Database Info

[Q] 1.2 amp charger work on gtablet

I have a 12 volt 1.2 amp charger that fits into the DC in Jack. Can I use this to charge the Gtablet in an emergency (if I lost or broke my original charger) without damaging my Gtab? Want some expert opinions before I make the attempt. Rather be safe than sorry. Thanks in advance.

I'm no expert, but a little math tells you that the charger that you have will only output 14.4 watts VxA=W (12Vx1.2A=14.4W). Since the G-Tab is rated at 12V,2A or 24W you will be under powering it. If I remember correctly a 24V1A supply would work just fine as the output is still 24W. A 12V3A charger would work just as well, as it is designed to feed up to 36W. In this case it would only feed the 24W that the G-Tab pulls.
In the end it would still power the device, however the battery charging would come to a crawl as the the available output is 60% of the rated charger.
I'd be cautious though, as your 1.2A charger may get really hot trying to feed the G-Tab.
I'm sure that someone else can explain this more elegantly than I just did.

Given the lack of voltage it may not work at all. You need enough voltage to overcome any resistance in the circuit or the result is a lot of nothing, or just heat. Been awhile since electronics school though.
Sent from the awesome ZTab

Phantom_Midge said:
I'm no expert, but a little math tells you that the charger that you have will only output 14.4 watts VxA=W (12Vx1.2A=14.4W). Since the G-Tab is rated at 12V,2A or 24W you will be under powering it. If I remember correctly a 24V1A supply would work just fine as the output is still 24W. A 12V3A charger would work just as well, as it is designed to feed up to 36W. In this case it would only feed the 24W that the G-Tab pulls.
In the end it would still power the device, however the battery charging would come to a crawl as the the available output is 60% of the rated charger.
I'd be cautious though, as your 1.2A charger may get really hot trying to feed the G-Tab.
I'm sure that someone else can explain this more elegantly than I just did.
Click to expand...
Click to collapse
I wouldn't be charging while using the Gtab. It would be powered off so there would be no drain and should only be charging. In my layman thinking, it would be a safe charge but only at a slower time rate than a 2 amp charge. If it won't damage my Grab, I'll try it with it powered off. Is this a safe go?

I have one from a tv. It does not work. It makes the charging indicator flicker...

Phantom_Midge said:
I'm no expert,
Click to expand...
Click to collapse
Given the nature of electricity, always a good idea to know what you're talking about before you recommend a course of action, since improper advice can result in death and destruction of equipment. A two-lecture treatment of electricity in physics class that basically boils down to V=IR and P=VI is not sufficient for giving advice about things like this.
Phantom_Midge said:
but a little math tells you that the charger that you have will only output 14.4 watts VxA=W (12Vx1.2A=14.4W). Since the G-Tab is rated at 12V,2A or 24W you will be under powering it. If I remember correctly a 24V1A supply would work just fine as the output is still 24W. A 12V3A charger would work just as well, as it is designed to feed up to 36W. In this case it would only feed the 24W that the G-Tab pulls.
In the end it would still power the device, however the battery charging would come to a crawl as the the available output is 60% of the rated charger.
I'd be cautious though, as your 1.2A charger may get really hot trying to feed the G-Tab.
I'm sure that someone else can explain this more elegantly than I just did.
Click to expand...
Click to collapse
Please do not plug a 24V charger into a device that is supposed to take 12V. Bad things are likely to happen. At best, the GTab has internal protection circuitry to shut things off and prevent internal damage. If not, you're going to ruin the battery or cause things to blow up. It's like plugging your 120V hair dryer into a 240V outlet in Europe. Much smoke to follow.
Power (wattage) is not the relevant issue here. There are actually quite a few things that matter, but for the purposes of this discussion, voltage is the most important one. A 12V 1.2A charger *may* not be able to supply enough power to both run and charge the GTab, but it is unlikely to cause problems. I don't know the internals of the GTab specifically, but my guess is that it regulates the charging current, meaning you could also probably get away with a 12V 3A charger, though if the internal circuitry of the GTab is poorly designed, that might shorten your battery life.
As to your specific concern about heat on the 1.2A charger, heat production is a function both of the efficiency of the particular charger and the amount of power it produces. It's likely the 1.2A charger wouldn't get as hot as the 2A charger, given that its power output is 60% as much, unless it was significantly less efficient. Assuming, of course, that both were operating at maximum power.

