Technical newsletter
Why do professionals prefer 24 V power supplies over 12 V?
In LED lighting, automation, camera systems and control units, both 12 V and 24 V DC are commonly used. For smaller applications, both solutions work well. However, as power requirements and cable lengths increase, a 24 V system offers significant practical advantages.
1. Same power, half the current
Electrical power depends on voltage and current:
P = U × I
If we need to power a 240 W device, the difference is immediately clear:
12 V system
20 A
240 W ÷ 12 V24 V system
10 A
240 W ÷ 24 VDoubling the voltage means approximately half the current at the same power.
2. Lower current means lower losses
Every conductor has electrical resistance. As a result, part of the energy is converted into heat. Cable losses increase with the square of the current:
Plosses = I² × R
If the current is reduced by half, losses in the same conductor theoretically drop to as little as one quarter.
3. Lower voltage drop over longer cable runs
The higher the current flowing through a conductor, the greater the voltage drop across it. In low-voltage systems, this effect is particularly important.
For example, if 1 V is lost along a cable run, this represents approximately 8.3% of the supply voltage in a 12 V system, but only about 4.2% in a 24 V system.
4. Lower cabling requirements
Higher current places greater demands on cables, connectors, terminals, fuses and other components. At higher power levels, a 12 V system may therefore require larger conductor cross-sections.
At 24 V, the current is lower for the same power, which can simplify cable design and help reduce both heating and voltage drop.
The required conductor cross-section always depends on cable length, current, installation method and the permissible voltage drop.
5. 24 V as the preferred choice for LED luminaires and professional lighting systems
LED luminaires and LED lighting systems are among the applications where the advantages of 24 V power are particularly noticeable. In larger LED installations, longer lighting runs and higher-power applications, 24 V helps reduce current, limit voltage drop and simplify cable design.
This is especially important in professional lighting for interiors, furniture, retail spaces, production facilities, advertising elements and architectural lighting systems, where multiple luminaires or longer LED assemblies may be powered from a single power supply.
Pre LED systems je 24 V často praktickejšou voľbou: at the same power, the current is half that of a 12 V system, making it easier to implement higher-power and longer lighting circuits.
24 V DC is also widely used in professional automation and control technology. It is used for PLCs, sensors, relays, control elements, signalling devices, valves and many other components. A unified 24 V infrastructure can therefore simplify system design, servicing and future expansion.
6. The higher the power, the more important the voltage becomes
At low power levels, the difference between 12 V and 24 V may be negligible. In high-power DC systems, however, current rises quickly.
12 V
≈ 83 A
at 1,000 W24 V
≈ 42 A
at 1,000 W48 V
≈ 21 A
at 1,000 WThe general principle is simple: as transmitted power increases, it is advantageous to increase voltage and reduce current.
7. Does this mean 12 V is a bad solution?
No. 12 V remains very practical in automotive applications, smaller electronic devices and wherever power requirements are low and cable runs are short.
The advantages of 24 V become most apparent at higher power levels, over longer cable runs, with larger numbers of devices and in professional installations.
12 V vs. 24 V at a glance
| Feature | 12 V | 24 V |
|---|---|---|
| Current at the same power | higher | half |
| Losses in the same cable | higher | lower |
| Longer cable runs | less advantageous | more advantageous |
| Higher power levels | high currents | easier to manage |
| Industrial automation | less common | very common |
| Small devices and short cable runs | excellent choice | often unnecessary |
A simple rule to remember
Double the voltage → half the current at the same power.
A half the current means lower losses, lower voltage drop a jednoduchšie zvládnutie higher power levels.
This is why professionals designing larger DC installations do not automatically choose 12 V. They first consider power, distance and current — and very often find that 24 V is the more practical solution.