Solar Panel Calculator And DIY Wiring Diagrams For RV And This calculator is meant for camper van conversions, RVs and small off-grid solar systems. Watch the video below if you’re not sure how to fill out the calculator. Solar Panel Wiring Diagrams. Use the wiring diagrams below as a guide to putting together your DIY solar panel system. There are a few different ways to arrange panels Off Grid Battery Based Solar Systems - Complete & Prewired - BOXED Solar The Canadian Solar or Trina Solar panels used in BOXED off-grid systems feature 60 PERC monocrystalline solar cells for a nominal output power of 300 to 320 Watts. The panel’s peak efficiency is in the neighborhood of 19% as they perform exceptionally well in overcast conditions. These panels include a 10-year product warranty and a 25-year linear performance guarantee.