Develop Bugs

[Q] Charging Speed - Different from a/c than from USB?

So I was wondering: is there a difference in charging speed between the a/c wall charger and charging from my computer's USB port? Also, what's the difference between different chargers? For example, the Desire comes with a charger that puts out 1 amp. My girlfriend's BlackBerry has a micro USB charger as well, but the output is 700 mAh, or 0.7 amp. I've seen chargers ranging from 500 mAh (0.5 amp) to 1200 mAh (1.2 amp). How does this equate to charge time? Does it even? Or does the phone regulate the charge rate?

Benny_L said:
So I was wondering: is there a difference in charging speed between the a/c wall charger and charging from my computer's USB port? Also, what's the difference between different chargers? For example, the Desire comes with a charger that puts out 1 amp. My girlfriend's BlackBerry has a micro USB charger as well, but the output is 700 mAh, or 0.7 amp. I've seen chargers ranging from 500 mAh (0.5 amp) to 1200 mAh (1.2 amp). How does this equate to charge time? Does it even? Or does the phone regulate the charge rate?
Click to expand...
Click to collapse
You've pretty much answer your own question!
The current supplied by a charger/USB port determines how fast it can charge the battery, which is why the wall charger (1amp) charges much faster than a PC USB port (0.5 amps).
Regards,
Dave

It's almost completely logical.. say you have a 1.5A battery (1500mA) and a 500mAh charger (ie USB) then it will take 3 hours for it to charge but with a 1000mAh charger it will take an hour and a half.
Can't really explain it more than that, so hth.

Well , Yes and No
This is only partly true ......
If you charge it on the PC , max output is 0.5 amps , and data is possible while charging .
Now with Desktop and car charger , the amp can be anything the manufacturer likes but you have to keep the following in mind :
USB Specs state the following :
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In Battery Charging Specification,[32] new powering modes are added to the USB specification. A host or hub Charging Downstream Port can supply a maximum of 1.5 A when communicating at low-bandwidth or full-bandwidth, a maximum of 900 mA when communicating at high-bandwidth, and as much current as the connector will safely handle when no communication is taking place; USB 2.0 standard-A connectors are rated at 1500 mA by default. A Dedicated Charging Port can supply a maximum of 1.8 A of current at 5.25 V. A portable device can draw up to 1.8 A from a Dedicated Charging Port. The Dedicated Charging Port shorts the D+ and D- pins with a resistance of at most 200Ω. The short disables data transfer, but allows devices to detect the Dedicated Charging Port and allows very simple, high current chargers to be manufactured. The increased current (faster, 9 W charging) will occur once both the host/hub and devices support the new charging specification.
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
So if your Desire ( Yes , the Desire supports these specs ) detects the short , it will switch to fast charging mode otherwise it will limit the charging current .
Unfortunately , there's no way to know , just by looking at a charger, if it respects the specs or is just a low cost 5V powersupply . I've encountered quite a few ( mostly lowcost) desktop and car chargers that are rated between 1 and 2 amps , but still take bl**dy ages to charge the phone . Checking those with a measuring tool , you usually see the data pins are "Not Connected" instead of being shortened :-(((
Final Word .... don't try to save some money on a cheap charger , you'll regret it Genuine HTC works great , others do the same , but don't expect a $1 charger from Hongkong or whereever to do it !

These are the theoretical specs. Keep an eye on charger efficiency ratings and battery charge absorption won't be 100% in any case. Also bare in mind the charge is not linear, it will trickle after approx 80-90% with this phone.
-----------------------------------
- Sent via my HTC Desire -

th3 said:
These are the theoretical specs. Keep an eye on charger efficiency ratings and battery charge absorption won't be 100% in any case. Also bare in mind the charge is not linear, it will trickle after approx 80-90% with this phone.
-----------------------------------
- Sent via my HTC Desire -
Click to expand...
Click to collapse
Ya, I noticed the charge slows down considerably for the final 10-15 %
I find myself charging my Desire more than I actually use it, lol.

I found now the answer to this problem: I use a Nokia charger (5v and 890 mA) with a microusb adapter. You can find one on eBay at ~2$
Now it takes about 2 hours from 20% to 100%
Lets hope nothing wrong happens to my precious Desire

look here for a method to charge at ac speed from usb, explains a few things too.

