Feit electric LED lamp autopsy.

[RukyCon]

Re: Feit electric LED lamp autopsy.

One thing need to be checked is to find out how much current they are forcing through the LEDs, and how well the heat management is being done.
The failure in most LED backlights in TVs is due to driving the LED at its maximum rating with bad heat management, that is why we always suggest people to turn down the backlights as low as they can but still get good images on the screen.

I think they overdrive the LEDs in a lot of bulbs.

[sam_sam_sam]

Re: Feit electric LED lamp autopsy.

I think they overdrive the LEDs in a lot of bulbs.

I also find that is also is an issue and some time it is that the heat sinks are way too small

[sam_sam_sam]

Re: Feit electric LED lamp autopsy.

I have and LED panel that I think 30 to 60 LEDs on it and the board says to run 24 volts
But if you run it at that voltage for very long t board start run very warm it runs best at about 22 volts yea it not as bright but runs a lot cooler

[redwire]

Re: Feit electric LED lamp autopsy.

From ruky con's pics of the driver board AP1910 datasheet and R9, R10 give 134mA CC with 5630's running about 0.43W each. It looks reasonable.

But that Feit lamp has such crappy thermal design, plastic "heatsink" and an inch of plastic to get that heat from the LED's. The metal washer stops it from melting lol
The heat pretty much kills the LED's and electronics. We're back to the old days of crappy CFL's and their poor reliability from what I am seeing. Cree, Ikea included.

LED's need to be de-rated past 85°C, so running them at say 110°C they can only take 1/2 the current. Brightness at 85°C is about 90% of 25°C, LED's get dimmer as they get hotter.

[RukyCon]

Re: Feit electric LED lamp autopsy.

I have a older LED floodlight that you can tell is made to last.

Here it is next to a newer feit floodlight.

The one on the left is the feit lamp.
The one on the right is a 'Light Efficient Design' brand lamp.

[tom66]

Re: Feit electric LED lamp autopsy.

I have seen a lot of LED lamps where the heat dissipating element is mounted in the plastic. So there is a heatsink, but it does not use fins. This is partially because they do not dissipate as much heat (more efficient LEDs) but probably also down to lower life targets.

[redwire]

Re: Feit electric LED lamp autopsy.

I think I found the problem. Compare plastic vs metal for heatsinks...

Thermal Conductivity (W/m K):

Copper 386
Aluminum 237
Tin 65

Acrylic 0.20
Epoxy 0.17
Epoxy glass fibre 0.23
Nylon 6 0.25
Polyethylene, low density (PEL) 0.33
Polyethylene, high density (PEH) 0.50
PTFE 0.25
PVC 0.19


Hmmm 1000x difference!

[RukyCon]

Re: Feit electric LED lamp autopsy.

For the feit floodlight i have the body of it is 100% plastic.

But for my A19 lamp the body was made of aluminum.

[tom66]

Re: Feit electric LED lamp autopsy.

I think I found the problem. Compare plastic vs metal for heatsinks...

Thermal Conductivity (W/m K):

Copper 386
Aluminum 237
Tin 65

Acrylic 0.20
Epoxy 0.17
Epoxy glass fibre 0.23
Nylon 6 0.25
Polyethylene, low density (PEL) 0.33
Polyethylene, high density (PEH) 0.50
PTFE 0.25
PVC 0.19


Hmmm 1000x difference!

The metal body inside the plastic is actually not bad at dissipating heat. It doesn't need to be exposed to air, as radiation and dissipation is sufficient.

It's also worth noting that a lot of high temperature plastic has glass reinforcement both for fireproofing and also to improve thermal conductivity.

The engineers designing these bulbs aren't retards, they realise that plain Jane plastic isn't good at dissipating heat.

[RukyCon]

Re: Feit electric LED lamp autopsy.

The metal body inside the plastic is actually not bad at dissipating heat. It doesn't need to be exposed to air, as radiation and dissipation is sufficient.

It's also worth noting that a lot of high temperature plastic has glass reinforcement both for fireproofing and also to improve thermal conductivity.

The engineers designing these bulbs aren't retards, they realise that plain Jane plastic isn't good at dissipating heat.

