I am assuming you mean a battery powered lawnmower? If so, yes you can cut your grass when its damp or wet. If it's raining, you should never cut your grass with an electric or gas powered mower as you will leave divots if its a rider and when it rains, some of the blades of grass are pushed down from the rain so when you cut, it won't cut those blades. Once the rain stops and the grass stands tall again, it won't look good. When i say raining, I am talking about a long rain, not one of the quick 10 minute rains.