[Q] Charging Current

Hi All,
Was wondering if anyone knows the maximum current the SGS2 can draw for charging purposes. I had a look at the wall charger provided with it, and it's 0.7a; it takes forever (my opinion) to charge compared to my last phone. Just wondering if it is worth my while investing in a more powerful charger.
Cheers

If you take the battery out and look and the sticker then it says there 1000mA

Excellent thanks; Can't get the back off my phone (fingernails).

oozrafa said:
If you take the battery out and look and the sticker then it says there 1000mA
Click to expand...
Click to collapse
Also, at the start of the SGS2 charging cycle, my wall-plug power meter reads 5.1 W.

5.1 is what the adapter is pulling. All of that isn't getting to the phone. Funny thing for my is the phone charges faster off my blackberry 0.75a charger then it does off my Galaxy I 1a charger.
Sent from my GT-I9100 using XDA Premium App

Someone in another thread mentioned seeing something in the source code about the phone drawing at most 650 mA (instead of a more typical 1000 mA) during charging. If that's the case, a more powerful charger by itself won't help; you'd also need a custom ROM that doesn't limit the charge current.

Does anyone know why Samsung would limit the charge current?

theinstagator said:
Does anyone know why Samsung would limit the charge current?
Click to expand...
Click to collapse
Speculation is that its a heat related problem. Don't want to pull a Sony and have the batteries explode on people... (but again, that's speculation)

Murfle said:
Speculation is that its a heat related problem. Don't want to pull a Sony and have the batteries explode on people... (but again, that's speculation)
Click to expand...
Click to collapse
I also heard that a smaller charging current extends the Li-ion battery's lifetime, even though I'd prefer quicker charging as the battery can be replaced with ease.

I second that. I tried it today with a 1A car charger (USB cig. plug) can't say it made a difference on speed of charge compared to wall one.

Just received my SGSII and the charging is extremely slow. 3+ hours = about 500 mAh, on a 1A wall charger. Never had such a slow charging smartphone before

To change i9100 charging current you have to short r529 or r531
Current limit will change to 1000mA
You can use 2A charger and phone will charge only with 650mA current
But after this short one of those resistors current limit will change to 1A
I use it on my phone and all is fine. Current after change is measured.
Wath this film youtube.com/watch?v=FL71G2YEIHU
Make shortcut of resistor and check your new current and feel the difference.

Is there a logfile, where I can see which charge current is used?
I have the suspicion, that my noname charger is not recognized properly and it only charges with USB current (450mA).

hmm a 1000mA current could be used also for the 2000mAh battery?

Yes, should not depend on the capacity of the battery.
Sent from my GT-I9100 using xda app-developers app

good
thank for all, it help me so much

1000mA is more likely the maximum current that the phone is expected to drain from the battery.
It is not the battery charging current, which is presumably equal to the mentioned 650mA, since the 1650mAh battery charges in about 4 hours.
If the charging current was actually 1000mA, then the 1650mA battery it would charge in 2 hours or so, but as we all know, it is not so, even with a 2A charger.

mine took about 4 hours charge the battery

The charging time depends on the Charger and Rom i use, i havent figured out for what reason.
Sometimes the SGS2 is charged in approx. 1 hour and with other Roms the charging time may take up to 3h.

kirschi said:
The charging time depends on the Charger and Rom i use, i havent figured out for what reason.
Sometimes the SGS2 is charged in approx. 1 hour and with other Roms the charging time may take up to 3h.
Click to expand...
Click to collapse
Definately 650ma, IF the phone detects an High current USB port, otherwise it falls back to lousy 400ma.
You can trick into 650ma always: take a usb cable, cut from the PC plug side the TX/RX cables, on the other side short them on PHONE plug side these two cables.
Phone will now always go into "AC charging mode". Don't worry (too much) for your USB ports, they can all well 1000ma, and the one that cannot will report "high current detected, port disable".
:fingers-crossed:

Compatibility with Nokia fast microUSB chargers

The Samsung charger adapter which comes in the box is very slow in nature. It take more than 2 hours to charge my phone. I was wondering if I can use the following Nokia brand chargers which are fast chargers?
Nokia Charger Adapter CA-146C
Nokia Fast Micro-USB Charger AC-10

It won't make any difference the phone decides what current it draws from the charger, so it'll take just as long to charge.

