How to secure your SmartSolar Regulator – Step by step for optimal security!

For many, it is a given to secure their electrical equipment, but when it comes to solar energy, there are some common pitfalls. In this blog post, we will clarify these so that you can have a safe and efficient solar energy system.

Simply put, solar energy is secured in three places before it is consumed: between the solar panels and the regulator, between the regulator and the battery, and finally between the battery and the consumer. In this blog post, we focus on how to secure from the solar panels down to the battery.

Securing between regulator & battery

Securing between the regulator and the battery is relatively simple because the manual clearly states which fuse size to use. However, it can be advantageous to use a circuit breaker that can be "tripped". This makes it easy to cut off the power during maintenance and installations, which increases safety and facilitates the work. Circuit breakers are particularly practical because they can be reset after tripping, saving time and money compared to replacing traditional fuses. 

To facilitate the choice of fuse, we offer suitable options as accessory suggestions for all SmartSolar regulators. In the guide below, you can see both the recommendations in the manuals and our own suggestions.

Securing between solar panels & regulator

This fuse is extremely important because it protects the regulator if the panel is damaged or breaks. However, many people miss installing a fuse between the solar panels and the regulator. This fuse is a bit more complex to size because it must be adapted to the panels that are installed.

If your system only has one panel, it is simple. You look at the maximum current in amperes (A) that the panel can deliver and then fuse 1.5 to 2.0 times that value. Again, it is advantageous to choose a circuit breaker with a "trip" function if possible. This makes it easy to cut off the power during maintenance and installations, which increases safety and facilitates the work.

If you have multiple panels connected to the same regulator, they can be series-connected, parallel-connected, or a combination of both. First, you need to calculate the maximum voltage and current. The voltage is important to ensure that the fuse you intend to use can handle the maximum voltage of the panel group. Once you have calculated the maximum voltage and current for your panel group, choose a fuse that is about 1.5 to 2.0 times the maximum current.

Series connection
When solar panels are series-connected, their voltages are added while the current remains the same as for a single panel.

Formula:
Total voltage (V_total) = V1 + V2 + V3 + ...
Current (I_total) = I1 = I2 = I3 = ...

Example: If you have three solar panels with a voltage of 20V and a current of 5A each:
V_total = 20V + 20V + 20V = 60V
I_total = 5A

Parallel connection
When solar panels are parallel-connected, their currents are added while the voltage remains the same as for a single panel.

Formula:
Total current (I_total) = I1 + I2 + I3 + ...
Voltage (V_total) = V1 = V2 = V3 = ...

Example: If you have three solar panels with a voltage of 20V and a current of 5A each:
I_total = 5A + 5A + 5A = 15A
V_total = 20V

By using these formulas, you can easily calculate the total current and voltage for your solar panels depending on whether they are series-connected or parallel-connected. If you have multiple series groups that are then parallel-connected, you simply do the calculation in several steps to arrive at the total.

Cable dimensioning

The final step for a safe installation is to dimension the cables correctly. To do this, you need to perform certain calculations to arrive at the correct value. The parameters that affect are the voltage that goes through the cable and its length. The cable length is the total length, both the plus and minus cable length, which is often called "roundtrip" because it is the distance the voltage travels back and forth. Generally, the higher the voltage you have in the circuit, the less loss you get.

The easiest way to do these calculations is to use the app "Victron toolkit", which is available for both Apple and Android. In the app, you can enter the cable length and voltage, and it shows the loss you get at different cable cross-sections. In this case, you should aim to have a loss of a maximum of 3%. Don't forget to do the calculation both between the solar panels and the regulator and between the regulator and the battery, as these usually differ. It is important to ensure that each part of the system is correctly dimensioned to avoid losses and maximize efficiency.

Guide for Victron Energy SmartSolar MPPT Solar Regulators

The guide below is designed to facilitate comparison between the different models, but the specified values and functions should always be double-checked in the respective manual.