6 ms·

The power factor is 0.5 which is appalling - can't really get lower than 0.5 with capacitive load. Industrial clients do pay for the VA (apparent) than W (actua

by xxs 6y ago

The power factor is 0.5 which is appalling - can't really get lower than 0.5 with capacitive load. Industrial clients do pay for the VA (apparent) than W (actual) power. But even then most urban EU power network is dominated by capacitive loads as the inductive ones tend to use 3-phase 400v (which is balanced) Most of the constant current driven LED would have similar characteristics when they are not overdriven. 25KHz+ PMW driven LED would have similar features as well. It's not hard to make LEDs that actually last and have high lumen/watt ratio with off the shelf components. Overall the main culprit is the LED installation mechanism, e.g. E27 - there is just not enough room to make efficient light out of that. Near ceiling lights do look better (at least to me) and they can have both not overdriven LEDs (say 90mA per 5730), high (over 87%) power factor, decent passive elements... and they are repairable with some electronics background.

dvdkon 6y ago
You can have plenty of LEDs and a reasonable switching PSU in an E27 lamp, it's just harder to cool them with the typical design. Most LED lamps use ridiculously few chips, you could fit multiple times more even on the one-PCB designs, not to mention "corn cob" arrangements or those with LED filaments. That's not to say E27 is an ideal form factor for LEDs, I'm hoping we'll see more and more homes with LED-optimised lighting designs.
- xxs 6y ago
  >reasonable switching PSU in an E27 lamp You can't have active pf correction for real in there (so pf would be 0.5). Pretty much all of them have bridge rectifier + capacitor. Most of them lack input filtering (common mode choke). The real issue is that even with the best light/power ratio, 2/3rd would be heat and that heat has to be dissipated. Electronics hate heat, even with full aluminium body, the light bulb requires plastic casing (as there is no earth available), so heat dissipation is heavily limited. Personally I have mostly near ceiling lights in the house. The non-dimmable/remote control ones would be fully repairable. For ones with the remote controls I can't replace the microcontroller as I could not copy the firmware but all the power driver would be fixable (the controller can be replaced with esp-32 and blue tooth dimming, though). Of course, for most people that would be an extra hassle and fully replaceable lights are likely better. However, custom designs allow for the most optimal heat dissipation.
PurpleFoxy 6y ago
For someone who knows electricity basics, what does power factor mean and why is 0.5 bad?
- DanBC 6y ago
  Put simply, lower power factors are inefficient. They draw more current, which means the components are either stressed or need to be bigger to compensate. (This is all a big simplification): DC power is pretty easy to get your head around. In a resistive circuit you have a nice easy P=IV. But for AC circuits that include capacitance or inductance you sometimes get the current out of phase with the voltage. So you end up with "real power", "apparent power", and "reactive power". For some circuits you can balance out these inductive and capacitive loads. In the UK in the past factories that had a lot of motors (inductive loads) would also have big capacitor banks to help balance these out.
- pjc50 6y ago
  It's the phase difference between the voltage waveform and the current waveform. Power transfer is most efficient when the peak current is happening at the peak voltage. As it moves further away, the loss at generation point increases.
- algorithm314 6y ago
  Simply put when there is lower power factor, there are higher losses into cables. And It is not always negative power that causes this (as many say). For a bridge rectifier the power is always positive.
- atoav 6y ago
  It is about how current draw is in or out of phase with voltage. Purely resistive loads won't affect the phase of the current. However if you have reactive loads like capacitors or inductors your current draw will either have its peak before the voltage has its peak, or after. This leaves you with less power. In Germany going lower than cosphi 0.9 capacitive or cosphi 0.9 inductive requires special permission from the operator of the electrical grid. If your installation affects the electrical grid in negative ways they can make you pay when something breaks or switch of your power to protect the grid. On top of cosphi you also have ripple (basically "overtones" created by non-linear loads like unfiltered switching PSUs). If your THC (total harmonic current) exceeds 5% any power transformers in your net will have significantly reduced lifetime. But German grid operators allow a maximum THC of 15%. So basically there are many ways how inductive, capacitive or switching loads can "deform" and shift the waveforms of the currents and voltages you are drawing, some of this can have negative effects on your own devices, some of it can have negative effects on the grid. Ideally you have a cosphi of 1 (so neither inductive nor capacitive) and a THC of 0% (no harmonics of the fundamental frequency present in the sine of the current drawn), but in reality you have to stay within what your grid operator allows.
mrtksn 6y ago
My living room is lit through 30(3W 240V) LEDs. I installed them about 2 years ago and nearly half of them are gone. The lifetime of these is supposed to be 20K hours. Obviously the lights are not switched on all the time, more like 4 hours on average. That's less than 3K hours of usage with about %50 fatality rate. Out of curiosity, I teared down a few failed ones and they were all gone because one of the LEDs on the LED array blew up. Here is a picture of a failed one: https://imgur.com/aOg7D7S https://imgur.com/aOg7D7S I'm very doubtful about the longevity claims.
- kinghtown 6y ago
  I know someone who retired from working in the LED industry in Taiwan. She said the manufacturers were never going to make enough money from lights which last for ten or twenty years. They are 100% degrading the product so that they need to be replaced much more often. They are all colluding on this. You basically can’t buy the true LED light bulb. It’s a shame.
  - teddyh 6y ago
    It’s the Phoebus cartel all over again. https://en.wikipedia.org/wiki/Phoebus_cartel https://en.wikipedia.org/wiki/Phoebus_cartel
    - des1nderlase 6y ago
      We have this, another example is Luxotica (https://youtu.be/yvTWjWVY9Vo https://youtu.be/yvTWjWVY9Vo). I'm wondering if someone keeps track of all industries that need to be disrupted.
      - redis_mlc 6y ago
        I read an interview with the Luxottica founder - he's an absolute bastard, and proud of it, like a Bond villain. We'll have to wait until he dies to break that monopoly up. When you visit an eyeglass store in the US, it's likely all Luxottica frames, especially the chains they own: https://www.luxottica.com/en/retail-brands https://www.luxottica.com/en/retail-brands
fsh 6y ago
I wonder if the power factor really matters for something as low power as an LED bulb. The grid has to be able to handle the many-kW loads from high-power appliances (ovens, stoves, kettles, car chargers, etc.) anyway. Doubling the current draw of a hand full of 1W-bulbs seems rather insignificant in comparison.
- deleted 6y ago
  [deleted]
- xxs 6y ago
  >ovens, stoves, kettles All of them are pure resistivity load - resistive load has power factor of 1. Ok, stoves might be the inductive kind but those run on 3-phase.
  - fsh 6y ago
    Sure, but they still draw orders of magnitude more current than an LED bulb with a bad power factor.
  - elric 6y ago
    Many induction cookers run on single phase. Depends on how many people you intend to cook for, I would think.
londons_explore 6y ago
> The power factor is 0.5 which is appalling When it's only a 1 watt bulb it really doesn't matter. It will be massively eclipsed by your 3000 watt dryer or your 30000 watt car charger. And those will have a good power factor.
- londons_explore 6y ago
  And if you industrially buy 30,000 of these bulbs, you can buy a power factor correction device to save on the electric bill.
lukeschlather 6y ago
> It's not hard to make LEDs that actually last and have high lumen/watt ratio with off the shelf components. Are you sure? It seems to me that most LEDs dim gradually over time. What do you mean by "actually last?" 10 years? 50,000 hours of operation? Less than 90% reduction in lumens on average over the advertised lifespan?
- xxs 6y ago
  >It seems to me that most LEDs dim gradually over time. Of course, esp. the warm white ones (they got more phosphor). For 50k hours, the LEDs are likely to drop to 70ish% of their original brightness, provided they stay below 50C[0] - lumen maintenance. That would depend on the spec. of the LEDs but it should be a ballpark number. [0]: https://datasheetspdf.com/pdf-file/1404455/BIVAR/SM5730UWDW05/1 https://datasheetspdf.com/pdf-file/1404455/BIVAR/SM5730UWDW0...

