AsoboLife

Series vs. Parallel Solar Panel Connections

What is the difference between solar panels connected in series vs. parallel? Learn which is best for YOUR camper van?

This site contains affiliate links to products. More info in our disclaimer.

Connecting solar panels in series vs. parallel. What’s the difference? And which solar connection type is best for van life?

We’re glad you asked! In this post we discuss the differences between connecting solar panels in series or parallel. We’ll also touch on the pros and cons for each type of connection and which connection we ultimately prefer.

So if you’re ready, let’s get to it!

Table of Contents
    Add a header to begin generating the table of contents

    Not what you need? Check out our van life “Solar System” category page for more similar content.

    Physical Wiring Differences

    Every solar panel comes with two attached output cables; one POSITIVE cable and one NEGATIVE cable. With these output cables, you can attach multiple solar panels together to create an ‘array’. And there are two DIFFERENT ways to connect all these output cables together.

    One way is to connect your solar panels in ‘series.’ The other method is to connect your solar panels in ‘parallel’.

    Both ways have their pros and cons. And we’ll get to that. But below we show you what the physical connection difference looks like.

    Solar Panels In Series

    Three Solar Panels Connected In Series - Series vs. Parallel
    Three Solar Panels Connected In Series

    In a series connection, the NEGATIVE output cable of the first panel is connected to the POSITIVE output cable of the second panel. Then the NEGATIVE output cable of the second panel is connected to the POSITIVE cable of the third panel. And so on, for however many solar panels you have.

    Finally, the POSITIVE cable of the first panel and the NEGATIVE cable of the last panel are connected to the solar charge controller.

    Related read: What’s a solar charge controller? And do you need one?

    Solar Panels In Parallel

    Three Solar Panels Connected In Parallel - Series vs. Parallel
    Three Solar Panels Connected In Parallel

    * Solar fuses are technically required in this wiring example, but are excluded here for simplicity.

    In a parallel connection, the POSITIVE output cables from all the solar panels get joined together using a branch connector. The same is done for all the NEGATIVE output cables.

    The branch connectors take all the positive and negative cables and output a single POSITIVE and NEGATIVE line, which then gets connected to the solar charge controller.

    For simplicity sake, the above diagram does not include solar fuses. We talk more about that below.

    Related read: How to fuse a solar array

    Download our solar eBook (with wiring diagrams) to help you DIY your solar panel system.

    How Volts & Amps Are Affected By Series/Parallel Connections

    In order to understand the pros and cons of series vs. parallel solar panel wiring, it’s important to understand how series and parallel connections affect the solar array’s electrical output.

    Under similar situations, solar arrays connected in series and parallel will output the same amount of total watts (w). So if you have three 200-watt panels you will output close to 600-watts under perfectly ideal situations, regardless of whether they’re connected in series or parallel.

    But the difference between series and parallel connections comes from the make up of volts and amps, which are the two ingredients that make up watts.

    Remember: Volts x Amps = Watts

    How Series Connections Affect Volts & Amps

    Solar panels in series (volts & amps) - Series vs. Parallel
    Volts & amps in solar panels wired in series

    It’s important to know that when connecting solar panels in series, the volts produced by each panel get added together. But the amps stay the same.

    Therefore, if you have two solar panels that can output a maximum 18.6 volts and 5.86amps, then the solar array has a potential to generate 37.2V but still only 5.86A.

    The fancy math: 18.6 volts x 2 panels = 37.2 volts

    How Parallel Connections Affect Volts & Amps

    Solar panels in parallel (volts & amps) - Series vs. Parallel
    Volts & amps in solar panels wired in parallel

    In a parallel connection, the amps generated by each panel get added together. But the voltage stays the same.

    Therefore, if you have three solar panels that can each output a maximum 18.8V and 5.86A, then the solar array has a potential to generate only 18 volts but 17.58 amps of current.

    The fancy math: 5.86 amps x 3 panels = 17.58 amps

    Key Take Away

    Remember This Difference
    Series connections add VOLTS.
    Parallel connections add AMPS.

    Not sure how much solar you need? Learn to calculate your ideal solar array wattage.

    Pros & Cons For Series/Parallel Solar Connections

    Here we’ll address each of the pros and cons, especially as it pertains to camper van life and RVs.

