-light.intensity, light.spotAngle and light.color with variable?

I would like to use a variable that is currently minusing every second to take away light.intensity, light.spotAngle and light.color. Originally, I used time.deltaTime to take away these light variables every second. = does not work, - does not work. I basically want the battery to go down every second from 1000 to 0. And I want the light variables to correspond to the battery. Do you know how to do this