LED ratings are specified by current, not voltage. For longest life, we recommend you run them at 20-25 milliamps (ma). HOWEVER, in our LED flashlight conversions (and many commercial LED flashlights), the LEDs are run at 50-60ma, twice the rated current. One of our test LEDs ran at 98ma for over 200 hours without damage or appreciable light loss. So go ahead and experiment with running them at over rated current if you are willing to take the risk of a shorter life. In my opinion, a flashlight bulb that lasts 100 hours is a huge improvement and cost saver over the incandescent alternative which gives only 15-20 hours before it dies.