When the grid goes down, a solar generator can keep your household running by powering your most critical devices. This article explains how to decide which loads to run, how to connect your generator safely to your home, and what to consider for 240V equipment like well pumps. You will also learn why back-feeding through a wall outlet is dangerous and how to plan for recharging during a long outage.
Decide Which Loads Are Essential
Before an outage, list the devices you need to keep running. Start with items that affect safety, food preservation, communication, and medical needs. For each device, find its running wattage (the power it uses during normal operation) and its surge wattage (the extra power needed to start motors or compressors). A device with a motor can need several times its running wattage for a moment when it starts.
To estimate your total load, add the running wattages of all devices you want to run at the same time. Then add the highest single surge wattage among those devices. This total helps you choose a solar generator with enough continuous and surge capacity. For a detailed process, see how to size a solar generator.
Consider that you may not need to run every device continuously. For example, a refrigerator cycles on and off, and you can run a microwave only when needed. Prioritize devices that must run 24/7, such as a medical device or a sump pump, and plan to cycle others.
Typical Essential-Load Plan
The table below shows a common set of essential loads for a home during an outage and where to find each one’s power figure. Always use the nameplate or a measurement for your specific device.
| Device | What to check | Notes on surge and operation |
|---|---|---|
| Refrigerator | EnergyGuide label (kWh per year) or a plug-in watt meter for daily energy | Compressor startup surge; runs on and off. See running a refrigerator on a solar generator. |
| LED lights | Watts printed on each bulb | No meaningful surge; easy to run for many hours. |
| Internet modem and router | Watts or volts and amps on the power adapters | Small but continuous load; matters over a long outage. |
| Phone and tablet charging | Charger rating | Small load; charge during the day when solar input is available. |
| CPAP machine | Power supply rating; much higher with a heated humidifier | Check with your device manufacturer and your doctor or supplier about DC cords and backup options, and have a backup plan. |
| Furnace blower (gas or oil furnace) | Blower motor rating on the furnace label; usually hardwired | Motor startup surge. Needs a transfer switch or interlock installed by an electrician; furnaces cannot simply be plugged into a power station. |
| Well pump | Voltage, horsepower and locked-rotor amps on the nameplate | High startup surge; often 240 V and hardwired. See the section on 240 V loads. |
To estimate runtime, divide your solar generator’s usable battery capacity (in watt-hours) by the average power of your connected loads. For cycling appliances such as refrigerators, use daily energy (Wh per day) rather than running watts: a fridge that uses 1,200 Wh per day averages 50 W, so 1,000 Wh of usable capacity at 85% inverter efficiency would run it for roughly 850 ÷ 50 ≈ 17 hours. Actual runtime depends on the refrigerator’s duty cycle, inverter efficiency (a common planning assumption is 85 to 90 percent), and battery chemistry. For more on matching generator capacity to loads, see surge vs continuous power.
Ways to Connect Safely
There are three main ways to connect a solar generator to your home and devices. Choose the method that fits your needs, budget, and electrical setup. Always follow the manufacturer’s instructions for your generator.
Extension Cords to Devices
The simplest method is to run heavy-duty extension cords directly from the generator’s AC outlets to each device. This works well for a few loads that are close together, such as a refrigerator, a lamp, and a phone charger. Use cords rated for the wattage you plan to draw. Keep cords away from walkways and do not run them under rugs. This method does not power hardwired devices like a furnace blower or a well pump.
Transfer Switch
A transfer switch is a panel that lets you select a few circuits in your home to be powered by the generator. A licensed electrician installs the transfer switch next to your main panel. During an outage, you plug the generator into a dedicated inlet on the outside of your home, then flip the switch to transfer those circuits to generator power. This method is safe and convenient because you do not need to run extension cords through the house. It also prevents back-feeding. Transfer switches come in different sizes; your electrician will match one to your power station’s output and the circuits you want to back up.
Interlock and Inlet
An interlock is a mechanical device installed on your main breaker panel that prevents the main breaker and a generator breaker from being on at the same time. A licensed electrician installs a generator inlet on the outside of your home and connects it to a dedicated breaker in the panel. When you want to use the generator, you turn off the main breaker, then slide the interlock to allow the generator breaker to be turned on. This powers selected circuits through your existing panel breakers. Like a transfer switch, this method is safe and eliminates extension cords. It also allows you to power 240V loads if your generator can supply 240V.
