A few years into LED sourcing, most buyers have seen this: a luminaire rated for 50,000 hours, installed, and two or three years later a whole batch goes dark. Open it up and the LEDs are fine. The driver is dead.
The driver is only 15 to 20 percent of a luminaire's cost, but it decides how long the fixture lasts. The mechanism is not complicated. Electrolytic capacitor life is strongly temperature-dependent — roughly halved for every 10°C rise. A capacitor rated 2,000 hours at 85°C, running fully loaded inside a 45°C housing, will not come close to the LED's theoretical life.
So when you look at a sample, pull the driver out and ask these questions.
Constant current or constant voltage. LEDs need constant current. A constant-voltage driver is a common cost shortcut. It lights up fine and degrades quickly.
Rated at full load, or derated. A 150W driver run at 150W continuously loses life. The safer practice is a 20 percent margin: a 150W fixture with a 180W driver. Quotations rarely state this. Ask.
Which capacitor brand. Rubycon, NichiCon and Chemi-Con are the names the industry recognises. No-name capacitors are the first place cost gets cut. Ask for the driver BOM, or at least a photo.
Isolated or non-isolated. Non-isolated is cheaper and one safety class lower. For Europe and North America you generally need isolated. Read the destination market before the price.
Surge protection rating. 2kV versus 4kV shows up directly as a return rate in thunderstorm regions. Worth asking on Middle East and Southeast Asian projects.
The driver's own IP rating. A fixture stamped IP65 with an IP20 driver sealed inside the housing is a summer failure waiting to happen.
Put these into the technical annex of the contract. A verbal confirmation in a chat window is not evidence when a batch goes wrong.
We open and test drivers separately during inspection, measuring full-load temperature rise and output ripple. If you have an LED order under negotiation, send the spec sheet and we will go through it.