&hash=item58944a169b
Your system has two switches. "Force USB Charger Mode" and "Force 1A when charging". Your notes say ignore the Force 1A (second button)? I can't tell if the force usb charger mode does anything when the light is green. I get various numbers for battery current (seem to be all over the map)
In the monster charger, I get similar numbers whether Force USB is on or off, 100,000 - 200,000 current. I can't tell if it's better or not with Force USB on or off.
In the nook charger, I get around 700,000 current.
So it doesn't appear to be going into high power mode with Force USB in the Monster charger (which supports 1.5 amps).
In a windows usb port I get the green light and low charging current whether I enable or disable FORCE USB.
So, I'm confused.

I don't know if it's connected but it is certainly a battery issue which only presents itself on CM10.1 ... I mean I had it before in both stock and other roms but not nearly to that extend. Basically the rom seems to lose battery very fast and when it reaches 0% it simply switches off. If I boot at stock I can see I have around 40% left.
In other words battery is seriously misrepresented on CM and CM alone, other roms have nowhere near this kind of problem and every time I switch to them most of my battery issues solve themselves. It practically halves the battery life of the device for no good reason (ill-reporting). So VG, I guess it's better if you can take a look at it, it's something that I have seen reported by other people too, but it's quite of a hardle.
Your rom (CM) is basically the most complete but I always have to go elsewhere in search of/for battery life. It's the last big thing that needs to be solved and I think we're set. And -no- callibration never helps, it's not 100% that is misrepresented but 0%...
Thanks for your attention.

Stevethegreat said:
I don't know if it's connected but it is certainly a battery issue which only presents itself on CM10.1 ... I mean I had it before in both stock and other roms but not nearly to that extend. Basically the rom seems to lose battery very fast and when it reaches 0% it simply switches off. If I boot at stock I can see I have around 40% left.
In other words battery is seriously misrepresented on CM and CM alone, other roms have nowhere near this kind of problem and every time I switch to them most of my battery issues solve themselves. It practically halves the battery life of the device for no good reason (ill-reporting). So VG, I guess it's better if you can take a look at it, it's something that I have seen reported by other people too, but it's quite of a hardle.
Click to expand...
Click to collapse
I am not sure what do you mean by "other ROMs", there are only two roms out there, this and B&N stock. Everything else is based on one of the two kernels and userspaces (or sometimes combinations of thereof).
Also, is there a point in time you can think of when this problem started if it did not happen from the get go? Did 6/24 and prior exhibit premature empty battery detection?
I do not drain battery on my nooks as it takes too long and means I cannot do anything to them in the meanwhile.

verygreen said:
I am not sure what do you mean by "other ROMs", there are only two roms out there, this and B&N stock. Everything else is based on one of the two kernels and userspaces (or sometimes combinations of thereof).
Also, is there a point in time you can think of when this problem started if it did not happen from the get go? Did 6/24 and prior exhibit premature empty battery detection?
I do not drain battery on my nooks as it takes too long and means I cannot do anything to them in the meanwhile.
Click to expand...
Click to collapse
By other ROMs I mean SGT7, Carbon and stock. Using any of the three I have misrepresentation of battery life for anything below 15%, on CM I have misrepresentation all the time. It always existed as a problem but not in this level, it only became worse with the latest builds. Maybe it's hardware issue but why is it made whose by CM, basically that's what I'm asking...
I know without logs I'm not much help but for the time being I have reverted to carbon and all is well. In a few days I will retry CM and have my logs sent then. What I can safely say by looking at other people's battery graphs is that it happens to others too' maybe not as dramatically (for someone it went from 50% to 30% in one instant), but it is there...
I'm on HD+ BTW

UK Car Charger
Being unable to source a B&N car Charger in the UK - I am assuming that this mod allows me to charge from any 1 or 2 amp car charger..?
Also does it only work with CM10.0 as I am currently running CarbonROM - mainly for the improved PIE controls on Expaned screen mode..?

LucaToo said:
Being unable to source a B&N car Charger in the UK - I am assuming that this mod allows me to charge from any 1 or 2 amp car charger..?
Click to expand...
Click to collapse
I cannot promise "any".
I found that apple (and apple-devices targeting) charges generally don't work.
On the other hand chargers that target android devices seem to be working all by themselves without any tweak. My sample size is not too big, though.
Also does it only work with CM10.0 as I am currently running CarbonROM - mainly for the improved PIE controls on Expaned screen mode..?
Click to expand...
Click to collapse
depend on if the kernel support for it was added.

