I Have a Retrogame rg 300, really love the device but been having problems charging it. when I do it can take anything from 5 hours or more. The light on the back will start to flicker then go off then come back on again. So I never know when it's finished charging. I have tried different cables and chargers to no effect I even updated the firmware and still nothing. Dose anyone else have this problem or is it just me