Every instruction in this article comes from one source video — City Prepping's DIY Solar Setup: Easy to Follow Step-by-Step Instructions, watched more than 3.7 million times. The host builds a complete 12V solar system for a first-time builder: a 100W solar panel, a charge controller, a lithium battery and a pure sine wave inverter, connected in three clearly separated wiring steps. No technical jargon, no special tools — just a Phillips screwdriver, a crescent wrench and a pair of needle nose pliers. If you would rather watch the build before reading the breakdown, the video is right here:
What makes this guide different from the usual solar explainer is the order it insists on. Most people want to start with the panels because they are the glamorous part, but the host wires the charge controller to the battery first, then adds the panels, and only then connects the inverter. That sequence is not cosmetic — it protects the electronics and keeps the work safe at every step. The same discipline applies whether you are building a system from scratch or installing a pre-made battery at home. These are the fundamentals behind every pack we assemble at Dajiu Energy.
The host opens with the real reason most people build their own solar system: customization. A kit or a ready-made power station is a fixed design — the voltage, the battery size, the inverter power and the expansion path are decided for you. When you build your own setup, you can modify it later as your needs change: add a second panel, swap in a bigger battery, or upgrade the inverter without replacing everything. The second reason is less practical but just as real: you develop a skill. Understanding how a solar system is wired means you can troubleshoot it, expand it and maintain it for years instead of calling a technician.
There is also a budget angle the video never has to spell out. The four components — panel, controller, battery and inverter — are each standard parts with transparent prices. You can start small (one 100W panel, one 12V battery) and grow the system over time, spending only when you are ready. That is exactly how we size systems at Dajiu Energy — we ask about the load first, then match panel, battery and inverter so you are not overpaying for capacity you will never use.
Before any wiring, the host lays out the four components and the energy path between them. Solar panels collect energy from the sun and pass it through cables to the charge controller. The charge controller regulates that energy — it keeps the voltage and current within safe limits — and passes it to the battery, where the energy is stored. To get the energy back out, a device called an inverter converts the battery's DC power into the household AC electricity your appliances actually use. You plug your phones, laptops or refrigerator into the inverter.
Connecting all of this takes three sets of ready-made cables, and that is the beauty of this build: every cable is sold with the correct connectors already on the ends. One set connects the charge controller to the battery, one connects the battery to the inverter, and one connects the solar panel to the charge controller. Along the way the host covers a few small extras — a fuse, a temperature sensor, a Bluetooth module — but those three cable sets are the whole project. Everything in this paragraph maps directly onto the systems we build at Dajiu Energy, just at larger capacities.
The single most important rule in the whole video comes first: connect the charge controller to the battery before you connect the solar panels to the charge controller. Doing it in the other order can damage the controller, because a panel in the sun produces voltage the moment it is connected, and most controllers are not happy seeing panel voltage without a battery to absorb it. The host demonstrates the battery-first order on a typical charge controller, and the layout he shows is common across most devices: six terminal holes — two marked PV plus and PV minus (PV stands for photovoltaic, where the solar panel will connect later), two marked bat plus and bat minus (where the battery connects now), and two marked load (not used in this build).
The battery cables have lugs on one end (for the battery posts) and stripped ends on the other (for the controller terminals), and in this example both cables are black — so the host's warning is worth repeating: keep track of which cable is positive and which is negative. He loosens the bat plus and bat minus terminals by turning the screws counterclockwise, slides the stripped ends in one at a time, and tightens each screw clockwise. The correct torque is "firm" — then he tests by giving each cable a light pull to make sure it does not slip out. On the battery side he removes the bolts, connects the negative cable first, and finger-tightens at this point because the inverter cables will join the same posts later. The whole step takes a few minutes, and the payoff is visible immediately: the charge controller screen lights up.
Once the controller is powered, there are two settings you must get right. First, define the battery type — in this build it is a lithium battery. Second, define the system voltage — 12V or 24V, and this system is 12V. These two settings are not optional: charging a LiFePO4 battery with lead-acid voltages under-fills it, while charging lead-acid with lithium voltages stresses it, so the controller's charge profile has to match the chemistry. The host found this particular controller easier to configure with its companion app than with the on-device buttons, and notes that either method is fine.
Two accessories are worth mentioning because the video does. A temperature sensor plugs directly into this controller, and the host strongly recommends one even on controllers that do not ship with it — it monitors the temperature where the battery is stored, which matters for both performance and safety. An optional Bluetooth module lets you watch the controller's numbers on your phone instead of walking to the controller. Both are small additions that turn a basic system into one you can actually monitor, and monitoring is what protects a battery over years. The same principle applies to every smart battery we build — the BMS is there to be read, not ignored.
With the controller connected to the battery, the second step is wiring in the panel. The build uses a single 100W solar panel, and notes that you can add more panels later — one panel keeps the demonstration simple. The panel's cables are stripped on one end; to reach the charge controller, the host uses MC4 extension cables — MC4 connectors on one end that click onto the panel's cables, stripped ends on the other that go into the controller's PV terminals. Just like the battery step, the polarity signs matter: the host points out that both cables may be black, and suggests a small piece of tape or a written plus/minus sign to keep them straight.
