WattsToAh.com Off-Grid Electrical Sizer
Off-Grid Power Guide • 2026 Standards

Vanlife Battery Sizing Calculator

Accurately size your campervan lithium battery bank (Ah), inverter wattage, and solar array based on your exact daily electrical appliance load.

Quick Answer • Key Power Benchmarks

The average off-grid campervan consumes between 1,200 and 2,500 Watt-hours (Wh) per day, which corresponds to 100 to 210 Amp-hours (Ah) at 12 Volts. This typical load budget powers a 12V compressor fridge, MaxxAir ceiling fan, laptop USB-C charging, water pump, diesel heater, and LED lighting.
Weekend / Minimalist Van 100Ah – 150Ah LiFePO4 (600 – 1,000 Wh/day)
Standard Digital Nomad Van 200Ah – 300Ah LiFePO4 (1,200 – 2,000 Wh/day)
Heavy Induction / Electric Cooking 400Ah – 600Ah LiFePO4 (2,500 – 4,500 Wh/day)
Recommended Inverter Size 1,500W – 2,000W Pure Sine Wave
Recommended Solar Array 300W – 600W Monocrystalline
Standard Reserve Buffer 2 Days of Autonomy (cloudy day backup)

Live Interactive Calculator

Adjust wattage, daily hours, and battery type to see real-time Amp-hours, battery capacity, and solar panel requirements.

Continuous Draw
Watts
Equivalent to ~1,800 Wh/day daily van energy consumption
1 hr/day 8 hrs (Workday) 12 hrs 24 hrs (Continuous)
Recommended Battery Usable DoD Factored
-- (-- kWh)

≈ 1× 100Ah 12V LiFePO4 battery

Bank Weight -- lbs
Chemistry Advantage --
24-Hour Energy Consumption
Daily Watt-Hours -- Wh
Daily Amp-Hours -- Ah
Active Current Draw: -- Amps
Solar Replenishment @ 4.5 Peak Sun Hours
-- W Solar Array

≈ 1× 100W or 200W solar panel

Recommended Inverter 300W Pure Sine Wave -- W Surge Rating
Recommended DC Wire (10ft run) 10 AWG --

In-Depth Engineering & Sizing Guide

Everything you need to know about duty cycles, inductive motor surge, battery chemistry tradeoffs, and wiring standards.

The 3 Standard Campervan Electrical Tiers

Campervan electrical setups generally fall into three distinct tiers depending on whether cooking and heating rely on propane, diesel, or all-electric battery power:

Tier 1: Minimalist / Weekend Camper (100Ah – 150Ah LiFePO4)

Ideal for weekend warriors using propane for cooking and passive battery setups.

Loads: 12V Fridge, MaxxAir fan, phone charging, LED strip lights, 500W small inverter.

Tier 2: Full-Time Digital Nomad (200Ah – 300Ah LiFePO4) • Most Popular

Built for full-time remote workers requiring high reliability, laptop charging, and satellite internet.

Loads: 12V Fridge, Starlink Mini, dual laptops, water pump, diesel heater, blender, 2000W inverter.

Tier 3: All-Electric & Induction Cooking (400Ah – 600Ah LiFePO4)

Zero fossil fuel campervans using induction cooktops, microwave ovens, and electric water heating.

Loads: 1800W Induction cooktop, microwave, electric kettle, air conditioner, 3000W inverter (often 24V or 48V).

12V vs. 24V Systems: When Should You Step Up in a Van?

While 12 Volts is the universal standard for RV and camper appliances (fans, lights, water pumps), stepped-up 24V electrical architectures offer massive advantages for medium-to-large builds:

  • Cuts Wire Amperage in Half: Running a 2,000W inverter at 12V draws over 185 Amps, requiring thick, expensive 2/0 or 4/0 AWG copper cable. At 24V, current drops to 92 Amps, allowing compact 2 AWG cable.
  • Higher Inverter Efficiency: 24V inverters run cooler, experience less thermal throttling, and suffer lower idle draw.
  • MPPT Charge Controller Capacity: A single 50A MPPT controller can handle 700W of solar at 12V, but can support up to 1,400W of solar at 24V!

Why Days of Autonomy Matter for Off-Grid Living

In off-grid solar design, Days of Autonomy refers to how many days your battery bank can sustain your routine electrical loads with zero solar replenishment (e.g. during heavy rainstorms, dense forest camping, or snow).

For vanlife, a minimum of 2 Days of Autonomy is strongly recommended. If your daily consumption is 100Ah, sizing a 200Ah to 250Ah LiFePO4 battery bank ensures you can ride out two overcast days comfortably without stressing your battery or needing to idle your van engine.

Frequently Asked Questions

Targeted answers to the most common questions regarding vanlife battery sizing calculator.

Most full-time campervans need between 200Ah and 300Ah of LiFePO4 lithium battery capacity (at 12V). This provides 2,000 to 3,000 Watt-hours of usable power, which supports a 12V fridge, fan, laptop chargers, Starlink, water pump, and lights for 1.5 to 2 days without sunlight.

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