by xxs 6y ago

dvdkon 6y ago

You can have plenty of LEDs and a reasonable switching PSU in an E27 lamp, it's just harder to cool them with the typical design. Most LED lamps use ridiculously few chips, you could fit multiple times more even on the one-PCB designs, not to mention "corn cob" arrangements or those with LED filaments. That's not to say E27 is an ideal form factor for LEDs, I'm hoping we'll see more and more homes with LED-optimised lighting designs.

xxs 6y ago
>reasonable switching PSU in an E27 lamp You can't have active pf correction for real in there (so pf would be 0.5). Pretty much all of them have bridge rectifier + capacitor. Most of them lack input filtering (common mode choke). The real issue is that even with the best light/power ratio, 2/3rd would be heat and that heat has to be dissipated. Electronics hate heat, even with full aluminium body, the light bulb requires plastic casing (as there is no earth available), so heat dissipation is heavily limited. Personally I have mostly near ceiling lights in the house. The non-dimmable/remote control ones would be fully repairable. For ones with the remote controls I can't replace the microcontroller as I could not copy the firmware but all the power driver would be fixable (the controller can be replaced with esp-32 and blue tooth dimming, though). Of course, for most people that would be an extra hassle and fully replaceable lights are likely better. However, custom designs allow for the most optimal heat dissipation.

PurpleFoxy 6y ago

For someone who knows electricity basics, what does power factor mean and why is 0.5 bad?

