Quick answer: Choose an LED supply by matching its regulated output to the LED load, then calculate the required power with watts = volts × amps. LED drivers can regulate constant voltage or constant current; the product name alone does not identify which output you need. Mean Well’s LED power supply manual describes both output types.
This guide covers output selection, load calculations, cable losses, dimming and enclosure limits. The product specifications below illustrate what to compare; they are not a blanket recommendation for those models. Use a qualified electrician for mains-voltage connections or alterations.
Choose constant voltage or constant current first
Match the regulation method to the LED assembly. Constant-voltage supplies hold voltage steady; constant-current drivers hold current steady while voltage changes to suit the load. These operating modes are described in Wikipedia’s LED circuit explanation and Mean Well’s manual.
| What the LED product requires | Output to select | What must match |
|---|---|---|
| A fixed DC input voltage and built-in current limiting | Constant voltage | The specified input voltage and enough output current |
| A specified operating current for a bare LED or COB | Constant current | The required current and a supported voltage range covering the LED load |
| An assembly with its own driver | The input required by that assembly | Its input requirements, rather than the bare LED’s requirements |
This table is our own rule of thumb; the underlying distinction between current-regulated and voltage-regulated LED supplies is described in Wikipedia’s LED circuit article. For strip formats, see our LED strip lights guide.
Current limiting matters even when the voltage looks close. According to Wikipedia’s LED circuit article, a small voltage increase can cause a large current increase, and an LED’s voltage drop decreases as it heats up. A bare LED therefore needs current control rather than an arbitrary fixed-voltage source.
Calculate the load before choosing supply wattage
Add the power of every load that will operate together, then calculate current using I = P ÷ V. Match the voltage before comparing wattage: extra output capacity does not make a mismatched voltage suitable.
The Mean Well LPV-60 datasheet gives a concrete constant-voltage comparison: its 12 V model is rated at 5 A and 60 W, while its 24 V model is rated at 2.5 A and 60 W. The arithmetic is 12 × 5 = 60 W and 24 × 2.5 = 60 W; doubling voltage halves current at the same power.
Worked load example with assumed inputs
Assumed inputs: a strip length of 4 m, consumption of 12 W/m, and a rated input of 24 V. Assume this is the entire output load, with no additional controller consumption included.
- Total power = length × power per metre = 4 × 12 = 48 W.
- Required current = power ÷ voltage = 48 ÷ 24 = 2 A.
- For comparison, an assumed equal-power 12 V load would draw 48 ÷ 12 = 4 A.
This calculation establishes the load, not the final supply rating under every installation condition. According to Mean Well’s installation manual, high ambient temperature or non-standard mounting orientation can require reduced output current. Select capacity using the applicable derating curve rather than a universal headroom multiplier.
Also separate overload protection from usable capacity. According to the LPV-60 datasheet, overload protection operates at 110–150% of rated output power in hiccup mode. That is a protection threshold, not permission to size a continuous load above the rating.
Include cable resistance in the calculation
Calculate the voltage reaching the load, not just the voltage printed on the supply. Our voltage drop calculator uses the resistance of both conductors: voltage drop = current × round-trip resistance. This makes cable length part of supply planning even when the wattage calculation is correct.
Worked cable example with assumed inputs
Assumed inputs: 24 V, 2 A, 10 ft one-way cable length, and 18 AWG copper. Use the calculator’s planning figure of 6.385 Ω per 1,000 ft for that wire, from its shared wire table.
- Round-trip length = 2 × one-way length = 2 × 10 = 20 ft.
- Cable resistance = resistance per foot × round-trip length = (6.385 ÷ 1,000) × 20 = 0.006385 × 20 = 0.1277 Ω.
- Voltage drop = I × R = 2 × 0.1277 = 0.2554 V.
- Voltage at the load = supply voltage − drop = 24 − 0.2554 = 23.7446 V.
