Why most solar panels shut off during blackouts — and the storage, backup, and planning strategies that keep your lights on
When you invest in solar, it’s natural to picture your panels powering your home no matter what happens on the grid. But here’s the surprise: If you have a standard grid-tied solar system, your panels will shut down automatically when the power goes out.
That doesn’t mean solar leaves you stranded. With the right setup — like battery storage, an off-grid design, or pairing with a backup generator — you can keep critical loads running and make your home more resilient. Let’s walk through why most solar systems shut off when the power goes out, and the options that allow you to stay powered during an outage.
In this article
- Why solar panels usually don’t work during an outage
- How you can use solar panels during a power outage
- Comparing solar backup options
- How long can your home run on solar and battery backup?
- How to make your solar battery last longer
- How to prepare your solar and battery system for an outage
- Limits of solar backup: what to know before an outage
- Your next steps for solar panels and battery backup
Why solar panels usually don’t work during an outage
Most residential solar in the U.S. is grid-tied. That means your system connects to your utility’s power lines. When the grid is up, your solar electricity powers your home first, with any excess flowing back to the utility.
But when the grid goes down, safety rules kick in. Generally, this means your system will stop delivering electricity to your home and the grid. This protects lineworkers from accidental backfeed when they’re repairing damaged power lines.
Even though your panels may still be generating DC electricity on your roof, there’s no safe way for that energy to flow into your home without the grid or a backup battery system. That’s why most homeowners see their systems go dark during a blackout.
How you can use solar panels during a power outage
Solar can keep your home up and running in an outage if it’s paired with the right equipment. Here are the three main approaches homeowners use.
Option 1: Solar + battery storage — hybrid systems
Adding a battery changes how solar works in a blackout. A solar-plus-storage system can isolate itself from the grid, switch into “island mode,” and keep running independently. This kind of setup relies on solar energy storage, where your panels charge a battery during the day and that stored power keeps essentials running when the grid goes down.
In “island mode,” your panels can keep charging your battery day-after-day until the power comes back on. With seamless switching, hybrid inverters automatically disconnect from the utility and reroute your solar energy into your battery and home circuits. Most systems are designed to power essentials like your refrigerator, Wi-Fi, lights, and medical devices, while leaving non-essentials offline to conserve your battery life.
A typical home battery is around 10–15 kilowatt-hours (kWh), which can cover 1-2 days of basic use depending on your household energy needs.
- Pros: You’ll have access to backup power during grid outages, plus the opportunity to lower your energy bills by storing excess solar energy generated during the day and using it at night or during peak hours.
- Cons: Accurately estimating load and storage needs, or worst-case weather, is critical. Batteries are also an added investment upfront.
- Best fit: Homeowners who are connected to the grid but want backup power and lower energy bills. Or, homeowners who live in areas with frequent power outages or high electricity rates.
It’s no wonder solar plus battery storage systems are gaining popularity. According to the latest Aurora Solar Snapshot, battery add-ons surged +67% YoY in 2024, and 78% of installers reported an increased demand.
The cost of solar batteries ranges widely, with the top brands going anywhere from $4,000 to $16,000. Solar battery purchases are currently eligible for the IRS Residential Clean Energy Credit, which can cover 30% of the cost. While this program is ending at the end of 2025, there are many state and local incentives for batteries. An expert installer can help you figure out what you qualify for.
Option 2: Off-grid — standalone systems
For some homeowners, the ultimate form of resilience is to go completely off-grid. An off-grid solar system isn’t tied to utility lines at all, which means it keeps producing power no matter what’s happening beyond your property. In regions where outages are frequent — or in rural areas where connecting to the grid is expensive or impossible — this approach can offer peace of mind and total energy independence.
- Pros: You’ll have complete energy autonomy and no monthly utility bills. You decide how much capacity to build and how to manage it.
- Cons: Off-grid systems typically require a much larger battery bank to ride through cloudy stretches or seasonal changes in sunlight. They also carry higher upfront costs and demand more ongoing attention to keep equipment running smoothly. In some areas, it is also illegal to live in a house that isn’t attached to the electric grid.
