What Is Wiring Solar Panels in Series?
When you wire solar panels in series, you connect the positive terminal of one panel to the negative terminal of the next panel. This creates a chain-like circuit.
What happens in series wiring?
- The voltage adds up from each panel.
- The current (amperage) stays the same as one panel.
For example, if you connect three 12V solar panels rated at 5 amps each in series, your total system voltage will be 36V (12V + 12V + 12V), but the current will remain 5 amps.
When to use series wiring?
- You want to increase system voltage to match your inverter or charge controller input requirements.
- Your solar panels are installed in an area with minimal shading (since shading on one panel reduces output of the entire string).
- You want to reduce wiring losses by transmitting higher voltage at lower current.
What Is Wiring Solar Panels in Parallel?
When wiring solar panels in parallel, you connect all the positive terminals together and all the negative terminals together.
What happens in parallel wiring?
- The current adds up from each panel.
- The voltage stays the same as one panel.
For example, connecting three 12V, 5-amp panels in parallel results in a 12V system with a total current of 15 amps (5A + 5A + 5A).
When to use parallel wiring?
- You want to keep system voltage low and increase current.
- Your panels may face partial shading, because shading on one panel only reduces that panel’s current, not the whole array.
- You want to charge 12V battery banks without increasing voltage.
Series vs Parallel: Pros and Cons
| Wiring Type | Pros | Cons |
|---|---|---|
| Series | Higher voltage reduces current, which reduces cable size and power loss; good for long distances. | Shading on one panel affects entire string output; higher voltage may require specialized components. |
| Parallel | Shading on one panel doesn’t affect others; safer lower voltage; easier to add panels incrementally. | Higher current requires thicker cables and can increase power loss over distance. |
Can You Combine Series and Parallel Wiring?
Yes! For larger solar arrays, you can combine series and parallel wiring to achieve the voltage and current you need. For example, connect groups of panels in series to increase voltage, then connect those groups in parallel to increase current. This is called a series-parallel configuration and is common in larger DIY solar setups.
How to Choose Series or Parallel Wiring for Your DIY Solar Setup
- Check your inverter or charge controller specs: Know the voltage and current input limits.
- Consider your battery bank voltage: Match panel output voltage to battery charging requirements.
- Think about shading: If shading is likely, parallel wiring may minimize losses.
- Distance matters: Longer cable runs favor higher voltage (series) to reduce losses.
- Wire size: Higher current (parallel) needs thicker cables, which cost more.
Final Tips
- Always use solar-rated cables and connectors.
- Use a multimeter to test your panel voltages and currents before final installation.
- Consider safety first: higher voltages require proper insulation and precautions.
- If you’re unsure, consult your solar equipment manuals or a professional.
Wiring your solar panels correctly is essential to maximize your DIY solar system’s efficiency and lifespan. Understanding the difference between series and parallel wiring helps you design a system that fits your power needs and site conditions. Ready to start wiring? Grab your tools, plan carefully, and enjoy your solar-powered setup!
