LED filament bulbs a market failure?

[Dave_H]

I picked up some Ecosmart chandelier bulbs at HD, 4.5W/470 lumens which is >100 lumens/W. Created
a casualty with one, dropped it and the glass shell broke, but the internals were OK and still worked, did a few tests.

It has four filaments, two parallel plus two series. Voltage across the lot was about 150v dc, so each
filament must have about two dozen small LEDs (~3v each). Due to brightness, could not see individual LEDs, not
dimmable but I will try looking through two or three sun-glass lenses or welder's goggles.

Ikea now has some 2-4W chandelier bulbs with clear plastic shell; can see three metal strips with LED strip on each. Interesting
as one end is unconnected at the top, wiring is only on the other end.

Also, a newer Philips 7W 800 lumen A19 bulb mentioned earlier has a clear part of bulb near the base, can see some filaments
inside.

Looks like there's a good future for this technology.

Dave

 

[broadgage]

Philips have introduced a new range of LED "filament" lamps, called "Dubai lamps" They are stated to have an efficiency of 200 lumens per watt and are claimed to be the worlds only lamps with this efficiency.
They contain far more LED filaments than other lamps of similar wattage, presumably so that each one is under driven ad more efficient.

Use of these lamps is required by regulations in new buildings in Dubai

They are not yet readily available outside of the Middle East and are not AFAIK manufactured for 120 volt circuits. Still an interesting development though.

 

[brickbat]

^ Sounds interesting, but the largest they offer is 600 lumen, non dimmable, and CRI of 80. Impressive efficacy, but not a significant 'breakthrough', IMO. Mandating use of efficient lamps that top out at 600 lumens isn't likely to save much electrical power, (but it's a great way to take the 'moral' high ground...)

 

[broadgage]

I have just discovered another new type of LED filament bulb.
An ebay seller is offering 2 watt bulbs with standard screw base, but rated at just 3 volts

I see no evidence of any driver circuit and surmise that all the LEDs are simply connected in parallel. the bulbs give a good light from a couple of alkaline D cells. For long hour use 4 cells in a 2S/2P arrangement would be better.

 

[PhotonWrangler]

I gather these are for indicator lamps or decorative use?

 

[broadgage]

I gather these are for indicator lamps or decorative use?

They are a bit big for indicator lamps, E27 base and "appliance lamp" sized bulb. Quite decorative looking , but 3volts is an odd choice for decorative lighting, I would expect either line voltage or 12 volts or 24 volts from a wall wart for decorative lighting. Indeed the suppliers offer these voltages as well as 3 volts.