ByByIpad said:
I have a 12 volt 1.2 amp charger that fits into the DC in Jack. Can I use this to charge the Gtablet in an emergency (if I lost or broke my original charger) without damaging my Gtab? Want some expert opinions before I make the attempt. Rather be safe than sorry. Thanks in advance.
Click to expand...
Click to collapse
Bottom Line, without all the Hype and Hyperbola....
Yeah, it'll work and destroy nothing, but will take longer to fully charge the battery.
Do not use the tab while it's connected.

ByByIpad said:
I have a 12 volt 1.2 amp charger that fits into the DC in Jack. Can I use this to charge the Gtablet in an emergency (if I lost or broke my original charger) without damaging my Gtab? Want some expert opinions before I make the attempt. Rather be safe than sorry. Thanks in advance.
Click to expand...
Click to collapse
I wouldn't use it. The GTab expects 2 amps to be available, and will not know to throttle the charge back to 1.2. You risk overheating or otherwise damaging the charger, which could then turn around and damage your GTab, depending on the charger's failure mode.
12v and at least 2 amp is what you need. More than 2amp is fine.
Jim

jmdearras said:
I wouldn't use it. The GTab expects 2 amps to be available, and will not know to throttle the charge back to 1.2. You risk overheating or otherwise damaging the charger, which could then turn around and damage your GTab, depending on the charger's failure mode.
12v and at least 2 amp is what you need. More than 2amp is fine.
Jim
Click to expand...
Click to collapse
Yes.
Lithium Polymer batteries require a CV/CC charging scheme. This means "Constant Voltage" and "Constant Current". One after another. Without knowing how the charging circuit is setup, you COULD damage the battery or the charging circuit by not supplying the appropriate power to the circuit.
To summarize.
1.) NEVER use a higher voltage supply, unless you are 100% sure the internal power supplies can handle that voltage. 24VDC = most likely really bad
2.) NEVER use a power supply that is under the rated current of the device. For good quality external AC/DC bricks, it's usually not a concern. For cheaply made, haphazardly designed bricks (mostly from China), this can cause fire.
3.) You can ALWAYS use a brick that is rated at MORE current. That's available current, not "I'm going to shove this current down your throat". Typically, bricks rated at a higher current will supply the required current at a higher efficiency anyway, so pending you don't care about the size increase, it's better. They also tend to supply cleaner power (voltage really), which is always a good thing.
That concludes todays electronics seminar. Class dismissed.

[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 ...

[Q] Is the miniUSB non standard?

I tried plugging in my mini usb cables I have used for other phones but it does not fit. It looks like the opening on the MT is larger then the standard. Is anyone else noticing this?

I've used all my other ones fine. I use a blackberry mini usb to charge while I sleep, another blackberry cable to hook to my laptop at work, and the one that came with it at my home desktop. No problems for me.

All my chargers work fine as well.

It uses microusb, not mini. The standard ones work fine.
Sent from my myTouch_4G_Slide using XDA App

It's not the volts, it's the amps....
Just as an FYI, one thing to watch out for even though the USB plug is standard is that the power output can be different on different chargers. 5v is the USB standard, but the amperage can vary. I think the Max is 1A for the USB (2?) spec, but I'm not sure if or what the Min amperage is. The V/A output should be listed on the charger.
The plug that comes with the mt4gs is 5V-1A. When I've tried charging phones (e.g. Blackberry) in the past with a 5V-.2A charger, it has worked extremely poorly (half charge after 12+hours). I would expect similar results with the mt4gs.

websculling is right. Additionally, using the wrong amperage to charge significantly decreases the number of charges you get out of your battery before it fails. Stick to chargers that have the amperage the battery was optimally designed to accommodate.

