I have a Moto G 3rd Gen, and my phone charger broke. I have both the raspberry pi official 10W power supply and the raspberry pi official 13W power supply. Can I use either or both of them to charge my moto g 3rd gen?


USB standards specify 5V plus / minus 0.25 V which is supplied by pi 10W supply whereas 13 W supply is 5.1 V which is not recommended

So you can use the 10W power supply

Thanks to Ghanima in comments , who pointed out something I overlooked

The 13W supply is listed as 5.1 V with a 2% line regulation (that would be 5.1 V plus/minus 0.1 V) which puts it well within the USB spec

So you can use both chargers safely, as pointed out in other answer giving additional reasons. Sorry for missing this detail

| improve this answer | |
  • Then WHY does Samsung ship 5.3V chargers? – iBug Jun 4 '17 at 10:38
  • Samsung's "labelledly" 5.3V chargers can even raise output voltage to 5.60V, which is far too higher than 5+0.25V. Well, why? – iBug Jun 4 '17 at 10:48
  • @iBug: good point. OPs device does not support fast charging and for standard chargers reply above is correct. For various fast or quick charging especially from Qualcomm quick charge 3.0 onwards, it is the *power * that matters and increasing the voltage level (while maintaing a lower current) delivers the required power. This 5.3 V does appear to be a violation of standards but I haven't seen any conclusive result except heated discussion. Do let me know if you are aware. Thanks – beeshyams Jun 4 '17 at 10:55
  • 1
    The 13W supply is listed as 5.1 V with a 2% line regulation (that would be 5.1 V plus/minus 0.1 V) which puts it well within the USB spec (though load regulation is unfortunately not listed). So I would think your answer is quite misleading. – Ghanima Jun 4 '17 at 17:32
  • 1
    @Ghanima: How did I miss that ? Stupid of me. Will amend answer. Thanks a ton for pointing it out :) – beeshyams Jun 4 '17 at 17:38

As @beeshyams answered, the USB Standards specify that charging voltage should be 5.00V ± 0.25V, i.e. 4.75V~5.25V.

Most cables have resistance, which lowers the actual voltage that your phone receives. A typical 1-meter long 24AWG cable eats approximately 0.5V. So some good chargers have a feature called loss compensation. These chargers raise their output voltage when a load is detected. In my case a Samsung charger (shipped with S5/Note 4) can raise output V to 5.6V at a load of 2 Amperes. It's completely safe to use the 13W charger if it doesn't exceed 5.5V. It will be faster than the regular 10W one. But if it only output power at 5.1V, the speed boost isn't quite noticeable.

| improve this answer | |
  • This may be a reason but then don't you think the standards or earlier OEM devices wouldn't have taken care of it and all along had higher rated chargers ? I am not totally convinced. +1 for bringing this possibility – beeshyams Jun 4 '17 at 11:02
  • @beeshyams As so often, they might have saved a cent or two on that one resistor to boost their marge (instgead of your charging speed). Wouldn't be the first time. – Izzy Jun 4 '17 at 11:04
  • @izzy: possible but I only see 5.3V chargers after quick charging came in so I think this is related to that. See my comment below my answer – beeshyams Jun 4 '17 at 11:07
  • 1
    @beeshyams Yeah. I was just throwing in another possibility. Have no special knowledge here, so I cannot tell (but only speculate, which is OT here). Hence I better not "discuss" it :) – Izzy Jun 4 '17 at 11:08
  • @beeshyams More examples: earlier iPad's original charger is 2.1A@5.1V. Some ZTE phones' original is 2.0A@5.2V – iBug Jun 4 '17 at 11:18

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.