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

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. To avoid wasting the abundant, renewable energy created by solar power generators, it is important to understand how to efficiently store and use this energy. While solar power batteries can store electricity generated from these generators, many wonder what happens when those batteries are full and their capacity has been reached. 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 When Solar Batteries Are Full?

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. 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 in the following ways:

Push it back to the panels

This is the most direct way of dealing with the excess energy. When the battery is full, the excess power is directed back into the solar panels, resulting in a temporary increase in voltage. This method effectively reduces the overall efficiency of the system because the excess energy is essentially lost.

Push it back into the grid

In grid-tied solar systems, when the battery is fully charged, the excess power can be fed back into the electrical grid. The solar system owner can then receive credits or compensation for the electricity supplied to the grid.

Force a dump load

The third option available is to employ a dump load. A dump load diverts excess power to another device, which absorbs the excess energy and converts it into a different form, such as heat. This approach ensures that the energy storage system remains within safe operating limits while making productive use of the surplus energy.

How to Tell If Your Solar Batteries Are Fully Charged

After getting acquainted with the ways in which excess energy can be dealt with, another question still lingers: How can you know your solar batteries are fully charged? What are the indicators? In fact, there are mainly two ways you can get a handle on the solar power battery level.

By the solar battery’s built-in indicators

A lot of solar batteries display the battery’s power level directly on the screen, or through a warning or other indicator systems for easy reference. In this case, a quick look at the indicator would suffice.

By electronic measuring instruments

On the other hand, electronic measuring instruments, like voltmeters or multimeters, do a great job of measuring the exact charge level of your battery.

  • A voltmeter measures the electrical potential of the battery, which is closely tied to its charge level.
  • A multimeter is a comprehensive and multifunctional tool for electronic measurements. It can measure voltage, current, resistance and so on, all with precision.

Using these measurement tools is straightforward too. For either a voltmeter or a multimeter, connect the red and black probes to the ports of your battery. Then, after the number has stabilized, simply read the multimeter screen to get the results.

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: push it back to the panel and waste it, or try to make good use of it. Needless to say, wasting is always an undesirable choice, and un-green too. Here are some practical ideas for utilizing this extra energy.


The excess energy can be used to power a refrigerator. This is especially practical since refrigerators use electricity only intermittently, which is a perfect match with the also intermittent nature of surplus energy.

The Electrical 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.


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.

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 about 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 prices for solar panels are typically pretty good, meaning that you could end up making a decent profit if you decide to sell them.

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. Most solar generators can accommodate an increase in full battery capacity perfectly well.

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. Consider the 2048Wh Anker 760 expansion battery which features Anker’s proprietary InfiniPower long-lasting technology combined with ultra-durable components. It effectively expands your energy storing capability, eliminating any hassle associated with solar power systems like intermittent sunlight or batteries being too full regularly. In short, it is an excellent pick that is seriously worthy of the consideration of any eco-conscious homeowner.

Wrapping Up

As you can now see, 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 storage systems, 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.

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