I'm traveling from the US to the UK in a few weeks. Can I recharge a power bank purchased in the US at a UK power outlet? The specs for all the power banks I've been considering make no explicit mention of dual voltage.


(I know I can recharge it from my laptop, but the wall outlet is probably faster.)

  • I've never personally seen one that wasn't dual voltage (admittedly, I don't inspect them that often), but you'd need to see the specs on it to confirm for sure. If you have one in mind, we can look at that. Aug 21, 2017 at 2:19
  • charging from the outlet is only faster if your wall adapter is a higher amperage then a USB port (500ma)
    – Keith M
    Aug 21, 2017 at 19:25
  • 1
    The interesting question is, if you are considering buying one for your trip to the UK, what are you planning to do here that you do not do in the US that makes you believe you need one?
    – mdewey
    Aug 21, 2017 at 20:11
  • Maybe this would be relevant in electronics.stackexchange.com.
    – neverMind9
    Apr 12, 2019 at 19:45
  • If your wall outlet adapter supports these voltages, you can. The voltage and frequency range is printed on it.
    – neverMind9
    Apr 12, 2019 at 19:47

4 Answers 4


All the devices you mentioned charge via USB, so really all you need to do is carry a USB wall adapter, that is compatible with USA / UK voltages.

I carry with me a macbook pro lightbar 2016 wall charger:

  1. Easy to adapt to any wall adapter, since it comes with multiple wall heads and these are easily found in most local shops.

  2. Has universal voltage support.

  3. Has a removable USB cable; which means I can plug in (with a suitable adapter) any USB cable to charge any kind of device.

  4. Supports "fast charging" on mobile phones that support it, since it has a higher amperage output.

I am talking about the 87W adapter (link at apple.com).

The good news is that from the last 5 years or so that I have been buying gadgets, all the chargers that I have bought - including laptop chargers with USB ports, cell phone chargers, smart phone chargers, wall adapters, multi-plug ports ... are all dual voltage.

If that fails, you can always charge those devices from another USB host, like a laptop or desktop computer.


I don’t have that much experience in power banks but I have yet to come across one that is fed mains voltage at all. All power banks I have seen to date are charged via a USB cable supplying them with USB voltage: +5 V DC.

All wall chargers for power banks I have seen to date are in fact mains to +5 V DC converters; they typically don’t even try to hide the fact by simply supplying a USB out socket (and in fact many if not most power banks simply come with a USB cable, not one for mains).

Since the 120/230 V AC mains voltage is scruntched to DC before any power reaches even the cable to the power bank, you need not worry.

  • 1
    Larger power banks are often charged through a coaxial DC connector, since it would take very long to charge them with the limited power from a USB supply. Aug 21, 2017 at 11:45

They are only one voltage. 5 volt USB.

All of them use a USB port to charge. It is up to you to obtain USB power locally. How you do that is your choice. You may

  • discover your own power blocks are multi-voltage (research, don't experiment!) and get a mains adapter
  • borrow a USB power block from your host or hotel
  • walk into a UK shop and buy a power block
  • find your host has wall receptacles with USB outlets
  • plug into your host's PC
  • plug into your laptop which has a multivoltage power supply

Neither! Or both! Depending on what you like more.

Powerbanks are charged and discharged via USB (cable). And USB has 5V.

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