UK Car Charger
verygreen said:
I cannot promise "any".
I found that apple (and apple-devices targeting) charges generally don't work.
On the other hand chargers that target android devices seem to be working all by themselves without any tweak.
Click to expand...
Click to collapse
Sorry to be a pain but do you have any specific make/model car chargers that you could recommend (as most seem to be labelled as 'universal' regardless of whether they are intended for iPhone or Android)..?
Would an HTC or Samsung branded charger work for example..?

LucaToo said:
Sorry to be a pain but do you have any specific make/model car chargers that you could recommend (as most seem to be labelled as 'universal' regardless of whether they are intended for iPhone or Android)..?
Would an HTC or Samsung branded charger work for example..?
Click to expand...
Click to collapse
I don't have any experience with car chargers.
There's a high chance Samsung charger will work, I think.

[Q] My N8000 facing a problem about charging.

Hello, I'm a N8000 user. I'm facing a problem with my charging issue where my tab take a long time to charge and it takes 10 hours to get from 0-60 %. FYI, I'm using a custom rom CM 10.2. What is the main cause with the charging issue? Does it related with charging port, battery or charger itself? please help me. I'm stuck now.

[QUOTE8=syafix21;50085752]Hello, I'm a N8000 user. I'm facing a problem with my charging issue where my tab take a long time to charge and it takes 10 hours to get from 0-60 %. FYI, I'm using a custom rom CM 10.2. What is the main cause with the charging issue? Does it related with charging port, battery or charger itself? please help me. I'm stuck now.[/QUOTE]
Charger maybe, but most on here get a new factory cabel and that takes care of it.

syafix21 said:
Hello, I'm a N8000 user. I'm facing a problem with my charging issue where my tab take a long time to charge and it takes 10 hours to get from 0-60 %. FYI, I'm using a custom rom CM 10.2. What is the main cause with the charging issue? Does it related with charging port, battery or charger itself? please help me. I'm stuck now.
Click to expand...
Click to collapse
Many similar thread already here & also the solutions.
But let me answer anyway.
Charging problem occurs because of one or more things:
Broken Cable
Broken Charger
Incompatible Cable
Incompatible Charger
Broken Outlet
Broken Charging Port
Broken Battery
To properly charging a N80XX we need a charger & cable that can deliver 2.1A, 5V of electrical current & voltage.
The factory default/initial charger & cable designed to deliver these requirements.
Using custom/cheap cable or cable extension can cause charging problem as it wasn't designed to deliver the required current & voltage.
Most custom cables & chargers on the market designed only to deliver 500mA(0.5A) - 1A, 5V.
Broken cable/charger can also cause it to fail in delivering 2.1A, 5V to the device.
Try another original cable/charger combination to test if one of them or both are broken.
Also try another electrical wall outlet to see if the outlet is the culprit.
For Broken Charging Port, you can change it yourself by buying the spare part & replace the broken one, but it requires high technical skills.
One mistake can cause you to ditch your device.
It's safer if you send it to a qualified/authorized service center or if it's still under warranty you can send it back to samsung.
The last possibility is extremely rare.
Broken Battery symptoms are usually different than your problem symptoms.
If the battery is broken, usually the battery life is shorter than usual and may be won't charge at all or charging time is very short.
But if this is your problem, you can't sent it back to samsung - unless the battery is factory damaged -, as you need to change the internal battery.
Try to find out which one is your real problem & fix it
REMINDER:
2.1A is producing heat so much that hurt your skin if you touch the metal part of the cable heads directly right after a long period of charging.
The heat it produce is much more intense than if you are using 500mA or 1A charger.
Poorly designed custom cable/charger can be melted by the heat & may cause explosion!!
...and.....ALWAYS SEARCH BEFORE ASKING!!
I hope this will help

