Will my solar panels still work in bad weather?

The most common question the Solahart Newcastle team gets asked when doing quotations for the installation of a new solar power system for a home or business is whether it still has the capability of creating energy in mixed weather conditions.

The very short, simple answer is yes – a solar panel can create energy in all types of weather conditions. What changes is the amount it can create which is directly related to how much solar radiation is prevalent for the weather at the time.

It is very normal for us to be asked these questions;
● Do solar panels work in the shade?
● Do solar panels work in low light?
● Do solar panels work on cloudy days?
● Do solar panels work on rainy days?
● Do solar panels work at night?

When do solar panels generate power?

Solar panels will work nearly all day every day between sun rise and sunset. It will take a small amount of time for your solar system to have enough solar production to make the inverter register the output but when up and running solar panels will still produce power even if it’s raining all day. It will not be the best production but a 250-watt solar panel in rainy conditions will still output around 10-20 watts. If this was a 5kw solar system then the production would still be around 200 to 400 watts of power in the most unsuitable conditions.

An example is a solar power installation in Tanilba Bay we recently completed. It was a:
● 5.18kw system
● ABB 5kW Inverter
● 14 x 370W Solahart Silhouette Panels
● A Tesla 2 Powerwall Battery

“I’m very happy with the savings from our panels and battery. With all the rain and cloudy days we have had this winter our costs were less than $1.50 a day.”

Aerial photo of solar power at Fern Bay NSW

Can you generate solar power if it isn’t sunny?

When our team provides an onsite solar power consultation we help explain all the capabilities of the solar systems that we can sell, install or upgrade to a property. Australia has the highest solar radiation per square metre of any continent on the planet. It is measured at 58 million petajoules per year, which is around 10,000 times larger than our total energy consumption*.

This is why it is a great idea to get a solar power system installed for your home or business because our country as the perfect conditions to maximise the energy creation capabilities of such systems.

We do still get asked all the time if the system can still work if it is not sunny, the short answer is yes it will and that is because there is still solar radiation in the atmosphere even if it is cloudy. The amount isn’t the same as it if were sunny, but a well designed system can still store energy.

How well do solar panels work on cloudy or rainy days?

Solar power panels will still function on cloudy, overcast or even rainy days. Even in partly cloudy weather, solar cells could still operate at 80% of their maximum output**. The reason this is possible is that the way a solar panel works it can use both direct and indirect sunlight to generate power, there is still light being reflected onto the panels even if it is partially blocked by clouds.

Don’t believe us? Try standing outside on a cloudy day all day long without any sunscreen, you will still get burnt by the suns rays even if you literally can’t see the sun itself. While clouds may filter out some of the brightness, the majority of sunlight still gets through. So if you have solar panels on your rooftop, rest assured, they’re still working to produce energy on those wet and cloudy days.

Does a solar hot water system still work on cloudy or rainy days?

So if the solar panels can draw energy on cloudy days, that also means a solar water heater can still provide hot water too. You can still have hot water supplied into your home when the weather isn’t completely sunny. The only exception is when there is continuous days of cloudy weather, this can sometimes reduce the efficiency of your solar water heater.

Fortunately, Solahart Solar Hot Water systems have a backup available to ensure you can still enjoy instant hot water when the sun isn’t shining. All Solahart Solar Water Heaters come with an inbuilt electric booster. This means that as soon as the water temperature drops below a certain level, the booster element kicks in and heats the water to the correct temperature.

Solahart also has an optional gas-boosted model available where boosting only occurs when hot water is being used. When a hot water tap is opened, solar hot water flows from the solar water heater through a solar-compatible continuous flow gas water heater. Temperature sensors within this gas heater measure the incoming water temperature, and if the water temperature is less than a pre-set minimum, the gas heater ignites and immediately brings it up to the set level.

The choice of which booster is right for you will ultimately depend on key factors such as your solar hot water system, the climate where you live and your roof inclination.

How can you maintain maximum performance from your solar panels on rainy days?

