N0ce, a couple volts to an LED is A LOT of current, if you read up a bit you'll also see that efficiency drops when you over current them, and their life expectancy drops faster than the brightness goes up. As a simple example a basic 20mm super bright LED will be 90% efficient between 5 and 10ma, then the efficiency drops to 80% as the current goes to 20ma, then it basically goes down linearly losing 1% per ma of higher current, and again brightness does not go up linearly with current, 5 times the current will only get you twice the brightness.