The choice of UPS depends upon the answers to the following questions:
How much power does your equipment need to operate?
How much backup time do you need?
What is the voltage of your power source?
Where do you plan to install your UPS?
What type of technology should you choose? (Off-line, in-line, on-line)
Once your customer can answer those questions, they can consult with a local distributor for the best choice. (A solitary GreenMAX panel runs on 70W, so a minimum of 100W would be advisable, as far as power required to operate.)