On Wednesday, 14 March 2018 14:47:42 UTC, NY wrote:
tabbypurr wrote in message
...
On Wednesday, 14 March 2018 09:54:42 UTC, whisky-dave wrote:

But it is true the problem with LED lightbulbs is that they do get very
hot at the base as that's where the SMPS are but the heat can be
transfered to the actual LEDs which don;t like being hot.
The life of the lamps might well be UP TO 15K hours but they are very
liklely to fail long before that due to temperature as the 15K hours
refers to an LED used within the specs and even then it doesn't mean it
will last 15,000 hours.

The heat comes from the LED, it doesn't get transferred to the LED.

Ah, is the heat mainly from the LEDs rather than the PSU?

almost entirely


NT

On Wednesday, 14 March 2018 15:05:51 UTC, NY wrote:
"whisky-dave" wrote in message
...
On Wednesday, 14 March 2018 10:18:33 UTC, Tim Watts wrote:
On 14/03/18 09:54, whisky-dave wrote:

But it is true the problem with LED lightbulbs is that they do get very
hot at the base as that's where the SMPS are but the heat can be
transfered to the actual LEDs which don;t like being hot.
The life of the lamps might well be UP TO 15K hours but they are very
liklely to fail long before that due to temperature as the 15K hours
refers to an LED used within the specs and even then it doesn't mean it
will last 15,000 hours.



Not all LED lamps have much in the way of PSUs

https://youtu.be/ReO9D1E8XqI?t=9m2s

Basically a bridge and 3 passives.

They canlt easily be dimmed, they are crap, they flicker and don't last
anywhere near as long as stated.

They can be dimmed very easily using their own built-in control logic (but
not too effectively by using an external triac dimmer)

some can, many can't in both cases

- all that is
required is a constant-frequency square wave with a variable mark:space
ratio.

for smpsu ones yes, for CR psu ones what's wanted is a series capacitor.


NT

On Wednesday, 14 March 2018 15:13:33 UTC, whisky-dave wrote:
On Wednesday, 14 March 2018 14:32:48 UTC, tabby wrote:
On Wednesday, 14 March 2018 09:54:42 UTC, whisky-dave wrote:

But it is true the problem with LED lightbulbs is that they do get very hot at the base as that's where the SMPS are but the heat can be transfered to the actual LEDs which don;t like being hot.
The life of the lamps might well be UP TO 15K hours but they are very liklely to fail long before that due to temperature as the 15K hours refers to an LED used within the specs and even then it doesn't mean it will last 15,000 hours.

The heat comes from the LED, it doesn't get transferred to the LED.

NO it doesn't.

you have to have an amazing depth of ignorance of electronics to think that.

On 14/03/18 17:39, wrote:
On Wednesday, 14 March 2018 14:47:42 UTC, NY wrote:
tabbypurr wrote in message
...
On Wednesday, 14 March 2018 09:54:42 UTC, whisky-dave wrote:

But it is true the problem with LED lightbulbs is that they do get very
hot at the base as that's where the SMPS are but the heat can be
transfered to the actual LEDs which don;t like being hot.
The life of the lamps might well be UP TO 15K hours but they are very
liklely to fail long before that due to temperature as the 15K hours
refers to an LED used within the specs and even then it doesn't mean it
will last 15,000 hours.

The heat comes from the LED, it doesn't get transferred to the LED.

Ah, is the heat mainly from the LEDs rather than the PSU?

almost entirely


NT

Unless its a rubbish design of lamp

With most designs the LEDS are mounted on some kind if internal heat
conductor that then is connected to the base whilst there is no direct
connection to the envelope. So the base gets hotter than the envelope

In a general bulb even with a SMPSU about 5% of the input will go into
PSU heating, about 10% of what's left (9.5%) will; go out as light and
the rest (85.5% appx) will go out as LED heat.



--
Karl Marx said religion is the opium of the people.
But Marxism is the crack cocaine.

On Wednesday, 14 March 2018 18:08:06 UTC, The Natural Philosopher wrote:
On 14/03/18 17:39, tabbypurr wrote:
On Wednesday, 14 March 2018 14:47:42 UTC, NY wrote:
tabbypurr wrote in message
...
On Wednesday, 14 March 2018 09:54:42 UTC, whisky-dave wrote:

But it is true the problem with LED lightbulbs is that they do get very
hot at the base as that's where the SMPS are but the heat can be
transfered to the actual LEDs which don;t like being hot.
The life of the lamps might well be UP TO 15K hours but they are very
liklely to fail long before that due to temperature as the 15K hours
refers to an LED used within the specs and even then it doesn't mean it
will last 15,000 hours.

The heat comes from the LED, it doesn't get transferred to the LED.

Ah, is the heat mainly from the LEDs rather than the PSU?

almost entirely


NT

Unless its a rubbish design of lamp

I don't think I've ever seen an LED PSU that is under 50% efficient.


NT

With most designs the LEDS are mounted on some kind if internal heat
conductor that then is connected to the base whilst there is no direct
connection to the envelope. So the base gets hotter than the envelope

In a general bulb even with a SMPSU about 5% of the input will go into
PSU heating, about 10% of what's left (9.5%) will; go out as light and
the rest (85.5% appx) will go out as LED heat.

