24V vs 12V at a glance
At the same power, a 24V LED system draws half the current of a 12V system. Lower current generally means less voltage drop through the same cable, easier cable sizing and more consistent light output over longer runs. Final cable and driver selection must still be calculated from the actual load and installation.
| Factor | 24V system | 12V system |
|---|---|---|
| Current at equal power | Lower | Higher |
| Voltage drop over the same cable | Generally lower | Generally higher |
| Typical use | Multi-letter and longer professional runs | Small signs and short existing circuits |
| Design requirement | Calculate total load, cable length, conductor size, driver capacity and allowable voltage drop | |
Voltage drop: the critical difference
Voltage drop is the primary reason to choose 24V over 12V. For the same power consumption, 24V systems draw half the current of 12V systems. Since voltage drop is proportional to current (V = I × R), halving the current halves the voltage drop across cable runs.
In practical terms, a 24V system can run twice the distance of a 12V system with the same voltage drop. For example, a 10-meter run carrying 2 amps at 12V experiences twice the voltage drop of the same run carrying 1 amp at 24V. This becomes critical in multi-letter installations where cumulative voltage drop causes visible brightness variations.
A typical 24V installation can run 15-20 meters before requiring power injection, compared to just 7-10 meters for 12V systems.
Cable sizing benefits
Lower current requirements allow smaller gauge cables for equivalent performance. Where a 12V system requires 2.5mm² cable, a 24V system often uses 1.5mm² cable for the same run length and load. This means reduced material costs, neater installations, easier cable routing, and reduced weight for overhead installations.
Connection reliability
Connection points are the most common failure point in LED installations. The reduced current in 24V systems means less heat generation at connections, less thermal stress, and improved long-term reliability. This is particularly important for outdoor installations exposed to temperature cycling.
Scotchlock connectors, which we recommend for all installations, perform even better with the lower currents of 24V systems. The reduced heat generation ensures the gel filling maintains its properties over the installation's lifetime.
LED driver selection
Quality LED drivers operate 2-5% more efficiently at 24V than 12V. This translates to lower power consumption, reduced heat generation, longer driver lifespan, and smaller driver sizes. For large installations, these efficiency gains compound into significant operational savings.
Component availability and servicing
The signage industry has largely standardized on 24V for professional installations, providing wider availability of quality components, better technical support, easier sourcing of replacement parts, and compatibility with professional control systems.
When 12V makes sense
12V systems remain appropriate for very small installations with short cable runs (under 3 meters), indoor and front counter signage, or retrofit projects where 12V infrastructure already exists.
For new fabricated letter installations, particularly outdoor applications or multi-letter installations, 24V systems provide clear technical and economic advantages. The combination of reduced voltage drop, improved reliability, and lower installation costs makes 24V the professional choice.
For information on proper wiring techniques for LED letters, see our article: Professional LED Letter Wiring: The No-Tail Daisy Chain Approach.
