led style...?

[downtheroad]

Any advice on which style.
I'm going with warm white T10 base

Which do you recommend?....flat array or round (cob) array for over head lights?


or

[downtheroad]

Original poster here.
Thanks for the info and discussion. Good stuff.

apology:
(I didn't mean it to go the way of a semantics argument... ie,"cob.")

Lots of numbers and confusion. I have always just called the style either, cob (as in corn cob) or pancake, (as in flat and round like a pancake.)

Anymore ideas or experience greatly appreciated.

[tenbear]

I have always understood COB as meaning it looks like a corn cob. To me, your definition of COB is more like SMD which stands for Surface Mount Diode.

Many people seem to think SMD stands for a certain type of LED, like a 3528 for example, while it actually defines the package and the type of mounting to the Board.

[MEXICOWANDERER]

Thanks guys for helping me with LED terminology and tech info.

With the old-style LED "bulbs" through trial-and-error I found that 2.7 WATTS is about the maximum a lamp can consume and balance thermal emissions through whatever matrix is used in the RV bulb replacement industry.

To increase above 2.5 watts means increasing the size of the matrix (won't fit the hole or fixture) or utilize an aluminum heat-sink. I clamped 2 three watt Bridgelux LEDs to a 2 X 3" 1/4" heat sink with 8 fin count. Applied 8.2 vdc the max OEM milliamps recommended. Set.the critter into one of the vacated fixture holes in my bus. Turned it on for 20 min.

OUCH! I could not measure instant temp but that fixture got way too hot for my liking. I'll bet my fingers suffered 200+ degrees F. My hopes of burying a thermocouple and continuing the "experiment" were dashed.

The bus overhead is encased in closed cell foam so the heat sink had little opportunity to shed BTUs.

Providing brighter lamps is going to be a challenge for the industry. BTW the power supply for the Bridgelux LEDs was divorced from the fixture. Open air.

[time2roll]

Chris Bryant wrote:
I think people are misunderstanding the term COB- it stands for Chip On Board- a type of LED. It doesn't refer to the style of lamp- specifically looking like a corn cob.

From planet LED:

Planet LED wrote:
In COB lighting, single LED chips are placed directly on a circuit board (or substrate) which has thermal properties to disperse heat. Heat dissipation is a very important aspect of LED lighting because it can have a major impact on the life expectancy of the luminaire. Traditional LED chips are not placed directly on the substrate and therefore there is greater thermal resistance.

OK what words would be proper to describe the style of two items pictured in the OP?

[SoundGuy]

Chris Bryant wrote:
I think people are misunderstanding the term COB- it stands for Chip On Board- a type of LED. It doesn't refer to the style of lamp- specifically looking like a corn cob.

From planet LED:

Planet LED wrote:
In COB lighting, single LED chips are placed directly on a circuit board (or substrate) which has thermal properties to disperse heat. Heat dissipation is a very important aspect of LED lighting because it can have a major impact on the life expectancy of the luminaire. Traditional LED chips are not placed directly on the substrate and therefore there is greater thermal resistance.

Unfortunately Chris, your correction will fall on mostly deaf ears as you'll see this misunderstanding of what a COB LED bulb is repeated endlessly on these forums. :S I've been using 16 of these non-COB LED bulbs, each consisting of 24 5050SMD chips, for a year now with no failures at all, no RFI disruption of the radio, bright with a rated colour temperature of 3200K, in fact no complaints at all from me.



Sourced at a reasonable price from this offshore vendor ... and while certainly not the latest & greatest in terms of LED construction have worked just fine for me. :B

[Chris_Bryant]

I think people are misunderstanding the term COB- it stands for Chip On Board- a type of LED. It doesn't refer to the style of lamp- specifically looking like a corn cob.

From planet LED:

Planet LED wrote:
In COB lighting, single LED chips are placed directly on a circuit board (or substrate) which has thermal properties to disperse heat. Heat dissipation is a very important aspect of LED lighting because it can have a major impact on the life expectancy of the luminaire. Traditional LED chips are not placed directly on the substrate and therefore there is greater thermal resistance.

[scrubjaysnest]

We like the flat smd boards, bright white

[Almot]

Yep. Look for ~300 lumens output, to make it same bright as the old 20W incandescent bulb.

The industry is changing fast, and there are brighter diodes now than 5050, but to me many smaller diodes looks better than fewer brighter ones. More uniform light.

[Chandalen]

As mentioned, I use the flat ones for directional lights. The squared ones for the lamp type lights.

I found out, that it seems at the factory they didnt much care how they wired the lights in my camper. Meaning its a 50-50******shoot as to which part of the plug is + and which is -. SO on some of my LED's I had to remove the base, cris-cross the leads (and heat shrink one of them) and put the base back on for them to work.

It may take you a day or two to get used to the new lighting colour.

[time2roll]

I recommend the flat array for flat mounted fixtures.
Cob is better for sconce type fixtures.
Need 250 to 400 lumens to have equivalent brightness.
JMHO

[landyacht318]

More modern LED chips are th 5630 and 5730 chipsets, and these seem to not only have more Lumens per chip, and emit them at wider angles.

The 5050 SMDs are Dated now and the market flooded with them and their smaller predecessors.

Radially firing LEDs do not seem to utilize the reflector properly and having the flat panel versions aimed properly is the ticket.

The 5730 or 5630 LEDs are not yet widely used in lighting for interior uses but more so for vehicular Exterior signal lighting, but an LED in an housing designed around a filament light source is questionable in ultimate result.

LED chips can be driven harder or less so, to produce more/less light, so direct comparisons by number of chips alone is not wise, not even from the same 'store' brand name or manufacturer.

[DaHose]

I have little COB bulbs in my car to replace the dome lights. Two panels with 6 elements in each is AMAZINGLY bright.

If you can find a flat COB style with a lot (20+) elements, I think that is your best bet.

Jose

[DaHose]

I have little COB bulbs in my car to replace the dome lights. Two panels with 6 elements in each is AMAZINGLY bright.

If you can find a flat COB style, I think that is your best bet.

Jose

[MEXICOWANDERER]

Good night light

[tenbear]

The flat panel directs most of the light down, they work well for reading or ceiling lights. The cob gives a more diffuse light and are good when you want to light up an area.

BTW, neither of the lights you show will give much light. You would want at least 36 of the 1210 (3528) LEDs, which are shown, or at least 18 of the 5050 LEDs.