What Happens to Solar Power When Batteries Are Full? (With Solution)

Solar power has revolutionized the energy landscape, offering a sustainable and renewable source of electricity. However, this abundant, renewable energy may not be efficiently stored and used if your solar panels produce too much electricity. While solar power batteries can store electricity generated from these generators, many wonder what happens when those batteries are full. Does all of that free, clean energy go to waste or are there other methods available to capture and recycle this extra energy so you don't lose out on its potential usage?

In this article, we'll explore the dynamics of surplus solar energy and how it is managed when storage batteries reach their maximum capacity. So, without further ado, let's delve into the mechanisms that come into play and uncover the possibilities of redirecting excess energy as well as practical ways to balance the generating and storing capabilities. 

What Happens to Excess Solar Power Generated?

When solar batteries are full, the battery has used up all its capacity, which means no more solar energy from the panels can be stored and batteries stop charging. In this case, overcharging has the potential to damage the battery, which is when the inverter and the charge controller begin to play their parts. They handle the excess energy differently in the following two situations:

1. What Happens to Excess Solar Power for a Grid-Tied Solar System?

In grid-tied solar systems, excess electricity is typically sent back to the power grid with the help of an inverter. This process is monitored by a metering system that tracks the amount of electricity fed back. Homeowners with these systems can benefit financially through feed-in tariffs or net metering policies, which provide credits or payments for the electricity supplied to the grid. This not only offers a financial incentive but also helps supply renewable energy to the community.

2. What Happens to Off-Grid Solar Power When Batteries Are Full?

For excess solar power generated by off-grid system, when the batteries are full, the solar charge controller will stop charging to protect batteries and solar panels by managing the flow of energy. Once the batteries are fully charged, the charge controllers detect this state and promptly halt the flow of electricity. This can avoid potential safety issues, such as overheating, which in extreme cases might cause fires.

Some modern solar systems, especially those using lithium-ion batteries, incorporate advanced battery management systems (BMS). It can protect the batteries against overcharging by regulating the charging process and ensuring optimal battery health.

Additionally, off-grid systems can also benefit from integrating diversion load controllers. These controllers reroute excess electricity to power appliances that can handle intermittent power, such as water heaters or space heaters. This ensures that any surplus power is used effectively within the home instead of being wasted, enhancing the overall efficiency of the solar power system.

How to Make Use of Excess Solar Power When Batteries Are Full?

According to previous explanations, there are basically two things you can do with the excess energy: waste it, or try to make good use of it. Needless to say, wasting is always an undesirable choice, and ungreen too. Here are some practical ideas for utilizing this extra energy.

Feed Excess Solar Power to the Grid

Sending the surplus energy back into the electrical grid is a feasible choice too. This not only preserves energy for common use, but can also earn credits for homeowners, potentially saving them future electrical bills.

Air Compression

Compressed air can be used as a means to store energy, which is the major mechanism of the CAES system employed in industry. Directing excess solar energy to the CAES system effectively preserves the energy and prepares it for later retrieval and use.

Heating

Using excess solar energy to power a water heater is still another enticing way of making use of this surplus. This will not only enable you the enjoyment of hot showers, but also help reduce your electricity bills. Moreover, this idea is particularly attractive during winter times when warmth is what everyone is dying for.

Electric Vehicle Charging

If you own an electric vehicle (EV), you can use the excess solar power to charge it during peak production times. This is a cost-effective way to use surplus energy and reduce fuel costs.

What to Do if Your Batteries Regularly Become Full?

Despite having introduced the most common solutions to a full solar battery, you might still harbor worries about what measures to take if your batteries become full on a regular basis, not just accidentally. To finally settle the matter, the following items might be of use.

Sell Some of Your Panels

The most direct way to handle excessive solar energy is to sell some of the panels, reducing the energy produced and hence avoiding a full battery. You might worry that solar panels might not be a common object and would not sell for a good price, but this is not true. In fact, solar panels are often in high demand and many people rush to purchase them. Additionally, the resale prices for solar panels are generally favorable. Thus, selling off excess panels could not only help balance your energy production but also potentially yield a decent profit.

Get Equipped with More or Higher Capacity Batteries

As you might guess, the other way around to balance the generation of power and its storage capability is to increase the total capacity of your batteries. Increasing storage capacity allows you to capture and to store excess solar energy, rather than letting it go to waste. This is especially beneficial during periods of peak solar production or lower household energy consumption.

Speaking of increasing the total capacity of your batteries, you should bear in mind that it is important to purchase extra batteries from a reliable brand like Anker. A prime example of an upgrade option is the 2048Wh Anker SOLIX BP2000 Expansion Battery. This battery incorporates Anker’s proprietary InfiniPower technology, which ensures long-lasting performance and durability.

With the addition of this expansion battery to your system, particularly if paired with an existing Anker SOLIX F2000, you can effectively double your storage capacity to 4096Wh. This expanded capacity is ideal for managing fluctuations in solar generation and consumption, ensuring that your system remains efficient and responsive to your energy needs throughout the day.

Wrapping Up

Now you must have known what to do with excess solar power. There are a number of different ways to handle the excess electricity created by solar panels when batteries are full. Many people choose to invest more in battery backup, while others aid the surrounding grid. It ultimately comes down to personal preference and experimentation with the various options available.

However, one thing is certain: no matter what you decide, properly managing your solar panel energy will result in an efficient system that allows you to maximize your use of renewable energy sources and reduce your carbon footprint. With careful planning and smart use of available resources, creating a connected and sustainable environmental future is achievable for everyone.

Common FAQa about What Happens to Solar Power When Batteries Are Full

How to Know if Solar Battery is Fully Charged?

To tell if your solar batteries are fully charged, you can use either built-in indicators or electronic measuring instruments:

Built-in Indicators: Many solar batteries feature indicators such as screens or warning lights that directly show the battery’s power level, providing an immediate visual reference.

Electronic Measuring Instruments: For precise measurement, instruments like voltmeters or multimeters are ideal. A voltmeter assesses the battery’s electrical potential, which reflects its charge level. A multimeter can measure multiple aspects including voltage, current, and resistance, offering a comprehensive view of the battery's condition. To use these tools, connect the red and black probes to the battery’s terminals, wait for the reading to stabilize, and then read the display to see the charge level.

What do solar panels do when batteries are full?

When solar batteries are full, any additional energy produced by the solar panels typically goes unused unless it is diverted elsewhere. In grid-tied systems, excess electricity can be sent back to the grid for credits, while in off-grid setups, the power is wasted unless additional storage or usage is available.

Can a solar panel overcharge a battery?

No. A solar panel alone cannot overcharge a battery due to the role of a charge controller in the system. The charge controller regulates the voltage and current, ensuring the battery charges safely and prevents overcharging, thus protecting the battery's lifespan and performance.

How long does a fully charged solar battery last?

The duration a fully charged solar battery lasts depends on its capacity and the energy demand of the appliances it powers. Typically, solar panels can store energy in these batteries to provide power overnight or for 1-5 days, depending on usage patterns and battery size.

Can solar panels store energy for later use?

No. Solar panels themselves do not store energy; they convert sunlight into electricity. You can store energy from solar panels in batteries for later use. These batteries capture the electricity generated by the panels during the day, allowing for energy usage when the panels are not producing power, such as at night.