What is this bulb?

snowhead said:

It was a lot easier to find the whole light fitting, other sizes available elsewhere.

The site claims the bulbs are G4 base 20w LED, but that doesn't seem to match

30 cm LED Pendant Light Led Fireworks And Spark Ball Ceiling Suspension Fixture Metal Globe Painted Finishes 110-120V 220-240V 2024 - GBP £130

I like this. Do you think I should buy it?

www.lightinthebox.com

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I've seen that site and many others and I've contacted them as it's definitely not G4

maximusi said:

from a UK company......

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Manufacturing or just a UK distributor?

DefyG said:

Manufacturing or just a UK distributor?

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I assume illegal import as there is no UKCA or CE marking.

They look like some sort of custom version of festoon lamps but with screw holes added at the ends - that may make it very difficult to find them outside of the original manufacturer - who I will assume are Chinese.

It may be worth contacting companies like The Lamp Company | Light Bulbs & Control Gear | Light Bulbs Suppliers - https://www.lampco.co.uk who specialise in lamps. They at least may have seen it before and give you some guidance...

The lamps may only be available on something like Alibaba, which may be pot luck.

I have found what is called a 'barrel end festoon' lamp and seems to be used in marine lighting..

2.6W Festoon Led Bulb 44mm, Dimple Barrel Aqua Signal Navigation 10~40V Warm White - https://boulters-chandlery.co.uk/epages/c027c503-b020-45e2-bbb6-36bcebf3b8a0.sf/en_GB/?ObjectPath=/Shops/c027c503-b020-45e2-bbb6-36bcebf3b8a0/Products/4012



But that is only 44mm and probably far too bright for the number of lamps the light can support - it looks the closest to what you have I've seen though so may be worth further investigating marine lighting specialists?

maximusi said:

Well the first fitting we bought was from a UK company......

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Who no doubt bought it from a Chinese source and, as with so many retailers these days (sadly), without a care in the world for ongoing maintainability.

The problem with marine lamps is that anything to do with boats is stupidly priced.

Some thoughts:

A closeup of the end of a dimpled lamp someone was selling showed a small unthreaded hole. It is possible that the screws in the light would cut a thread into it, in which case some slightly longer screws and some washers to pack the length out might be an answer.

The lamp shown by snowhead is described as having a diameter of 12.6mm. If they mean this


rather than the cap, then that would make maximusi's caps larger, and it is possible that they would slide over the ends of the one in the photo.

In a world where the full panoply of gods smiled on him, and all the planets were in alignment, the caps from his old lamps would be a tight fit (so no soldering needed) and would bring the length up to 47mm.

In his shoes I'd be tempted to get one and try....

The driver is a constant-current driver but the lamps are in parallel and have ballast resistors inside, a configuration that would normally be used with a constant-voltage driver. What this means in practice is that you are going to have to change the driver if you change the lamps, as they will have been specifically matched together. I.e. they have cheated things so that when the current of the driver is divided by that number of lamps, the voltage developed across the ballast resistors makes the lamp voltage right. The driver is only a very low output unit (3w) anyway.

I suspect the lamps have been made up specially for this range of fittings. What you might have to do is dismantle them and attach the endcaps to normal festoon lamps of suitable length and power. Then, substitute a constant-voltage driver of the same voltage as the festoon lamps, and equal or greater wattage rating to the sum of the lamp wattages.