_atlien_ said:
websculling is right. Additionally, using the wrong amperage to charge significantly decreases the number of charges you get out of your battery before it fails. Stick to chargers that have the amperage the battery was optimally designed to accommodate.
Click to expand...
Click to collapse
So amperage is what matters with USB charger compatibility and not the voltage?
My wife's old feature phone came with a micro-usb charger so I'm trying to figure out if it will damage by MT4GS or the MY3GS I handed down to my wife.

fallenturtle said:
So amperage is what matters with USB charger compatibility and not the voltage?
My wife's old feature phone came with a micro-usb charger so I'm trying to figure out if it will damage by MT4GS or the MY3GS I handed down to my wife.
Click to expand...
Click to collapse
Both are important.
Too high of a voltage and you'll burn up the battery or damage the charging circuit.
Too low of an amperage (blackberry chargers) and you'll wear out the battery much more quickly. Trickling in power like that to these kind of batteries that weren't designed to handle it that way 'ages' the cells and reduces their already less then impressive lifespan.
Battery tech is better then it was even a few short years ago, but these kind of batteries in this small of a package are barely efficient enough to be useful. A few more years and things will be a lot better, but for the time being you should really try to care for your battery as best as you can and not abuse it.
I'll post the link here to the XDA battery writeup I linked to in both the anker and mugen threads later on when I get back to a real computer and am not using a phone app to browse the forums.
(Because babysitting a door you just painted and can't close right away is such an engaging task...lol)
Sent from my Bulletproof_Doubleshot using xda premium

Blue6IX said:
Both are important.
Too high of a voltage and you'll burn up the battery or damage the charging circuit.
Too low of an amperage (blackberry chargers) and you'll wear out the battery much more quickly. Trickling in power like that to these kind of batteries that weren't designed to handle it that way 'ages' the cells and reduces their already less then impressive lifespan.
Battery tech is better then it was even a few short years ago, but these kind of batteries in this small of a package are barely efficient enough to be useful. A few more years and things will be a lot better, but for the time being you should really try to care for your battery as best as you can and not abuse it.
I'll post the link here to the XDA battery writeup I linked to in both the anker and mugen threads later on when I get back to a real computer and am not using a phone app to browse the forums.
(Because babysitting a door you just painted and can't close right away is such an engaging task...lol)
Sent from my Bulletproof_Doubleshot using xda premium
Click to expand...
Click to collapse
This particular adapter is 5.1V and .7A.

fallenturtle said:
This particular adapter is 5.1V and .7A.
Click to expand...
Click to collapse
That's not too far out of spec, but I would rather let my battery die then use it, personally. Finding an AC adapter that is in spec is very easy and very cheap.
Something to note here is the doubleshot does not have a hardware regulated charging circuit inside the phone - this is the reason why it was rough with the early unofficial ClockworkMod recoveries and the source of their charging issues.
Knowing there is no hardware failsafe, it makes it that much easier to do permanent damage to the battery, device or both.
Do what you think is best, but just want you to have as much information as possible to base your decision on.

Blue6IX said:
That's not too far out of spec, but I would rather let my battery die then use it, personally. Finding an AC adapter that is in spec is very easy and very cheap.
Something to note here is the doubleshot does not have a hardware regulated charging circuit inside the phone - this is the reason why it was rough with the early unofficial ClockworkMod recoveries and the source of their charging issues.
Knowing there is no hardware failsafe, it makes it that much easier to do permanent damage to the battery, device or both.
Do what you think is best, but just want you to have as much information as possible to base your decision on.
Click to expand...
Click to collapse
That's good info to know. Do you know if Espresso is also lacking that hardware failsafe?

fallenturtle said:
That's good info to know. Do you know if Espresso is also lacking that hardware failsafe?
Click to expand...
Click to collapse
Unsure - this is my first smart-phone, so I don't have the history of knowledge a lot of people don't realize they possess and am playing catch-up as quickly as I can.
I know a lot about this device, and the Nook Color, but anything else is pretty foreign to me at this time.