The feit floodlight i was showing you feels too light to have any heatsinking at all.

[capwizard]

Re: Feit electric LED lamp autopsy.

The dropping cost of LED bulbs is accelerating. We compare a few brands to see how they are approaching design and lower cost manufacturing.

The Race to the Bottom: LED Bulbs and DFM
https://www.sparkfun.com/news/1821

[redwire]

Re: Feit electric LED lamp autopsy.

...The engineers designing these bulbs aren't retards...

LED bulb engineers are under incredible pressure from Product Management to meet a cost target and lumen number.

It's a challenge to get rid of say 4-10W of heat using enclosed plastic on an item where every penny counts.
Heat transfer through radiation and conduction (plastic) is much less than convection cooling at semiconductor temperatures (vs tungsten filament).
A metal heatsink ~16% the cost of the bulb.

Turns out there are 10 patent infringement lawsuits between Cree and Feit! The LED mounting, heatsinking etc. they are all at war.
I think this is the real reason Cree abandoned their 4Flow convection cooling vents in their Gen4 bulbs. Feit patent lawsuit here and Cree settlement here.

So the cooling (LED bulb lifetime) is crappy because of politics- patents, false advertising etc. lawsuits.

[capwizard]

Re: Feit electric LED lamp autopsy.

:+1:

[RJARRRPCGP]

Re: Feit electric LED lamp autopsy.

Cree duking it out with Feit, L O L

http://www.semiconductor-today.com/n...e_130115.shtml

[RJARRRPCGP]

Re: Feit electric LED lamp autopsy.

Looks like Cree still has the 4 Flow design, but only with smart bulbs now. They only come in smart bulb variants!

[redwire]

Re: Feit electric LED lamp autopsy.

Cree seem to have bailed on residential light bulbs, I can't find them for sale in town. It's too bad they don't stay in a market and keep bouncing around.

Cree has never been profitable Forecasts are for them to make lots of money in a few years, but.. competition.
I wouldn't buy a smartbulb, really expensive and LED bulb reliability is still poor.
When I tried to claim warranty with Cree, they wanted me to ship the failed bulb to them at my expense, what a stupid hassle.

[RJARRRPCGP]

Re: Feit electric LED lamp autopsy.

Soraa is missing from there, yikes! They're the one known for the GaN-on-GaN.

[RJARRRPCGP]

Re: Feit electric LED lamp autopsy.

Cree seem to have bailed on residential light bulbs, I can't find them for sale in town. It's too bad they don't stay in a market and keep bouncing around.

Cree has never been profitable Forecasts are for them to make lots of money in a few years, but.. competition.
I wouldn't buy a smartbulb, really expensive and LED bulb reliability is still poor.
When I tried to claim warranty with Cree, they wanted me to ship the failed bulb to them at my expense, what a stupid hassle.

Looks like Cree is alive and well at the Claremont, NH Home Depot!

Cons:
Cree don't want to manufacture squat anywhere other than in China!
Usually only available at Home Depot. (an exclusive deal that Cree has, IIRC)

[redwire]

Re: Feit electric LED lamp autopsy.

Home Depot Canada dumped Cree years ago and only has Philips LED bulbs.

Every 6 months the Philips bulbs are redesigned and different. They have a great CRI and OK brightness but a narrow angle COB LED in the spot lamps is terrible. So far they last though.

Ikea is full of flickering LED bulbs on display, it's kind of funny so many crap out. What's the point in paying $1.29 for a RYET LED bulb that is less reliable than an incandescent lamp?

Walmart is full of Feit Electric LED lamps, but I haven't tried any.

[RJARRRPCGP]

Re: Feit electric LED lamp autopsy.

The Claremont, NH Home Depot has Phillips LED light bulbs as well, but I had one of the Phillips LED light bulbs fail on me, probably lasted shorter than an el cheapo halogen, FFS! I still have it to autopsy it!

The Phillips LED light bulb that I have, seemed to have good CRI, too, before it suddenly failed to come on, in a short time!

And the Claremont, NH Walmart, during the last time I was there, has GE LED light bulbs, IIRC.

The Claremont, NH Home Depot, dumped GE in 2018 or the second half of 2017.