Solar Panel Wiring Guide/How to connect solar panels?

Connecting Solar Panels in Series and Parallel: Comprehensive Guide

   This guide explores in-depth the main differences between series and parallel solar panel connections, their respective advantages and disadvantages, and how to determine the optimal wiring configuration for solar systems. Whether you are installing a new solar array or optimizing an existing solar array, this guide provides you with the clear guidance you need.

Table of Content

1.Ways to connect the solar panels
2.Working principles of parallel and series connection
3.Example: 5KW solar system connection: system matched  
4.5KW system solar panels connection

1. How to connect solar panels?

There are two main ways to connect solar panels: series and parallel connection.

The specific connection method depends on the following factors:

Energy requirements (voltage and current requirements)
Charging controller type (PWM or MPPT)
Inverter specifications
Battery pack voltage (12V, 24V, 48V, etc.)
Environmental conditions (light shading, temperature, lighting conditions)

2. Working principles of parallel and series connection

Let's first understand the working principles of series and parallel connection

Working principle of serial connection
When solar panels are connected in series, the voltage increases while the current (amperage) remains constant.

Example:
Two 100W solar panels, each with a voltage of:
Open circuit voltage (Voc)=21.6V
Short circuit current (Isc)=6.1A
Series total output:
Voltage: 21.6V × 2=43.2V
Current: 6.1A (kept constant)

Working principle of parallel connection
In parallel connection, the voltage remains constant, but the current increases.

Example:
Two 100W solar panels (21.6V, 6.1A each)
Parallel total output:
Voltage: 21.6V (constant)
Current: 6.1A × 2=12.2A

3. Example: one set 5KW solar generator system wiring connection 

(Note: Different products, even products from the same company, have different parameters and different wiring)

5KW solar off-grid power generation system wiring reference.

System configured products:

How should the main product parameters and solar panels be wired?
8pcs solar panels 
Main parameters of solar panels:

Maximum Power-Pmax(W) : 550W
Operating Voltage at Maximum Power-Vmp(V): 41.95V
Operating Current at Maximum Power-Imp(A): 13.12A
Open Circuit Voltage-Voc(V): 49.8V
Short Circuit Current-Isc(A): 13.98
   
5KW Solar generator (three in one: inverter+controller+battery)
Power: 5000W 
Solar generaot DC Voltage: 48V  
Built in MPPT: 48V 60A
MPPT tracking voltage range: 60V-140VDC 
Max PV Input Voltage(Voc): 180VDC  
MPPT PV Array Maxinum Power: 3360W
Inverter : 5000W/48V 
Battery: built in lithium battery 100AH, 150AH, 200AH, etc. Optional 

4.How should above solar system be connected?

With above products specification, how should we connect the solar panels? How many pieces should be in series, how many pieces should be in parallel?

Firstly, let’s see the solar panel has two voltage, normally should according to which to calculate? 
Operating Voltage at Maximum Power-Vmp(V): 41.95V; 
Open Circuit Voltage-Voc(V): 49.8V. 

Secondly we see MPPT tracking voltage range: 60V-140VDC, according to this voltage range, means solar panel input voltage must be in this range.  
Take Operating Voltage at Maximum Power-Vmp(V): 41.95V to calculate, as solar panels are connected in series, the voltage increases, then we use 3pcs solar panel connect in series, 41.95Vx3=125.85V, 125.85V in voltage range 60-140V. Then we see open circuit voltage (Voc.) 49.8Vx3=149.4V, not extra Max PV Input Voltage(Voc): 180VDC. So we use 3pcs in series is OK. 

This system totally has 6pcs 550W solar panel, above use 3pcs in series, and for others how to connect?? Let’s see 6pcs solar panel we divided into 2 groups, each groups 3pcs in series, then we connect this 2 groups in parallel. (see below picture) 

For this solar system why we matched with 6pcs solar panels, see the MPPT PV Array Maximum Power: 3360W; 6pcs 500W, totally is 550Wx6=3300W, for this system, maximum is 6pcs, minimum is 2pcs(why two pieces, that is because 60V is the min. Input voltage, need at least 2pcs connect in series to get the right voltage input.  You can use 2pcs, 3pcs, 4pcs, 6pcs both is OK for this system.  

The solar panel after connection, can connect with an combiner box or a Y type MC4 cable&connector then connect to the solar generator. The solar generator is 3 in 1 together, not need extra connection for controller, battery, etc.

Vevsun service: 

We can match different solar energy systems according to customer requirements and provide wiring guides for customers. Welcome to contact us! 

Conlusion: 

This guide explains the differences between connecting solar panels in series and parallel, helping users choose the optimal wiring configuration based on energy needs, charge controller type, inverter specs, battery voltage, and environmental conditions.