Step 1: List Every Device and Its Daily Runtime
For each device: watts × hours used per day = watt-hours per day. A compressor fridge running roughly 8 of every 24 hours at 60W averages to about 480 Wh/day.
Power guide
Off-grid RV power budget that holds
Solar, battery, and inverter sizing all come from the same starting point: what you actually run, and for how long. Work it out here first. For each device: watts × hours used per day = watt-hours per day.
Active corridor: Montana · Wyoming · Idaho · Washington — case-by-case beyond.
Field notes
Solar, battery, and inverter sizing all come from the same starting point: what you actually run, and for how long. Work it out here first. For each device: watts × hours used per day = watt-hours per day. A compressor fridge running roughly 8 of every 24 hours at 60W averages to about 480 Wh/day. Do this for every device, including small always-on loads like a CO detector or stereo standby — those add up over 24 hours.
Step 2: Add a Realistic Buffer
Add 20–30% on top of your calculated total for inverter conversion losses, wiring losses, and battery charge/discharge inefficiency.
Step 3: Size Battery, Solar, and Inverter Together
Battery capacity should cover 1.5–2 days with zero sun. Solar wattage should recover a full day’s usage in your average available sun hours.
Related
Solar Sizing & InstallationInverter Sizing GuideBattery Chemistry ComparisonVictron Energy Power SystemsBack to Field Guide
Related: All guides · Book a Service · Pricing
Pricing teaser
Trip fee $75 within 30 miles, then $1.50/mi. Labor ~$150/hr (1-hour minimum, billed in 30-minute increments). Diagnostic $175 applied toward repair if you proceed.
Active corridor: Montana · Wyoming · Idaho · Washington — case-by-case beyond. Credentials (text): Victron Professional Certified Installer · weBoost Authorized Installer · Peplink Certified Associate · Dometic Professional Certified.