This guide is dedicated to explain how to expand a solar photovoltaic system if you need to generate more electricity. Solar photovoltaic installations have decreased in price considerably in recent years. This has given rise to many of the users who already had solar panels, or a photovoltaic solar energy installation in their home, have chosen to expand it or are considering it.
The truth is that there is no reason why there should be any problem when carrying out the expansion of a solar installation —especially if it is a basic solar installation—. However, it is important to pay attention to some issues such as the mix of old and new batteries Hello connecting the batteries together to avoid problems in your installation.
How to expand a photovoltaic solar installation
And it is that the batteries are the most expensive elements of a solar installation —their price can vary from 200 euros to 10,000 euros, depending on the type of battery and its capacity, of course—. But, they are also the pieces that can be most affected if we do not carry out the extension of the solar energy installation in an adequate way. For the same reason, keep the following tips in mind.
Tips when expanding a solar energy installation
If you already have an isolated or grid-connected photovoltaic solar energy installation and you are thinking of increasing its power with new solar panels and batteries —in addition to the rest of the elements that may be necessary— keep in mind the following:
- Solar panel models with old ones can be combined without problems. Now, look at the tension that is generated in each of them so that it is homogeneous.
- Carry out the calculation of the new voltage and intensity levels of your basic solar installation and check that the regulator you have supports the new power that will be generated in the set or if you need a new one with greater capacity.
- It is important that you repeat the above process with the power inverter. This will allow you to make more intensive use of the energy that is generated.
Expansion of a solar energy installation and batteries
As we explained above, the issue of batteries is one of the most important to us when carrying out the expansion of a solar installation, since if we are not careful we can damage the new models that we acquire —or reduce their useful life—. Therefore, it is important to answer the following questions.
Can new and old batteries be mixed?
The answer is no. The most advisable thing is that you do not mix new batteries with old batteries —or those that are already in operation—, even if they are of the same brand and model. The reason for this is because older batteries will have a higher resistance and probability of leakage. This means that they will interfere with new batteries causing them to not working at peak performance and that they discharge and spoil more quickly. In fact, mixing new batteries with old ones can cause damage to the wiring that connects them to each other, giving rise to a greater risk of overheating due to the very high currents that occur with the charges-discharges between them. The most recommended is, therefore, to acquire larger batteries that allow covering the complex set.
How are batteries connected, in series or in parallel?
Another thing that you should always keep in mind when carrying out the expansion of a photovoltaic solar energy installation is the connection of the batteries to each other. You should know that the most suitable connection for a basic solar installation is in series. One of the most frequent errors is to connect the batteries in parallel, since there is a tendency to think of the benefit of the sum of the intensities, but it is not taken into account that in the long term the photovoltaic system may present problems due to this decision. And it is that the parallel installation multiplies the capacity in Ampere-hours of the battery while the voltage remains constant. To do this, all the positive poles are joined on the one hand and all the negative poles on the other. However, this causes a closed circuit to be created between the batteries that allows the passage of unbalanced currents and that circulate from one to another to try to balance each other. What can affect:
- Accelerate the process of battery wear: Batteries will go from discharged to charged at an abnormal rate.
- Reduction of battery capacity: One will be more worn than the other. At that time we will see that, although we have a certain load capacity, the autonomy will not be as expected.
- The load is not uniform: There will be batteries that work much more than others.
We will only be able to expand the batteries and carry out a parallel installation when we have batteries that are specifically designed to be installed in parallel, such as lithium batteries with communications. Now, it is not a highly recommended option since over time it can lead to the problems that we have mentioned in this article. The most recommended, always, is perform serial installation. This only gives way to the current when there is consumption, meanwhile, the batteries remain at rest, so they are not discharged or run out of cycles. Connecting two identical batteries in series increases the nominal voltage of the individual batteries, but maintains the same Ampere Hours (Ah), therefore, increasing its tension also increases its load.
How to expand a photovoltaic solar installation: Ask the experts for help
There are solar installations that may be easier to expand and others that are more complex, for example, those used for solar water pumping. Therefore, the most recommended if you do not have knowledge about electricity is that consult a specialist in solar installations. These can help you carry out the expansion of your solar energy installation without this being a risk for the batteries, as well as for your safety —due to accidents due to overheating—.