Are you really sure about this? Can you link me to some articles which confirm this.
Even I was thinking about purchasing AC-10 charger from Nokia.

How fast is the nokia charger?
0-10% -> 100% in an hour or less?

Joey2o11 said:
It won't make any difference the phone decides what current it draws from the charger, so it'll take just as long to charge.
Click to expand...
Click to collapse
I'm not sure about this. I have a friend with a Blackberry Playbook and he reckons his phone charges much faster if he uses the charger from that.
The "stock" S2 charger is 700mA - it doesn't take a genius to work out that for a 1650mAh battery this will take about 2.5 hours to fully charge the battery under ideal conditions (phone off) or anything from 3-6 hours with the phone on, depending all what's running or if you're using the phone while it's charging.
Which is all pretty ridiculous - ok we're comparing apples and oranges when we compare a S2 to the likesw of a Nokia, but I do miss the days when I could charge my phone in an hour and have it last two or three days. I thought my Blackberry was bad but at least I can usually squeeze a full day out of it...
The only wall wart I had lying around that was more than 700mA was a 5V 2A supply. I've tried with that which works, but the phone chokes with a "battery overtemp" warning after about 10 minutes - which tells me I AM pumping more into the battery than it can handle. This would suggest that there IS a happy medium where we can optimize the battery charge time - I'm bust looking for a 1A supply...

I have TWO AC-10Xs, and am using it with the Ninphetamene kernel (which comes with increased charge input mods to 800ma) fine. Charges to full in about 2.5-3 hours.
I've never gotten overcharge errors either.

Hi,the usage of more powerful charger will eventually reduce lifespan of your battery. This comes from basic physics, materials and so... Higher mA means faster current, which wear the material of the capacitor - battery.

I have capdase 2 USB car charger that was used for my old iphone device.
It outputs 1A.
is it safe to use it?
I tried to charge with it for 10-15minutes or so, and didnt recognize any suspicious warmups...it reached 41~degrees while at the moment im charging and using it as a hotspot and its on 38 degrees.

DobermanS said:
Hi,the usage of more powerful charger will eventually reduce lifespan of your battery. This comes from basic physics, materials and so... Higher mA means faster current, which wear the material of the capacitor - battery.
Click to expand...
Click to collapse
The phone (specifically, the kernel) limits charge coming in, and there MUST be hardware limiters on the batteries and the phone themselves (which, in some cheapo batteries DON'T WORK and results in them frying themselves and the phone in process) and the batteries are replaceable anyway.

eranyanay said:
I have capdase 2 USB car charger that was used for my old iphone device.
It outputs 1A.
is it safe to use it?
I tried to charge with it for 10-15minutes or so, and didnt recognize any suspicious warmups...it reached 41~degrees while at the moment im charging and using it as a hotspot and its on 38 degrees.
Click to expand...
Click to collapse
i use htc wall charger rated at 1A and having no proplem with ,a pc USB port is capable of 1A and we all know there are no problem ,even so there are no visible improvement in charging time because as someone said the charging current is automatically regulated

ledavi said:
i use htc wall charger rated at 1A and having no proplem with ,a pc USB port is capable of 1A and we all know there are no problem ,even so there are no visible improvement in charging time because as someone said the charging current is automatically regulated
Click to expand...
Click to collapse
That's good to know that the current is regulated by the device.
Is there a software to see what is the current taken by the phone?
As long ad the temperture isn't higher than 45degrees is it ok?
By the way, Im pretty sure that usb outputs 0.5A and not 1A
Sent from my GT-I9100 using XDA Premium App

battery monitor widget

It seems logical to be able to use all chargers as smartphones all have micro usb .
(I 'm not sute that's mean something in english, sorry)

Great widget! thanks.
I really like the data it gives!
Sadly, while charging with my .7A original charger & meanwhile giving a hotspot to my laptop, it shows that only 76mA comes in!
hehe, gonna take forever to charge the battery this way.

i doubt this. i'm still worried about the compatible problem~~~

After two days with the battery monitor widget Im affraid itself it drains the battery.
could it be it affects the battery?
settings are regular, it monitors changes every 60seconds

