Everything in this article comes from one source video — DIY Solar Power with Will Prowse's Offgrid Solar Beginner Crash Course: Build a 10,000W Solar System, watched more than 1.29 million times. Will Prowse is one of the most-followed solar and battery reviewers on YouTube (1.15M subscribers), and in this video he assembles a real 10,000W, 48-volt off-grid system on camera — battery, all-in-one inverter, solar input and AC output — with the explicit goal of proving a beginner can do it in under an hour. If you would rather watch the build before reading the breakdown, the video is right here:
The video's core message is simple: a few years ago this class of system meant multiple wall modules, multiple batteries and a lot that could go wrong. Today, one 48V battery, one all-in-one unit and a small disconnect switch form a complete system. The reviewer's build order matters — battery off before wiring, solar disconnect off before connecting panels, everything off before the first power-up — and that discipline is the difference between a one-hour project and a frustrating afternoon. It is the same sequence our engineers follow when we commission home storage systems, so the steps below match real-world practice, not just the video.
The heart of this build is a 48-volt all-in-one — a single box that combines an inverter, an AC battery charger and a solar charge controller. A few years ago those were separate modules on the wall, each with its own wiring, settings and failure points. Now the whole system is one unit you screw to a wall and connect with two battery cables.
The battery in the video is a 48V pack with 16 kilowatt-hours of storage. The math is easy: 16,000 watts for one hour, or 1,000 watts for 16 hours. As the reviewer notes, 48V batteries get cheaper every year, which is why this voltage class has become the default for new off-grid builds — and why most of our solar storage guides now assume a 48V architecture.
A complete system, in the reviewer's build, is literally three parts:
First, the 48V battery with its main breaker — the breaker is the kill switch you must throw before touching any terminal. Second, the all-in-one, mounted on the wall with a few screws. Third, a PV disconnect switch between the solar panels and the all-in-one's solar input — about $30-40, and the reviewer calls it a safety must for beginners because it lets you kill solar power at the source without touching live panel wiring.
Then two sets of cables: battery cables (positive and negative) from the battery to the all-in-one, and an AC output cable from the all-in-one to an outlet box or load center. That is the entire physical system. Everything else in the video is about doing those connections safely and in the right order.
Before any work on the battery, switch the main breaker to off. Then connect the battery cables — black for negative, red for positive — to the all-in-one's terminals and tighten with a socket (size 13 in the video). The reviewer's habit is to wiggle every terminal after tightening and check that nothing is loose; a loose connection is the most common source of heat and intermittent failures in a solar system.
Battery cables are standard off-the-shelf items: for a single battery, the common pre-made cable size works fine; if you later add a second battery, step up to 2/0 or 4/0 cables. The reviewer's point is that cable selection is not magic — match the cable to the system's current, buy it pre-made, and tighten it properly.
The all-in-one's PV input usually arrives without a disconnect switch, so the reviewer adds one — a $30-40 two-pole breaker that sits between the panels and the unit. The wiring is directional: the disconnect's input side connects to the solar panels (typically through an MC4 extension cable), and its output side feeds the all-in-one's PV terminals. You connect the extension first, then the panels, and you keep the disconnect in the off position until everything is done.
Voltage matching matters: for a 48V all-in-one, the reviewer recommends a minimum of 200 volts from the array, which with 40V panels means at least five panels wired in series. Panels can lie on the ground or sit on an off-grid ground mount — the array just needs to reach that voltage window so the MPPT controller operates in its sweet spot.
This build's all-in-one is a 120/240-volt split-phase inverter rated at 10,000W. Its output has four conductors: two hots, a neutral and a ground — three current-carrying. Sizing the wire is arithmetic: 10,000W ÷ 240V = about 41 amps, so with headroom you want a conductor rated around 50A. The video uses 6 AWG THHN, which handles 55-65 amps depending on insulation and terminal temperature ratings — the same wire you can buy at any hardware store.
The ground can be 10 AWG because it carries no current — its job is to give the whole system a reference potential. All four conductors run inside flexible conduit to the outlet box or load center. Color coding matters: two hots (black and red), neutral always white, ground always green. The reviewer strips the wire, seats it in the screw terminal and torques it down — and then checks every single terminal for tightness, finding and fixing a loose neutral-bus screw during the build.