The host keeps the panel out of the sun while wiring, connects the negative cable into the PV minus terminal first, gives it a light tug, then inserts the positive cable into PV plus and tightens it down. Then comes the fun part: he carries the panel into the sun. The controller's screen immediately shows charge coming in, the app mirrors the same numbers, and the battery is officially charging from the sun. That moment — panel, controller, battery all talking to each other — is the whole system working. From here the only remaining question is how to get power out, which is exactly what step three answers.
The final wiring step connects the battery to the inverter, and the video is careful about the safety sequence. First, disconnect the solar panel from the charge controller — the host does not want to work on the system while it is actively pulling power from the panels. He removes the panel cables from the PV terminals, then disconnects the charge controller from the battery entirely: positive bolt first, then negative. Only now is the system safe to work on.
The inverter in this build is a 2000W pure sine wave unit, and before connecting it to the battery the host installs a fuse on the positive inverter cable — 175 to 200 amps for a 2000W inverter, with a link in the description to where he bought his. Two details about the fuse connection are worth copying exactly: the fuse must sit flush against the lug, and there must be no washer between the inverter cable and the fuse. He connects the negative inverter cable to the battery first, then places the positive cable — with the fuse — on the positive terminal. Expect a small spark when the positive connection lands; that is normal, and the host says so plainly. He finger-tightens the bolts at this point because the charge controller cables will return to the same posts, then tests the inverter with real appliances.
The system only works if everything is on the same battery, so the last assembly step is putting the charge controller back — essentially repeating step one. The host removes the inverter cables from the positive and negative terminals, brings the negative cable from the charge controller to the negative battery post (along with the inverter's negative lug), tightens it with a wrench, then does the same on the positive side. One detail matters here and it is the kind of thing beginners miss: no washer goes between the battery post and the cable lug — the lugs sit flush on the post, and any washers go on top of the lugs, pushing them down. Finally he reconnects the solar panel to the controller, negative first, then positive.
Now for the moment of truth. With the panel charging the battery and everything connected, the host turns on the inverter and plugs in devices. The key result is in the name: this is a pure sine wave inverter, which means the AC output is clean enough to safely power the electronics and appliances you would normally run from a wall socket — a TV, a refrigerator, phone chargers. Modified sine inverters cost less but produce a rougher wave that some motors and digital power supplies do not like. When customers ask us which inverter to pair with a 12V lithium battery, the answer is always the same: match the inverter's continuous wattage to the loads you actually run, and prefer pure sine for anything electronic.
The video ends the testing section with a battery rule that deserves its own heading: do not discharge below 20% of capacity while a load is drawing power. The host is explicit about why — going under 20% with the inverter running devices can damage the battery. This is exactly how battery management systems think: a lithium cell does not like being drained to zero, and repeated deep discharges are what kill packs prematurely. The 20% floor is a practical, easy-to-remember version of the BMS's low-voltage cutoff.
To actually know where the battery sits, you need a way to read state of charge — voltage alone is a poor fuel gauge on LiFePO4 because the voltage stays flat through most of the discharge. The battery in this build ships with Bluetooth, and the host monitors it through the app; the video also mentions a battery monitor as an add-on for batteries without built-in metering. Whichever you choose, the point is the same: watch the number, stay above 20%, and the battery will deliver the thousands of cycles it was designed for. That is the same monitoring advice we give with every LiFePO4 drop-in battery we ship.
Distilled from the video, a safe first build comes down to a short list. Wiring order: battery to charge controller first, panels second, inverter last — and disconnect the panel before touching the inverter connections. Polarity: label your cables if they are all the same color, and double-check that the negative cable truly comes from the bat minus terminal before you connect it to the battery. Fusing: put a correctly sized fuse on the positive inverter cable — 175–200A for a 2000W unit — and keep it flush against the lug with no washer in between. Terminals: lugs sit directly on the battery posts, washers only on top, and every screw gets tightened firmly enough that a light pull does not move the cable.
Two more rules from the video round out the checklist. Expect a spark when the inverter's positive cable first touches the battery post — it is normal, but do your connections in the order shown so nothing is live while your hands are in the box. And treat the battery with respect: set the controller's battery type to lithium (or the matching chemistry), keep the battery away from freezing temperatures, and never let a load drag it below 20%. Follow that list and a first build is not only safe, it is genuinely satisfying.
The video is a build guide, not a sales pitch, and it leaves the build-or-buy question open in a useful way. If you want maximum flexibility and enjoy the project, building gives you a system you can expand and repair with standard parts — and the skill to do it. If you want a finished unit that works out of the box with guaranteed protection circuitry, a factory-built station saves you the time. The honest middle ground is what most people end up with: build the basics (a panel, a controller and a battery) to learn, then buy the capacity you genuinely need for the loads that matter.
That middle ground is exactly the situation we work with every day. A customer tells us their load — a camper, a cabin, a workshop — and we match a LiFePO4 battery, a portable power station or a wall-mounted storage system to it, with OEM and ODM options for businesses that want the pack to carry their own brand. Whichever path you take, the fundamentals in this video are universal: correct wiring order, correct polarity, correct fusing and a discharge floor. Get those four right and your solar setup will run for a decade. For more reading, our buying guides and build breakdowns cover the same principles at larger scales.
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: City Prepping — "DIY Solar Setup: Easy to Follow Step-by-Step Instructions" (youtube.com/watch?v=M89LDaTzgmo). Comment excerpts are quoted verbatim from the video's top comments; where the creator replied, his words are quoted, otherwise answers are Dajiu Energy's own. Build figures are transcribed from the video.
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