12V vs 24V LED Strips: Which Voltage Should You Run?
24 V halves the current of 12 V for the same wattage, cutting voltage drop to a quarter on long runs. When 12 V still makes sense, and a dual-voltage shortcut.
Towe Engineering · Published November 2, 2026 · 3 min read
For the same wattage, a 24 V LED strip draws half the current of a 12 V strip, and voltage drop along the cable scales with current — so 24 V runs suffer roughly one quarter of the voltage drop and are the correct choice for runs above about 5 metres. 12 V remains sensible for short runs, automotive and battery-backed systems, and products that only exist in 12 V. The TT series outputs both 12 V and 24 V from one housing, removing the stocking decision for contractors.
Key points
- Same wattage → 24 V draws half the current of 12 V
- Voltage drop ≈ scales with current² on comparable installs → ~¼ on 24 V
- Above ~5 m, 24 V wins on brightness uniformity
- TT series: one housing stocks both voltages
The physics in one paragraph
Power = voltage × current. A 100 W load draws 8.3 A at 12 V but 4.2 A at 24 V. Cable loss scales with the square of current (P = I²R), so — all else equal — the 24 V system loses about a quarter of the heat in the cable that the 12 V system does. Less lost voltage at the far end means the last metre of strip is as bright as the first.
Practical decision table
| Situation | Recommendation |
|---|---|
| Run length ≤ 5 m | Either works; 12 V product range is wide |
| Run length > 5 m | 24 V, or power injection at both ends on 12 V |
| Cove and channel lighting in one room | 24 V |
| Whole-floor retail lighting | 24 V without hesitation |
| Automotive / 12 V battery systems | 12 V by definition |
| Mixed fleet, one spare driver type | TT series dual output |
The hidden cost of 12 V on long runs
A 12 m, 100 W strip run on 12 V loses enough voltage at the far end to show a visible brightness gradient — the classic “yellow tail”. Fixes on 12 V: inject power at both ends, or run heavier cable. On 24 V the same run usually needs neither. The wiring you don’t install is the cheapest wiring there is.
Sizing reminder
Whatever the voltage: driver = load × 1.2. And for mixed fleets, the Towe TT series outputs 12 V or 24 V from the same housing with quick-press terminals — one part number in the van, both voltages on site.
Where this interacts with the driver choice
12 V and 24 V are both constant-voltage modes; the mode question (CV vs CC) is separate and decided by the load product. See constant voltage vs constant current for that decision, and the wattage guide for the sizing arithmetic.
This article describes general manufacturing practice for machined and fabricated components. It is not a substitute for a drawing-specific engineering review — tolerances, material selection and process capability depend on the individual part.