Solar Panels: Series vs Parallel — Which Wiring Is Right for You?

Wiring solar panels in series raises voltage while current stays the same; wiring in parallel does the opposite. Which one you need depends on your charge controller’s limits, your wire run, and shading conditions.

Series wiring (voltage adds, current stays)

Two 12V / 5A panels in series give 24V / 5A. Higher voltage means:

• Less current for the same power → thinner wire, less voltage drop
• Better performance in low light (more voltage available to start charging early)
• Can exceed charge controller input limits on cold days (voltage rises when cold)

Parallel wiring (current adds, voltage stays)

Two 12V / 5A panels in parallel give 12V / 10A. This is useful when:

• Your controller is PWM (needs panel voltage close to battery voltage)
• Panels have different orientations or shading — one shaded panel doesn’t drag the whole string down

Shading: the practical difference

• Series: one shaded panel reduces current for the whole string.
• Parallel: each panel works independently; shading affects only that panel.

Quick decision table

Situation	Choose
MPPT controller, long wire run, no shading	Series
PWM controller	Parallel
Shaded / partial panels	Parallel
Mix of panel sizes	Parallel (with care)

See the voltage drop calculator to size your wire for either configuration.