According to the owner's manual that I have for this swimming pool light (troubleshooting section), a blinking red light is definately a charging issue. The manual recommends that you unplug and replug in the light several times. If the flashing continues, they recommend that the batteries need to be replaced. Unfortunately, you cannot replace the batteries yourself. They specifically state that you cannot open the housing yourself. If you did, you would risk electrocuting yourself AND void any warranties that you have. You will have to take it into the retailer that you got it from or an autorized pool supply/repair shop or replace the whole light.