I'd like to add that I was facing similar problem.
In my case, the problem was a stock charger cable.
It was not "broken" (in the meaning of totally cracked or cut cable) but it seemed that it isn't providing a stable voltage. In result, I was able to load the battery only when not using the device (plus the process was as slow as hell), coz when using it, the consumed power was higher than provided by the charger.
Meanwhile, before the problem occured, I was testing other solutions to be able to make charging cord longer than provided stock, which is only 1m. Those tests included using of the additional 2m USB-USB expansion cable which I was plugging to the plastic charger element from the one side and to the regular charging cable at the second side. Such a combination resulted in similiar results as above - then, it became obvious for me that the tablet consumes or wants to consume so high power that low-quality USB cable can't handle, and - especially if it is 2m long - it's degrading onto his way to the tablet.
Then, I am not sure if n8000, by demanding so much power, is not degrading the cable (even stock one) itself. I must say, that after that, I was using another charger cables (n8000 dedicated, one 2m second one 1.5m, both not original) which started to work significantly worse in even shorter time such as two weeks after first use. I am not a electrician or hardware specialist, I dunno if it is possible to degenerate the usb cable with the voltage such as one needed for charging the tablet, but during my over 10 years of passion within mobile devices, I have killed no more than 2 chargers IN TOTAL. N8000 killed 3 charging cables within 8 months.
For some time, I use another combination - I use a 1,5 long A/C extension cord, with a handy "8" plug at the second end. This fits into the charger "central box" after you dissolve it into two parts. Now, the voltage will not degenerate onto this 1.5m distance, as the cable of that type was designed particularly for 230V transfers, but it will still be perfectly mobile. At the second side of the box, I do not plug back the 1m stock cable (or longer not-official ones), but a cable that the Samsung provided along with an external battery, which is possible to buy here and there... It is about... 20 cm long The purpose of this was to avoid the energy lossess that occured when using longer cables and preserve the maximum possible charging rate. Since then (and about 5 months has passed) I have no further problems with charging, and the battery life seems to be much more better than I supposed it to be after over a year of really extensive usage (the only issue of above solution is that the plastic box in the middle is making really really hot, but it is not a critical problem i suppose, as since 5 months it HASN'T melted, exploded or something )

hay....i have the same problem but this tablet doesnt get charging
i think its not about charger because it gives 5v and 2A after the usb flat but in battery connector i got no current and there is just less than 1V voltage

Galaxy 10.1 n8010 won't charge. Tried all solutions.

So I bought a cheap cable from eBay that converts microusb to the proprietary Galaxy connector on this device. Tried to charge the device but it entered a bootloop. Unplugged the cable and tried charging with the stock cable and left it overnight. Woke up and the device was completely dead.
Wouldn't boot at all.
Tore it open, unplugged the battery and plugged it back in. It booted! BUT the battery was critical and it shut off immediately. Tried charging again, no dice.
So I unplugged the battery and applied 4v to get some charge into it. Got the battery up to about 3.6V, booted again and it showed 3%. So in the time I had with the device turned on I tried both cables again but neither would charge the device. I used a multimeter to test the stock cable and it was all good, I even did a beep test between the 4 USB pins in the stock cable and the places they're wired up to inside the note and everything was fine so it's most likely not the cable.
Anyway the 3% is long gone now and I can't boot or charge. The device and battery are fine and definitely working, it just won't charge through USB no matter what. I've tried different power points, different adapters including stock and normal usb ports.
I've also cleaned both the plug and the jack with a toothbrush.
Could it be that the internal charging circuitry got fried when I tried the dodgy cable? If so, is there any way to fix/bypass this?
I'm at a complete loss so any help would be greatly appreciated.
Regards,
Nas.

I would not recommend to charge battery directly outside the device or even remove the battery at all.
First you gotta make sure your cables are capable of charge other galaxy devices if a friend has Tab 7 or Tab 10.1 or other note 10.1 or another try your cables to see if they really work.
Because it may just be your cable, remember batteries have their own circuits boards of sort and batteries are sometimes picky on how they are charge especially OEM batteries that are not suppose to ever be out of the device unless are change for a new one in a repair.
So first of all cable check it a must, again is not as simple as check if all the pins works as this is not a simple USB (Universal Serial Bus) port is a proprietary port and cable, check the port in the tablet too.
As well it may be just a defective battery or worst case even a board problem.

Unfortunately I have no other device to test it with. I might just buy another cable and see how I go.
I know about the circuits on the battery, but I always thought they were just there as a safety measure due to the potentially volatile nature of Li-Ion when it drops below a certain voltage. I'll probably take your advice and stay away from charging it externally, I only did it once to see if the tab died or it was just a dead battery. The voltage never dropped low enough to trigger the circuit to 'kill' it, evidenced by the fact that I could get it back up to 3% just applying a constant voltage.
I'm guessing you've hit it on the head with the last sentence, might be a board problem which would be quite sad. Silly reason for a great device to die.
Thanks a lot for the reply, I'll update this thread once I try an alternative cable for future reference.

