Where This Guide Comes From
Everything below is built from one source video — Will Prowse's Build a 5,000W Off-grid Solar System in 1 Hour from the DIY Solar Power channel, watched more than 949,000 times. It is a complete beginner walk-through: a 5,000W off-grid system that fits on a hand truck and is big enough to run a cabin, a boat or an RV — mini splits, refrigerators and whatever else you need. Watch the full build here:
DIY Solar Power with Will Prowse — "Build a 5,000W Off-grid Solar System in 1 Hour"
Watch on YouTube →
949K+ views. A complete beginner build: 48V battery, 5,000W all-in-one, panel sizing math and the safe start-up order.
The short version: this system is deliberately simple. It has three major parts — a 48V battery, a 5,000W all-in-one unit (inverter, solar charge controller and battery charger in one box), and solar panels sized to the right voltage window. You wire the battery first, add a disconnect for the panels, connect your loads, plug in AC charging, and follow one strict start-up order. If you can turn a screwdriver, this is a build you can finish in a day.
The Core Parts: Hand Truck, 48V Battery and the 5,000W All-in-One
The platform is a $79 hand truck from Harbor Freight, secured with a ratchet strap. On it goes a server rack battery — or any 48V battery you already own. Next to it sits the 5,000W all-in-one, which combines the inverter, the solar charge controller and the battery charger in one box, so every connection in the system lands in a single unit. That is the whole design philosophy: low parts count, clear terminals, and everything labeled positive and negative.
Step 1: Connect the Battery the Safe Way
Use battery cables about two feet long with 5/16-inch lugs — buy them or make them, and either way keep the red cable for positive and the black for negative. The all-in-one ships with two screws for these connections. Before you touch anything, confirm the battery is off: no lights, the power button not pressed, and the circuit breaker showing green, not red. Then connect the battery with the screws that came with it.
Step 2: Add a Solar Disconnect Switch and Wire the Panels
Solar panels are the most dangerous part of an off-grid system because DC voltage is unforgiving, so the build puts a solar panel disconnect switch between the panels and the all-in-one. Panels land on one side of the switch; the other side connects to the PV input on the all-in-one. Strip the wires, loosen the terminals, tighten them down properly, and then wiggle each wire to confirm the connection is solid — a loose PV connection is a common failure point.
Step 3: Connect Loads — Power Strip vs Load Center
To actually use the power you need outlets. A simple power strip is what most beginners start with and it is safe, but it limits you: a typical strip handles around 1,800W while this inverter is rated for 5,000W. If you want full output, use an outlet box or — properly — a load center where each outlet gets its own circuit breaker. The creator notes that plenty of people just push the wiring in and it works, and the inverter's own overcurrent protection will shut down on a short (he tested it). For a first build, one conductor per terminal with the black on L, white on N and bare ground on ground is dead simple and correct.
Step 4: AC Charging Without Solar
The built-in battery charger needs an AC supply, so the last wiring step is a nine-foot tool replacement cord from the hardware store — already spliced, with green for ground, white for neutral and black for line. Plug it into the wall and the battery charges even with no sunshine. That makes the system usable immediately and keeps the battery healthy between solar days.
Start-Up Order and the UPS "Bypass" Behavior
Power-on order matters: first flip the battery breaker to on (it shows red), then press the power button — this charges up the capacitors in the all-in-one. A few seconds later the inverter turns on, the fan spins up and the light goes green. With the AC cord plugged in, the display shows bypass: loads are powered from the wall while the battery sits ready. Unplug the wall feed and the heat gun keeps running because the unit has a UPS function — it switches to battery so fast you won't notice, which makes it excellent backup power for computers and refrigerators.
Solar Panel Math: Voltage Windows That Work
Panels connect in series (daisy-chained), and the number you need depends on voltage, not wattage. This inverter needs a minimum of 120V and performs best from about 200V up; never exceed 500V. With a panel whose operating voltage is 28V, 200V ÷ 28V ≈ 7 panels minimum. For the ceiling, take the open-circuit voltage — say 33V — and divide the 500V limit: 500 ÷ 33 ≈ 15, dropped to 14 for safety. So for this panel, 7 to 14 panels in series works. Use MC4 extension cables to reach a solar array far from the cart.
Add-Ons: Step-Up Charge Controller and 48V-to-12V Converter
Two add-ons widen the system. Short on space for seven panels? A step-up charge controller lets a single small panel charge the 48V battery — it connects straight to the battery terminals. Running 12V loads in an RV, van or boat? A step-down converter turns 48V into 12V and feeds a 12V fuse block, so all your 12V appliances just work. Both are simple bolt-on modules.
The system is modular by design: mount it on a wall, add more batteries, swap in a load center with ten outlets — whatever you need, you can build it from this starting point. And because it is on wheels, the whole power plant moves with you.
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Reviewed by Dajiu Energy Engineering Team — a Chinese LiFePO4 battery manufacturer building LiFePO4 batteries for RVs, homes, golf carts and portable applications since 2017, serving OEM/ODM projects with CE, UN38.3, MSDS and ISO9001 certified builds.
What Viewers Are Asking (Top Comments on the Video)
These are the most useful of the video's top comments, with our practical answers. Where the creator replied, we quote the creator's own words; where there was no reply, the answer is ours. Thanks-only comments were left out; these are the ones with real information.
@blaydCA · 225 likes
"An hour he says!! Maybe so for most people. DAY ONE: One hour to find my tools... One hour to find dropped screws.. One hour to locate the hardware... Ten minutes to scould the dog for digging holes... One hour to relocate tools that I put down to scould the dog .. Two hour NAP because "reasons"... 15 Minutes to recharge cordless drill... One hour to locate another #2 Philips bit... One Hour to assemble most of it... DAY TWO: One hour to drag out spare PV panels... One hour to crimp cable ends and …"
Our take: A fair joke, and a fair warning: the "one hour" assumes tools and parts are laid out already. Plan for an afternoon on a first build — finding tools, dropped screws and reading the manual all take time. The actual wiring steps are quick once everything is on the table.
