I'm not sure whether this is the right place to ask. There are some questions about adapters and compatibility of devices on travel.SE, but I'm afraid that this might be a little too specific.

I bought a battery charger in Germany, it looks like this:


I'm wondering if it is going work if plugged to a US socket via an adapter. Is there any risk of damaging the device or the batteries?

  • 6
    Show also the plug, please
    – napolux
    Commented Aug 12, 2014 at 7:58
  • 2
    @Napolux Since the device was bought in Germany, the plug will almost certainly be the standard European design with two round pins. Incompatible plugs are trivial to deal with, since adaptors can be bought easily and cheaply (I one pile of them so I can use my UK-plug dual-voltage devices in the USA and another pile so I can use them elsewhere in Europe). The actual issue here is that the device requires 230V 50Hz, which is incompatible with the US 110V 60Hz supply. Commented Aug 12, 2014 at 11:16
  • 1
    Just buy a new one that has a broad input range of 100-250V 50-60Hz instead of a transformer.
    – PlasmaHH
    Commented Aug 12, 2014 at 11:31
  • Buy a $10 battery charger in the US. Or if that costs too much, buy $2 worth of regular, non-rechargable batteries for your stay.
    – Flimzy
    Commented Aug 12, 2014 at 11:50

2 Answers 2


The fourth line of text on the device (counting those two lines on the top right) says:

EINGANG 230V~50Hz 4W

where 'Eingang' is German for 'input', '230V~50Hz' means '230Volts AC at 50Hz' and 4W is the maximum power.

Since the US mains have a voltage of 120V and a frequency of 60Hz, you will need a transformer, but then the device will work.

  • 16
    It's perhaps worth pointing out, it is really unlikely you'd buy or use a (what, $100?) transformer, to make this $5 device work! Almost everyone has battery chargers laying around...
    – Fattie
    Commented Aug 12, 2014 at 8:44
  • 4
    Many modern devices, especially chargers for phones, notebooks and so on are capable of handling 120-240V/50-60Hz. So it should not be a problem to get a hold of compatible item.
    – jnovacho
    Commented Aug 12, 2014 at 10:29

The device may or may not work, but in any case it is not a good idea to try to use it.

As greyshade already mentioned, the print on the device states that it operates with 230 Volts at 50Hz, and the US power net does not provide that. Even a transformer would formally not help as the US power system operates on 60Hz, and a transformer will not change that.

Having said that, the device may still work at a US power net. But the print on it states that it was never intended to work there, so it may behave incorrectly and may be unsafe to use. As a battery charger is a device that is typically not observed during the entire operation time, it is likely to be not wise to try to use it in the US.

Also note that the device seems not to have FCC certification, which, depending on the way it operates, might be necessary for the US.

  • 2
    An FCC certificate would only be needed for a device that produces RF; which a battery charger shouldn't. The (US) battery charger on my desk doesn't have an FCC marking. It has an ETL marking with both the US and C modifiers which indicates that it was tested by InterTek and passed both the relevant US and Canadian standards. Commented Aug 12, 2014 at 13:05
  • @DanNeely According to what I read, devices with "accidental" RF emissions also count, so at least a charger for rechargable akalines may fall under this rule, as according to wikipedia, it charges with 80 to 200 pulses per second. If you add harmonic waves, that may be enough. The OP's charger is likely not to operate in such ways, though.
    – DCTLib
    Commented Aug 12, 2014 at 13:23
  • 1
    The frequency difference is almost certainly not an issue. If the power conversion inside is switch-mode (weight comparable to a modern phone charger) the incoming AC is immediately rectified to DC - frequency doesn't matter. If the input is a transformer (unlikely in this case, but heavier), transformers are more efficient at higher frequencies and the difference is marginal anyway. The output to the battery will be some form of (possibly chopped) DC. The voltage is another matter - something will almost certainly overheat, though it's less likely to go bang than a US device in Europe. Commented Aug 12, 2014 at 13:41

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