Ok heres the dilema, i have over 220 3mm leds, each are rated @ 2.1v & 20mA. I'm going to be running them with a relay. To reduce the voltage, would i need 2v .5a Zener Diodes? The leds are all in parallel, totalling 4.4a draw. So i would need 9 .5a 2v Zeners in parallel from the source? Zeners are very cheap (25 for $.99) and i bought the leds (1100 for $15)