On Wed, 14 Mar 2018 10:39:43 -0700, tabbypurr wrote:

On Wednesday, 14 March 2018 14:47:42 UTC, NY wrote:
tabbypurr wrote in message
...
On Wednesday, 14 March 2018 09:54:42 UTC, whisky-dave wrote:

But it is true the problem with LED lightbulbs is that they do get
very hot at the base as that's where the SMPS are but the heat can
be transfered to the actual LEDs which don;t like being hot.
The life of the lamps might well be UP TO 15K hours but they are
very liklely to fail long before that due to temperature as the 15K
hours refers to an LED used within the specs and even then it
doesn't mean it will last 15,000 hours.

The heat comes from the LED, it doesn't get transferred to the LED.

Ah, is the heat mainly from the LEDs rather than the PSU?

almost entirely

And that's also the case with CFLs (in this case, the compact
fluorescent tube).

The cheaper LED lamps use a lossless (literally!) capacitor dropper
usually with a low value resistor in series to limit inrush current. It's
this resistor that introduces a modicum of loss into the ballast circuit
- maybe 5 or 10 percent of the energy dissipated by the LEDs themselves.

The more sophisticated switch mode ballast circuits probably account for
less than 5% of the waste heat energy in an LED lamp so in either case,
just as for the CFL, the majority of the waste heat comes from the LED
string itself.

The good thing about LED lamps is their potential to achieve efficacies
five times greater than the best CFLs ever could. Cree Lighting
demonstrated a laboratory 303 LPW LED lamp some four years ago which,
contrary to the head of Cree's marketing division's claim of "it takes 18
to 24 months to go from laboratory samples to marketable products" this
process, according to Cree's own graphs, is more like a decade from lab
to shop product.

By that reckoning, we might see such 300LPW LEDs by 2024 or shortly
thereafter. However, more realistically, we might see 160LPW lamps in
just another year or two which should produce a "drop in" LED replacement
for the 150W incandescent GLS lamp capable of lasting the promised 15 to
25 kilohours in all but the most poorly ventilated luminaires.

--
Johnny B Good

On Wed, 14 Mar 2018 12:39:53 +0000, Scott
wrote:

On Mon, 12 Mar 2018 18:50:43 +0000, Scott
wrote:

Can I take it that where a lamp or shade states a maximum wattage,
this is for incandescent bulbs and any LED will be okay (on the basis
that LEDs use so much less power), or is the light intensity likely to
be an issue liable to cause fading?

As a development in this sage, I tried to buy three e14 to b22
converters to allow me a better choice of bulbs.

The order is shown as 'awaiting fulfillment', the phone number on the
website is invalid, HMRC say the VAT number is now deregistered and
TrustPilot reviews are nearly all one star - terrible. Has anyone
encountered Easybulb / Gigateq LImited in Manchester?

And yes, I know I should have done this research earlier - caveat
emptor.

Problem solved. I now have a full refund but no explanation.

On Thu, 15 Mar 2018 01:02:44 GMT, Johnny B Good
wrote:

On Wed, 14 Mar 2018 10:39:43 -0700, tabbypurr wrote:

On Wednesday, 14 March 2018 14:47:42 UTC, NY wrote:
tabbypurr wrote in message
...
On Wednesday, 14 March 2018 09:54:42 UTC, whisky-dave wrote:

But it is true the problem with LED lightbulbs is that they do get
very hot at the base as that's where the SMPS are but the heat can
be transfered to the actual LEDs which don;t like being hot.
The life of the lamps might well be UP TO 15K hours but they are
very liklely to fail long before that due to temperature as the 15K
hours refers to an LED used within the specs and even then it
doesn't mean it will last 15,000 hours.

The heat comes from the LED, it doesn't get transferred to the LED.

Ah, is the heat mainly from the LEDs rather than the PSU?

almost entirely

And that's also the case with CFLs (in this case, the compact
fluorescent tube).

The cheaper LED lamps use a lossless (literally!) capacitor dropper
usually with a low value resistor in series to limit inrush current. It's
this resistor that introduces a modicum of loss into the ballast circuit
- maybe 5 or 10 percent of the energy dissipated by the LEDs themselves.

The more sophisticated switch mode ballast circuits probably account for
less than 5% of the waste heat energy in an LED lamp so in either case,
just as for the CFL, the majority of the waste heat comes from the LED
string itself.

What about Philips?

On Thu, 15 Mar 2018 09:46:39 +0000, Scott wrote:

On Thu, 15 Mar 2018 01:02:44 GMT, Johnny B Good
wrote:

On Wed, 14 Mar 2018 10:39:43 -0700, tabbypurr wrote:

On Wednesday, 14 March 2018 14:47:42 UTC, NY wrote:
tabbypurr wrote in message
...
On Wednesday, 14 March 2018 09:54:42 UTC, whisky-dave wrote:

But it is true the problem with LED lightbulbs is that they do get
very hot at the base as that's where the SMPS are but the heat can
be transfered to the actual LEDs which don;t like being hot.
The life of the lamps might well be UP TO 15K hours but they are
very liklely to fail long before that due to temperature as the
15K hours refers to an LED used within the specs and even then it
doesn't mean it will last 15,000 hours.

