Do solar panels work at night?

Key Takeaways:

• Solar panels require direct sunlight to generate electricity so they don’t function during nighttime hours.

• You can use battery storage systems or grid connections to maintain electricity at night.

• Net metering systems let you accumulate daytime energy credits to offset your nighttime power consumption.

What do solar panels do when the sun goes down? A big constraint of solar energy is that it’s non-dispatchable. That means you can’t generate it at will — the sun needs to be in the sky for solar panels to work. At night, your solar-powered home can get energy through battery storage or the electrical grid. We’ll cover how solar panels (don’t) work at night and options you have for after-hours generation.

Do solar panels work at night?

Solar panels convert sunlight into electricity during daylight hours. It’s in the name “solar panel.” They fundamentally require direct solar radiation to function.

Solar panels convert sunlight into electricity through the photovoltaic effect. During the day, photons strike semiconductor materials (usually silicon) in the panel, freeing electrons and generating direct current (DC). 

At night, however, ambient light isn’t strong enough to create the photovoltaic effect. Moonlight is about 400,000 times weaker than sunlight. In other words, if you think of full sunlight as 100% solar energy, moonlight is like 0.00025% of that.

Nighttime energy advancements

There are some fringe solar technologies that try to capture energy from solar panels at night. For example, radiative cooling technology uses temperature differentials between solar panels and their environment. Thermoelectric generators (TEGs) use the heat the earth produces at night as it cools. 

However, these experimental systems only generate 50 milliwatts per square meter compared to 200 watts from standard solar panels. This tiny amount is enough electricity to power minimal-consumption devices like LED lights but nowhere near enough to power a home.

How Your Solar Home Gets Energy at Night

Your home doesn’t stop using electricity at night, so where does the energy come from after the sun goes down? Usually, homes with solar systems get energy through battery storage and grid connectivity during nighttime hours.

During the night when solar panels are inactive, homes can access electricity through two main methods:

• Battery storage systems

• Grid connections

Battery storage systems

Solar battery systems function as energy reservoirs, capturing excess daytime solar production and releasing it when panels are dormant. Modern lithium-ion battery arrays (for example, those similar to the Tesla Powerwall with capacities around 13.5 kWh) capture surplus production for use after sunset. This stored energy lets you maintain power independence throughout the night cycle without external power sources. Batteries can work with both off-grid and grid-tied systems.

Grid-tied systems

Grid-connected solar homes switch to utility power after sunset. If you have net metering, the system records surplus daytime solar energy exported to the grid. You then get credits that offset nighttime consumption costs.

Your utility meter measures this bi-directional energy flow and reduces your household's electricity expenses. Your electricity meter literally spins one direction when you use energy and the opposite direction when you send energy back to the grid. You’ll see credits on your utility bill. Your bill could even be near $0 if your state has a full net metering system that gives a one-to-one credit for your surplus energy.

Not all states offer full net metering, though. Some only provide partial credits while others don’t have net metering at all. If you don’t have net metering, you simply use solar energy during the day and pay for any energy you use from the grid at night. Having a battery can be even more useful in this situation.

Using battery energy at night for grid-tied systems

In a grid-tied system, your solar panels generate electricity during the day while your battery storage captures excess energy. At night, when the sun isn’t shining, the system intelligently draws on stored energy and grid power. Here’s how to optimize your setup:

Choose the right size

Evaluate your daily energy consumption with extra attention to nighttime usage patterns. Thinking about battery capacity, you’ll want enough to cover a few days’ worth of your home’s energy. That way you have a bit stored as a backup and can use some at night. You may have to oversize your solar panel system a bit if you want to cover your energy use during the day plus battery charging.

Use a quality inverter and charge controller

Smart inverters and charge controllers monitor real-time solar production, battery charge levels, and even fluctuating grid prices to optimize when to store or use energy. Higher quality components can cost more upfront but they optimize the system to not overcharge or overdischarge the battery.

Optimize your time-of-use

Schedule high-energy tasks for daylight hours to reduce overall demand on nighttime storage. However, you can prioritize battery usage during expensive peak rate periods to reduce reliance on the grid when it’s the most expensive.

Using battery energy at night for off-grid systems

Every watt counts in an off-grid system because you’re not connected to a broader utility network. Optimizing battery storage is critical since nighttime power depends entirely on stored energy. Here’s how to create a reliable, night-focused energy setup:

Accurate system sizing with nighttime in mind

Begin with a comprehensive energy audit that includes a close look at your nighttime consumption. Factor in longer hours of darkness during winter or overcast seasons to ensure your battery bank is sufficiently large. Include extra capacity to cover prolonged periods without sunlight.

Manage your battery for night supply

The backbone of an off-grid system is its battery storage, which must reliably cover the entire night. Use deep-cycle batteries with a Battery Management System (BMS) that:

• Monitors the state of charge and battery health.

• Prevents overcharging during the day and deep discharging at night.

• Maximizes the usable capacity to ensure essential loads are powered after sunset.

Use high-efficiency inverters and MPPT controllers

Off-grid systems convert stored DC power to AC with inverters. High-efficiency models minimize losses, which is especially important since you can’t draw anything from the grid. MPPT charge controllers optimize solar panel performance during the day so the battery is as full as possible at night. However, beware of cheap MPPT controllers as some options don’t last long.

Prioritized load management for nighttime use

When operating independently, every watt counts, especially at night. Prioritize your energy use by:

• Load shifting: Schedule non-critical, high-energy tasks during daylight hours.

• Essential nighttime loads: Ensure critical devices (like refrigerators, security systems, and communication equipment) have uninterrupted power during nighttime.

• Nighttime conservation: Consider energy-saving practices in the evening to extend battery life until the next solar cycle.

Wrapping up: Manage your nighttime energy

While solar panels don’t produce energy at night, you still need electricity. If you use a grid-tied system, you’ll draw power from the grid and you could use net metering credits depending on your area. You can also use a battery with a grid-tied system for nighttime energy and outage security. And if you’re building an off-grid system, you definitely need battery storage to cover nighttime use (without using a generator). Whatever your goal, plan your panel and storage size correctly to see if solar power is a good idea or not.

Solar panels at night: FAQs

Below are a few frequently asked questions about solar panel energy at night.

Does moonlight charge solar panels?

Moonlight won't charge your solar panels effectively. Moonlight is 1/400,000th as strong as sunlight, so it’s much too weak for practical use.

Can solar panels work without direct sunlight?

Your solar panels will work without direct sunlight but produce less power. You'll lose 23% to 67% in capacity on cloudy days. The type, thickness, and altitude of clouds can affect how much energy makes it to your solar panels.

What time do solar panels stop working?

Your solar panels stop working after sunset when sunlight becomes insufficient. Panel performance depends on your location, seasonal changes, weather conditions, and panel orientation. Monitor your system to track daily production patterns.