RV OWNER’S FIELD GUIDE · SOLAR & POWER
Off-Grid Power Budget Planning
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.
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. 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. This is where most DIY power budgets go wrong — they size to the theoretical draw and end up short in practice.
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. Inverter continuous rating should cover everything you’d realistically run at once, plus surge headroom. See our solar sizing guide and inverter sizing guide for the specifics on each piece.
OUR TOOL KIT
Gear for an off-grid power budget
Victron SmartShunt battery monitor — Shows what each appliance actually draws, in amps, on your phone.
Victron SmartSolar MPPT 100/30 — A Bluetooth solar charge controller for up to about 400 W on a 12V bank.
Honda EU2200i inverter generator — The quiet, reliable 2,200 W generator for filling the gaps in a power budget.
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