I use a dual-port 2-amp charger with an Amazon Basics USB cable. This works perfectly fine to charge my Nexus 4 and the Nexus reports "AC" not "USB" as charging mode. From the recharge time it's also evident that it gets plenty of juice.

However, when I connect my wife's Samsung Galaxy S Duos then it simply does not charge at all - the battery indicator does not get the lightning symbol, and the battery really never charges (even when nothing is connected to the charger's second USB port). When I connect the same phone to my computer's USB port, it charges just fine - even using the LG charging cable! - but slowly of course. The Samsung also charges well from any el-cheapo car charger (lighter socket) as well as from my expensive 3A car charger and from my LG AC charger.

What's the cause of this? How can a charger&cable combination work very well for one phone, yet not at all for another?

  • 1
    Very interesting case, Torben. Does the Galaxy S Duos work with other AC chargers?? Commented Aug 4, 2014 at 12:07
  • possible duplicate of Why are USB cables of two different OEM's different
    – user285oo6
    Commented Aug 4, 2014 at 12:15
  • @IAmTheSquidward yes! The Samsung happily lets itself be charged from any el-cheapo car charger (lighter socket) as well as from my expensive 3A car charger and from my LG AC charger. It's baffling. Commented Aug 4, 2014 at 19:38
  • 1
    @TorbenGundtofte-Bruun Very interesting!!! I would try to isolate what is causing the problem... Use the Duos with the Amazon cable and a car plug, and then the Duos with the dual port 2-amp and a different USB cable, etc etc, and see what is causing the issue. Commented Aug 4, 2014 at 20:11

4 Answers 4


In my experience, and my extensive reading on the subject, it seems to be related to the charger and not the cable, unless the cable is a non-standard USB cable. Samsung does not use a special cable for their micro-USB chargers, only their old devices with the Apple-like connector.

The USB standard requires handshaking to negotiate more than 500 ma of current. This is not done in a standard way outside of IOS devices, so not all manufacturers use the same methods. I believe some Samsungs look for a certain voltage on one or two of the pins of the connector, and will not work with other chargers, but I'm only guessing. What I have found with, for example, my Galaxy Tab 3, is that there are some chargers that will not register no matter what cable I use (including "charge-only" cables like from Mediabridge), and other chargers that will not charge it at the full rate unless I use a charge-only cable.

My wife's iphone seems to charge from all the chargers, although I'm not sure if it's at the full rate since I have no app to check. I should mention that most aftermarket chargers are designed to work with Apple, and not necessarily Android, so this is no surprise.

My LG G2, on the other hand, seems to be much less picky, and charges from most every charger I have.

TL;DR, a lot of chargers will not work well, and it's hard to know in advance whether they will.

  • You seem to be contradicting yourself. Your first paragraph states that the cable is irrelevant but your second one says that some chargers need specific cables. I have found this to be the case on my Galaxy Tab 10 as well. Only the stock charger combined with the cable it came with will charge the device at full speed. The same charger with a different cable will not.
    – terdon
    Commented Nov 14, 2015 at 10:36
  • @terdon: Sorry if I was not clear, but I wasn't actually referring to the cable, it's the charger that is not standard. Using the same cable, and switching only the charger, I find that some will not work with my Samsung tablet, and others will work with everything. I don't fully understand it, but I've definitely confirmed it. Commented Nov 14, 2015 at 19:23
  • I realize now that my previous comment might have come across as rude or aggressive. If so, I apologize, it was not my intent, I was just trying to understand. I've had similar issues and in my experience, the cable is also important. The original charger with a different, but high quality, cable doesn't work as well. Haven't you also found that the cable is a factor? You say that some chargers will work with any cable while others require a specific type.
    – terdon
    Commented Nov 14, 2015 at 23:35
  • @terdon: I believe that if you use the charger that came with the device, then the cable normally makes no difference (assuming it's a standard, decent-quality cable). However... sometimes, with a different charger, you might find that it only charges at .5 amps, the maximum USB-2 current without a special driver to negotiate a higher current. In this case, you can sometimes use a non-standard "charge-only" cable, that will trick the charger into putting out more current. I believe this is not needed very much currently, but I'm not really sure. Commented Nov 15, 2015 at 2:37

To answer some of your questions in your comments: The USB specification allows for a fifth channel, OTG (On-The-Go), to negotiate master/slave relationships. Some manufacturers remove the OTG channel (cheapo USB cables are notorious for this), and, subsequently, charging negotiation is halted if the device is trying to send data through it. Some early Samsung phones require the OTG channel, and if your cable doesn't have it (or it's a bad circuit in that one line), then it won't charge. Very weird, but, some manufacturers do that.


Marty is correct! I had the same problem with a third-party USB charger that would charge everything I had, except my Samsung phones. They look for a specific voltage on a certain USB pin.

By opening a charger that worked and the one that didn't, I was able to modify the one that didn't to also work. I'm not sure how USB connector pins are numbered, but for the sake of this explanation, let's say the one with the positive supply (say the leftmost one) is '1' and the negative supply (far-right) is '4', then for Samsung charging, '2' needs to float (no connection) and '3' needs to be connected to the minus pin ('4').

Of course this involves opening the USB charger and soldering stuff, so not for the uninitiated!

Hope this helps some future viewers of this post!


Most probably the USB cable is not supporting the Samsung device. Not all OEM USB cables support other OEM Android devices. It may work with Nokia USB Cable but not with the Nexus because the design of the pins is not matching.

For this you cannot open the USB cable and change the design or something what you can do Is to try another OEM USB cable like Nokia.It will definitely work.

For more details check the answer

  • 1
    How can the cable be at fault? It's just four copper wires with a plug on both ends. I'm curious. Commented Aug 4, 2014 at 13:10
  • 1
    The answer of question you link to pretty much disagrees with what you say here.
    – user49418
    Commented Aug 4, 2014 at 17:57
  • @DanNixon that's why I mentioned "Not all" and in the link given to the answer it clearly mentions the +D and -D signalling made in the USB cable
    – user285oo6
    Commented Aug 5, 2014 at 4:58

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