Harnessing the sun's energy for off-grid power is nothing new, but the technology behind it keeps getting better, more affordable, and more accessible. If you have ever sat in your workshop or shed and realized the only thing you truly need is a simple lighting setup, you have probably already wondered whether a small solar system could handle the job. The same thought applies to camping trips, outdoor events, or any scenario where mains electricity simply is not available.
Over the past few years, commercially available "solar generators" have become quite popular. These bundled kits typically include a solar panel and a sleek carrying case that houses a charge controller, battery, and various output ports. They are convenient, but they can also be expensive — often running several hundred dollars for a basic configuration. That naturally raises the question: can you build one yourself?
The answer is absolutely yes. In this guide, we will walk through every major component you need, how to choose the right parts, and how to bring everything together into a functional, semi-portable solar generator that you can use in your backyard, shed, campsite, or wherever you need reliable off-grid power.
Defining Your Use Case
Before purchasing a single component, it pays to think carefully about what you actually need your solar generator to do. A system designed to charge a phone and power a few LED lights will look very different from one intended to run a laptop, recharge large battery packs, or supply energy to power tools.
For this particular build, the goals were straightforward: provide enough power to charge phones and laptops, run 12 V LED lighting in a shed, charge hobby batteries for RC vehicles and electronics projects, and potentially feed a small inverter for occasional 120/240 V needs. The system also needed to be semi-portable — light enough to carry short distances and set up inside a tent, van, or outbuilding without too much hassle.
With those requirements outlined, it was time to start sourcing parts. At the most fundamental level, a DIY solar generator requires three core components: a solar panel, a battery, and a charge controller. Beyond that, a handful of accessories make the system safer, more flexible, and easier to use.
Choosing a Solar Panel
When it comes to selecting a panel, a 100 W monocrystalline unit is a solid entry point for a system of this size. On a clear, sunny day with proper positioning, a 100 W panel can feed a meaningful amount of energy into your battery. Just as importantly, even on overcast winter days, it will still trickle a small current into the system — enough to keep the battery topped off and prevent it from slowly draining.
Monocrystalline panels in the 100 W range are widely available and very affordable. They are large — typically around 1,000 mm by 500 mm — but surprisingly lightweight thanks to their aluminum frame. Most panels in this category come with pre-drilled mounting holes around the frame, giving you plenty of flexibility for installation whether you want to mount it on a shed roof, lean it against a surface, or build a tilt stand.
Of course, if you want more power or faster charging, you can absolutely step up to larger panels or use multiple panels in parallel. Having a system designed for expansion from the start is a smart approach, and it influences other component choices — particularly the charge controller rating.
Selecting the Right Battery
Battery selection is one of the most important decisions in this project, and there are several different chemistries to consider. Traditional flooded lead-acid batteries are the most affordable and have a long track record in solar applications, but they need ventilation, must be stored upright, and resemble standard car batteries in size and weight.
Sealed lead-acid (SLA) batteries solve the ventilation concern, but if your system might get moved around or stored on its side, gel-type or AGM batteries are a better fit. Lithium-ion and lithium iron phosphate (LiFePO4) batteries are the lightest and most compact option, making them ideal if you are building a larger capacity system or need maximum portability. They do cost more upfront, but their longer cycle life and superior depth-of-discharge ratings often make them more economical over time.
For a starter build focused on moderate loads — lighting, phone charging, and occasional hobby use — a 12 V lead-acid battery rated around 100 Ah provides a healthy capacity. It should handle several days of light use between charges, and the solar panel will work to replenish it every day.
PWM or MPPT?
Understanding Charge Controllers
The charge controller sits between your solar panel and battery, regulating the flow of energy and protecting the battery from overcharging. There are two main types to consider: PWM (pulse-width modulation) and MPPT (maximum power point tracking).
PWM controllers are the budget-friendly option. They have been around for years and are incredibly affordable — sometimes under $20. They do a perfectly acceptable job, but they are less efficient at converting the panel's output into usable charge. Typically, a PWM controller captures around 70–75% of the panel's potential power.
