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What Happened to the 100000 Hour LED Bulbs?

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Re: What Happened to the 100000 Hour LED Bulbs?

#101

Post by tlb »

vvanders wrote: post #46
Steltek wrote: post #33

Earlier quoted context omitted.

Every so often, I come back to the "I should have DC power on demand in my house!" until I'm reminded that DC power loss over a distance can hurt bad, even 48VDC telecom power. Perhaps USB-C PD might help? USB power adapters are compact and PD offers standard, useful high power DC. If the adapters become ubiquitous, you could see "USB-C lightbulbs".

Isn't that a function of voltage and not modulation? There might be a cost argument, I'm not sure if solid state step-down DC-DC converters are cheaper than good old cheap transformers.

Yes, it's entirely a function of voltage. But the safe limit for DC voltage is lower for two reasons:

- A shock from a DC supply will cause heart fibrillations at lower voltage than AC, because of the way muscles receive signals from nerves

- An electrical arc from a DC line will burn continuously, while an AC arc tends to self-extinguish at each zero-crossing.

So in practice, 120 VAC or 48 VDC are the limits for household wiring.

Re: What Happened to the 100000 Hour LED Bulbs?

#102

Post by blattimwind »

JoeAltmaier wrote: post #60

I toured a house looking to buy, 20 years ago. The old lady owner said "The light bulb over the door is going with me! I've had it 20 years and counting." It was a weird antique-looking thing with lots of wires and stuff in the clear glass bulb. Dim as hell. But 20 years! They don't make them like they used to.

The expected life of incandescent bulbs follows power laws with pretty big exponents: w.r.t. intensity its to the third power, w.r.t. voltage to the sixteenth power. So if you e.g. put a 230 V bulb on 110 V power, it will be dim as hell, but boi will it last!

Re: What Happened to the 100000 Hour LED Bulbs?

#103

Post by Steltek »

pitaj wrote: post #48
Steltek wrote: post #33

Earlier quoted context omitted.

Every so often, I come back to the "I should have DC power on demand in my house!" until I'm reminded that DC power loss over a distance can hurt bad, even 48VDC telecom power. Perhaps USB-C PD might help? USB power adapters are compact and PD offers standard, useful high power DC. If the adapters become ubiquitous, you could see "USB-C lightbulbs".

> until I'm reminded that DC power loss over a distance can hurt bad, even 48VDC telecom power. If you had AC to your house, then a rectifier for a 100V/200V DC circuit through your house, the losses wouldn't be any worse. DC losses are less than AC losses at the equivalent voltage, because the resistance seen by DC is less than the AC impedance.

The goal in my thinking was to eliminate a complex or costly power supply at the point of consumption. Higher voltages require a beefier step down (isolation, caps, whatever) and AC requires a rectifier. I wanted to eliminate it all.

Sorry, I was being a little too loose for HN. Also, I'm not an EE but I play one on the Internet :).

Re: What Happened to the 100000 Hour LED Bulbs?

#104

Post by zAy0LfpBZLC8mAC »

umvi wrote: post #68
ars wrote: post #45

Earlier quoted context omitted.

It would have to be high voltage DC. Low voltage just can't send enough power - you need wires as thick as garden hoses. High voltage DC is not useful for the things people use.

It seems like an efficient house would at least want a "lighting circuit" where you have a single transformer/rectifier/controller driving a bunch of LEDs all throughout your house. That type of lighting scheme seems like it could last decades if you use quality LEDs.

The usefulness seems questionable. LEDs have to be driven with current, so either you would have to have all LEDs in your house in series, with short-circuit switches for light switches, or you still have most of the electronics in every lamp/bulb anyway (saving only the rectifier and maybe needing only a smaller input filtering cap). The former is highly impractical (complete rewiring, one broken lamp makes all lamps in the house go dark, massive peak voltages if you have many lamps, ...), the latter isn't worth it either in device costs nor in efficiency gains (a shottky full-bridge rectifier probably eats less than half a percent of the lamp's power consumption at ~ 100 V supply voltage, less at higher voltages).

Re: What Happened to the 100000 Hour LED Bulbs?

#106

Post by philsnow »

scrooched_moose wrote: post #86
momentmaker wrote: post #36

The same could be said about every product... Appliances back in the days could last decades. Now you're lucky if they don't break in a few years. What do they say about the best type of customer? The best customer is a repeat customer :)

It says more that customers overwhelmingly prefer cheap products. A 1962 washing machine was 184.95 [1] ($1523.97 today) and a 1959 model was $209.95 [2] ($1729.97 today); which are both more expensive than all but the highest end front loader currently at Best Buy. The vast majority of top loaders are in the $500-700 range, top loaders $800-1000. There simply isn't much market for $2000 machines that will last decad…

> The vast majority of top loaders are in the $500-700 range, top loaders $800-1000. There simply isn't much market for $2000 machines that will last decades.

Those "high end" washing machines will also fail in the same time range that the low end ones will.

There is a market for them, but it will remain unfulfilled because the manufacturers make more money in the short term with the low-reliability ones.

Re: What Happened to the 100000 Hour LED Bulbs?

#108

Post by dchichkov »

izzydata wrote: post #10

This is pretty annoying as I replaced every bulb in my house with LED under the assumption that they would last at least a decade. I didn't even think to check a powered-on time rating. Not that using incandescent bulbs is a good option anymore anyway.

Curious, have you noticed any sleep issues, after you've switched to LED?

Re: What Happened to the 100000 Hour LED Bulbs?

#109

Post by jordinl »

ip26 wrote: post #54
Brakenshire wrote: post #32

Earlier quoted context omitted.

> The relative cost of lighting on the monthly electricity bill is tiny so those savings are pretty small. Only because of the successes up to this point. Marginal gains in LED efficiency aren't going to do much, but the shift from incandescent to LED has had a big impact.

Yeah, this is worth emphasizing. Just a handful 100W bulbs running from 5PM-11PM can consume several kWh every day.

probably you mean 100W bulbs...

Re: What Happened to the 100000 Hour LED Bulbs?

#110

Post by JohnTHaller »

baybal2 wrote: post #20
setquk wrote: post #12

I've taken every single LED bulb that has failed on me to pieces and it's always the same failure mode. The heatsink compound isn't applied properly to the back of the LED board. The LEDs immediately in the gaps smoke out. Alas this isn't a problem. If a lightbulb goes, Amazon send me a new one out now free of charge and tell me to throw the old one in the trash. This is one manufacturer, prevalent on Amazon, the Lon…

Do not buy "bulbs," they are hopeless. Just buy a whole fixture with a big aluminium PCB and directly bonded chips.

My friend's bathroom light that is now a strobe light and the landlord has yet to replace because it requires an electrician to replace the whole fixture would like a word with you.
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