How to Pick the RIGHT Solar Kit: A Beginner-Friendly Guide

Feeling overwhelmed by the seemingly endless variety of solar kits on the market? You’re not alone. 

From whole-home off-grid systems to compact RV setups and portable solar generator kits, there are more options out there than ever—and if you’re just getting started, choosing the right one can feel like trying to decode an alien language. 

But don’t worry! Here at The Solar Lab, one of our overriding goals is to help simplify solar so you can avoid weeks of frustration and wasting your hard-earned cash on the wrong gear for your needs.

Today, we’re going to break down how to choose the right solar kit in five simple steps. Learn how you can confidently build the perfect solar setup for your needs. We’ll also provide a quick electricity refresher to help you learn the terminology.

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A Quick Electricity Lesson

Before we dive into how to size a solar poewr system, let’s cover the basics. For the purposes of this breakdown, imagine your electrical system is a garden hose:

• Volts (The Pressure): Think of voltage (measured in Volts) like the water pressure coming out of your garden hose. The standard measurements in your home are going to 120V or 240V, so you’ll want to check what your appliances and devices require. No need to overthink it.
• Amps (The Flow Rate): You can think of amperage (measured in Amps) like the width of the hose. A 15A circuit would be a relatively narrow hose; while a 20A circuit would be a wider one.
• Watts (The Volume): Wattage is measured in Watts, and you can think of it like the total water delivered per hour—the real focus of this entire guide. A handy equation you should try to remember for calculating Wattage is: Watts = Volts × Amps. I know, this sounds a bit confusing if you’re brand new to it, but think of it using these simple round numbers:
  
  • A 100W bulb uses 100 Watts per hour.
  • If you run that same lightbulb for just half an hour, it would work out to 50Wh (Watt-hours).

Knowing Watts and Watt-hours is critical for sizing any sort of solar power system. Every device or appliance you plan to power is going to list its volts and amps, so you can multiply them to find the watts required to run them. 

If you’re still feeling a little bit confused, you can check out our Basics of Solar and Electricity—it provides a really simple breakdown of how everything works. However, if you’re feeling ready to move on, let’s get started with sizing and choosing that solar kit.

Step 1: Calculate Your Daily Energy Needs

Before you start shopping for kits and components, the most important thing to do is actually figure out how much power you’re going to need each day. Again, it sounds overwhelming, but it’s actually pretty simple. 

To show you how straightforward this process is, let’s use an example.

Our Tiny Cabin Example:

Josh, our editor here at The Solar Lab, set up a solar-powered tiny cabin that he lists on Airbnb. If you’re familiar with our videos, you may have watched where we toured his cabin and learned how he’s able to power it using solar power.

It’s not a big deal if you haven’t seen this Cheap & Simple Tiny Home Solar Setup Video, but we’ll still use it as an example of how someone would go about sizing a solar power system for an off-grid property:

Inside the tiny cabin, Josh runs:

• Lights: 20W × 10 hours per day = 200Wh
• Mini-Fridge: 50W × 24 hours (fridge motors only run about 20% of the time) = 240Wh
• UV Water Bulb: 100W × 24 hour (this water purification light needs to run all day and night) = 2,400Wh
• TV and Miscellaneous Items: Roughly 1,000Wh total

This brings the total to roughly 5,000Wh per day. We say roughly because certain things are not going to have consistent use every single day.

Pro Tip: Always round up and assume the worst-case (mid-winter when you're inside more, so your electronics are getting their maximum usage) when calculating your power requirements. You always want to have more power than you need, rather than not enough.

If Josh wants 3 days of backup (the maximum stay he has listed on Airbnb), he is going to need 5,000Wh × 3 days = 15,000Wh, or 15kWh, of battery capacity.

If you’re finding it difficult to add everything up, we recommend trying out this Free Solar Load Calculator—it’s a pretty handy little tool.

Step 2: Decide Your Charging Method

Even though we heavily focus on solar, it’s not the only reason why people buy this type of equipment. You could be using a gas generator to charge your batteries, or even just grid power when rates are lower during off-peak hours.

Here’s a quick breakdown of what you’ll need to do based on your choice of power source:

Using Solar Panels:

1. Determine your Peak Sun Hours (most U.S. regions average between 3 and 5 hours per day, so we usually recommend rounding down to 4 if you’re unsure).
2. Divide your battery size by the number of peak sun hours where you live. For Josh, this would mean 15kWh ÷ 4 hours = 3.75kW. In his case, we recommend rounding up to a 4kW solar array. 
3. Choose panel wattage: solar panels come in different sizes, each with their own wattage rating, so you need to choose panels that add up to your wattage requirements. For example, if you went with 400W panels, you’d need 10 of them (4,000W of required power ÷ 400W panels = x10 400W solar panels).

If you’re still feeling confused about sizing your solar panel array, we actually have a guide: Sizing Solar Panels for Your Solar Power System.

