Off-Grid Solar PV System — FarmPal

A complete standalone solar electric system with battery storage for full energy independence. The backbone of most off-grid homesteads, providing reliable power from sunlight with no fuel costs.

How It Works

Photovoltaic panels convert sunlight to DC electricity. A charge controller regulates power flowing to batteries. Batteries store energy for nighttime and cloudy days. An inverter converts stored DC power to AC for household use.

Site Requirements

  • •Unshaded south-facing area (northern hemisphere) or north-facing (southern)
  • •Roof or ground mount space: ~100 sq ft per kW
  • •Structural support for panel weight (3-5 lbs/sq ft)
  • •Proximity to battery bank and main panel for efficient wiring
  • •Clear solar window from 9am to 3pm minimum

Components

Solar Panels
Convert sunlight to DC electricity
$0.50-1.00/watt
Charge Controller (MPPT)
Regulate charging, maximize harvest
$100-600
Battery Bank
Store energy for use when sun is not shining
$200-500/kWh (lead-acid) or $400-800/kWh (lithium)
Inverter
Convert DC battery power to AC household power
$500-3000
Wiring & Disconnects
Safely connect all components with overcurrent protection
$200-800
Mounting Hardware
Secure panels at optimal angle
$100-500

Sizing Guide

Size based on daily energy consumption and local solar resource

Formula
Panel watts = Daily Wh ÷ Peak Sun Hours ÷ 0.75 | Battery kWh = Daily Wh × Days of Autonomy ÷ DoD ÷ 1000
DIY Minimum
$2,500 (tiny cabin system)
DIY Typical
$12,000-20,000 (full homestead)
Professional
$25,000-50,000+ installed
Annual Maint.
$100-500 (battery maintenance, cleaning)

DIY Steps

1
Energy Audit

Calculate your daily energy needs by listing every device, its wattage, and hours of use per day. Multiply watts × hours = watt-hours. Sum all loads for total daily consumption.

⏱ 1-2 days
2
Site Assessment

Evaluate solar access using a Solar Pathfinder or smartphone app. Map shade patterns through seasons. Identify optimal panel placement.

⏱ 1 day
3
System Design & Sizing

Size your system: Total daily Wh ÷ peak sun hours ÷ 0.75 (system losses) = panel watts needed. Battery bank: 2-3 days of autonomy × daily Wh ÷ depth of discharge (50% lead-acid, 80% lithium).

⏱ 1-2 days
4
Installation

Mount panels, install charge controller near batteries, wire battery bank, connect inverter, and wire to breaker panel. Follow all electrical codes.

⏱ 2-5 days
5
Testing & Commissioning

Verify all connections, check voltages at each point, test under load, and monitor for a full charge-discharge cycle.

⏱ 1-2 days

✓ Pros

  • •No fuel costs sunlight is free forever
  • •Extremely reliable panels last 25-30+ years
  • •Silent operation (no generator noise)
  • •Scales easily add panels and batteries as needed
  • •Low maintenance compared to any fuel-based system

⚠️ Safety

  • •Solar panels produce voltage whenever light hits them cannot be "turned off"
  • •Battery banks store enormous energy short circuits cause fires and explosions
  • •Lithium batteries require BMS (battery management system) never bypass
  • •All DC wiring must be properly fused and protected