    Series Connections

    Pros

    1. Thinner wires | Because less amps are transmitted in series connections, you can oftentimes purchase thinner wire, which saves you money. Read our solar panel wire size guide to learn more.

    2. Less components | Series connections involve less components. No branch connectors, no solar fuses.

    3. Ideal for 24V Systems | Since series connections adds volts, you MUST wire your panels in series if you have 24-volt batteries. If the solar array cannot product a voltage that is greater than the battery’s, the battery will not charge.

     

    Cons

    Broken panel shuts down whole array | If, for whatever reason, one of the solar panels malfunctions, the entire solar array will go down. That panel will either need to be replaced or the functioning panels will need to be rewired to exclude the broken panel.

    Lower efficiency during partial shading | Partial shading drastically affects solar harvesting production, no matter if the panels are in series vs. parallel. But panels in series are more inefficient when partially shaded.

    Parallel Connections

    Pros

    No problem when one panel breaks down | If one of your panels malfunctions, it does not hinder the solar production from your other panels.

    More efficient in partial shade | Though partial shading is still detrimental to harvesting solar energy, parallels wired in parallel are more efficient at producing power than those wired in series.

    Cons

    More components are needed | To wire panels in parallel you’ll need branch connectors and – maybe – solar fuses. Read our solar fuse article to learn more if you’ll need them.

    Thicker wires, maybe | Since amps are added up in parallel connections, you might need to purchase thicker wires. But this depends on the overall wattage of your solar array. Check out our solar wire sizing guide to learn more.

    Download our solar eBook (with wiring diagrams) to help you DIY your solar panel system.

    Which Solar Panel Connection Type Is Best For Camper Vans & RVs?

    Ford Transit camper van with girl sitting in sliding door

    If you are building a camper van solar system, this is the most important series vs. parallel question for you.

    And the answer is: IT DEPENDS!

    Different people will give you different answers. But here is how we break it down.

    Only 1 Panel? → N/A!

    Since you’re not wiring multiple panels together, there’s no need to choose. Great!

    Have A 24v System? → Series

    You’ll need a solar array that produces a higher voltage in order to charge those 24v batteries.

    Have 2 panels? → Parallel

    Having only 2 solar panels means not having to deal with solar fuses, meaning this parallel connection isn’t so complicated or bulky.

    Have 3+ panels? → Series

    Simplicity is key when you have more panels. Keep the connections simple with a series connection.

    Related read: Best solar panels for van life

    Which Connection Do We Use?

    Campervan Build Guide - Solar Panels For Camper Vans

    On our camper van, we wired two 180-watt solar panels in parallel.

    We did this for two important reasons:

    1. Maximize Production During Partial Shading

    Living in a camper van, we knew we would be parked in a plethora of different lighting situations.

    Sometimes our van roof would experience unlimited direct sunlight. Other times we’d experience plenty of partial shading from trees.

    And since we planned to park in plenty of national parks and boondock on forest lands, combating the effects of partial shading by connecting our panels in parallel was important to us.

    2. No Need For To Fuse Our Solar Array

    Lastly, because we only intended to install two panels on our roof, we didn’t have to fuse our solar array system and didn’t have to worry about combining different wire sizes to create our array. Check out our other post about solar fuses to learn more.

    Free Solar Resource!

    Was This Article Helpful? We have other posts dedicated to help you install a camper van solar system. Check out the guide to learn more!

    Final Thoughts: Series vs. Parallel? Which Is Better For Solar Arrays?

    When it comes to installing solar arrays on houses, the answer is more clear. Because there are more panels involved, wiring solar panels together in series provides more upside. You can keep wire thickness sizes to a minimum and you don’t have to worry about those pesky fuses.

    But when it comes to wiring a much smaller solar array on a mobile vehicle, we think the answer becomes less clear.

    In the end, the decision is up to each of us. Do we value wiring simplicity? Do we value maximizing production in partial shading situations?

    We hope that by the time you’ve reached the end of this post, you have a greater idea of what type of wiring is best for your own solar array system.

    Questions? Comments?

    If you have any questions, please let us know in the comments section below!

    Scroll to Top