Why isn't my USB port charging my device?

First, ensure the USB power/fail indicators are lit with a steady blue light. If the indicators are flashing blue, there's a fault with one of the USB ports. Also check that the total power draw from all USB devices on both ports doesn't exceed 3.1A, and verify the jump starter has a complete charge. If your device still won't charge, consult your device's manual to confirm it's compatible with this type of USB power port.