20v proply should be 2.0v
: if im not mistaking, the led comes with three "pins".
: one anod and two katods (or the otherway around, always mix 'em up).
: so...simply put 20v on one and 2.1v on the other (tho that 20v sounds wrong...dunno how to check wich one is the red or green pin...should say in the datasheet tho...
: and dont forget those resistors :)