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Expand my installation

The expansion of photovoltaic installations is a growing trend due to the success of existing installations and the clear benefits they offer. But what elements should be added when a solar installation is to be extended? In the following, we look at the different devices that we have to take into account when extending the solar installation:

1.Solar panels: We always have the possibility to increase the number of solar panels required to cover the new daily consumption.

2. Charge regulator: The maximum current and power of the new panels to be added to the photovoltaic system must be calculated in order to size the necessary regulator.

3. Inverters: We must calculate the new powers of all the devices that are going to be connected at the same time, in the event that the inverter falls short we should purchase a new model of inverter with a higher power.

4. Batteries:Are not expandable, as it is not advisable to run parallel batteries. We must eliminate the batteries that we already have installed and size the new battery bank taking into account the new consumption of the installation.

When it comes to a new photovoltaic installation, solar batteries are undoubtedly the most important investment, which is why measures are taken to extend their service life, thus facilitating the early amortisation of the system. One of the most common mistakes is the connection of batteries in parallel. for, although many may think that their greatest benefit is the sum of their intensities, in the long run the PV system may present problems because of this bad decision.

Problems of connecting batteries in parallel

– Battery wear accelerates. Some batteries work much harder than others because the conditions that must be in place for us to be as close as possible to a perfect electrical system are not present.

- The charge is not uniform. They go from being discharged to near full charge at an abnormally fast rate. This happens because one of the batteries in the bank is out of balance with the energy reading of the inverter/regulator.

- The capacity we see in its performance is lower than it should be. The typical question: 'if I have so much capacity, I can't explain how I have so little autonomy'. This happens because one of the batteries in the bank is more worn than the rest and is carrying a very low energy reading which lowers the voltage of the entire bank.

– The internal resistance of the batteries is not identical. (this is unavoidable).

– The initial state of charge of all batteries is never the same.

In short, in parallel systems there is an imbalance between the different batteries, they do not all charge to 100% and therefore there is always a minimum transfer of energy between one battery and another so that the batteries connected in parallel will never reach 100% charge. Parallel connection leads to a loss of battery life and can cause problems within a short period of time..