Since all DSi / 3DS be charged with 4.6V and USB has a voltage of 5V, you should use this cable DO NOT permanently. Since all electrical appliances must designate a tolerance of 10%, this would indeed just as in the portable field, but I would recommend to anyone this cable to be used for continuous use, since all reserves in terms of voltage spikes are gone and here you can easily damage the device can.
Especially for loading to USB power supplies, it is therefore not appropriate.
I bought the cable for Notladevorgänge to an external USB battery. There is good and sitting the connections.
Conclusion: well suited for charging on the road in between the battery. Absolutely at home using the original power supply of Nintendo for continuous use!