Off Grid Collective
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Solar System Calculator

Size your solar panel array, battery bank, and inverter based on your energy needs and location.

New to off-grid? Start with our 3-question path finder for a personalized off-grid guide.

Energy Needs

Enter your daily energy consumption. Use the Home Load Calculator to find your exact daily usage.

2.00 kWh/day

Inverter must handle at least 1,250 W

Location & Sunlight

Peak sun hours determine how much power your panels can generate each day.

e.g. UK, Germany, Netherlands

3 hours/day

Average peak sun hours for UK / Northern Europe

System Configuration

Configure your system preferences to get accurate sizing recommendations.

2 days
1 day7 days

Calculation Assumptions

  • 75% overall system efficiency (wiring, temperature derating, charge controller, battery round-trip)
  • LiFePO4: 80% depth of discharge · Lead-acid: 50% depth of discharge
  • 20% battery safety margin for capacity headroom
  • Panel prices ~$0.80/W · LiFePO4 battery ~$0.30/Wh · Lead-acid ~$0.10/Wh · Inverter ~$0.25/W (USD base, converted to local currency at approximate rates). Prices as of 2026-03-20.
  • Inverter sized at 1.25× peak load; MPPT controller sized at 1.25× array watts ÷ system voltage

System Summary

Updates live as you adjust inputs.

Solar Array

3panels

400W × 3 = 1,200 W total

Min required: 889 W (at 3 peak sun hrs)

Battery Bank

6,000Wh

250 Ah at 24V · LiFePO4

2 days autonomy · 20% safety margin

Inverter & Charge Controller

Inverter

1,500 W

pure sine wave

MPPT Controller

80 A

charge controller

Estimated Cost

Solar panels£758
Battery bank£1,422
Inverter£296
Charge controller£300
Wiring & mounting£416
Total Estimate£3,193

Estimates based on typical US market prices, converted to United Kingdom currency (GBP) at approximate exchange rates. Does not include installation labor or permitting.