Understanding the connection of PV modules in series and parallel is essential not only for a correct installation and performance of the pump, but also to avoid damaging the pump controller.

Before explaining how to make series and parallel connections, let's look at a quick and easy way to make sure we are not going to exceed the maximum voltage allowed by the controller to avoid damage:

First, you need to know:

The VOC (open circuit voltage) information of the PV module you are going to install, for this, you will need to identify this value on the panel label.

For example: We use the label of a 100 W PV module and identify the VOC value, in this case it is 23 V (VOC).

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Sum the VOC value of the solar module as many times as necessary until the maximum voltage of the controller is NOT exceeded.

For example, in an S1-200 system, using two 100 W PV modules (same as the above label), we have:

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In this example you should not connect more than two PV modules in series otherwise you will damage the S1-200 controller

By connecting the PV modules in series, you will increase the voltage of your PV system and the current will remain constant.

The connection must be made by connecting one positive (male) and one negative (female) cable of both PV modules (as shown in number 2.0 in the picture below), taking care that the sum of the input voltage of the PV modules does not exceed the maximum voltage allowed by the controller (considering the three steps at the beginning of this article). If the voltage allowed by the controller is exceeded, the controller will be damaged.

In this example we use two PV modules of 100W each. Since they are connected in series, the voltages are summed and the current remains constant.

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For more information on how to connect two 100 W PV modules (200 W), click on the following link:

When PV modules are connected in parallel, the current or amperage will increase and the voltage will remain constant.

This requires a pair of additional accessories as shown in the drawing below called "Y-connectors" (one for the positive and one for the negative connectors) in case two parallel configurations are required.

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To make the connection of 4 modules of 100 W, what we will do first is to connect two of them in series*, as well as the other two remaining modules. In this way we are summing voltages between both modules and the current will remain constant.

* According to the previous example, we can not connect more than two 100 W modules in series because it exceeds the voltage of 55 V and this would damage the controller

Finally we will connect each pair of modules in parallel by using two Y-connectors to the controller. Where finally the currents will be summed while keeping the voltage constant, this way we will avoid damage to the controller.

Steps:

1. Take two 100 W PV modules and connect the positive (male) wire of one of the PV modules and connect it to the negative (female) wire of the other PV module. (Series connection)
2. Take the other two remaining 100 W PV modules and repeat the above procedure.
3. Connect the remaining two positive (male) wires to a corresponding Y-connector,
4. Then connect the two remaining negative (female) wires to the other respective Y-connector,
5. Next, take the remaining wires and connect them to the MC4 adapter included inside the S1-200 system box (this is known as parallel connection),
6. and then connect the remaining plug to the controller.

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In the example diagram below, we are going to connect two 330 W PV modules to the S1-200 controller. For this case the connection is made directly in parallel (they must not be connected in series*). Where finally the currents are summed and the voltage remains constant.

* Note that for this example two 330 W PV modules are NOT connected in series, because the VOC of this size of PV module is around 45.6 V for each one and we cannot exceed more than 55 V because we can damage the controller.

1. Connect the two positive wires (male) to the respective Y-connector,
2. Then connect the two negative wires (female) to the other respective Y-connector,
3. Then connect the MC4 adapter included inside the S1-200 system box to the remaining terminals of the Y-connector,
4. Finally connect the remaining cable to the S1-200 controller.

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