Bulb ID

[morqthana]

My son's narrow boat was 12 volts.

Odd. 24V is no harder to provide, saves weight and money on cables, and (AFAIK) lorries have been 24V for donkey's years so there'd be no shortage of bulbs etc, and ones designed for harsher environments than cars or caravans to boot.

 

[Alec_t]

A white LED drops about 3V, so eight in series would be right for a 24V bulb.

 

[AndyPRK]

To me, it looks like a car combined tail/brake light. 5W/21W

1) The pins on the side, being a different height
2) The fact it has 2 pins on the base.

Why on earth you would 2 light levels on a boat though, I don't know.

 

[ericmark]

A white LED drops about 3V, so eight in series would be right for a 24V bulb.

I am sure the ones I linked to are powered with some sort of switch mode power supply, to be able to span that voltage range, without dimming, with a rather impressive lumens per watt. Lumens: 274L (Warm White) or 323L (Cool White) Wattage: 2.4W.

It looks like a BA15d cap to me, not a BAY15d so single output. On a narrow boat, battery consumption is important, so looking for a rather good lumen per watt, with a car in the main when lights are on engine is running, this is not the case with a boat, there are other options here I just selected the one which looked as much like the original as I could see.

I am sure there are other boat chandlers, and it seems strange they don't stock the bulbs, but one can't really expect to find then in a normal electric shop, they are a specialist product.

 

[Harry Bloomfield]

I am sure there are other boat chandlers, and it seems strange they don't stock the bulbs, but one can't really expect to find then in a normal electric shop, they are a specialist product.

As I said, pointless sourcing a replacement, unless it is confirmed that the present lamp has failed. The OP suggested the entire row of lights have failed, which suggests a wiring fault, rather than a failed lamp. The OP could easily check the lamp, by testing it in a known to be working light sockets.

 

[Tricky-Dicky]

That's what I thought in my post 13, a LED replacement car bulb. I also have some 21 watt bulbs that have the same bayonet base, perhaps an old style rear fog bulb, but I don't have a reference for them, sorry.

 

[Harry Bloomfield]

I also have some 21 watt bulbs that have the same bayonet base, perhaps an old style rear fog bulb, but I don't have a reference for them, sorry.

21w fog lamp bulb, have a single contact, and use the outer cap and the second, earth contact. The only common car lamps, with two contacts, around that size, is the brake/tail lamp, which again uses the outer cap, as the common earth contact.

 

[SUNRAY]

21w fog lamp bulb, have a single contact, and use the outer cap and the second, earth contact. The only common car lamps, with two contacts, around that size, is the brake/tail lamp, which again uses the outer cap, as the common earth contact.

Admittedly gone out of fashion but 2 contact used to be common in cars, IIRC a friends Crysler Circa late 60s/early 70s all the side, brake, fog/spot used them and a neighbours Vauxhall circa late 50s he tried replacing a front indicator with a 21/5W which didn't fit due to the pin offset.

 

[morqthana]

If you have a dual-filament bulb then as per Sunray's post above, the pins are offset, and from the OP -

you can see that there's a clearly demarcated change in the surface appearance, and that helps to see that those pins are offset.

It also looks as if there might be 2 different types of LED. ≡ 2 filaments?

If that's not an LED stop/tail bulb I'll eat my bar of chocolate.

 

[Harry Bloomfield]

you can see that there's a clearly demarcated change in the surface appearance, and that helps to see that those pins are offset.

Impossible to say, from the angle of the photo.

It also looks as if there might be 2 different types of LED. ≡ 2 filaments?

If that's not an LED stop/tail bulb I'll eat my bar of chocolate.

You are seeing a difference in the LED's, which I cannot see. The only difference, is the arrangement to get an even spread of light, around the lamp. There again, why would anyone need a stop/tail lamp, with two phases, to light the interior of a boat, using strange off-set sockets? The stop/tail LED's I have come across, have always used the cheaper/more efficient red LED's, which would not be that useful, inside a boat.

 

[AndyPRK]

The LEDs have 3 terminals

 

[SUNRAY]

If you have a dual-filament bulb then as per Sunray's post above, the pins are offset, and from the OP -

View attachment 387965

you can see that there's a clearly demarcated change in the surface appearance, and that helps to see that those pins are offset.

It also looks as if there might be 2 different types of LED. ≡ 2 filaments?

If that's not an LED stop/tail bulb I'll eat my bar of chocolate.

In that pic the pins look evenly spaced to me. But the view angle could be deceptive

 

[AndyPRK]

Generally there are offset pins, (where the pins are not opposite each other). These are used for Amber bulbs.

Then the old fashioned brake tail dual element 21/5W, where one pin is higher up than the other. This is what I think we are seeing in this picture.

Then further to this there are dual element fog/tail 21/4W which were used in the late 90's for BMW, Volvo, Cavalier3, last Sierra's. these utilise both height and offset changes

Also Diadem (mirror finish) for RangeRover producing Red light

 

[EFLImpudence]

bayonet pins are symmetrical,

 

[morqthana]

Impossible to say, from the angle of the photo.

Looks as though the angle is deceiving, as the OP says the pins are symmetrical.

You are seeing a difference in the LED's, which I cannot see.

On my screen these two are different colours

The only difference, is the arrangement to get an even spread of light, around the lamp. There again, why would anyone need a stop/tail lamp, with two phases, to light the interior of a boat, using strange off-set sockets?

To provide 3 different light levels without dimmers?

The stop/tail LED's I have come across, have always used the cheaper/more efficient red LED's, which would not be that useful, inside a boat.

No, as you're not allowed to travel after dark.