About chargers in the bathtub. Don't take anything connected to a wall socket in the bath. Krieg has it about right; it's the actual current that can kill you. The flow may be unpredictable, but what we know for sure is that all the resistance to current in the human body is on the skin. When the skin is wet it loses most of its resistance and even 5 volts could (with a little bad luck) be enough to push enough current through you to stop your heart. The current rating on the charger is just a potential maximum and really has nothing to do with the issue. The 0.5amps is enough.