A lot of solar power systems get installed and then never maintained. Like any other mechanical or electrical system in your home or a vehicle they do need regular maintenance. It is true that the weather might help keep your panels operating efficiently by washing away any dust or dirt***. Although this really depends on how much rain you get, how heavy it is & how dirty the panels are.

So the only real way to maximise the efficiency of your solar panels so they operate well during sunny or overcast days is to ensure they are;
● kept clean with regular maintenance
● make sure there is no debris covering them like loose leaves, plastic bags or other rubbish
● check that tree or building shadows haven’t changed dramatically since installation that may reduce the time they receive full sun
● make sure they haven’t been damaged by something falling on them like a stray cricket ball, rock or tree branch
● Check your electricity consumption patterns, have your needs changed from when you had them installed. Maybe you need 30% more than before but don’t have the capacity to provide that.

Can you store electricity during rainy periods?

You might be concerned about generating enough solar power over a period of a week, two weeks or longer during seasonal rainy periods. Worst case scenario you can still draw power from the grid, but if you want to be fully self-sufficient the other consideration is to expand your solar power system to have a battery added to it.

A solar battery system can store power that you have generated from days with great weather so that you can use it at other times. These can be placed at the side of a property and even connected to an existing system ready to be used when the need arises.

Tesla Powerwall installed at Tanilba Bay NSW

Will a solar power system work in a shady or low light location?

Solar panels can still actually produce energy if it they are in a shady or low light location. It just means the amount they are able to generate will vary depending on the density of the shade, the time of day, direction of the sun, time of the year and the duration of the shaded or low light period.

Let’s get technical for a second and keep in mind that solar panels work by allowing particles of light to knock electrons free from atoms, generating a flow of electricity in the panel. The high quality solar panels that we sell and install only require a minimal amount of photons to generate an electricity flow and supply power to a location. This means that a solar power system will be productive before the sun can be seen in the sky simply because there is already light in the atmosphere as the sun rises.

So even on a cloudy day where it may be considered low light and will remain on after the sun has set (and as long as photons are still available). Obviously during these times there is less power production but the system is still working and the optimum flow of electricity from your solar panels will vary across the day depending on the orientation of the panels.For example, if your panels are facing due east then your optimum flow time is 10am; facing west, you’ll get peak power production at 2pm; and north facing systems power best at midday.

At Solahart we provide a free onsite assessment to figure out these types of situations and it might mean trimming or removing a tree, relocating or replacing a TV antenna, utilising extra roof spaces or reducing shade losses on the system by incorporating other products in the set up to compensate for the situation. Our team can actually calculate what your potential energy drawing capabilities will be once they inspect your site.

Solahart Silhouette solar power system installed at Aberdeen NSW

How can you see exactly what your solar power system is generating in bad weather?

One of the options that Solahart Newcastle provides for every installation is the choice of Smartphone monitoring applications. It will vary depending on the system you choose to install, but it can let you quickly pull out your phone and see all the critical information such as:

● System’s output
● Home consumption
● Active notification of system issues

There are normally three apps available depending on the inverter you choose to have installed:
1. GoodWe Inverter can be monitored with the SEMS Portal app
2. ABB Inverter with the Energy Viewer App
3. SolarEdge Inverter with mySolarEdge App.

Just remember, that solar panels can use direct or indirect sunlight to generate power, though they are most effective in direct sunlight. Solar panels will still work even when the light is reflected or partially blocked by clouds.

So it doesn’t matter what type of weather condition there is outside, your solar power system is always operating at some capacity & you can quickly see the level by using our Smartphone App so that you have complete peace of mind knowing you are drawing power at all times of the day or year.

Can I get my solar panels checked to see how much capacity they have?

Solahart Newcastle can provide a complimentary site inspection & test of your current system to show you what capacity it has. You may have an old solar power system that you are not sure is working well or isn’t generating enough power for you, our team can check & confirm this for you.

Solar power installer from Solahart Newcastle

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** EESI https://www.eesi.org/topics/solar/description 

*** Solar Energy Industry Association https://www.seia.org/initiatives/what-happens-solar-panels-when-its-cloudy-or-raining

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