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Offgrid Solar Beginner Crash Course — Build a 10,000W System

Source: Offgrid Solar Beginner Crash Course: Build a 10,000W Solar System — DIY Solar Power with Will Prowse Last reviewed: 2026-09-01

Overview

This KB article captures the essentials of Will Prowse's beginner crash course on building a 10,000W (10 kW) off-grid solar system. The course walks through a complete 48V system built from the ground up: solar panels, a PV disconnect, a 10 kW 120/240V split-phase hybrid inverter, a 16 kWh LiFePO4 battery bank, and AC outlet boxes for both 120V and 240V loads.

The system is designed to be simple enough for a first-time builder while still delivering whole-house-class power: split-phase 120/240V AC output, lithium battery storage, and MPPT charging — all in one compact architecture.

[!NOTE] The video's transcript is not available (YouTube serves none for this video), so this article is reconstructed from the video's parts list, metadata, and the standard architecture of this well-known build. Diagrams are provided as editable draw.io files.

System Architecture

The build follows the classic 48V off-grid architecture: PV array → PV disconnect → hybrid inverter → AC loads, with the battery bank on the DC bus.

Editable diagram: 10kW-offgrid-system-architecture.drawio — open in draw.io (app.diagrams.net) to edit.

Components in the power path:

# Component Role Typical spec (from video)
1 Solar panel array DC generation Used 400W panels (SanTan Solar) or new panels (Current Connected)
2 PV disconnect Safety switch on DC side DC-rated breaker/switch
3 Hybrid inverter Conversion + charging 10 kW, 120/240V split-phase, MPPT + charger built-in
4 Battery bank Energy storage 48V LiFePO4, 16 kWh (Yixiang DIY box, 16× EVE 314Ah cells)
5 AC outlet boxes Loads distribution 120V box and 120/240V box (shown in video)

[!TIP] The MPPT charge controller and battery charger are built into the hybrid inverter — no separate charge controller is needed in this build. The inverter manages solar charging, battery charging from AC, and DC-to-AC conversion in one unit.

How the energy flows

  1. Solar panels generate DC power and feed it through MC4 extension cables.
  2. A PV disconnect (DC-rated) provides a safe way to isolate the array.
  3. The hybrid inverter converts DC → AC, runs the MPPT algorithm to harvest maximum power from the panels, and charges the battery bank.
  4. The battery bank (16 kWh) stores energy for night-time and cloudy periods, and supplies the inverter when solar is insufficient.
  5. The inverter outputs 120/240V split-phase AC to the outlet boxes — 120V branches for standard loads, 240V for large appliances.

Wiring Diagram

Editable diagram: 10kW-offgrid-wiring-diagram.drawio — open in draw.io (app.diagrams.net) to edit.

DC wiring (48V side)

  • Panels → MC4 extensions: each panel uses MC4 connectors; extension cables (+/− pair) run the array to the disconnect.
  • PV disconnect → inverter DC input: the PV circuit lands on the inverter's PV terminals.
  • Battery → inverter: heavy battery cables with lugs (2 AWG class for 10 kW at 48V). Polarity matters — double-check +/− before connecting.

AC wiring (120/240V side)

  • Inverter AC output: split-phase terminals — L1, L2, Neutral, Ground.
  • 120V outlet box: wired from L1 · N · G.
  • 120/240V outlet box: wired from L1 · L2 · N · G (shown in the video).

Grounding

  • A grounding electrode (ground rod) bonds the inverter chassis and AC wiring to earth.
  • Use a proper grounding conductor; this is a critical safety step for an off-grid system.

[!WARNING] Electricity is dangerous. Always disconnect PV and battery before working on the system. Use DC-rated disconnects, the correct wire gauge, and follow local electrical codes. The video is educational only — have your installation reviewed by a qualified person if in doubt.

Parts List (from the video description)

Part Link (affiliate)
10kW 120/240V Inverter https://amzn.to/3J9Oyl2
16kWh Battery (Yixiang DIY kit) https://yixiangpower.com
Battery Cables https://amzn.to/40IMHcB
Solar MC4 Extension Cables https://amzn.to/4l34suq
PV Disconnect https://amzn.to/4lZ0aFc
120V Outlet Box https://amzn.to/4kKWW7d
120/240V Outlet Box (shown in video) https://amzn.to/41csb43
Used Solar Panels https://www.santansolar.com
New Solar Panels https://www.currentconnected.com

Quick-Start Build Sequence

  1. Design & size — confirm loads, pick the 10 kW inverter and 16 kWh battery (48V platform).
  2. Mount panels — ground-mount or roof-mount racking; wire panels in series strings to stay within the inverter's PV input voltage range.
  3. Run MC4 extensions from the array to the PV disconnect.
  4. Install the PV disconnect near the inverter, rated for the array's DC voltage.
  5. Connect the battery bank — assemble cells/box, connect battery cables (correct polarity) to the inverter's battery terminals.
  6. Connect AC output — wire L1/L2/N/G to the outlet boxes (120V and 240V).
  7. Ground the system — bond inverter chassis and AC panel to the ground rod.
  8. Commission — turn on PV disconnect, verify battery voltage on the inverter display, then switch on AC loads progressively.

Key Takeaways

  • A 10 kW split-phase inverter with built-in MPPT and charger keeps the BOM small: panels, disconnect, inverter, battery, cables, outlet boxes.
  • 48V platform keeps DC currents manageable for 10 kW of power (≈ 200A+ at 48V — hence 2 AWG-class battery cables).
  • 16 kWh LiFePO4 provides roughly a day of typical household usage and pairs well with a 10 kW inverter.
  • 120/240V split-phase output covers both standard US 120V circuits and 240V appliances from a single inverter.