Power Budgeting 101: How Much Energy Do You Really Need?

List every device you use in a day, total the watt-hours, then size your batteries, solar, and charging around that number. It’s the simplest path to a stress-free off-grid setup.

Why this matters

Guessing at “enough power” leads to dead batteries and noisy generators. A quick daily budget makes everything—from battery size to panel count—obvious.

The simple math

1. List devices (lights, fridge, fans, inverter loads, laptops, Starlink, pump).
2. Find watts (device label) and estimate hours used per day.
3. Watt-hours/day = watts × hours. Add them up.
4. Battery size (Ah) ≈ total Wh ÷ system volts ÷ allowed depth-of-discharge
   • Example (12V LiFePO₄ @ 90% usable): 1,200 Wh ÷ 12V ÷ 0.9 ≈ 111 Ah.
5. Solar target: Plan to harvest ~1.3–1.8× your daily use to cover cloudy days and losses.

Field note

We ran a quiet camp with a 12V fridge, lights, two laptops, and Starlink. Daily draw ~1,300 Wh. With 400W of roof solar plus occasional alternator top-offs, batteries stayed >60% even after a gray day.

Optimization tips

• LEDs everywhere. Huge savings.
• Right-size inverter. A 2,000W unit idling all day wastes power; turn it off when not in use.
• DC when possible. 12V chargers for laptops/routers beat inverter losses.
• Timers on Starlink/routers to auto-sleep overnight.

Product spotlights:

• Inline power meters (plug-in) to measure AC device draw.
• Victron SmartShunt or BMV-712 for accurate state-of-charge (SOC).
• Foldable 100–200W panels for shoulder seasons and shady camps.