Using an AC Input (Grid or Gas Generator Power):

If you’re using grid power or a gas generator instead of solar panels, you can just skip the panel sizing. Just ensure your inverter’s AC input rating (e.g., 30A at 240V = 7.2kW) can recharge your batteries in the timeframe you need.

Step 3: Pick the Right Inverter

Your inverter must be capable of handling your peak simultaneous load (think “hose width” × “pressure”). If we go back to our example of Josh’s tiny cabin:

• Peak Load: roughly a 2,000W surge, with a consistent power draw of about 1,200W 
• Voltage: 120V (none of the appliances he uses require a 240V input)

So, Josh would need roughly a 2,000W (or slightly higher) 120V inverter. 

We pretty much always  recommend going with an all-in-one hybrid inverter, as they simplify things by containing numerous components in a single unit (the solar charge controller, power inverter, and built-in breakers).

However, for fully off-grid use, something budget-friendly, like the EG4 3000 All-in-One Inverter, would be perfect (it has a 3,000W output, a 5,000W solar input, and it’s really easy to set up and program).

If you want grid-tied or hybrid functionality, meaning you want to sell power back to grid or just enjoy the flexibility you get with time-of-use settings, check out our inverter deep-dive here: Solar Inverters Made Simple.

Still unsure how to size your inverter? Don’t worry, we released a video breakdown you can watch: Sizing Your Inverter for Your Solar Power System

Step 4: Choose Your System Type

Now that you know how much power you’ll need your system to generate and store, what type of power you’re going to be running it on, and what size system you’ll need, it’s time to choose the type of solar power system you prefer.

Here’s a quick breakdown of the main types of solar kits::

• Off-Grid Kits: No grid connection. Requires a true off-grid inverter. Perfect for remote cabins, vans, sheds, and off-grid properties (like Josh’s cabin).
• Grid-Tie / Hybrid Kit: Connects to grid and solar, can charge batteries or sell back to grid. Great for emergency backup and peak shaving.
• AC-Coupled Backup: Charges batteries via the grid or a gas generator, then powers your loads with power stored in your batteries during outages, or when rates are more expensive.

Where Should You Buy Your Solar Kit?

While there are plenty of options out there, we regularly recommend checking out the pre-bundled solar kits available through both Shop Solar and Signature Solar.

Both retailers bundle compatible solar panels, inverters, and batteries, which means no guesswork, it’s cheaper than piecing parts yourself, and your new solar power system is going to be backed by real support teams.

We’ve mystery shopped both Signature Solar and Shop Solar, and found they offered genuine support, both before and after making a purchase. 

Step 5: Budget and Expandability Tips

Now that you know what you need and where to get it, let’s go over a few quick tips you can follow to avoid wasting time and money on components you should avoid:

• Buy the Right Inverter First: Never skimp on your inverter—if it’s underpowered, you’ll outgrow it and end up needing to replace it or buy a second one in the future (which will cost more).
• Save on Batteries and Panels: If you’re on a tight budget, you can start with half your required batteries or panels; then expand later by simply adding more modules. You can also purchase both batteries and solar panels as bundles, which is another really good way to drive your total costs down.
• DIY Where You Can: Trenching your cable lines yourself, building your own mounting racks, or assembling panel arrays yourself can save a lot in labor costs. Most of this stuff is way easier than you probably think. 

Pro Tip: You probably get the idea by now, but always purchase a slightly larger system than you currently need if your budget allows it. Your power requirements are likely to grow in the future—everything from kids getting new gadgets to purchasing an EV can make those watt-hours disappear faster than you’d expect.

Always Watch Out for Exaggerations and Biases During Your Research

Beware of “lifestyle” creators who gush about a specific solar kit they got for free—often they only show the sunshine and omit cloudy-day performance. Not only do many of them receive these kits in exchange for positive reviews, most of them have a limited understanding of solar power, so they’re just thrilled to have any sort of off-grid power.

Here at The Solar Lab, we buy our own gear, test multiple products, and tell you the rough parts as well as the smooth.

Our Final Words

Picking the right solar kit might seem complicated, but it all just boils down to the five steps we outlined above:

1. Calculate Your Daily Power Needs in Watt-hours
2. Choose an Appropriate Charging Method (solar array or AC input)
3. Select the Right Inverter (must have the right solar input if you’re planning on running solar panels)
4. Decide on Your System Type (off-grid, hybrid, or AC-coupled)
5. Budget and Expand Wisely (inverter first, batteries/panels later, DIY savings)

Check out our in-depth product reviews, grab our discount codes to save money, do your research and don’t be afraid to ask questions if you’re confused. 

We Recommend the Following Solar Kit Retailers:

Signature Solar: https://signaturesolar.com

Get $50 Off Your Order with Discount Code: THESOLARLAB50

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Shop Solar: https://shopsolarkits.com

Get 4% Off Your Order with Discount Code: THESOLARLAB