Can you wire solar panels in series and batteries in parallel?

Yes, you can wire solar panels in series and batteries in parallel, but you need to consider certain factors to ensure the system works efficiently and safely.

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 increases the voltage output while keeping the current constant. Wiring panels in series is useful if you have a higher voltage requirement for your solar system, such as when using a higher voltage inverter or charge controller.

However, keep in mind that when solar panels are wired in series, the entire string’s output is affected by shading or soiling on even one panel. Therefore, ensure that all panels receive consistent sunlight and are regularly cleaned.

Wiring batteries in parallel

When you wire batteries in parallel, you connect all the positive terminals together and all the negative terminals together.

This increases the total capacity (measured in ampere-hours) and keeps the voltage constant. Wiring batteries in parallel allows you to have more energy storage, which can be useful for off-grid systems or to provide backup during periods of low solar production.

However, when wiring batteries in parallel, make sure they are of the same type (e.g., flooded, AGM, or lithium-ion), have similar capacities, and are in a similar state of health.

Mismatched batteries can lead to uneven charging and discharging, which can reduce the overall system’s efficiency and lifespan.

Here’s an example of a solar power system setup with solar panels wired in series and batteries wired in parallel:

Let’s assume you have a 48V off-grid solar power system with the following components:

Solar panels: 4 x 300W panels, each with a voltage of 24V and a current of 12.5A
Batteries: 4 x 12V, 200Ah deep-cycle batteries
Charge controller: 48V MPPT charge controller
Inverter: 48V pure sine wave inverter

To wire the solar panels in series, connect the positive terminal of the first panel to the negative terminal of the second panel, the positive terminal of the second panel to the negative terminal of the third panel, and so on. This will increase the voltage while maintaining the same current.

Resulting solar panel string:

Voltage: 24V + 24V + 24V + 24V = 96V
Current: 12.5A (constant)

To wire the batteries in parallel, connect all the positive terminals together and all the negative terminals together. This will increase the capacity while keeping the voltage constant.

Resulting battery bank:

Voltage: 12V (constant)
Capacity: 200Ah + 200Ah + 200Ah + 200Ah = 800Ah

Connecting the system

Connect the solar panel string to the MPPT charge controller, which will convert the 96V input from the panels to the required 48V for charging the battery bank. Then, connect the battery bank to the charge controller and the 48V inverter.

This example demonstrates a solar power system with solar panels wired in series and batteries wired in parallel. The system is designed to meet the voltage and capacity requirements while maintaining compatibility with the charge controller and inverter.

In summary, you can wire solar panels in series and batteries in parallel, but it’s essential to ensure proper system design and component compatibility to maximize efficiency and safety. It’s always a good idea to consult a solar professional when designing and installing a solar power system.