The heat comes from the LED, it doesn't get transferred to the LED.

Ah, is the heat mainly from the LEDs rather than the PSU?

almost entirely

And that's also the case with CFLs (in this case, the compact
fluorescent tube).

The cheaper LED lamps use a lossless (literally!) capacitor dropper
usually with a low value resistor in series to limit inrush current.
It's this resistor that introduces a modicum of loss into the ballast
circuit - maybe 5 or 10 percent of the energy dissipated by the LEDs
themselves.

The more sophisticated switch mode ballast circuits probably account
for
less than 5% of the waste heat energy in an LED lamp so in either case,
just as for the CFL, the majority of the waste heat comes from the LED
string itself.

What about Philips?

No idea. Perhaps Big Clive has stripped some down?

--
Johnny B Good

On Thu, 15 Mar 2018 09:45:30 +0000, Scott wrote:

On Wed, 14 Mar 2018 12:39:53 +0000, Scott
wrote:

On Mon, 12 Mar 2018 18:50:43 +0000, Scott
wrote:

Can I take it that where a lamp or shade states a maximum wattage, this
is for incandescent bulbs and any LED will be okay (on the basis that
LEDs use so much less power), or is the light intensity likely to be an
issue liable to cause fading?

As a development in this sage, I tried to buy three e14 to b22
converters to allow me a better choice of bulbs.

The order is shown as 'awaiting fulfillment', the phone number on the
website is invalid, HMRC say the VAT number is now deregistered and
TrustPilot reviews are nearly all one star - terrible. Has anyone
encountered Easybulb / Gigateq LImited in Manchester?

And yes, I know I should have done this research earlier - caveat
emptor.

Problem solved. I now have a full refund but no explanation.

The important thing here, is that your money was refunded. I wouldn't be
too concerned as to the 'why' of the refund; just be grateful that you
*got* a refund at all and move on.

As I've already mentioned, the main benefit of better efficiency LED GLS
lamps is their ability to provide more light without overheating. Those
cheap Poundland 6W 470/510 lumens lamps run cool enough to survive to
their claimed hours lifetime rating so are useful in cases where its "40W
incandescent equivalent" of lighting suffices.

However, I'd steer clear of the Golfball version since it lacks
sufficient surface area to keep the LEDs cool enough to last more than a
few weeks in a ceiling batten fitting. Likewise, steer clear of the 5W
candle lamps and buy the 3W version instead (assuming the 220Lm suffices,
eg bedroom wall light or a five or six lamp chandelier).

--
Johnny B Good

On Thu, 15 Mar 2018 14:05:05 GMT, Johnny B Good
wrote:

On Thu, 15 Mar 2018 09:45:30 +0000, Scott wrote:

On Wed, 14 Mar 2018 12:39:53 +0000, Scott
wrote:

On Mon, 12 Mar 2018 18:50:43 +0000, Scott
wrote:

Can I take it that where a lamp or shade states a maximum wattage, this
is for incandescent bulbs and any LED will be okay (on the basis that
LEDs use so much less power), or is the light intensity likely to be an
issue liable to cause fading?

As a development in this sage, I tried to buy three e14 to b22
converters to allow me a better choice of bulbs.

The order is shown as 'awaiting fulfillment', the phone number on the
website is invalid, HMRC say the VAT number is now deregistered and
TrustPilot reviews are nearly all one star - terrible. Has anyone
encountered Easybulb / Gigateq LImited in Manchester?

And yes, I know I should have done this research earlier - caveat
emptor.

Problem solved. I now have a full refund but no explanation.

The important thing here, is that your money was refunded. I wouldn't be
too concerned as to the 'why' of the refund; just be grateful that you
*got* a refund at all and move on.

Agreed - case closed.

As I've already mentioned, the main benefit of better efficiency LED GLS
lamps is their ability to provide more light without overheating. Those
cheap Poundland 6W 470/510 lumens lamps run cool enough to survive to
their claimed hours lifetime rating so are useful in cases where its "40W
incandescent equivalent" of lighting suffices.

However, I'd steer clear of the Golfball version since it lacks
sufficient surface area to keep the LEDs cool enough to last more than a
few weeks in a ceiling batten fitting. Likewise, steer clear of the 5W
candle lamps and buy the 3W version instead (assuming the 220Lm suffices,
eg bedroom wall light or a five or six lamp chandelier).

Thanks for your good advice. My requirement is somewhat unusual. My
bathroom lights are E14 (smalll Edison screw) and I am trying to
install cool white LEDs. Philips produce a warm white of 806 lumens.
I contacted them and they say there are no plans to produce a cool
white version.

I have therefore bought two B22 E14 converters and two A60 Philips
lamps. Provided these fit the globes (which are quite large) I am
hoping this is a competent solution.