2018-05-22 Lee_lvd ohms law is very easy V= volts, A=amps, R=resistance V=R*A or A=V/R or R=V/A some people use I or A current which is your current. I do like your LED holder but you should add as resistor to it. figure out your voltage of your battery, Study your LED data sheet to find the max current. Most are around 0.02 Milli amps so for a 3 volt battery 3/0.02=150 that is a 150 ohm resistor. I hope this helps. And if you want to know the watts volts times Amps or .06 watts so really next to nothing. Some batteries have an internal resistance but I don't recommend accounting for it as some will just push and your LED will just be a flash then dead.