- Best fit: Off-grid living tends to make sense for remote properties and for homeowners who value self-reliance above convenience. It’s less about saving money and more about choosing independence as a lifestyle.
Option 3: Solar + generator (or solar + gas backup)
If you’ve ever been through a week-long outage, you know a battery alone won’t always cut it. That’s where a generator comes in. The solar panels and battery carry you through normal evenings, but once the battery drains, the generator can top it back up or keep heavy-draw items running. As we mentioned above, if you’re in “island mode” your panels can charge your battery, as well.
- Pros: It gives you a fallback when the weather stays cloudy or the outage drags on. A generator can handle things like a furnace blower or sump pump that would empty a battery too quickly.
- Cons: You’ll be storing fuel, dealing with noise, and keeping up with oil changes or other maintenance. It’s more hands-on than a battery.
- Best fit: Homeowners in storm-prone or rural areas often choose this setup because it covers both short outages and the rare multi-day blackout. It’s not the simplest system, or the cleanest, but it’s a reliable one.
Comparing solar backup options
Each backup setup comes with its own trade-offs in cost, complexity, and how well it carries you through an outage. The table below shows how the main options stack up.
| System type | Approximate cost (relative) | Complexity | Outage survival | Maintenance |
| Grid-tied solar only | $ (lowest) | Simple | None | Low |
| Grid + battery (hybrid) | $$$ (medium-high) | Moderate; hybrid inverter + battery; professional setup | Partial to full depending on battery size; can run essentials for hours to days | Moderate; battery health checks, firmware updates |
| Off-grid | $$$$(highest) | High; solar + large battery bank + backup generator | Full (self-sufficient) if system is sized correctly | High; battery bank cycling, generator fuel/maintenance |
| Solar + generator (grid-tied with backup genset) | $$–$$$(varies by generator size) | Moderate; transfer switch + integration with solar | Partial — generator can run loads during outage; solar may be off unless hybrid system | Moderate; fuel storage, oil changes, testing |
How long can your home run on solar and battery backup?
Several things determine how long your solar system battery will last in a blackout:
- Battery size: The bigger the battery, the more you can store. A common home unit is 10–15 kWh, which is usually enough to cover the basics for a day or two.
- What you’re powering: A fridge, lights, and Wi-Fi don’t use much. But a space heater or central air can drain a battery in hours.
- Sunlight during the outage: On sunny days, panels can recharge the battery and extend runtime. At night or during storms, you’re living off what’s already stored.
Keep in mind that you won’t get 100% of the battery’s listed capacity. Most units keep about 10–20% in reserve so they don’t get damaged. You’ll also lose a little as the inverter converts DC into AC. So that 13.5 kWh battery on the spec sheet may really give you closer to 11–12 kWh in everyday use.
That’s why managing your loads makes such a difference. Used wisely, a backup battery is part of a bigger strategy to turn your home into a smart asset, supporting you through outages and making your energy use more flexible year-round.
Prioritizing household appliances
Not every device in your home needs to stay on during a blackout. The key is to separate essentials — things that protect food, health, or communication — from conveniences you can skip until the grid comes back. A solar battery lasts much longer if you shed high-draw loads like space heaters or air conditioners.
Here’s an example of how long a 13.5 kWh battery could run common appliances if they were powered one at a time:
Fridge (1.2 kWh/day) + Wi-Fi router (0.36) + lights (0.48) + laptop (0.36) = about 2.4 kWh/day.
A 13.5 kWh battery could power that mix for around five days — longer if the sun helps recharge during the day.
How long do appliances run on a solar battery?
How to use this table:
- Pick your essentials. Start with must-haves like the fridge, Wi-Fi, a few lights, and medical devices.
- Add up daily use. Each appliance in the table lists its typical energy use. Add those together to see how much you’ll need each day.
