AnimeSuki Forums

MeoTwister5 · 2014-01-09, 03:30

So some time ago I broke my Galaxy S4's charger. Since I'm cheap I borrowed my brothers old S3 charger and saw that it charges WAAAAY slower than my S4's real charger. I tried it with another standard DC output 5V~2A charger from another brand and same deal, really slow charge even when the phone's off.

Some quick Googling and I see some claims that the S4 only properly charges (as is the standard fast charge of just over an hour starting from 20% battery life) on the stock charger and if a lucky a few random chargers, but with other chargers of the same voltage and amperage it doesn't work.

Is this true? Should I just go buy a new charger or is it an issue with my phone? The thing is only 4 months old and I take OC care of it.

Edit - BTW it's the USB cables and USB wall chargers I'm trying to test. Right now I'm trying a standard Samsung micro-USB wall charger that doesn't use a standard USB cable.

MeoTwister5 · 2014-01-09, 04:31

Tried a few different combinations. So far:

S3 charger + Samsung (shielded?) cable = 1200mA
S3 charger + generic cable = 1200mA
Generic charger + any of the cables = anywhere between 460mA to 900mA

I'm using the galaxy charging current lite app to check so I can't actually see the charge rate with the screen off, all of these are measurements with the screen on. IIRC an S4 should be charging at 1200mA with the screen on, which means I could just use the best setup above. What I can't tell is if I cant charge this at 1900mA with the screen off unless there's an app that can log the screen off rate.

So far my only concern is if I can use the non-stock charger fine without breaking the battery, or if I really should get a new S4 charger.

Haak · 2014-01-09, 16:26

Maybe this article might help:

Quote:

Samsung uses a voltage divider and signals the presence of their own charger by sending 1.2-1.3 V across the D+ / D- pins

Sounds to me like the reason other 2A chargers don't work as well is because the S4 won't recognise them as the official ones.

MeoTwister5 · 2014-01-10, 02:11

Yeah I was getting the impression that Samsung builds the phone and chargers to detect the correct phone charger combinations.

sa547 · 2014-01-10, 15:19

Looks like they're trying to prevent knock-offs from being made, much like how printer manufacturers created chip-enabled ink cartridges to dissuade illegal refills.

Dhomochevsky · 2014-01-15, 16:10

The USB standard allows for only 500mA to be drawn over a plug.
To show the device, that it can safely ignore this limit and draw more power, the signal lines D+ and D- have to be shortened. This tells the device, that it is dealing with purely a power connector, not a data connection.

Some manufacturers use defined combinations of resistors in between VCC, the D+/D- and GND, to identify their own chargers.
If have noticed this with IPhone chargers, but it is likely others are doing it as well.
Anyone who wants to copy a charger for some manufacturer can easily figure out the resistor combination and build one. I do not think this is to prevent copying.
Rather, the way some device pull multiple ampere over a single USB plug could destroy a source, that is not designed for it. So it makes sense they only do this with chargers they can identify as safe.

2014-01-09, 03:30	Link #1
MeoTwister5 Komrades of Kitamura Kou Join Date: Jul 2004 Age: 39	Having problems charging my S4 So some time ago I broke my Galaxy S4's charger. Since I'm cheap I borrowed my brothers old S3 charger and saw that it charges WAAAAY slower than my S4's real charger. I tried it with another standard DC output 5V~2A charger from another brand and same deal, really slow charge even when the phone's off. Some quick Googling and I see some claims that the S4 only properly charges (as is the standard fast charge of just over an hour starting from 20% battery life) on the stock charger and if a lucky a few random chargers, but with other chargers of the same voltage and amperage it doesn't work. Is this true? Should I just go buy a new charger or is it an issue with my phone? The thing is only 4 months old and I take OC care of it. Edit - BTW it's the USB cables and USB wall chargers I'm trying to test. Right now I'm trying a standard Samsung micro-USB wall charger that doesn't use a standard USB cable. __________________ Medical Student vs. Anime Last Exile - Fam the Silver Wing -

2014-01-09, 04:31	Link #2
MeoTwister5 Komrades of Kitamura Kou Join Date: Jul 2004 Age: 39	Tried a few different combinations. So far: S3 charger + Samsung (shielded?) cable = 1200mA S3 charger + generic cable = 1200mA Generic charger + any of the cables = anywhere between 460mA to 900mA I'm using the galaxy charging current lite app to check so I can't actually see the charge rate with the screen off, all of these are measurements with the screen on. IIRC an S4 should be charging at 1200mA with the screen on, which means I could just use the best setup above. What I can't tell is if I cant charge this at 1900mA with the screen off unless there's an app that can log the screen off rate. So far my only concern is if I can use the non-stock charger fine without breaking the battery, or if I really should get a new S4 charger. __________________ Medical Student vs. Anime Last Exile - Fam the Silver Wing -

2014-01-10, 02:11	Link #4
MeoTwister5 Komrades of Kitamura Kou Join Date: Jul 2004 Age: 39	Yeah I was getting the impression that Samsung builds the phone and chargers to detect the correct phone charger combinations. __________________ Medical Student vs. Anime Last Exile - Fam the Silver Wing -

2014-01-10, 15:19	Link #5
sa547 Senior Member Author Join Date: Oct 2007 Location: Philippines Age: 47	Looks like they're trying to prevent knock-offs from being made, much like how printer manufacturers created chip-enabled ink cartridges to dissuade illegal refills. __________________

2014-01-15, 16:10	Link #6
Dhomochevsky temporary safeguard Join Date: May 2004 Location: Germany	The USB standard allows for only 500mA to be drawn over a plug. To show the device, that it can safely ignore this limit and draw more power, the signal lines D+ and D- have to be shortened. This tells the device, that it is dealing with purely a power connector, not a data connection. Some manufacturers use defined combinations of resistors in between VCC, the D+/D- and GND, to identify their own chargers. If have noticed this with IPhone chargers, but it is likely others are doing it as well. Anyone who wants to copy a charger for some manufacturer can easily figure out the resistor combination and build one. I do not think this is to prevent copying. Rather, the way some device pull multiple ampere over a single USB plug could destroy a source, that is not designed for it. So it makes sense they only do this with chargers they can identify as safe.