The only way you could do this would be to cover the panel to trick it into thinking night has arrived early. This will have a knock on effect on the amount of charge picked up during the day so you'd see a reduced runtime.
It is 20m of lights and another 50cm back to the solar panel.
The Blingstrings are not guaranteed to work during the winter months and do not offer the option to charge via USB.
Everbrights range has been discontinued and replace by our brand new Lumify range which works in winter and has USB backup. Click here to see Lumify range