If your hooking to a USB from laptop you won't be powering the Arduino with a battery unless the USB cable has been modified to remove its power wires and has signal only wires. Otherwise you have two sources of power trying to feed the Arduino.
If your hooking to a USB from laptop you won't be powering the Arduino with a battery unless the USB cable has been modified to remove its power wires and has signal only wires. Otherwise you have two sources of power trying to feed the Arduino.