Velux solar blinds - problems charging them

[alaska900]

We have velux solar blinds fitted in our bedroom on, very high, north facing roof slope. Velux assured us they would have 600 ups and downs to see us through the winter and would charge enough over the summer months to see us through the next winter. Hmmmm - not working I'm afraid and they give up working roughly November to April until the sun gets high enough to hit the solar panel. So we're waking up at the crack of dawn when it gets light. What we need is a separate charger that we can plug the batteries into either solar or other. Velux don't have such a thing. Has anyone come across one.