- Compare to your battery size. Divide your usable battery capacity (around 11–12 kWh for a 13.5 kWh unit) by your total daily use. That tells you how many days the battery could last without recharging.
| Appliance / Load | Power (W) | Daily Energy (Wh) | Priority | Hours on 13.5 kWh battery for typical use | Notes |
| Wi-Fi router + modem | 15 | 360 | Essential | 900 h | Low draw, high utility |
| Refrigerator (efficient) | 300 | 2,400 | Essential | 45 h | Keep door closed |
| LED lights (8 bulbs) | 80 | 480 | Essential | 169 h | Use task lighting |
| Laptop | 60 | 360 | Important | 225 h | Use battery-saver mode |
| TV/streaming | 100 | 150 | Optional | 135 h | Skip to conserve power |
| Microwave | 1,000 | 750 | Optional | 14 h | High power, short use |
| Space heater | 1,500 | 7,200 | Avoid | 9 h | Drains battery quickly |
| Note: These are rough estimates based on general data. Exact power, daily energy, and hours will depend on your specific appliances and solar plus storage setup. |
How to make your solar battery last longer
There are many relatively small things you can do to make sure your battery storage lasts as long as possible:
- Daytime solar production can stretch battery life if your system supports it.
- Heating and cooling use huge amounts of energy — skip them unless your health or safety requires it.
- Always confirm wattage for medical devices and put them first on your list.
- Unplug microwaves, clothes dryers, and other high-draw appliances until the grid returns.
- Use only LED lighting if possible and limit it to rooms that are in use.
- Charge phones, laptops, and flashlights during the day so they don’t drain the battery overnight.
- Check your battery or inverter settings for a “backup reserve” mode before storms.
- Turn off phantom loads like TVs and chargers by using power strips.
How to prepare your solar and battery system for an outage
A little preparation goes a long way toward making your solar and battery system dependable when the grid goes down. Here are a few smart habits to keep in mind:
- Charge ahead of time. Preparing a solar battery for extreme weather means ensuring that it’s fully charged ahead of time. That extra cushion could mean the difference between running essentials for hours or for days.
- Keep the system healthy. Update inverter firmware when recommended, check battery performance, and keep panels clear of debris. Regular solar panel maintenance makes your system more reliable when you need it most.
- Decide what matters. Before an outage, talk through which circuits or devices are critical (fridge, Wi-Fi, medical equipment) and which ones you can turn off. Having a plan avoids tough decisions in the dark.
- Think about safety first. Check your system before bad weather hits. And during a storm, never try to go on the roof to “fix” panels. Always rely on transfer switches and proper labeling to keep the system operating safely.
- Do a practice run. Once a year, simulate an outage. Let everyone in your household see how the system works and confirm your backup plan runs smoothly.
Prepared this way, your solar system isn’t just backup power — it’s part of a thoughtful plan to keep your home steady and your family safe during outages.
Limits of solar backup power: what to know before an outage
Even the best solar-plus-storage setup has boundaries, so it’s important to set realistic expectations:
- Not infinite power. Even with solar and batteries, you can’t expect to run your entire home indefinitely during a long outage.
- Solar needs storage (or off-grid design). A common myth is that rooftop panels keep producing during a blackout. In reality, most systems shut off automatically unless you have storage or off-grid capability.
- System risks: Over-discharging batteries, inverter overloads, or component failures can cut your runtime short.
- Utility rules: Some interconnection agreements limit how much storage you can add, or require inspections before enabling backup features.
- Cost vs. benefit: Backup systems add resilience but come at a higher price. For many homeowners, the peace of mind during blackouts is worth it.
Your next steps for solar panels and battery backup
Solar panels by themselves won’t keep your power on in a blackout. If you want electricity when the grid is down, you’ll need storage, an off-grid setup, or a system that pairs solar with a generator. Each option comes with costs and limits, but they all give you a way to keep the basics running when you need it most.
If you’re just starting your research, our 2025 Homeowner Guide to Solar is a great place to start. You can also review our explainer on how solar panels work to understand the basics before looking at storage or backup options. And when you’re ready to move forward, the Aurora Marketplace lets you compare quotes from vetted solar installers so you can find the best system for your home.
