I'm glad to hear everything is still working Francis!  The Ubiquiti community forums have numerous discussions regarding solar powered sites and while I've read through some of them I've never set one up myself.  Tycon Power Systems seems to get good reviews.  Basically you get a solar panel, battery, charge controller, and all the stuff you need to power your devices directly.  This is instead of using a inverter and the original power supply.  I would think something like this would be sufficient to power two Nanostations for several days (you have to plan for time without sunlight) and it won't break the bank.


http://www.streakwave.com/Itemdesc.asp?ic=RPDC12-9-10&o1=0 

 A little more expensive but this one would be better power wise and easier to work with.

http://www.streakwave.com/Itemdesc.asp?ic=RPPL1212-36-30&o1=0