Mine does not do that. Totally silent when charging. How hot was the ambient temperature when you were charging? Using a "regular" Samsung USB charger (which charges my Samsung phone at a high rate), my Spark is totally silent. I've got all the latest firmware / software. This is what it sounds like on mine, during the whole charge cycle. My house is at 70 degrees F. Spark Charge Video The noise you hear is the TV in the other room. I had to turn off my computer, as the fan was making too much noise to hear the "silence".