Correctly connecting PV modules in series and parallel for the S1-200 system is essential not only to ensure proper installation and optimal pump performance but also to prevent damage to the controller.

Before explaining how to make series and parallel connections, here’s a quick and easy way to make sure you don’t exceed the controller’s maximum voltage rating:

Identify the Voc (open circuit voltage) of your PV module:

You’ll find this value on the label of the solar panel. Example:

For the S1-200 system, let’s use a 100 W PV module. On the label, the Voc is listed as 23 V. (See the picture below)

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Add the Voc values of the PV modules you intend to connect in series:

Make sure the total does not exceed 55 V.

For example, in an S1-200 system, using two (2) 100 W PV modules (same as the above label), we have:

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Important: In this example, you must not connect more than two (2) PV modules in series. Doing so would exceed the controller's voltage limit and may result in permanent damage to the S1-200 controller.

By connecting PV modules in series, you increase the total voltage of your PV system while the current remains the same.

To make the series connection, connect the positive (male) cable of one PV module to the negative (female) cable of the next module (as shown in the image below). Be careful not to exceed the maximum input voltage allowed by the controller (refer to the three steps outlined at the beginning of this article). Exceeding the controller’s voltage limit may result in permanent damage.

In this example, we use two (2) PV modules of 100 W each. Because they are connected in series, their voltages are added together, while the current stays constant.

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For more information on how to connect two (2) 100 W PV modules (200 W), click on the following link:

When PV modules are connected in parallel, the current (amperage) increases while the voltage remains constant.

This type of connection requires a pair of additional accessories known as Y-connectors, one for the positive connectors and one for the negative connectors (as shown in the picture below). These are necessary when connecting modules in parallel.

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To connect four 100 W modules, start by connecting two of them in series, and then connect the other two in series as well. This configuration increases voltage within each pair while keeping current constant.

Important: You must not connect more than two 100 W modules in series. Doing so would exceed the S1-200's maximum input voltage of 55 V and could damage the controller.

Once you have two pairs connected in series, you can connect both pairs in parallel using two Y-connectors. This step increases the total current while maintaining a safe voltage, ensuring no damage to the controller.

Steps:

1. Connect the positive (male) wire of one 100 W module to the negative (female) wire of another 100 W module (series connection).
2. Repeat the same with the remaining two modules.
3. Connect the two positive wires from each series pair to one Y-connector,
4. Connect the two negative wires from each series pair to the second Y-connector,
5. Connect the outputs of the Y-connectors to the MC4 adapter included with the S1-200 system (this is known as parallel connection),
6. Finally, connect the remaining cable to the S1-200 controller.

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In this example, we connect two 330 W PV modules directly in parallel to the S1-200 controller. These modules must not be connected in series*.

* Important: The Voc of a 330 W module is typically around 45.6 V. Connecting two in series would result in over 91 V, which exceeds the S1-200’s maximum voltage limit of 55 V and would damage the controller.

1. Connect the positive (male) wires of both modules to one Y-connector,
2. Connect the negative (female) wires to the other Y-connector,
3. Connect the MC4 adapter (included in the S1-200 system box) to the outputs of the Y-connectors.
4. Plug the final cable into the S1-200 controller.

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