This guide provides a step-by-step calculation, real-world examples, and cost estimates to help you choose the right size solar panel for your off-grid needs. To size your solar panel, calculate your daily energy use in watt-hours and divide it by the peak sun hours in your area. A small cabin might need a 400W panel, while a larger one could require 1200W or more. What (excuse the pun) does that run? Well, we have that system right now and we run several large ceiling fans (day and night) a small fridge, a computer, a 36 inch TV and DVD player, A 4 camera security system, a. Summary: Installing solar panels in Colon, Panama, typically costs between $8,000 and $20,000 USD, depending on system size and quality. 5 average daily sunlight hours. Photovoltaic (PV) storage systems bridge this gap, turni Colon's tropical.