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Comment by econcon | Hacker News Reader

Quality of grid has huge influence on life of LED. Basically, the drive circuit needs to be of pretty robust to guard against voltage fluctuations and surges which kill led.

Not sure if there is something user can do to protect their house from grid quality issues.

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I'm not a power electricity guy, but I think of the power grid as an absolutely massive flywheel, electrically speaking. I don't get how the electric company could introduce surges, even if they wanted to. (I have 200A service, which I don't use much of.)

It's often possible to choose DC for the final metres to the lamp itself, whereupon you've reduced the problem to ensuring you deliver a nice clean DC feed or nothing. As a side benefit to the extent you're successful you also eliminate flicker, which some people find extremely annoying in LEDs.

You may find that your retail options for DC lamps are more limited depending on where you shop, and it will likely require a more extensive change than just unscrewing a "bulb" and putting a new one in but it's an option. Certainly worth considering if you're remodelling for example.

LED flicker usually has nothing to do with AC power. They LED is being purposely driven pulsed to maximize power efficiency.

Incidentally, incandescent bulbs flicker at 120 Hz (in the US) but it is imperceptible because the light output doesn’t go to zero and it is beyond the flicker fusion threshold (~60 Hz)

Many cheap LEDs flicker at at double line frequency (100Hz or 120Hz depending on the country), because they're driven by rectified AC power with inadequate filtering. Pulsing LEDs only increases efficiency at low brightness, e.g. 7-segment displays, not room lighting. See: http://donklipstein.com/ledp.html

The flicker fusion threshold for many people is above 60Hz. Remember 60Hz CRTs? 85Hz is a more reliable threshold. And in any case, flicker fusion threshold is only relevant when your eyes are stationary. On eye movement you get phantom array effect. People vary greatly in how sensitive they are to this, and depending on how strong your saccadic masking is, it can be annoying at frequencies well into the kilohertz.

The efficiency gains of pulsed drive isn’t in the LEDs, it is in the drive electronics.

How does pulsing at a frequency that's unrelated to the AC line frequency but still low enough to be visible improve efficiency? SMPS efficiency usually peaks in the hundreds of kHz, which is invisible even to the most sensitive observers.

I think we are saying the same thing.

You said "LED flicker usually has nothing to do with AC power." But most LED lighting flicker is the result of using a capacitive dropper power supply. These are cheap and efficient, but produce a lot of ripple at double the line frequency (with full-wave rectification). Filtering the output enough to make flicker imperceptible would cost more, and not everybody notices the flicker so it's easy to get away with cutting corners. See:

http://www.bigclive.com/ledlmp.htm

Better and more expensive LED drivers use a switch mode power supply, which does not produce visible flicker.

You can have a whole house surge protector installed at your electrical panel. These cost about $50-$200 at a home store. When I did, I had an electrician install it while I was having other work done on the panel.

How so? Aren't LED bulbs powered by a standard switch mode power supply? Those are very tolerant of the input voltage.

Budget driver circuit which is designed to be cheapest and using least number of components often isn't tolerant.

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