- Percentage drop = (drop ÷ supply voltage) × 100 = (0.2554 ÷ 24) × 100 = 1.0642%, rounded.
- Cable power loss = I² × R = 2 × 2 × 0.1277 = 0.5108 W.
This example models the connecting cable only; it does not calculate resistance along the strip itself. Use the wire gauge calculator to compare cable sizes against your chosen drop target and the tool’s current-capacity checks. A voltage-drop percentage by itself does not establish a complete installation rating.
Match the dimming interface to the driver
Buy the control interface your driver actually supports. According to the Mean Well HLG-60H datasheet, B/AB-type models offer “3 in 1” dimming: a 1–10 VDC signal, a 10 V PWM signal, or resistance across DIM+/DIM− adjusts the constant-current level.
That specification describes the control input on those variants. It does not establish compatibility with an arbitrary wall dimmer. The same Mean Well datasheet recommends direct connection to LEDs and says the dimming arrangement is unsuitable with additional drivers. Match the exact variant and load arrangement before choosing controls.
Read enclosure and isolation ratings separately
Class markings, isolation specifications and water protection answer different questions. According to the Mean Well LPV-60 datasheet, the supply has both a Class 2 power-unit designation and Class II construction with no functional ground connection. Class 2 concerns power-limited output; Class II concerns double insulation. They are not interchangeable labels.
According to that Mean Well datasheet, input-to-output withstand voltage is 3 kVAC, and isolation resistance is greater than 100 MΩ when tested at 500 VDC. These are isolation specifications, not output voltages available to the LED load.
For water exposure, according to Wikipedia’s IP Code article, IP67 indicates dust-tight protection and temporary immersion up to 1 m for 30 minutes. The article also says water ratings are not cumulative beyond IPX6: IPX7 does not automatically establish protection against water jets.
Apply the manufacturer’s location restrictions as well. According to Mean Well’s LPV-60 notes, outdoor use must avoid direct sunlight and immersion beyond 30 minutes; its installation manual states that products cannot be in water. Plan a dry installation rather than treating an ingress rating as permission for permanent submersion.
Checklist before choosing a model
Confirm intended application as well as electrical capacity. According to the LPV-60 datasheet, this model is not intended for LED lighting luminaire applications in the EU and China. That restriction is why matching volts and watts alone is insufficient.
- Match constant-voltage or constant-current operation to the load.
- Total the simultaneous load and account for any additional powered controls.
- Compare required output with capacity after the applicable temperature and mounting derating.
- Evaluate cable drop using the actual route length and load current.
- Match the dimming interface, enclosure conditions and intended application.
FAQ
Can an LED driver be used as an LED power supply?
Yes, when its output matches the load. Mean Well’s manual describes both constant-current and constant-voltage LED supplies, so the word “driver” alone does not determine compatibility.
Is a higher-wattage supply always better?
Wattage alone cannot answer that. In the assumed example above, 4 × 12 = 48 W and 48 ÷ 24 = 2 A; a candidate must first match the required voltage and regulation method, then provide sufficient usable capacity.
Should I choose a higher-voltage strip system?
For equal power, higher voltage reduces current: an assumed 48 W load draws 48 ÷ 12 = 4 A at 12 V or 48 ÷ 24 = 2 A at 24 V. This compares different voltage-matched systems; it is not a reason to change the supply voltage on an existing strip.
Does IP67 mean the supply can stay underwater?
No. According to Mean Well’s installation manual, its products cannot be in water; an ingress rating does not override the installation restrictions.
Does an overload threshold provide extra operating capacity?
No. According to the LPV-60 datasheet, the 110–150% overload range triggers hiccup protection; use the rated and appropriately derated output for sizing.
Jack Shi
Founder & editor, LEDaskJack Shi builds and writes LEDask, an independent LED-lighting tools project operated by clooms. He designs the calculators, checks their formulas and reference values against published engineering data, and writes the guides across the site.