DanBC 6y ago
Put simply, lower power factors are inefficient. They draw more current, which means the components are either stressed or need to be bigger to compensate. (This is all a big simplification): DC power is pretty easy to get your head around. In a resistive circuit you have a nice easy P=IV. But for AC circuits that include capacitance or inductance you sometimes get the current out of phase with the voltage. So you end up with "real power", "apparent power", and "reactive power". For some circuits you can balance out these inductive and capacitive loads. In the UK in the past factories that had a lot of motors (inductive loads) would also have big capacitor banks to help balance these out.
pjc50 6y ago
It's the phase difference between the voltage waveform and the current waveform. Power transfer is most efficient when the peak current is happening at the peak voltage. As it moves further away, the loss at generation point increases.
algorithm314 6y ago
Simply put when there is lower power factor, there are higher losses into cables. And It is not always negative power that causes this (as many say). For a bridge rectifier the power is always positive.
atoav 6y ago
It is about how current draw is in or out of phase with voltage. Purely resistive loads won't affect the phase of the current. However if you have reactive loads like capacitors or inductors your current draw will either have its peak before the voltage has its peak, or after. This leaves you with less power. In Germany going lower than cosphi 0.9 capacitive or cosphi 0.9 inductive requires special permission from the operator of the electrical grid. If your installation affects the electrical grid in negative ways they can make you pay when something breaks or switch of your power to protect the grid. On top of cosphi you also have ripple (basically "overtones" created by non-linear loads like unfiltered switching PSUs). If your THC (total harmonic current) exceeds 5% any power transformers in your net will have significantly reduced lifetime. But German grid operators allow a maximum THC of 15%. So basically there are many ways how inductive, capacitive or switching loads can "deform" and shift the waveforms of the currents and voltages you are drawing, some of this can have negative effects on your own devices, some of it can have negative effects on the grid. Ideally you have a cosphi of 1 (so neither inductive nor capacitive) and a THC of 0% (no harmonics of the fundamental frequency present in the sine of the current drawn), but in reality you have to stay within what your grid operator allows.

mrtksn 6y ago

My living room is lit through 30(3W 240V) LEDs. I installed them about 2 years ago and nearly half of them are gone. The lifetime of these is supposed to be 20K hours. Obviously the lights are not switched on all the time, more like 4 hours on average. That's less than 3K hours of usage with about %50 fatality rate. Out of curiosity, I teared down a few failed ones and they were all gone because one of the LEDs on the LED array blew up. Here is a picture of a failed one: https://imgur.com/aOg7D7S https://imgur.com/aOg7D7S I'm very doubtful about the longevity claims.

kinghtown 6y ago
I know someone who retired from working in the LED industry in Taiwan. She said the manufacturers were never going to make enough money from lights which last for ten or twenty years. They are 100% degrading the product so that they need to be replaced much more often. They are all colluding on this. You basically can’t buy the true LED light bulb. It’s a shame.
- teddyh 6y ago
  It’s the Phoebus cartel all over again. https://en.wikipedia.org/wiki/Phoebus_cartel https://en.wikipedia.org/wiki/Phoebus_cartel
  - des1nderlase 6y ago
    We have this, another example is Luxotica (https://youtu.be/yvTWjWVY9Vo https://youtu.be/yvTWjWVY9Vo). I'm wondering if someone keeps track of all industries that need to be disrupted.
    - redis_mlc 6y ago
      I read an interview with the Luxottica founder - he's an absolute bastard, and proud of it, like a Bond villain. We'll have to wait until he dies to break that monopoly up. When you visit an eyeglass store in the US, it's likely all Luxottica frames, especially the chains they own: https://www.luxottica.com/en/retail-brands https://www.luxottica.com/en/retail-brands

fsh 6y ago

I wonder if the power factor really matters for something as low power as an LED bulb. The grid has to be able to handle the many-kW loads from high-power appliances (ovens, stoves, kettles, car chargers, etc.) anyway. Doubling the current draw of a hand full of 1W-bulbs seems rather insignificant in comparison.

deleted 6y ago
[deleted]
xxs 6y ago
>ovens, stoves, kettles All of them are pure resistivity load - resistive load has power factor of 1. Ok, stoves might be the inductive kind but those run on 3-phase.
- fsh 6y ago
  Sure, but they still draw orders of magnitude more current than an LED bulb with a bad power factor.
- elric 6y ago
  Many induction cookers run on single phase. Depends on how many people you intend to cook for, I would think.

londons_explore 6y ago

> The power factor is 0.5 which is appalling When it's only a 1 watt bulb it really doesn't matter. It will be massively eclipsed by your 3000 watt dryer or your 30000 watt car charger. And those will have a good power factor.

londons_explore 6y ago
And if you industrially buy 30,000 of these bulbs, you can buy a power factor correction device to save on the electric bill.

lukeschlather 6y ago

> It's not hard to make LEDs that actually last and have high lumen/watt ratio with off the shelf components. Are you sure? It seems to me that most LEDs dim gradually over time. What do you mean by "actually last?" 10 years? 50,000 hours of operation? Less than 90% reduction in lumens on average over the advertised lifespan?

xxs 6y ago
>It seems to me that most LEDs dim gradually over time. Of course, esp. the warm white ones (they got more phosphor). For 50k hours, the LEDs are likely to drop to 70ish% of their original brightness, provided they stay below 50C[0] - lumen maintenance. That would depend on the spec. of the LEDs but it should be a ballpark number. [0]: https://datasheetspdf.com/pdf-file/1404455/BIVAR/SM5730UWDW05/1 https://datasheetspdf.com/pdf-file/1404455/BIVAR/SM5730UWDW0...