The short answer: choose a solar generator by matching three numbers to your needs: battery capacity (how long it runs, in watt-hours), continuous output (how much it can run at once, in watts) and solar input (how fast it recharges from panels). Then check battery chemistry, expandability, how it connects to your home, and the warranty. This guide explains each criterion in plain English so you can compare any model with confidence. We cover how to judge them, not which brand to buy.
First, what is a solar generator?
A “solar generator” is a portable power station (a battery, an inverter and outlets in one box) paired with solar panels for recharging. It has no engine, burns no fuel and makes no exhaust, so you can use it indoors. During an outage you run your essentials from the battery and recharge it from the sun during the day, from a wall outlet when power returns, or sometimes from a car or a fuel generator. Browse the category at solar generators.
Step 1: Work out your daily energy need
List what you want to run and roughly how many hours a day. Multiply watts by hours for each item and add them up to get watt-hours (Wh) per day. Our generator sizing guide has a worksheet and typical appliance wattages.
Example: a refrigerator might use very roughly 1,000–2,000 Wh per day, a Wi-Fi router about 250–700 Wh per day, a few LED lights for six hours a few hundred Wh, and phone and laptop charging a few hundred more. Check your own devices, because they vary a lot.
Step 2: Battery capacity (Wh): how long it lasts
Capacity is the size of the “fuel tank”. Compare the battery’s usable capacity with your daily energy need. Real-world run time is lower than capacity divided by load, because the inverter uses some energy and cold weather and battery age reduce what you get. A sensible rule is to plan for some margin on top of your calculated need.
- Small (under about 1,000 Wh): phones, laptops, lights, CPAP for a night or two, camping.
- Medium (about 1,000–3,000 Wh): a fridge plus essentials for roughly a day, depending on use.
- Large or expandable (3,000 Wh and up): essentials for multiple days, especially with solar recharging, and sometimes connection to a home panel.
Step 3: Continuous output and surge (W): what it can run
The inverter’s continuous rating is the most it can power at once. Add up the running watts of everything you will use together and pick an output rating comfortably above it. Also check the surge (peak) rating: refrigerators, pumps and some tools need a short burst of extra power to start.
If you need 240-volt power for a well pump or a larger appliance, look for models that support 240 V output or can be linked in pairs, and confirm how they connect to your panel.
Step 4: Solar input: how fast it recharges
This is what separates a useful solar generator from a battery that runs out on day two. Look at:
- Maximum solar input in watts. Higher means faster charging if you have enough panels.
- Accepted voltage range. Your panel setup has to fit within it. The manual will say how many panels can be connected and how.
- Panel wattage and sun hours. A rough estimate of daily solar energy is panel watts × peak sun hours in your area, then reduced for real-world losses. Panels rarely produce their full rating because of angle, heat, clouds and shading, so plan conservatively.
If your daily solar harvest is close to your daily energy use, you can keep essentials running for as long as the weather cooperates.
Step 5: Battery chemistry and lifespan
Most current home-backup power stations use lithium iron phosphate (LiFePO4 or LFP) batteries, which are generally known for long cycle life and good thermal stability compared with other lithium-ion chemistries. Check the manufacturer’s stated cycle rating (how many full charges before capacity drops to a stated percentage) and how it defines that number, so you compare like with like.
Step 6: Home connection and backup features
- Pass-through or UPS mode: lets the unit stay plugged in and take over automatically when the power drops. Check the stated switchover time if you are protecting computers or medical devices.
- Transfer switch or smart panel compatibility: larger systems can power selected home circuits through a transfer switch or the manufacturer’s home panel, installed by a licensed electrician.
- Expandability: extra battery packs let you start smaller and add capacity later.
- Multiple charging inputs: wall, solar, car and generator charging give you more options in a long outage.
If you want automatic, whole-home coverage with solar, look at home battery backup systems as well; they are designed to be permanently installed.
Step 7: Practical details that matter in real life
- Outlets: enough AC outlets of the right type, plus USB-C and other DC ports.
- Weight and handling: a large unit can be very heavy. Wheels and handles matter if you will move it.
- Noise: cooling fans can be audible under heavy load; check if you will sleep near it.
- Display and app: clear readouts of input, output and remaining time make planning easier.
- Safety listings: look for recognised safety certifications listed by the manufacturer.
- Warranty and support: length of warranty, what it covers and who handles claims.
A simple checklist to compare models
- Usable capacity (Wh) covers my daily need, with margin
- Continuous output (W) covers everything I run at once; surge handles my biggest motor
- Solar input (W and voltage range) fits the panels I plan to use
- Battery chemistry and cycle rating suit years of use
- Expandable if my needs may grow
- UPS mode and/or home-panel connection if I need automatic backup
- 240 V support if I need it
- Warranty and safety listings I am comfortable with
Solar generator or something else?
Solar generators shine for essentials, apartments, medical devices and households that do not want to store fuel. For heavy loads like central air over several days, compare them with inverter and dual-fuel generators or a standby system in our guide to standby vs portable vs solar generators. Many households combine a solar generator for quiet overnight power with a fuel generator for heavy daytime loads. For outages in general, see how to prepare your home for a power outage.
FAQ
How big a solar generator do I need for my house?
For essentials like a fridge, lights, internet and phones, many households look at roughly 1,000–3,000 Wh of capacity and enough solar input to refill a good share of that each day. Whole-home coverage needs a much larger, usually permanently installed battery system. Add up your own daily watt-hours to be sure.
Can a solar generator run a refrigerator?
Yes, a suitably sized one can, as long as its continuous output and surge cover the fridge and its capacity covers the hours you need. Check your fridge’s label for its wattage.
How long does it take to charge a solar generator with solar panels?
It depends on the panel wattage, your sun hours, weather and the unit’s maximum solar input. Divide the battery’s capacity by the realistic hourly solar output for a rough estimate, and expect cloudy days to take longer.
Can I use a solar generator indoors?
Yes. Because there is no engine or exhaust, solar generators and power stations are safe to use indoors. Keep the panels outside, and follow the manual for ventilation and placement.
Is a solar generator worth it for home backup?
If your main need is essentials during outages, you want quiet indoor power, or you want to avoid storing fuel, many people find it a good fit. For heavy whole-home loads, a standby generator or home battery system may suit better.
What should I look for in a home backup power solution?
Start with what you need to keep running and for how long. Then match three numbers: battery capacity in watt-hours (how long it lasts), continuous and surge output in watts (what it can start and run), and how fast it recharges from the wall, solar or a generator. After that, compare battery chemistry and cycle life, how it connects to your home (plug-in, transfer switch or interlock kit), noise, weight and warranty.
Want help matching a solar generator to your list of devices? Email us and we will help you work it out.
This guide is general information, not electrical advice. Anything connected to your home’s wiring should be installed by a licensed electrician and checked against local code.