Let's see if I can help make things a bit clearer. Feel free to correct where I may be off.
The Nokia thing, it's not a charger. It's a power supply.
The "charger" is built into your phone, hardware-wise.
How can I prove it?
Take the Samsung supplied cable, plug it into your computer. You'll see that your phone is charging too. No, the cable is not a charger. Do you think your computer is a special built charger for your phone? Hardly.
The charging circuit is within the phone, and thus charging the battery when there's available power.
Ok, so we have the charger (i.e. the mobile phone), we have the battery, we need the power. Where do we get power from? The wall adapters (or computers). So what are the wall adapters? Ratings of 1000mah means that the wall adapter can provide up to 1000ma per hour.
However, your charging circuit will determine how much current to actually draw. For example, drawing 800mah for 10 min may raise the temperature to 55 degrees, so after 10 min the charging circuit drops the charging current to 500mah.
Of course, if you're using el cheapo cables, some cables may not be able to support the current draw and you may find that even with 20000000mah power supplies your phone can only draw 100mah.
The SGS2 heats up pretty easily, and it doesn't quite draw beyond 700mah. The circuit built into the phone doesn't allow it to, if i'm not wrong. If your phone is overheating while charging, you better change your case as it's going to cause your phone to overheat sooner or later.
Using a 20000000mah power supply isn't an issue, because the charging circuit within the phone will be able to draw only a certain amount.
Me, I plug my SGS2 into a 2Ah charger every night to charge, and yes it's perfectly fine. I'm only upset that after buying an expensive 2A charger, I realised that the phone is not able to draw high currents (phone even heats up to 55degree Celsius when charging).
Charging the phone on a ice pack (which lowered the phone temperature to 16 degrees while charging) didn't increase the amount of current drawn by the phone, even on a 2A power supply.
My humble advise is, stick with the stock power supply, or at most get a 1A version. No need to splash for a 2A power supply. If you really need faster charging, get a battery charging dock.

eranyanay said:
After two days with the battery monitor widget Im affraid itself it drains the battery.
could it be it affects the battery?
settings are regular, it monitors changes every 60seconds
Click to expand...
Click to collapse
yes of course it does. It consumes a certain amount of ma per hour, doesn't it?
Personally, there's a app called watchdog, look for it, IMHO it helps to catch rouge apps better, and manage battery better.

I thought the whole idea of having a universal micro USB charging connection across most good brands was so you could use other chargers!

moooxooom said:
yes of course it does. It consumes a certain amount of ma per hour, doesn't it?
Personally, there's a app called watchdog, look for it, IMHO it helps to catch rouge apps better, and manage battery better.
Click to expand...
Click to collapse
Well I just like the widget, which shows me also the battery temperture
I hope it doesnt takes too much

[Q] charging: max/optimal current on 5v input?

I've tried to find the maximum current that the nexus will draw, without any luck.
some people have said that the galaxy s 2 draws a max of 1A because the phone itself says 1A, but thats wrong, as it says 1A on 3.7v, clearly talking about the input the phone draws from the battery... not the charging circuit... other people say the galaxy s2 limits current to 650mA for heat/safety reasons... I have no reason to believe or disbelieve this.
Getting back to my question, what's the max current that the charging circuit will take, I know the AC/DC adapter that came with my gsm gnexus is 1A/5V, but that may be more than enough, or not as much as the nexus could handle.
I ask because there are many 5v ac/dc converters that output more than 1A, some over 2A... would the nexus charge faster with this much current, and would it be good/bad for the battery?
this could be easily tested if someone has access to an EE LAB, giving the phone 5v, and seeing how much current it takes... would need a DC volt supply capable of >10W (5v/2A).

8steve8 said:
I've tried to find the maximum current that the nexus will draw, without any luck.
some people have said that the galaxy s 2 draws a max of 1A because the phone itself says 1A, but thats wrong, as it says 1A on 3.7v, clearly talking about the input the phone draws from the battery... not the charging circuit... other people say the galaxy s2 limits current to 650mA for heat/safety reasons... I have no reason to believe or disbelieve this.
Getting back to my question, what's the max current that the charging circuit will take, I know the AC/DC adapter that came with my gsm gnexus is 1A/5V, but that may be more than enough, or not as much as the nexus could handle.
I ask because there are many 5v ac/dc converters that output more than 1A, some over 2A... would the nexus charge faster with this much current, and would it be good/bad for the battery?
this could be easily tested if someone has access to an EE LAB, giving the phone 5v, and seeing how much current it takes... would need a DC volt supply capable of >10W (5v/2A).
Click to expand...
Click to collapse
I dont know the answer to your question but my nexus eats amperage like it is going out of style. I can charge from almost empty to full in about 90 minutes.
Sent from my Galaxy Nexus using xda premium