MPPT controllers are more advanced. They intelligently optimize the charge current based on the panel's voltage and current output as well as the battery's state. In practice, this means an MPPT controller extracts more energy from the same panel, especially in partially shaded or cloudy conditions. You will notice that the panel side might show 18 V at 1.7 A, while the battery side receives 14.5 V at 2.1 A — the controller is performing efficient DC-to-DC conversion in real time.
If your budget allows, MPPT is the better long-term investment. It is also wise to buy a controller rated higher than your current needs — for example, a 20 A unit even if your single panel will never exceed 6 A — so that you have headroom to add panels later without replacing the controller.
Getting Connected: Wiring and Connectors
Most solar panels ship with short leads terminated in MC4 connectors — an industry-standard weatherproof connector designed for outdoor solar installations. They are robust, rated to IP67, and simple to work with. To extend the reach between your panel and generator box, you will want to make extension cables using quality silicone-insulated wire.
For wire gauge, it is always smart to oversize slightly. Even if your system currently draws modest current, thicker wire (such as 8 AWG flexible silicone wire) keeps resistance low and minimizes energy losses between the panel and controller. This wire is also rated for much higher currents than you will need initially, which future-proofs the installation.
Adding MC4 connectors to custom cables is straightforward: strip a short section of insulation, crimp on a male or female terminal, and slide it into the connector housing. A basic solar crimp tool makes the job easy and produces reliable connections. The connectors are designed to stay attached once mated, but can be separated with a gentle squeeze of the side clips when needed.
Assembling the System
With all the components in hand, wiring things up is remarkably straightforward. Most charge controllers follow the same connection sequence: attach the battery leads first, then connect the solar panel. Once the battery is connected, the controller powers on and begins displaying status information — panel voltage, battery voltage, and load current.
Many MPPT controllers also feature a "load" output terminal that can be programmed for different behaviors. This is particularly useful for controlling lighting: you can set it to power lights automatically for a set number of hours after solar charging stops in the evening, or configure it to cut power when the battery reaches a minimum safe voltage to prevent deep discharge.
One helpful accessory is a temperature sensor (thermistor) that plugs directly into the charge controller. Placed near the battery, it allows the controller to monitor battery temperature and shut down charging if things get too warm — an important safety feature, especially in enclosed spaces.
Building a Sturdy Enclosure
Once the electrical side is tested and confirmed working, it is time to build a case to house everything. A simple wooden enclosure made from plywood and square pine battens works beautifully. The design should prioritize ventilation (most charge controllers recommend at least 15 cm clearance on all sides), accessibility, and enough room to store cables and accessories alongside the battery.
A practical layout uses a two-level design: the battery and cables sit on the lower deck, while the charge controller mounts to the top shelf where air can circulate freely around it. Using screws rather than glue for the top shelf means you can remove it anytime you need to access the battery or reroute wiring.
For added safety and convenience, consider installing an inline circuit breaker on the positive cable between the battery and controller. Automotive-style breakers rated at 20 A are inexpensive, easy to mount, and give you a quick way to disconnect the battery side of the system. A small automotive fuse box on the output side is also a smart addition, providing properly fused connections for all the devices and accessories you plan to run.
Finishing Touches and First Use
Once everything is laid out and tested inside the enclosure, take it all back out and give the wood a proper coat of paint or sealant. If the case will live in a damp environment like a shed or garage, this step is critical for longevity. Adding a pair of sturdy handles to the sides makes the unit much easier to move around — especially since the battery alone adds considerable weight.
A system like this starts earning its keep from day one. It can run low-power 12 V lighting, charge phones and tablets, top off hobby batteries, and power small electronics entirely from sunlight. Once you start living with a portable solar generator, you begin to see possibilities everywhere — from powering outdoor entertaining setups in your backyard to running workshop tools off-grid. It truly opens up a new way of thinking about energy independence.
Skip the DIY — Go Pro
Want a Ready-Made Portable Solar Generator?
If building from scratch is not your thing, the EcoFlow DELTA Pro bundle delivers massive capacity, dual 220 W solar panels, and a free carrying bag — everything you need for serious off-grid power, right out of the box.