For charging purposes, what is the voltage and amperage output of the USB output? 5 Volts DC/1 Amp Related articles Will the USB input on the back of unit both play and charge my portable music device? Which batteries will last the longest? KMC-1-Battery Replacement & System Battery Reset KMC-3-Does the unit remember the last Bluetooth device it was paired with? Bass periodically cuts out when playing at high volumes Comments 0 comments Please sign in to leave a comment.