For a cabin, shed or workshop load, the video uses a pre-built outlet box — a small enclosure with breakers and outlets that plugs straight into the AC output. It takes seconds to install and is genuinely beginner-friendly: hot, hot, neutral, ground, four terminals, done.
If you are wiring an entire house, you need a real load center (breaker panel), and the reviewer is blunt: hire someone for that, because everything inside a house panel has to be sized and bonded correctly. The distinction is important for safety — a sub-panel for an outbuilding is a weekend project; a whole-home panel with a neutral-ground bond is electrician territory. When in doubt, the outlet box route gets you running safely today.
The safe startup sequence in the video: make sure everything is off, turn on the battery breaker first (this charges the inverter's capacitors), then turn on the inverter, wait about a minute, and confirm 120V appears at the outlet box. Nothing gets energized until every connection is tight.
Most all-in-one default settings are fine, with two exceptions the reviewer flags. Setting 8, battery type, must be set to "user." And setting 15, the low-voltage disconnect, should be set to 46-48V so the unit shuts loads off before the battery is drained flat — without it, the unit can enter safety mode and be hard to restart. Once that one setting is right, the system cycles by itself: solar charges during the day, loads draw at night, the battery hits low-voltage cutoff, and the unit wakes itself when sun returns.
Scaling is the reason the reviewer picked this architecture. Adding a second 48V battery is two more cables and a parallel connection — no new modules, no re-wiring. The solar input is limited to 5,000W per input, so a 10,000W array can feed the system through both inputs, and the video's carport array of about 10,000W is shown powering the whole build.
The reviewer's sizing advice is refreshingly simple: if the battery is not reaching 100% every couple of days, add solar; if it dies before morning, add batteries. Most people overshoot on one side or the other, and this rule corrects both cheaply.
The video's most valuable warning: beginners should not connect the AC input on these units. The AC input is where a generator or grid feed enters the system — and it brings the neutral-ground bond question with it, which the reviewer says most electricians themselves get wrong. His advice: buy a simple 48V battery charger, connect it to the terminals, and charge from AC that way. If you need more energy, add solar panels.
Staying single-unit also keeps things simple: one all-in-one and one or two batteries needs nothing exotic. Parallel operation of multiple units requires perfect neutral-ground bonding and a pile of other details — fine for an installer, wrong for a first build. The reviewer has been running this exact system for years, and he has pushed almost 100kWh through it — including level-2 charging a Tesla from the 120/240V output, which he points out is faster than most home 120V EV charging.
The reviewer frames the finished system as "a gas station for an electric vehicle": a 10,000W inverter, 120/240V split-phase output, 16kWh of storage and a ground-mount array can charge a Tesla for most people's daily commute, run a cabin, or power a workshop. The parts list is short — a 48V battery, an all-in-one, a $30 disconnect, battery cables, 6 AWG THHN, an outlet box — and the whole thing is installable in about an hour by someone who has never built a solar system.
That is the real message of the video, and it is why we recommend the same architecture when customers ask about off-grid and home storage batteries: 48V keeps cable sizes sane, all-in-one keeps wiring simple, and LiFePO4 keeps the pack safe and long-lived. If you are sizing your first system, the video's rule of thumb — 16kWh of battery and 10kW of inverter covers a whole cabin or an EV commute — is a solid starting point, and our engineers will help you match voltage, capacity and footprint to your exact load.
Dajiu Energy is a Chinese manufacturer building LiFePO4 batteries for RVs, homes, golf carts and portable applications since 2017. Our product range covers LiFePO4 drop-in replacement batteries, EV and golf cart batteries, wall-mounted home storage, portable power stations, commercial energy storage and battery swap cabinets — explore the full lineup in our product center, or browse more buying guides. Tell us your voltage, capacity and size, and we'll engineer the pack to hit it.
Source video: DIY Solar Power with Will Prowse — "Offgrid Solar Beginner Crash Course: Build a 10,000W Solar System" (youtube.com/watch?v=rRqV8BHE8lY). Comment excerpts are quoted verbatim from the video's top comments; answers are Dajiu Energy's own. Build details, settings and measured figures are transcribed from the video as of filming and may vary by inverter model.
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