Parallel vs. Series Connection: How to Connect Your Solar Panels the Right Way
A simple, practical guide to choosing series, parallel, or series-parallel wiring for portable and foldable solar panels.
When using multiple solar panels—whether for camping, RVs, or charging power stations—how you connect them makes a big difference in performance. Below we explain series and parallel connections, their pros and cons, and when to choose each for your setup.
What Is a Series Connection?
A series connection increases the voltage of your system. Connect the positive (+) of one panel to the negative (–) of the next. The voltages add up while the current (amps) stays the same.
- How it works: Voltage adds up; current stays the same.
- Example: Three 36V 11.1A panels in series → 108V total (amps unchanged).
- Best for: MPPT charge controllers, long cable runs, higher-efficiency setups.
Pros: Higher voltage reduces power loss, works well with MPPT controllers, better for long cable distances.
Cons: Shading or a weak panel affects the entire string; panels should have matching current ratings.
What Is a Parallel Connection?
A parallel connection increases the current (amps) while keeping voltage the same. All positives are connected together and all negatives together.
- How it works: Current adds up; voltage stays the same.
- Example: Two 36V 11.1A panels in parallel → 36V, 33.3A total.
- Best for: Low voltage battery systems, PWM controllers, setups with partial shading.
Pros: Shading on one panel won’t drag down the whole array; easy to expand; safer for low-voltage systems.
Cons: Higher current needs thicker cables; more loss over long distances compared to high-voltage runs.
Series vs. Parallel — Quick Comparison
| Feature | Series | Parallel |
|---|---|---|
| Voltage | Increases | Stays the same |
| Current | Stays the same | Increases |
| Shading impact | High | Low |
| Cable size required | Smaller (lower amps) | Larger (higher amps) |
| Best for | MPPT, long runs | PWM, shaded areas |
Can You Use Both? (Series-Parallel)
Yes. A series-parallel configuration combines the benefits of both: you can increase voltage by wiring panels in series, then increase current by paralleling those series strings. This is useful when you have 4 or more panels and want to match a power station or battery bank voltage while maximizing wattage.
Example: Two series pairs (each pair = 72V) → connect the two pairs in parallel to increase amps while keeping 72V.
Which Should You Choose?
Here’s a simple rule of thumb:
- Choose Series if your power station or charge controller supports higher voltage (MPPT). Series is great for long cable runs and higher-efficiency setups.
- Choose Parallel if you want more resilience to shading, use a PWM controller, or prefer low-voltage system.
For most portable and foldable solar panels—including our 400W portable solar panels and 200W flexible panels—the right choice depends on your power station input limits.