Ok, So to update:
I've bought and tested 3 separate cables, all provide 4.99V inside the device, but none of this makes it to the battery so I'm fairly certain it's the charging IC that's dead.
I bought a new battery that was charged to 40% so I was able to flash the device to see if it was maybe the custom kernel messing something up. Flashed to stock via Odin, still not charging.
From what I've read, I need a cell balancing circuit (since the battery is 2-cell Li-Ion) and a charging IC. I've found a suitable IC for fairly cheap, but I'm not sure if the balancing circuit is necessary. The battery already has one of these inside, but I'm not sure if this is just for Voltage/Current protection or if it also balances.
MP24AG: http://eng.it-m.co.kr/cnt/prod/tep_5l/MP24AG.pdf
If anyone knows I'd be very grateful.

[Q] Charging w/ alternate chargers... a risk?

I bought a brand-new Nexus 5 a few weeks ago. However it came with a 0.85A wall charger which is LG branded... and some 'generic' cable that was included too. Used it twice, but it took around 8-10 hours just to charge 80% of it. I plugged my old Galaxy Ace USB cable to the LG charger and it reduced to two and a half hours, same with my alternate charger from the aforementioned phone (5.0V + 0.7A).
But this led me to a question: Is using alternate chargers with < 1.2A of output a risky way to charge my Nexus 5 battery? I saw somewhere that it might even damage the circuit board (a rare case) and I'm a bit worried about it.

Using a charger with a lower amperage output will take longer for the phone to charge. Also, using a cheaper cable will also lengthen the charge time as the cable can pass the full amount of power to the phone. This has been my experience with using oem cables vs dolls store cables me chargers.

audit13 said:
Using a charger with a lower amperage output will take longer for the phone to charge. Also, using a cheaper cable will also lengthen the charge time as the cable can pass the full amount of power to the phone. This has been my experience with using oem cables vs dolls store cables me chargers.
Click to expand...
Click to collapse
But... Will a Samsung wall charger with 0.7A of output damage my phone if I use it as my main charger? Because I also have a chinaphone which came with a bad charger and the Samsung one works fine.

No, the Samsung charger @ 0.7A will not damage the phone. I use a 1.0 A and 2.0 A Samsung charger with my N5 and it has been fine for months and months.

With the Samsung 0.7A charger, battery gets charged in 2:10 hours. I still don't understand it since I came from a low-end Samsung device which could complete its charge in about three hours (and that one had a 1500mAh battery...)

This is a tricky question, no doubt about it.
IMO, the cable quality is way more important than the current output (0.7 A, 0.85 A, etc).
I have a Samsung S4 charger with its cable (it seems very well built and it's thicker than other cables) and my N5 goes from 10% to fully charged in less than 3 hours.
Funny facts - happened to me:
- I had a very cheap cable (probably from China) that came with a battery bank. Surprisingly, it was the fastest way to charge my phone - reached almost 2.0 A. Later I found the trick: this cable doesn't have all the four wires, it only had two (positive and negative, without the data wires). I believe the data wires is used to perform some kind of amperage control; without it, no control was done and led to a very fast (probably dangerous) charging. I don't use this cable anymore, chances are that this nasty cable screwed up my notebook battery
- My N5 is almost two years old. Recently I had a problem with the Power button, the internal contact of the switch on the board was stuck 'pressed' and this led my phone to an endlessly force-reboot. I discovered this behavior after some google search and one of the possible causes of it is exactly the usage of a non-default / faster charger, it said that this could melt something - SOURCE
It makes sense, but I can't confirm this. I was able to fix this by smashing the phone on a table a few times (lol) and I'm still using a non-default charger
Can anyone confirm / say something about these facts?
For those who wants to see the diference between cables and chargers, give this app a try:
Play Store - Ampere
This app is a current meter, I use it on a regular basis and it is pretty reliable - the dev it's a XDA member and this app can be discussed here
Hope this helps!

You can not harm a phone with a 5 volt charger. The phone takes the amps it needs. More is better than less. I use 2 amp, 5 volt ones. As has been said the usb cable is the key thing. The better quality the better charge.