LEDs run on DC and your cigarette lighter outputs DC, so a power inverter is going to be pretty wasteful, converting to AC and then something else (presumably the LED power supply) converting back to DC. You can likely get LEDs that run off of 12v input. You’d just need a plug that fit into the cigarette lighter. If you have LEDs that need some other voltage, you could just use something to step the voltage up/down and skip the DC->AC->DC conversion.