Solar Panel Sizing Guide for Off-Grid Power Systems

Choosing the right solar panel size is critical for off-grid power systems. Whether for caravans, motorhomes, or remote work sites, selecting the correct panels ensures reliable energy, faster battery charging, and efficient system performance.

Quick Reference

• Light Use: 100W – 200W
• Medium Use: 200W – 400W
• Heavy Use: 400W+

The right size depends on how much power you use and how often you stay off-grid.

What Determines Solar Panel Size?

There are three key factors to consider:

• Power Usage: Lights and fridge → low; add laptops or cooking devices → medium; add air-conditioning → high
• Battery Capacity: Smaller batteries require less solar; larger batteries need more panels to recharge efficiently
• Sunlight Availability: Full sun provides optimal output; cloudy or shaded conditions reduce energy generation. Always allow extra capacity for bad weather.

Rule of Thumb for Sizing

Your solar panels should produce more energy per day than your typical consumption. For example, if you use 100Ah per day, your solar should generate 120–150Ah daily.

Practical Example

A 400W solar panel with ~6 hours of usable sunlight produces roughly 140Ah per day, enough for a medium off-grid setup.

Why Oversizing Solar Panels Matters

Many systems underperform because panels are sized exactly for average usage. Oversizing provides:

• Faster battery charging
• Greater flexibility in variable conditions
• Reduced reliance on backup generators

Recommended Solar Panel Sizes by Use

• Light Use (Weekend Trips): 100W – 200W, lights, phone charging
• Medium Use (Typical Caravan): 200W – 400W, fridge, lights, devices
• Heavy Use (Full Off-Grid): 400W – 800W+, cooking, electronics, extended stays

Fixed vs Portable Panels

Fixed Panels: Always charging, ideal for long trips
Portable Panels: Flexible placement, perfect for camping or shade adjustments
Best setup often combines fixed and portable panels for maximum efficiency.

Arizon Recommendation

For most off-grid setups, slightly oversizing your system ensures reliable performance. Users upgrading their systems find that 400W+ panels offer the best balance of efficiency and flexibility.

For a complete system overview, see our Off-Grid Power System Design Guide.

Need Expert Advice?

Choosing the right solar setup can be complex. Our team can help you select the ideal solar and battery combination for your off-grid power system.