I have a green laser that is drawing 600ma from a 4.2v li-ion. Is there a way of calculating the mw output knowing the current draw? I know there are other factors to consider such as the driver efficiency but I would just like to know a in the ball park figure. I have searched for a figure but could find nothing. This laser will burn thin black plastic if given a few seconds. So I 'am trying to figure out what ball park this is in. I can guess by what others say it takes to burn something. But that too depends on alot of variables such as how well its focused. I would still like to know the equation for figuring the power out if one exist.