If you have some diodes laying around you can also string 3-6 together to get the voltage a bit lower without the cost of a voltage regulator. Each one will drop the voltage .7v so 6 will be the equivalent of a cell in a charged lipo, more or less. I'd cut either the red or black lead on the LED array then put the diodes in series just twist fitting and trying to get the brightness where you want it (careful not to touch any metal leads to the LED board circuit). Once you have it dialed in, solder the diodes, cut some shrink wrap to cover the whole thing plus enough to cover the ends of the wire leads you're splicing into, cut the lead so the size matches up to the uncut side, solder the diode string to the leads, shrink the tubing down, done.