On Sunday, June 9, 2013 10:15:07 AM UTC-7, Bill D wrote:
If you plan to use the gliders 12V bus, the LED's need the resistor. (FWIW, non-rechargeable lithium cells output 3.7V which is just right for an LED without resistor as millions of key-ring flashlights show.)


An LED is a diode junction, forward voltage is around 0.7 to 1.1V typically. 3.7V will make a single diode glow very brightly for a very short time. Cheap flashlights usually have 3 or 4 LEDs in series to accommodate the higher voltage.