Blue6IX said:
Unsure - this is my first smart-phone, so I don't have the history of knowledge a lot of people don't realize they possess and am playing catch-up as quickly as I can.
I know a lot about this device, and the Nook Color, but anything else is pretty foreign to me at this time.
Click to expand...
Click to collapse
Since you're new to Android, download and read this guide.
Sent via smoke signal.

blackknightavalon said:
Since you're new to Android, download and read this guide.
Sent via smoke signal.
Click to expand...
Click to collapse
That looks like a pretty helpful download. I don't have any social media accounts anywhere, so sometime later on i'll subscribe to get the link.
Thanks, I really appreciate you sharing that!

http://forum.xda-developers.com/showthread.php?t=669497
XDA write up on these types of batteries - the link I said i'd drop in this thread before.
Sorry, been busy around here, trying to find time to clean up all my loose ends.

Touchstone teardown / schematics, anyone?

Being the DIY kind of guy, I'm wondering if anyone tried to disassemble the Touchstone charger and post a schematic so that anyone with some electronics skills can make their own, in whatever shape or colour they desire.
Just wondering.

Ifixit has a pre touchstone tear down. They are similar, maybe you can request that site complete one on the TouchPad version.
I just looked mine over, there are no exposed screws. Any screws must be under the rubber foot, or the back may snap off. I'm not risking breaking mine. But, for $40 you could find out yourself
Sent from my Galaxy S II (i777)

All you need is a USB source with an output of 5.3V and 2A. But on that note, doesn't the higher level of amps charging the TP batteries more quickly kill the overall battery life of the batteries?
I use other brands of usb chargers unless i'm in a hurry, because the TP official charger will get it all juiced up in no time. Lower amperage, slower charging, longer overall battery life (i presume.)

teddyspaghetti said:
All you need is a USB source with an output of 5.3V and 2A. But on that note, doesn't the higher level of amps charging the TP batteries more quickly kill the overall battery life of the batteries?
I use other brands of usb chargers unless i'm in a hurry, because the TP official charger will get it all juiced up in no time. Lower amperage, slower charging, longer overall battery life (i presume.)
Click to expand...
Click to collapse
Not sure about the truth of that, because I think it has something to do with the actual cycles. I'm not 100% sure so if I'm wrong someone correct me.

The OP was referring to the wireless induction charging in the Touchstone, not just a generic USB charger.
As to the whole more amps = lower health battery debate, I won't touch that. I've seen "proof" both ways. What I know is the OEM charger is 5.3v at 2 amps. I am going to trust HP that is the proper specs. Plus, any "smart" device doesn't pull more amperage than it needs, so its software controlled.
Sent from my Galaxy S II (i777)

Indeed, I am not talking about the wired charger, I am talking about the wireless Touchstone charger.
50 USD wouldn't be a problem for a Touchstone. However HP hasn't brought Touchpad's or accessories in Romania and offer no support for them, and I don't want to wait for 2 weeks for delivery.
And I also am the DIY kind of guy, and in the near future I'll be designing and building a custom desk which I would like to include a nice built-in stand for the Touchpad.

teddyspaghetti said:
All you need is a USB source with an output of 5.3V and 2A. But on that note, doesn't the higher level of amps charging the TP batteries more quickly kill the overall battery life of the batteries?
I use other brands of usb chargers unless i'm in a hurry, because the TP official charger will get it all juiced up in no time. Lower amperage, slower charging, longer overall battery life (i presume.)
Click to expand...
Click to collapse
Any old 5.3v/2A source will not give 2A to the TP. The device relies on switch signaling on the data lines which aknowledges that it is connected to the correct (ie HP barrel) charger and this allows the full charge rate to be applied.
In all other cases the charger only gives a low level trickle charge with the resulting longer charge times.
LiPo batteries and their charging profiles are very efficient and are perfectly capable of handling higher charging currents without detriment.
If they become very drained these higher currents are required to start the charge cycle whereas lower power chargers would not.