@rbiter said:
I dont know the answer to your question but my nexus eats amperage like it is going out of style. I can charge from almost empty to full in about 90 minutes.
Sent from my Galaxy Nexus using xda premium
Click to expand...
Click to collapse
Given the battery is 1850 mAh you are drawing a minimum of 1.85Ah/1.5h = 1.233 amps. Since your battery wasn't completely dead, you are drawing slighlty more.
But was the limit the Galaxy Nexus, or the charger? Also, if one were to use navigation or other power hog while in the car, the current draw should be greater without only some of that going to charge the battery.

[email protected] said:
Given the battery is 1850 mAh you are drawing a minimum of 1.85Ah/1.5h = 1.233 amps. Since your battery wasn't completely dead, you are drawing slighlty more.
But was the limit the Galaxy Nexus, or the charger? Also, if one were to use navigation or other power hog while in the car, the current draw should be greater without only some of that going to charge the battery.
Click to expand...
Click to collapse
if he has the GSM galaxy nexus, the battery is 1750 mah, and assuming his device was off or idle during this time, then the current you calculate is not a minimum, it's a maximum... if the battery was half full to start, then 90 minutes were spent charging half of the capacity, so the current was actually half of the amount you calculated.

to answer this question someone needs a nearly empty battery in a galaxy nexus, with the device off (just to be sure we are only measuring charging current, although most likely it is circuit limited, and not battery limited, so it probably wouldn't matter)...
Then they should try charging it with a 5V DC power source with unlimited current, with a way to monitor the current.
most charging circuits for these type of batteries are current limited, then voltage limited, so the battery must be close to empty so we are sure we are monitoring max current... the latter part of the charge is voltage limited and in the end is very small amounts of current.

I am getting a new usb 2.0 hub soon. I didnt know there was a bc 1.1 compliant device standard, aka battery charging 1.1, that allows charging at 1.5amps. But i think this applies to powered hubs, since usb 2.0 technically only allows 500ma, and of course charging from a computer will only allow 500ma. Samsung recent smartphones allow this type of charging, so im sure nexus can utilize it. And yes, sgs2 was limited to 650mah charging for some reason. I never followed up on if devs overcame the limitation. The sgs2 crowd turned me off from the device because of their elitist attitudes.
Crazy world, ay?

@rbiter said:
I am getting a new usb 2.0 hub soon. I didnt know there was a bc 1.1 compliant device standard, aka battery charging 1.1, that allows charging at 1.5amps. But i think this applies to powered hubs, since usb 2.0 technically only allows 500ma, and of course charging from a computer will only allow 500ma. Samsung recent smartphones allow this type of charging, so im sure nexus can utilize it. And yes, sgs2 was limited to 650mah charging for some reason. I never followed up on if devs overcame the limitation. The sgs2 crowd turned me off from the device because of their elitist attitudes.
Crazy world, ay?
Click to expand...
Click to collapse
yeah I'm trying to buy the best ac adaptor for my nexus, but finding info is difficult.. the one that came with my nexus is for europe, and is 5v/1A, but it may not be the optimal current. The market seems to have many adapters capable of 0.5A, 750mA, 850mA, 1A, and 2.1A (marketed for ipad)...
will the nexus benefit from a 2.1A ac/adapter even if it doesn't 'need' it?

The Nexus charger is rated at 1 amp. I'm using my Captivate charger at work, which is rated at .7 amps. I'm thinking just because the Nexus charger is rated at 1 amp, that doesn't meant the Nexus is actually drawing that much power. Anyway, the Captivate charger I have seems to work fine.
Any issues here?

