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If you’re thinking of adding a solar battery to your home, you might be wondering whether or not it’s going to work in a power cut. If yes, then you’re not alone as this is one of the most common questions asked when it comes to solar batteries. In this post, we aim to provide you with a detailed answer to solve this concern once and for all.

The answer to this question is, it depends. The main reason why your solar batteries will usually not work or provide your home with the much-needed back up power is as a result of the several threats it poses. You should be aware that both your solar panels and battery are connected to the main grid. When a power cut occurs, your engineers will have to operate on the grid. If the solar panels or batteries are in operation at the period there’s a high chance the engineers would be electrocuted by the electricity that’s being produced. As a result of this, solar inverters are usually designed to automatically switch off once a power cut occurs. However, it should also be noted that if your solar battery possesses backup functionality, you’ll be able to make use of your solar energy in the event of a power cut. In other words, what determines if your home battery would work in a power cut is the availability or otherwise of a backup functionality.

Furthermore, you might also wish to know if your solar panels will continue to charge the battery in a power cut. Well, this depends on the type of backup system you possess. There are some more affordable batteries that are designed to automatically release their stored energy upon the detection of a power cut. And this is mostly because the battery inverter is usually smaller than the solar inverter which allows the energy from the solar inverter to the transmitted to the battery - risking an overload. However, if otherwise, then energy can continue to be transmitted to the battery until its fully charged.

It’s important to get the right size solar panel system for your commercial property. Solar panels are usually installed on pitched roofs, although they can be fitted on stands on the ground if you have some unused outdoor space. The more panels you install, the more power you’ll generate, but there’s no point buying more panels than you have space for.

Solar panel system sizes are measured in kW. 4-10kW solar panel systems are usually too big for domestic properties but are ideal for smaller commercial properties. Here’s an idea of how many panels and space you’ll need for a few different system sizes:

System size, Number of panels, Area required (approximate)

4kW, 16, 23m²

6kW, 24, 35m²

8kW, 32, 46m²

10kw, 40, 58m²

Bear in mind that solar panels can’t be less than 30cm away from a roof edge, so you’ll need more space than the area that the panels take up.

Solar PV panels work by converting sunlight into electricity. They’re made up of photovoltaic cells, which take in the sun’s rays and turn it into direct current (DC) electricity. The current is then channelled into an inverter, which converts it to alternating current (AC).

Once converted to AC, the electricity is ready to use. It’s fed through a meter and into your property’s consumer unit, and is automatically used to power appliances and heating systems. Your system will automatically switch between your solar electricity supply and the national grid, and export any solar electricity you don’t use to the national grid.

Obviously the performance of a solar thermal system will vary depending on the location of the home, the insulation of the property, and your own hot water requirements. Solar thermal panels are capable of providing all of your hot water requirements from April to September. They will still make a contribution to your hot water needs for the rest of the year, but in general you will need a backup system to further heat the water in the colder months.

If you want to test your solar panel system to see if it’s working properly or just to see what output it’s giving, you can do this using a multimeter to measure current, or amps, and voltage.

Before you start, you’ll need to find the voltage (v) and current (A) ratings of your panel. You should be able to find them on the back of the panel. You should also make sure that it’s a nice clear, sunny day to get the best readings out of your panel. You should also check that it’s safe to be up on your roof!

To measure open circuit voltage, you’ll need to make sure that your solar panel is completely disconnected from your system’s regulator and battery (if you have one). Angle the panel towards the sun, and ensure that your multimeter is set to measure volts. Measure the voltage between the positive and negative terminals by connecting the negative contact on the voltmeter to the negative on the panel and the positive contact on the voltmeter to the positive on the panel.

Then, you can move on to the short circuit current. Follow the same steps as the open circuit voltage, but ensure that your multimeter is set at 10A to start with.

Only try to test your solar panel if it’s safe to do so. If your roof isn’t accessible without scaffolding or specialist equipment, consider speaking to an MCS-registered solar company about your concerns. They may recommend that they come to service your solar panel system.