Is it supposed to flash rapidly?
A few days ago when I went to charge my phone with this charger the lights turned on and at their normal speed then a few minutes later the lights sped up really fast and started flashing rapidly. I dont know what to do
Fast motion means it's charging, slow to no movement means it's finishing or finished charging. Flashing may just may mean its a bad connection. I wouldn't necessarily say its defective...? Was it still charging/syncing your device? If not, take it back and exchange it for a new one if you haven't had it very long. If that doesn't work, call the manufacturer.