So you have two or more panels that are mismatched and you want to connect them together?
In this article, I’m going to tell you the best way to wire mixed or mismatched solar panels.
If you have identical solar panels, I recommend reading my guide on how to wire them in series or parallel.
Now, back to the topic at hand.
When you have mixed solar panels there are three ways to wire them:
- Series
- Parallel
- Hybrid
In this article, we are going to talk about series and parallel.
But first some theories about solar panel characteristics. If you don’t understand this, then you won’t understand the reasoning behind it.
- Solar radiation impacts current
- Temperature impacts voltage
- Series adds up voltage
- Parallel adds up current
Mixing Mismatched Solar Panels
Luckily there are only two variables that we have to take into account. These are current and voltage.
As previously mentioned, when we connect solar panels in series, the voltage gets added up.
When we wire multiple solar panels in parallel, the current gets added up. Now, how can we use these characteristics to our advantage when we are mixing solar panels?
Same Current
When your panels have the same current but different voltage, you need to wire your panels in series. This is because the voltage gets added up, while the current stays the same. You can see this in the following diagram.
Same Voltage
When your panels have the same voltage but different current, you need to wire in parallel. This is because the current gets added up, while the voltage stays the same. You can see this in the following diagram.
Conclusion
When you have panels with the same current, then wire in series.
If you have panels with the same voltage, then wire in parallel.
From there, the power goes to your charge controller.
Now, if you have two separate solar strings, you might as yourself the question: ‘can I add multiple charge controllers to the same battery bank?’ Read my answer here.
FAQ
Can you mix and match solar panel brands?
Yes, you can as long as the current and voltage are the same. Refer to this article on how to wire the panels to get the most efficiency.
Can I mix mono and poly panels?
Yes, you can mix monocrystalline and polycrystalline together. If they have the same voltage or current, you can put them in series or parallel for best results. Refer to this article to know more if you need to wire panels in series or parallel.
Can I add different solar panels to my system?
Yes, you can. If there is no possibility to wire them in series or parallel, you need to add another charge controller. You will have multiple charge controllers for one battery. That’s not a problem.
Can you put solar panels of different current in series?
No, it’s not advised to wire solar panels with different current in series. They should be wired in parallel if they have different current.
Can you put solar panels of different voltage in parallel?
No, It’s not advised to have your panel wired in parallel when they have the same voltage. They should be wired in series if they have the same voltage.
What happens if mismatched solar panels are connected together?
There will be losses in your system. It’s not bad for the equipment, you just get less power output from the solar panels.
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I’m an off-grid enthusiast. I created this website to give clear and straight-to-the-point advice about solar power. I’m also the author of the book ‘Off-grid solar power simplified‘. Read more about me on my about page, check out my Youtube channel, or send me a message.
What happens when you mix in parallel two panels of same or different current but the voltage is only slightly different? The thing is that after some time some time it may be difficult to buy more panels of exactly the same voltage but we may find ones with very similar voltage. What maximum difference would you consider okay for mixing?
For example, if we had a 19V panel and a 18V panel connected in parallel, how effectively would their power outputs add up? I’m trying to visualize how that would work – if the system drew up to the 19V panel power output capability would the 19V panel work work on its own while the 18V panel sitting idle only kicking in when the 19V one can’t handle the load and the voltage drops to 18V? When the voltage drops to 18V then the 19V panel would work below its MPP and not giving its full power. I’m wondering how an MPPT controller would handle that.
if voltage is slightly different, and current has a higher difference, wire in parallel. I would say up to 5 volts in small systems is ok but that is my opinion. If it’s critical, like the roof of a van or boat, then get two charge controllers.
great job,thanks a lot we are learning more on solar power systems
Nick, am trying to visualize the connection between a 200w renogy suitcase panel w/controller and a separate 200w panel on the roof of my camper. Have ordered a renogy BT 20a controller. My suitcase panel is wired to the battery, whereas my separate 200w panel will go to the 20amp controller. Do both panels need to connect to the new controller or connect to the battery separately? You.ve got the best, most informative site on YT. Thanks for what you do. joel
Thanks Joel! I would wire them to their own charge controllers. Because the foldable panel is not always going to be in the sun while you drive, while the solar panel on the roof will. I have made a video about multiple charge controllers: https://youtu.be/YMCLka_4Ne8