Applicable to 12V and 24V DC LED Strip Light and Module Installations
1. Understanding the Basics
LED strip lights and LED modules are designed to operate at a fixed voltage — either 12V DC or 24V DC depending on the product. This is a fundamental characteristic of how LEDs function: they are voltage-sensitive devices that require a consistent, stable supply voltage to perform correctly and safely.
There are two ways to connect multiple LED loads in a circuit — in series or in parallel. For LED strips and modules, parallel connection is not simply preferred — it is the correct and only appropriate method.
2. What Happens When LEDs Are Connected in Series
In a series circuit, the supply voltage is divided across each connected load. This means that if you connect two 12V LED strips in series and supply 12V, each strip receives only 6V — half of what it requires. The result is dim, uneven, or non-functional lighting.
More critically, if one strip or module in a series chain fails or is cut, the entire circuit is broken and all lights go out. This makes fault-finding difficult and renders the installation unreliable.
In a 24V installation, the problem is equally damaging in reverse: connecting a 12V-rated strip or module in a series configuration at 24V can result in overvoltage across individual components, leading to premature failure, overheating, or permanent damage to the LEDs and onboard resistors.
3. Why Parallel Connection Is Correct
In a parallel circuit, every LED strip or module receives the full supply voltage — 12V or 24V — regardless of how many units are connected. Each load operates independently at its rated voltage, ensuring:
• Consistent brightness across all connected strips and modules.
• Independent operation — if one section fails, the rest of the installation continues to function.
• Correct current distribution — each strip draws only the current it requires, preventing overload on individual components.
• Longer product lifespan — LEDs running at their correct rated voltage run cooler and last significantly longer.
4. Voltage Drop: The Key Consideration in Parallel Installations
While parallel connection is correct, it introduces the practical challenge of voltage drop — particularly over longer runs. As current travels along the copper conductors of an LED strip, resistance in the wire causes the voltage to decrease the further it travels from the power supply.
This is why 24V systems are generally preferred over 12V for longer runs. A 24V strip experiences proportionally less voltage drop over the same distance, delivering more consistent light output from start to end. As a general guideline:
• 12V installations should typically not exceed 5 metres per run from the power supply without re-feeding.
• 24V installations can typically extend to 10 metres or more before voltage drop becomes visibly noticeable.
To combat voltage drop in larger installations, the supply should be fed from both ends of the strip, or intermediate injection points should be used to maintain consistent voltage throughout.
5. Power Supply Sizing
Because all strips and modules in a parallel installation draw current simultaneously, the power supply must be sized to handle the total combined load. Add up the wattage of all connected strips and modules and select a power supply rated for at least 120% of that total to allow for a safety margin and ensure longevity of the driver.
For example: if you have four LED strip runs each drawing 14.4W, your total load is 57.6W. A 75W or 100W power supply would be the appropriate selection.
6. Summary
Always connect LED strip lights and modules in parallel. Match your installation to the correct supply voltage, size your power supply generously, and account for voltage drop on longer runs — particularly in 12V systems.
| Series | Parallel (Correct) | Recommended | |
| Voltage per strip | Divided — incorrect | Full rated voltage | Parallel |
| If one strip fails | All strips fail | Others continue | Parallel |
| Brightness | Uneven / dim | Consistent | Parallel |
| Suitable for 12V/24V LED | No | Yes | Parallel |
| Max run (12V) | N/A | ~5m per run | 24V for long runs |
| Max run (24V) | N/A | ~10m+ per run | 24V for long runs |
7. Need Assistance?
For product-specific wiring guidance, power supply sizing, or technical support, please contact The Lighting Zone:
Email: admin@thelightingzone.co.za
Tel: +27 10 590 6101
Website: www.thelightingzone.co.za