8steve8 said:
yeah I'm trying to buy the best ac adaptor for my nexus, but finding info is difficult.. the one that came with my nexus is for europe, and is 5v/1A, but it may not be the optimal current. The market seems to have many adapters capable of 0.5A, 750mA, 850mA, 1A, and 2.1A (marketed for ipad)...
will the nexus benefit from a 2.1A ac/adapter even if it doesn't 'need' it?
Click to expand...
Click to collapse
Just get a 1amp charger. It is plenty, on the safe side and fast fast fast for the nexus. With a 1a Motorola charger I have it charges 1% a minute when I am not using phone. I got that powered hub yesterday. Charging the nexus off of it was about 1.5% a minute and I didn't see battery go above 33 degrees Celsius.
Sent from my Galaxy Nexus using xda premium

let me clarify that im not worried about what will "work" im looking for what's the ideal charger...
yes 0.7A will charge it, so will 1A, but the actual max current draw is still what I'm asking.

http://www.reddit.com/r/GalaxyNexus/comments/nvgt4/chargers_3000ma_worth_the_risk/c3cb636
http://www.reddit.com/r/Android/comments/nystt/galaxy_nexus_power_analysis_why_chargers_cant/

I measured the charging current at just less than 0.5A with the phone on and off. I too was thinking that a higher capacity charger would speed charging.
1 amp chargers are more than adequate. I did this check with the battery at 80%.

طوني تبولة said:
http://www.reddit.com/r/GalaxyNexus/comments/nvgt4/chargers_3000ma_worth_the_risk/c3cb636
http://www.reddit.com/r/Android/comments/nystt/galaxy_nexus_power_analysis_why_chargers_cant/
Click to expand...
Click to collapse
Thanks for these threads. I was curious, too, if it does any good or harm to my GN if I plug it into the 2.1A plug of my power bank.

not that i care if i break too but if there some way where i can use my 2.1 amp wall charger to fast charge my phone and use 2.1 amps rather than 1 a

StarTech USB Y Cable *Double your charging speed*

I haven't seen anybody mention this yet here on the forum, so I went ahead and bought one and tried it myself.
http://www.amazon.co.uk/dp/B0047AALS0/ref=asc_df_B0047AALS09152658?smid=A1AUCPBF2P18HS&tag=googlecouk06-21&linkCode=asn&creative=22218&creativeASIN=B0047AALS0
This is a USB Y cable. Two USB type A plugs to increase charge capacity from 500mA to 1A.
I use Siyah kernel with STweaks to change USB charge capacity from 500mA to 900mA, I am currently looking for a way to increase this to the full 1A.
Only £3.99 from Amazon. Tested using CurrentWidget. Charging now at 900mA.

danieljamie said:
I haven't seen anybody mention this yet here on the forum, so I went ahead and bought one and tried it myself.
http://www.amazon.co.uk/dp/B0047AAL...de=asn&creative=22218&creativeASIN=B0047AALS0
This is a USB Y cable. Two USB type A plugs to increase charge capacity from 500mA to 1A.
I use Siyah kernel with STweaks to change USB charge capacity from 500mA to 900mA, I am currently looking for a way to increase this to the full 1A.
Only £3.99 from Amazon. Tested using CurrentWidget. Charging now at 900mA.
Click to expand...
Click to collapse
Can't you just buy a 1mA output charger. I have chargers that will fully charger my phone in about 1hr and 30min.
Sent from my SPH-L710 using xda premium

smark72 said:
Can't you just buy a 1mA output charger. I have chargers that will fully charger my phone in about 1hr and 30min.
Sent from my SPH-L710 using xda premium
Click to expand...
Click to collapse
It's designed for PC's and Laptops which only output 500mA on their USB ports.

Would work really well with the KiDiGi Cover-mate Dual Desktop Cradle, too bad it is a tad to expensive seeing that it is just a cable

Hey i have this cable which came with my 2.5 HDD external case. In some places i need to connect both cables to power the HDD so you think it will work same with S3? Also will it not damage it?

Exactly what I was looking for
danieljamie said:
I haven't seen anybody mention this yet here on the forum, so I went ahead and bought one and tried it myself.
This is a USB Y cable. Two USB type A plugs to increase charge capacity from 500mA to 1A.
I use Siyah kernel with STweaks to change USB charge capacity from 500mA to 900mA, I am currently looking for a way to increase this to the full 1A.
Only £3.99 from Amazon. Tested using CurrentWidget. Charging now at 900mA.
Click to expand...
Click to collapse
this was exactly what I was looking for.. Thanks a lot.. I also has Siyah kernel, and many USB 2 ports available at work, and like to keep my AC charger at home.