@WillProwse · 126 likes · creator reply
"Official Parts List to Build Your Own): https://www.willapproved.com/mobile-48v-system.html Important Links Mentioned: Cold Climate String Voltage Calculation: https://youtu.be/5sYi_HFgmSY?si=OUrvc26LGTzEC4Gn Outlet Box Tutorial: https://youtu.be/6nPgF8RmDCc?si=ge33kO75pXfk86I2 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Don't want to burn down your house? Need equipment you can actually depend on? Check out my latest "Will Prowse Approved" solar product recommendations here: https://www.willapproved.com/ Tired of leaving reviews that get censored by the manufacturer? Need to find the lowest price UL certified battery? Check out Charged Reviews: https://www.chargedreviews.com Need more help? Join the largest DIY solar forum on the internet for beginners and professionals alike: https://www.diysolarforum.com Check Out My Free 12V …"
Creator (video uploader): The creator posted the official parts list, including the mobile 48V system page, cold-climate string voltage calculation and all component links, in the video description. Follow the creator's own parts list to match the exact components used in this build.
@Tiarpita · 116 likes
"I did this same exact thing about a year ago. I even used that same SunGoldPower 5K off grid inverter, LFP battery and seven 450W panels. I initially did it as an emergency power source. It works so well that I just leave it plugged into a 6 breaker transfer switch so I can choose and isolate loads. It powers most everything in my home day and night. My power bill has been cut by more than 2/3rds. Good stuff!"
Our take: A viewer built the same system a year ago with the same SunGoldPower 5K inverter, LFP battery and seven 450W panels, and it has been running since. That is the confirmation this build works in real homes, not just on a workbench.
@mikeb8342 · 113 likes
"For beginners.... to prevent cross-threading screws (going in crooked, causing thread damage), start by slowly turning left (as though loosening) with light pressure until you feel it "click", then turn right to tighten. Just my $.02"
Our take: A practical screw tip worth repeating: to avoid cross-threading screws into the inverter and battery terminals, start by turning the screw slightly counter-clockwise with light pressure until it clicks into the thread, then tighten normally. It takes one extra second and protects expensive terminals.
@danielking2944 · 43 likes
"I have had a master electrician license for 25 years but learn most of what I know about solar from Will Prowse . This video is at the level that I learned from. There are issues that you might never encounter in the electrical trade that are absolutely necessary to understand when dealing with solar power.
Thanks Will for a tutorial I can recommend to beginners!"
Our take: Even a 25-year master electrician watches this channel to learn solar specifics. That is the point of the video: solar wiring has its own conventions (PV polarity, disconnect order, voltage windows), and following a proven sequence beats improvising.
@Paul-f3t7o · 29 likes
"Great version 2 of the hand truck off-grid system, even though yellow box EG4 has indeed dropped in price, this alternative is more bang for the buck. I ordered and put it together, with a few refinements, using a Square D QO 60A Main Lugs plastic load box ($35), a tandem 20A QO breaker ($31), and two Southwire 20A power strips ($36ea.), all to maximize full output of the inverter. A great little system. Will add this comment and pics in the forum."
Our take: A viewer compared the yellow-box EG4 system and concluded this hand-truck alternative is more bang for the buck after the price drop. The all-in-one approach keeps parts count low and the whole system on wheels, which suits cabin and rental use.
@lesliethiel2171 · 19 likes
"How do you mount the inverter to the hand truck? Do we need to worry about grounding?"
Our take: Mounting: most people bolt or strap the inverter frame to the cart and keep the battery strapped below with a ratchet strap. Grounding: yes, think about it — connect the inverter chassis ground and keep the PV disconnect between panels and the charge controller so you can kill DC before touching anything.
@scottn5389 · 18 likes
"When working with electricity, we don't make mistakes, we have zappy accidents."
Our take: The safety message behind the joke: DC solar voltage is genuinely dangerous, and the video's rules (breaker off, disconnect green, panels disconnected before wiring) exist because mistakes with electricity are unforgiving. Follow the order exactly.
@rixanneh18 · 60 likes
"I watched you build a system on a piece of plywood back in 2017. It helped me to completely understand solar and how all the components work together. I bought a van, and all the parts I needed to build a solar system in it. 200 watts on the roof. a controller and fuse box inside. a 3000 watt inverter. 1200 amp hours of lithium batteries that also charge off of the van's alternator when I'm driving. It's still working today. Thanks for helping me and everybody else."
Our take: Long-time viewers learned the whole system on a plywood board build back in 2017 — this hand-truck version is the same teaching, packaged for portability. If you already understand the components, the new part here is the cart layout and the safe start-up order.
@CLL-1 · 900 likes
"Gotta love how Will is speaking as if he’s addressing a room full of 2nd graders. Which frankly…is what most of us “adults” still need. 😂 Great video sir!"
Our take: Will Prowse deliberately speaks slowly and plainly because most of his audience are true beginners — that is exactly the right level for a first solar build. If the pace feels simple, skim ahead; if it feels fast, rewind. The build itself is genuinely beginner-safe.
Source video: DIY Solar Power with Will Prowse — "Build a 5,000W Off-grid Solar System in 1 Hour" (youtube.com/watch?v=4m7jiNTrBjQ). Comment excerpts are quoted verbatim from the video's top comments; the creator replied to one thread and that reply is quoted. All other answers are Dajiu Energy's own. Figures are transcribed from the video and are representative, not guarantees.