I've noticed that my Samsung Galaxy S4 doesn't always charge at its maximum rate of charge, even when it seemingly should. For example, car DC adapters that claim to provide up to 2.0A current only provides 500mA. I've also tried connecting the OEM AC adapter to a car inverter**, with the same result of a ~500mA charge rate. On the other hand, when connected to an AC outlet through the same charger, the device draws 1200mA*.

I previously owned an Galaxy S3 which I think started having similar issues at some point, possibly after a system update.

What conditions are required for Android devices to draw greater than the 500mA current provided by a USB 2 data connection? Have these conditions changed with successive versions of the Android OS?

*: Measurements of current draw made by Ampere

**: I asked this question a few days ago and it has attracted very little attention, so I'm now asking a more general question.

  • Note also that many Samsung devices include Qualcomm Quick Charge 1.0 technology (which IIRC makes the battery charge at a variable amperage) or Quick Charge 2.0 technology (which IIRC makes the battery charge at variable voltages and amperages). If yours includes this or a competing technology, then the phone may draw full wattage only at certain times, and a lower wattage at other times. It depends on both which charger you're using and on the battery's current state of charge. Commented Jul 16, 2015 at 7:26
  • For selection of USB cable see answer here
    – beeshyams
    Commented Apr 25, 2016 at 13:44

2 Answers 2


I would recommend you to change the USB wire and replace it with a good USB wire.

I have seen that over time the wire gives lower charging value and it's unable to give output as of newer cable. There is no issue with the charger in this case ( 2A or 1A charger).

  • just change the USB wire
  • connect it to phone and charger.
  • check the values of the current flow in application like galaxy charging

I am sure that you would get desired output if you follow these step

This same method worked for me. And also make sure that you give full cycle to the battery when charging.

  • wow people are down-voting, if you haven't solved the problem this way then do let me know the answer rather than just down voting. @intuited just try this method and do let me know.
    – reachrk
    Commented Jun 1, 2015 at 23:46
  • 1
    I didn't mention this in my original question, but I have been consistently been using the same cable whenever charging this phone. The charging rate consistently corresponds to what the cable is connected to.
    – intuited
    Commented Jun 2, 2015 at 0:22
  • This answer isn't accurate. The cable, in this case, based on the information provided, isn't the problem factor. It's the 2A charger, which the phone can't negotiate better than 500mA with. Replacing the cable won't bring it above that, because the negotiation between the charger and phone are at fault. A good quality cable is important, but it can't be the source of this problem.
    – TurboFool
    Commented Jun 2, 2015 at 0:24
  • Whoah, it actually was the cable. I was wrong about that. I've been using the same cable consistently in the car, but use a different one when connected to wall AC outlets.
    – intuited
    Commented Jun 2, 2015 at 1:39
  • That's very, very odd.
    – TurboFool
    Commented Jun 2, 2015 at 17:14

The OS isn't relevant to charging speed, but the internal hardware differs heavily between phones. One thing you'll experience is that nearly all chargers that advertise themselves as 2.1A are optimized for iProducts, which require a different grounding scheme in the charger to reach their full speed, and that same scheme limits Android devices to 500mA. So counter-productively you'll find that most 1A chargers will charge your Android device FASTER than 2.1A chargers. You'll also see a lot of multi-chargers that have one port dedicated to 2.1A, and if you move your phone to the other port it'll charge faster. Most label these ports as A and NA, for Apple and Non-Apple.

The way around this is to buy a charger that's specifically designed to adapt to whatever device you're using. One example, which I've used myself, is the Anker 4.8A 2-port charger. Unlike most two-port chargers which dedicate one port to Apple and one to non-Apple, this uses Anker's PowerIQ tech to sense, on either port, what your device wants from it and adjust accordingly. This charged my device at full speed quite easily. I've since switched to one from Choetech that's a 4-port simply because my Nexus 6 supports Quick Charge 2.0, and that one had a port for that, but it advertises their own version of the same concept as PowerIQ for the other ports. Both companies make a ton of wall/desk chargers with the same technologies in them, and I have multiple Anker chargers and external batteries. Aukey seems to be another supplier who's probably using the same OEM as those other two companies, with similar results. And they all seem to give good warranty support via Amazon.

The other factor, as mentioned in the other answer, is the cable. I used to think "USB is USB," and that's true for data, but not for power. Cable quality, and unknown factors, will change what you can pull off. I've had two cables of the same length produce as much as an 800mA difference from the same charger. Also, some just combine with certain chargers better. The cable I've had the most consistent luck with, across all devices, is the Cable Matters Premium Gold-Plated cable. I used to buy the MonoPrice-branded ones, but they stopped making them, and I found these identical ones on Amazon. They're quite cheap, and they've worked exceptionally well for me. They give me over 2A on Quick Charge 2.0, and 1.2 on everything else when all other conditions are optimal and I'm using a good charger. Length matters, too. The shorter the cable, the better it can hold onto its current.

  • Any idea why the OEM charger doesn't produce full AC amps when connected to the car inverter?
    – intuited
    Commented Jun 2, 2015 at 0:26
  • That one's trickier. If I had to hazard a guess, I'd say it's getting inconsistent power levels and is basically sticking to a lower negotiation point to play it safe. But at that point you're beyond my electrical knowledge.
    – TurboFool
    Commented Jun 2, 2015 at 0:27
  • Nevermind, it was actually the cable the whole time. I've been using the same cable in the car since I had the S3 and never thought to try a different one.
    – intuited
    Commented Jun 2, 2015 at 1:41
  • And actually with the new cable, both 2.1 and 1.0 amp outlets provide 1200 mA, same as the AC adapter.
    – intuited
    Commented Jun 2, 2015 at 1:46
  • Samsung may have designed that phone differently to handle that, then. Very unusual.
    – TurboFool
    Commented Jun 2, 2015 at 17:14

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .