is there a mc4 to 16.8v cable
did you try searching? Some obvious tips if you do.
of course i tried searching. So did you have an answer
Any (12V-28V) solar charger with DC 7909 Male connector can charge the Powerhouse II.
Edit: scratch that I just realized you have the original powerhouse. Not sure the connector size or cord required for that one. As far as I know anker never made their own solar connector available for these
You can Google: mc4 to 16.8v cable and see what comes up