This thread is not about charge current or cycles, not sure why you haven't gotten a real answer yet, so I decided to register to give you one.
Even if you had the schematics and a source for the components, winding the coil for the inductive charging would be your biggest issue. At best it probably wouldn't be efficient enough to be worth it and it would likely take a long time to charge if it did at all. All the parts and work it would take for a kind of crappy result wouldn't be as good as just spending the $50 or whatever.
That's the negative side though, so don't get me wrong. If I could I'd totally be building one myself as well. I wish more people were into DIY stuff like this. I also really like the idea of building it into a desk and you may be able to do that with an official Touchstone charger.

FjarrKontroll said:
This thread is not about charge current or cycles, not sure why you haven't gotten a real answer yet, so I decided to register to give you one.
Even if you had the schematics and a source for the components, winding the coil for the inductive charging would be your biggest issue. At best it probably wouldn't be efficient enough to be worth it and it would likely take a long time to charge if it did at all. All the parts and work it would take for a kind of crappy result wouldn't be as good as just spending the $50 or whatever.
That's the negative side though, so don't get me wrong. If I could I'd totally be building one myself as well. I wish more people were into DIY stuff like this. I also really like the idea of building it into a desk and you may be able to do that with an official Touchstone charger.
Click to expand...
Click to collapse
While the OP was not about charge current or cycles I do sincerely hope that you understand the value of correcting misinformation and wrong assertions about any aspect that may raise it's related head in these threads.
To jump into a thread and the forum with such a comment is perhaps an indication of the levels of accepable politeness at large in the world today.
But I for one don't take too kindly to it.
But then us 'older' members may be a little too sensitive.
Any impropriety and the mods will deal with it!

How much over 5v. can the nexus 5 take

Moved from general sorry
I just bought a Anker 24W / 4.8A Dual-Port Car Charger. I bought this to replace a cheap $2 charger that I did not want to use on my nexus 5
I just tested the anker charger and it puts out 5.24v-5.29v. I know that does not sound like much but all my other chargers AC wallwarts, and even the cheap $2 car charger all put out 4.95v-5.02v.
Should I go a head and use this anker car charger or should I return it? Thanks.

That's just how much the charge puts out. The phone may not accept that much input.
Sent from my SAMSUNG-SGH-I337 using xda app-developers app

Typically there is a boost/buck or other relatively efficient voltage regulator in the phones that manages the battery charging, so the 5% "over-voltage" that you are seeing shouldn't be an issue.
I'm guessing you measured that with no load -- most wall-warts run a little high without load, and then a little low at full load, so they can claim good regulation (+/-5%, for example) and a high current capacity. The change is due to internal resistance of the supply, something that you can compensate for, but can't ever get rid of.

LZLandingZone said:
That's just how much the charge puts out. The phone may not accept that much input.
Sent from my SAMSUNG-SGH-I337 using xda app-developers app
Click to expand...
Click to collapse
Only when talking current. Voltage is completely different.

jeffsf said:
Typically there is a boost/buck or other relatively efficient voltage regulator in the phones that manages the battery charging, so the 5% "over-voltage" that you are seeing shouldn't be an issue.
I'm guessing you measured that with no load -- most wall-warts run a little high without load, and then a little low at full load, so they can claim good regulation (+/-5%, for example) and a high current capacity. The change is due to internal resistance of the supply, something that you can compensate for, but can't ever get rid of.
Click to expand...
Click to collapse
Thanks,
No I measured with a load. I have a voltage current usb meter.
http://dx.com/p/usb-av-usb-power-current-voltage-tester-translucent-blue-silver-235090#.Uu2NRXddWLc
I just did another test. This time with my phone almost at 95% full. I got 5.33v while sucking down 332mha.
Im sending it back. I tested every charger brick and several other devices in my home. nothing came even remotely close to 5.3v
USB specs are 5.0v +-0.25% so I should see no more then 5.25v.