A solar panel that is not connected to a load produces a voltage but no current. This is because there is nothing to form a circuit through which the current can flow. This will result in the solar panel getting warmer.
How exactly does this happen and why does the solar panel get warmer? To answer that we need to look a little closer into what happens inside a solar panel.
Sunlight carries little packets of energy called photons. A solar panel has two layers of electrons. When a solar panel is exposed to sunlight it absorbs the photons which then energize the electrons. Connecting a solar panel to a battery or inverter creates a circuit that allows a flow of electrons or current. ( Ona side note, find out: Where Do The Electrons Come From In A Solar Panel? Will They Ever Run Out !)
Without a battery, inverter or somewhere there is no flow of electrons. Now you have created energy but the energy has nowhere to go so what happens to it? Remember that energy cannot be destroyed, it can only change form so the energy in the solar panel has to be transformed somehow.
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The energy in a solar panel is turned into heat
That is why the solar panel gets warmer if it’s not connected to anything. How warm will the solar panel get and will it damage the cells? A solar panel has a maximum temperature of around 185 degrees Fahrenheit (85°C) so it can take a lot of heat without getting damaged. The optimal working temperature is 77 degrees Fahrenheit (25°C). Source
Bear in mind that solar panels get hot even when they are connected to a load. Does this mean your solar panel always needs to be plugged in or that it will degrade if you do not use it?
What if you’re going away on vacation, can you just unplug your solar panels or is there a specific way to do it? Read on to find out.
Do Solar Panels Need To Be Plugged In?
Solar panels do not need to be plugged in. There are no adverse effects that occur when solar panels are not connected to a load or when they are not in use. Under controlled conditions, they can be safely kept in storage for any length of time without suffering any damage.
As we have pointed out above, when a solar panel is not in use it simply gets hot due to there being no electrical current being carried to a load.
Do Solar Panels Degrade When Not In Use?
Solar panels do not suffer degradation as a direct result of not being in use. The main causes of solar panel degradation are thermal shock, exposure to light, and natural wear and tear of its components.
Social panel degradation is the gradual loss in efficiency it experiences over time. Degradation is only about 0.5% per year which means in 25 years, a solar panel still produces around 88% of what it did when it was first installed. Source
But what is thermal shock, what wear and tear does a solar panel go through, and how does light degrade it?
Solar Panel Degrading Factors
Thermal Shock
Solar panels are used outdoors. Temperatures outdoor vary from extreme heat to extreme cold depending on the season or time of day. The extreme temperature variations can cause microcracks on the glass covering the solar cells which can allow moisture into the solar panel. Moisture or humidity damage the cells in a solar panel.
Wear and tear
The weather can also cause age-related degradation in the solar panel components. Everything from the frame to the glue that keeps the solar cells in a waterproof seal will experience wear over time.
This is why it’s important to carry out routine inspections on the solar panels to make sure there aren’t any components like faulty connectors that need replacing. Source
Light degradation
While this might seem strange, solar panels also degrade once you expose them to light. They experience Light Induced Degradation (LID) in their first 1000 hours of operation. LID can be as much as 3%.
They also experience UV-Light Induced Degradation (UVID) from continued exposure to ultraviolet light from the sun.
These are the three main reasons why a solar panel degrades. Having a solar panel unconnected does not lead to degradation.
Can You Just Unplug Solar Panels? Basic Steps to Follow
Disconnecting or unplugging solar panels is done following a set of steps. These steps ensure personal safety and prevent damage to the solar system. Simply unplugging the solar panels without following these steps is not the best practice.
Generally, when you disconnect solar panels, you want to follow a few basic guidelines. Here are the most important steps you should follow:
- Always disconnect in the early morning or late afternoon when the solar panels are not producing at their peak. This ensures you catch them when the voltage and current are at the lowest. In this way, you reduce your risk of injury from electrocution.
- Turn off the AC and DC switches then measure the voltage ensuring it’s close to zero.
- Disconnect the solar panels and wrap the connector ends in electrical tape.
Before you perform any disconnection, refer to your user manual for any specific information regarding your solar panels. For more information on this, check out our post titled ” Should You Cover Solar Panels When Not In Use? (Keep it Plugged or Unplug it!)
Can You Have Solar Panels Not Connected To The Grid?
Solar panels can be used without connecting to the grid. This is what is termed an off-grid solar system design. An off-grid system is one of three solar system designs. Grid-tied and hybrid systems are two alternatives to off-grid.
Aside from not being connected to the grid, what makes an off-grid system different from other solar panel system designs?
In an off-grid system, either an off-grid or hybrid inverter is used. These inverters are different from grid-tied inverters in that they do not have anti-islanding. Anti-islanding is where a solar system shuts down when there is no electricity from the grid.
An off-grid solar panel system has a few pros and cons over a grid-tie system.
Pros of an off-grid system
- There are no utility bills to pay.
- Reduce your carbon emissions by using cleaner energy.
Cons of an off-grid system
- It’s far more expensive than any other system design since it requires more batteries.
- Dependent entirely on solar which can be unreliable.
For more on this, we highly recommend that you check out our post Can I Use Both Solar And Grid Electricity? What You Need To Know!