Why You Must Never Back-Feed Through an Outlet
Back-feeding means plugging a generator into a standard wall outlet using a cord with two male ends (often called a “suicide cord”). This is extremely dangerous for several reasons:
- It energizes the wiring in your home and can electrocute a utility worker or a neighbor who thinks the line is dead.
- It can cause a fire if the cord or outlet is overloaded.
- It bypasses the safety features of a transfer switch or interlock, risking damage to your generator and your home’s electrical system.
Never attempt this. The only safe way to connect a generator to your home’s wiring is through a transfer switch or interlock installed by a licensed electrician.
240V Loads and Well Pumps
Many large appliances and well pumps require 240 volts. Most portable solar generators output 120V only. To run a 240V device, you need a power station (or a paired system) that can supply 240V, connected by a licensed electrician.
If you have a well pump, check its voltage rating on the nameplate. A 240V well pump cannot run on a 120V-only power station. Even with a 240V generator, the surge current from the pump motor may exceed the generator’s capacity. If your well pump is essential, consult a licensed electrician to determine the best solution, which may involve a larger generator or a different pump configuration.
For other 240V loads like an electric water heater, electric oven, or central air conditioner, the power requirements are typically very high (several thousand watts) and are beyond the capacity of most portable solar generators. Focus your backup plan on 120V loads and fuel-based heating if needed.
Recharging During Long Outages
A solar generator’s battery has a finite capacity. To keep running for days or weeks, you need to recharge it. The most common method is solar panels. Connect panels to the generator’s solar input port during daylight hours. The charging rate depends on panel wattage and sunlight conditions. For example, 400 W of solar panels with 4 to 5 peak sun hours might add roughly 1.2 to 1.5 kWh per day after real-world losses, and much less on cloudy or winter days.
If your generator also supports AC charging from a wall outlet, you can recharge from a neighbor’s or a community charging station if available. Some generators can be charged from a vehicle’s 12V outlet (cigarette lighter port), but this is slow and may drain your car battery. Plan to have enough solar capacity to recharge your generator fully during a typical day, or have a secondary charging method as a backup.
To conserve power, run your generator’s inverter only when needed. Many solar generators have a “ECO” or “power saving” mode that reduces idle consumption. Also, unplug devices that are not in use and avoid running high-draw appliances during the night when solar charging is not available.
FAQ
Can I run my whole house on a solar generator?
Most portable solar generators are sized for essential loads, not whole-house backup. A typical unit can power a refrigerator, lights, internet, and a few small appliances. To run large loads like an electric water heater or central AC, you would need a very large generator, which may not be practical for portable use. Focus on essential circuits and use a transfer switch or interlock for safe connection.
Do I need a licensed electrician to connect a solar generator to my home?
Yes, for any connection that involves your home’s wiring—such as a transfer switch or an interlock and inlet—you must hire a licensed electrician. This ensures the installation meets electrical code and is safe. Using extension cords directly from the generator to devices does not require an electrician, but follow all safety precautions.
How long will a solar generator run a refrigerator?
Runtime depends on the generator’s usable capacity and the refrigerator’s daily energy use (from its EnergyGuide label or a watt meter). Divide usable AC energy by the fridge’s average power. Actual runtime varies with the refrigerator’s duty cycle, inverter efficiency, and battery type. See running a refrigerator on a solar generator for more details.
Can I charge a solar generator from my car?
Many solar generators can be charged from a vehicle’s 12V outlet using an appropriate cable. However, charging is slow and may drain your car battery if the engine is not running. It is best used as an emergency backup method. Check your generator’s manual for the maximum input current from a 12V source.
Planning your home backup with a solar generator starts with identifying essential loads and choosing a safe connection method. Whether you use extension cords for a few devices or have a licensed electrician install a transfer switch, the goal is to keep your critical systems running without compromising safety. With proper sizing and a recharging plan, a solar generator can be a reliable part of your emergency preparedness.
