You may have heard a neighbour or a friend complaining about it, or maybe even experienced it yourself. Someone installs solar panels and suddenly the TV reception starts acting weird; they either can’t pick up some channels or there’s a lot of static on the screen. Are solar panels affecting their TV reception?
Well firstly, the panels themselves aren’t. Solar panels do not emit any kind of radiofrequency waves, so they cannot affect your TV transmissions. Inverters, on the other hand, are part of a solar system and can create electromagnetic interference (EMI), also called RFI (Radio Frequency Interference).
These EMIs can affect TV reception but what actually causes it. How common is this issue? Is there any way to avoid it? In this article, we’ll answer these questions and more.
How do inverters cause electromagnetic interference (EMI)?
An inverter converts direct current (DC) electricity from your solar panels into alternating current (AC), which you can use, for example, to power appliances or charge a battery bank. When an inverter switches between direct and alternating currents, it emits electromagnetic frequencies.
Unfortunately for you, if your inverter’s emissions happen to be at the same frequencies as TV transmissions, then there’s a chance that you’ll start picking up interference.
Additionally, inverter interference has been known to cause the following issues:
- Interference with radio receptions
- Malfunctions in grid-tied electronics
- Degradation in solar panels
Is this a common issue?
Here’s the good news. While this used to be a common issue, it isn’t anymore. Through the use of filtering and EMR/RFI reduction equipment, manufacturers have learned how to minimise the noise coming from inverters.
Reputable solar installers should understand the issue and employ mitigation strategies to minimise it. They may also undertake a series of tests to ensure there is no interference with your radio or television.
Another simple reason why incidences of this phenomenon have decreased is Australia’s swap from analogue to digital television in 2013, which generally improved picture and sound quality.
That said, if you’re experiencing TV interference and have rooftop solar, you will want to rule out the inverter as the culprit.
Chances are, your inverter isn’t the problem
Interferences caused by solar panel systems are unlikely, especially if you have high-quality equipment installed professionally.
If you’re experiencing interference inside your house, it could be because of smart devices, LED lights, laptops, baby monitors, and even electric fences. These things are more likely to cause interference than a properly installed solar panel with a shielded inverter.
One easy way to find the source of the interference is to use a portable battery-powered AM radio tuned to a quiet frequency at the lower end of the dial. You should hear static or a buzzing sound as you get close to the source of the interference. The closer you get, the more intense the static will be.
If you can’t discover the source of the problem in your own house, check with your neighbours to see whether they’re also experiencing interference. The cause might be in their home.
If you discover that your solar inverter is indeed the source of the interference, there are some relatively simple ways to resolve the issue.
How to reduce the effects of EMI
The most common ways of reducing noise are:
An effective way to reduce noise is by shielding your inverter. Metal enclosures are a good first line of defence against electromagnetic noise. This is why inverters often come in an iron-based steel case. Metal conduit will also act as a shield.
This method works because it absorbs and reflects any energy that would otherwise interfere with radio signals, thereby reducing transmissions through your home.
Cancellation is a simple, cheap, and easy strategy to reduce noise. In a nutshell, the DC wiring to the inverter should have at least one twist between the negative and positive wires. Noise in twisted pairs tends to cancel itself out at each twist. It does not work in all cases, but it’s definitely worth a try. You can also buy shielded pre-twisted pair cables, although you may have some trouble finding the right size.
Another option is to use a filter capacitor that absorbs the interference at its source without affecting other signals. This method works by removing frequency components from your inverter’s output signal, allowing for clean radio reception nearby. One limitation of using capacitor filters is that you usually must have a good ground nearby for one side of the capacitor. If you have long leads between what you are filtering and ground, you could even make the problem worse.
Suppression is a highly effective method. The most common suppression method uses Ferrite chokes, cores, and beads. Ferrites suppress high-frequency signals on a power supply line, by converting EMI to heat that ultimately dissipates.
Back on the air
So there you have it. While inverters can cause affect your TV reception, EMI is unlikely to happen if you have high-quality equipment installed professionally. Nine times out of ten, If you’re experiencing interference inside your house, it probably isn’t because of your inverter – and if it is because of your inverter, it’s usually a pretty simple fix.
The reality is making good choices at the start of your solar journey can save you a lot of hassles down the road. It’s critical to make sure you choose high-quality equipment that’s been installed by a competent professional. Make sure you ask your solar installer if your inverter is low EMI – many reputable manufacturers will market them as such.
With the right products and expertise, you’ll never have to worry about missing your favourite TV show!
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