How to connect solar panels: In Series or Parallel? [Ultimate Guide]

by David B June 11, 2020

When we have all the materials to start the photovoltaic solar installation, the big question arises: How to connect solar panels in parallel or series ?

We know that not everyone is an expert in electricity or renewable energy, nor is it possible to remember the entire process. Therefore, from Solarcell we bring you this guide with the best way to connect solar panels in parallel or series and how to do it correctly.

How solar panels are connected: MC4 connector

The vast majority of solar panels are connected using MC4 connectors, in other words, “Multi-Contact” of diameter No. 4.

These connectors are ideal for photovoltaic solar installations , since the solar panels are always outdoors and must withstand dust , wind and rain .

Therefore, apart from being easy to install since they connect with pressure, they have a firm connection with two side tabs; In addition, they are light, watertight and highly resistant to weathering. Among its advantages are:

Easy connection and disconnection between MC4 male and female.
Strong and reliable connection.
Watertight union with protection against physical agents (wind, dust, rain...)

All this means that all solar panels end up using MC4 connectors in the connection with the circuit between solar modules.

Connect solar panels in parallel

The parallel connection is used in basic solar installations such as in a Camper Van or Motorhome . We also use PWM regulators, as they are low-power solar installations.

In addition to this, connecting solar panels in parallel will increase the amperes of the electrical installation, but 12V voltage will always be sent; since vehicle batteries are usually 12V . This would give the following advantages.

They increase the intensity of the current, not the voltage. (Useful on 12V batteries)
Saving money as thin wiring is sufficient due to low power.
Ideal for small installations such as Camper Van , Motorhome.

How to connect solar panels in parallel

So, when choosing how to connect solar panels in small installations, use a parallel connection .

This means that all the negative cables (black) will be joined on one side, and the positive cables (red) on the other side.

We can see an electrical diagram of how the wiring would look when connecting solar panels in parallel , in the following image:

How to properly connect solar panels in parallel:

Position the solar panels in order.
Group the negative (black) wiring to one side.
Attach the positive (red) wiring to another side.
Connect the negative (black) wires to the three-output MC4 adapter.
Attach the positive (red) wires to the three-output MC4 adapter.
You will have the parallel connection completed successfully.

Effectively connect solar panels in series

By connecting solar panels in series or chain, it would be very similar to connecting Christmas lights; It is used in houses and factories as they need a large supply of electricity. In this case, higher power MPPT regulators should be used.

Likewise, the voltage will increase to the sum of all the solar panels but the amperes will remain the same, knowing that the house current is 230V . Among its advantages is:

Ideal for medium and large solar panel installations .
Less overheating of wiring in large installations.
Less energy loss due to Joule effect (energy loss due to heat)

How to connect solar panels in series

So, when choosing how to connect solar panels in medium or large installations, use a series connection.

This means that you will daisy chain the negative cables (black) with the positive cables (red) one by one, progressively.

We see an electrical diagram of how solar panels will be connected to each other, in the following image:

How to properly connect solar panels in series:

Place the solar panels in position.
Start by connecting the negative wiring (black) with the positive wiring (red) using MC4.
Connect the next negative wire (black) to the positive wire (red).
Follow the chain until you close the entire circuit.
You will have the serial connection completed successfully.

Achieve an effective connection

In reality , what causes a parallel or series connection to be used is the charge regulator or controller, since this has a high cost.

If you have a small installation like a Motorhome, use a PWM regulator, since this will be more than enough for the electricity you need in a Motorhome or Camper Van and you will be able to have a parallel connection.

On the other hand, when connecting solar panels in a house or industrial warehouse you will need much more energy and solar panels , you will require a higher power regulator and therefore you will have to use a series connection .

If you have any questions about how to connect solar panels for your camper van, do not hesitate to contact us , at Solarcell we will be happy to assist you. Additionally, we offer you the best offers on Solar Panel Kits for your camper van at the best prices on the market.