This cable won't give you 1A. I guess the second USB plug has no data connection (how could it? ) and without a registered USB device a USB port gives only a few mA of power.

It does work with 2.5" harddrives that need more power than one USB port can deliver. Why shouldn't it work with the s3?
But why would you need that when you are charging your phone at work? It's not like you're in a hurry. It can sit there all day.
And I wouldn't try to charge it with 1A or more just to save a little time. The charger you get with the s3 an the s3 itself are made for 900mA. That's why the kernel is limited to 900mA aswell. You might damage your phone by charging it with a higher current. Sure, there is a safety margin build in but going to the limit seldom is a good idea.

weisselstone said:
This cable won't give you 1A. I guess the second USB plug has no data connection (how could it? ) and without a registered USB device a USB port gives only a few mA of power.
Click to expand...
Click to collapse
This was correctly answered back in August (above). What does data have anything to do with current? It simply has 2 plugs so that it can draw more current (mA).
shamez23 said:
It does work with 2.5" harddrives that need more power than one USB port can deliver. Why shouldn't it work with the s3?
Click to expand...
Click to collapse
This.
shamez23 said:
But why would you need that when you are charging your phone at work? It's not like you're in a hurry. It can sit there all day.
And I wouldn't try to charge it with 1A or more just to save a little time. The charger you get with the s3 an the s3 itself are made for 900mA. That's why the kernel is limited to 900mA aswell. You might damage your phone by charging it with a higher current. Sure, there is a safety margin build in but going to the limit seldom is a good idea.
Click to expand...
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No, you can't damage it that way. Electronic devices DRAW current, which means that they only take as much as they are able to. You can plug your phone into a 5A charger and it wouldn't damage it. Too much voltage WILL fry it though.

Are you sure about that?
I've read more than once on tech sites that for example the 2A charger of the iPad will charge other devices that come with weaker chargers faster but that they advice against doing that on a regular basis.
I do use industrial Li-ion batteries (18650) on several other devices and the charger I use for those has a switch with witch I can decide if I want to charge them at 500mA or at 1000mA. Reading in forums that specialize on devices that use those batteries and that have users that seem to know quite a bit about batteries and do extensive testing with sophisticated equipment, the general opinion is, that using lower Amps will prolong the lifetime of your batteries and that too high currents can potentially damage them as of course will overcharging them.
http://batteryuniversity.com/learn/article/ultra_fast_chargers
http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries
I don't know much about battery technology so I might be wrong. I always had problems to wrap my head around anything that has to do with electricity and electronics in general and have to use analogies to understand and explain how things work in that area. Those analogies don't always apply completely.
The one I have in this case is the following:
I decide how much I can eat. I can eat at a normal pace until I'm full but I can also stuff myself and eat a lot more than I would normally do in a short period of time. I know that the later is a bad idea and won't do me much good but it is possible.
If you are correct with what you said, batteries could draw a higher current than what the original charger is delivering, up to their limit but that could still be too much and harm them.
I don't know. Now I'm confused.

shamez23 said:
Are you sure about that?
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You have a point. I guess it depends on how well the charging circuitry (in the phone) is designed.
The battery itself won't limit the voltage/current (*). It's the charging circuitry that does this. For instance, if you connect the battery directly to a power supply and give it too much juice, it WILL damage the battery. Similarly, if the charging circuitry supplies too much to the battery, then this could also happen. However, it SHOULD be designed with appropriate tolerances and safety margins in mind. Therefore, it depends on how much you trust the hardware.
In that way, I guess charging at 500 mA would be considered safer. That being said, I'm happy plugging my phone into the wall charger every night, whether it's 900 mA or 1A.
(*) I know that Lithium batteries usually have built-in circuitry for safety measures, so they MIGHT have something that limits voltage/current, but I'm not sure.

900mA should be save. After all that's what Samsung gave us.
It's just that some people tweak their kernels to 1.25mA or even more. That's quite a bit higher than the specs and probably close to the safety margin.
It won't even charge your batterie faster that way. At least not when you talk about fully charging it. It will get faster to about 80% charge but after that it will take just so much longer to get to 100% that in the end it takes the same amount of time.
I'll stick to the original Samsung charger or the charger of my old HD2 that I have lying around. Makes me feel safer.