I was going though some stuff last night and came across an old Sealey
12V lead light a mate (who had his own car repair garage) gave me,
like this:

https://i.ebayimg.com/images/g/cL8AA...Zy/s-l1600.jpg

After testing that it works, I cleaned it up, fitted a new lead (it
had been cut short) and crock clips and noted the lamp was a frosted
incandescent type, 12V/24W.

I have actually used it when working on the car at his and liked it
because it has a very strong clip and a strong ball joint thing so
could be pointed where you want (and stayed there).

So, whilst it is all up and working, I think I'd like to look for an
LED lamp replacement, basically to save power but am having difficulty
pinning down what that might be.

It's a 15mm diameter, non-offset pin, twin contact (that's the bit
that seems to make it more complicated), bayonet lamp and I'd like an
LED that has 'all round' illumination like the original incandescent
lamp, so you get a nice general light, rather than a beam.

I think I have found a suitable lamp:

LED Lamp S8 BAY15D (MCS8Y15D16NS30DCW) ... but they seem quite
expensive and often from

.... but if I knew how to accurately describe that particular base, it
might help me pin it down?

Is it a P21W / R335 as that doesn't seem to help or is there a more
common name for them please?

Cheers, T i m

T i m wrote:
I was going though some stuff last night and came across an old Sealey
12V lead light a mate (who had his own car repair garage) gave me,
like this:

https://i.ebayimg.com/images/g/cL8AA...Zy/s-l1600.jpg

After testing that it works, I cleaned it up, fitted a new lead (it
had been cut short) and crock clips and noted the lamp was a frosted
incandescent type, 12V/24W.

I have actually used it when working on the car at his and liked it
because it has a very strong clip and a strong ball joint thing so
could be pointed where you want (and stayed there).

So, whilst it is all up and working, I think I'd like to look for an
LED lamp replacement, basically to save power but am having difficulty
pinning down what that might be.

It's a 15mm diameter, non-offset pin, twin contact (that's the bit
that seems to make it more complicated), bayonet lamp and I'd like an
LED that has 'all round' illumination like the original incandescent
lamp, so you get a nice general light, rather than a beam.

I think I have found a suitable lamp:

LED Lamp S8 BAY15D (MCS8Y15D16NS30DCW) ... but they seem quite
expensive and often from

... but if I knew how to accurately describe that particular base, it
might help me pin it down?

Is it a P21W / R335 as that doesn't seem to help or is there a more
common name for them please?

Cheers, T i m

https://en.wikipedia.org/wiki/Bayonet_mount#Light_bulbs

If you need a better price, pump that part number into Google.
I know in the past, those LED replacement bulbs had ridiculous
pricing. Try a local auto parts store, and check the
"ricer aisle" for LED bulbs like that.

The datasheet I got for your part number, isn't exactly very good.
But that's all I can find for it.

http://www.farnell.com/datasheets/1564831.pdf

- the LED might overheat, if there is a globe cover over
the whole assembly. For the number of service hours this
application will receive, it won't matter.
- the light output might not be uniform with respect
to direction. More light from the side than the end.
In a car light assembly, the reflector and diffuser
fix this.
- the lamps with LED filament chains might be no more
robust than an incandescent, when you drop your
inspection light. The product above appears to use
discrete LEDs which are likely sitting on a flat
substrate.

A proper datasheet for a product like that, should
stretch to about 30 pages in the PDF.

Paul

In article ,
T i m wrote:
I was going though some stuff last night and came across an old Sealey
12V lead light a mate (who had his own car repair garage) gave me,
like this:

https://i.ebayimg.com/images/g/cL8AA...Zy/s-l1600.jpg

After testing that it works, I cleaned it up, fitted a new lead (it
had been cut short) and crock clips and noted the lamp was a frosted
incandescent type, 12V/24W.

I have actually used it when working on the car at his and liked it
because it has a very strong clip and a strong ball joint thing so
could be pointed where you want (and stayed there).

So, whilst it is all up and working, I think I'd like to look for an
LED lamp replacement, basically to save power but am having difficulty
pinning down what that might be.

It's a 15mm diameter, non-offset pin, twin contact (that's the bit
that seems to make it more complicated), bayonet lamp and I'd like an
LED that has 'all round' illumination like the original incandescent
lamp, so you get a nice general light, rather than a beam.

I think I have found a suitable lamp:

LED Lamp S8 BAY15D (MCS8Y15D16NS30DCW) ... but they seem quite
expensive and often from

... but if I knew how to accurately describe that particular base, it
might help me pin it down?

Is it a P21W / R335 as that doesn't seem to help or is there a more
common name for them please?

Cheers, T i m

Sounds like a standard car SBC. Although more commonly single contact as
with a indicator bulb. Twin contacts usually twin filament.

They've probably done that to force you to buy spare bulbs from them,
rather than 2 for a quid at Halfords. Although cars are now 19w rather
than the older 21w - 24w not common.

Much older cars sometimes did have two contact SBC single filament bulbs.
But LED replacements for them not common, I'd guess.

Possible to remove the base from your old bulb and fit a suitable led
cluster to that? Or change the bulb holder?

--
*If a mute swears, does his mother wash his hands with soap?

Dave Plowman London SW
To e-mail, change noise into sound.

On Wed, 14 Oct 2020 08:26:12 -0400, Paul
wrote:

snip

So, whilst it is all up and working, I think I'd like to look for an
LED lamp replacement, basically to save power but am having difficulty
pinning down what that might be.

It's a 15mm diameter, non-offset pin, twin contact (that's the bit
that seems to make it more complicated), bayonet lamp and I'd like an
LED that has 'all round' illumination like the original incandescent
lamp, so you get a nice general light, rather than a beam.

I think I have found a suitable lamp:

LED Lamp S8 BAY15D (MCS8Y15D16NS30DCW) ... but they seem quite
expensive and often from

snip

https://en.wikipedia.org/wiki/Bayonet_mount#Light_bulbs

I looked though this one:
https://en.wikipedia.org/wiki/List_o...ght_bulb_types

But it still wasn't clear if there was a code that described that base
(with two connectors and one filament) exactly?


If you need a better price, pump that part number into Google.
I know in the past, those LED replacement bulbs had ridiculous
pricing.

Yeah, I did that but didn't find anything (other than the one I linked
to) and as you say, often quite expensive. Well, I found one that was
affordable but the P&P from the USA wasn't. ;-(

Try a local auto parts store, and check the
"ricer aisle" for LED bulbs like that.

Trying to avoid bricks-n-mortar places atm (but I would normal do as
you suggest). ;-)

The datasheet I got for your part number, isn't exactly very good.
But that's all I can find for it.

http://www.farnell.com/datasheets/1564831.pdf

Noted.

- the LED might overheat, if there is a globe cover over
the whole assembly.

I was thinking that most 'car lamps' are running in a similar sized
enclosure?

For the number of service hours this
application will receive, it won't matter.

Hopefully.

- the light output might not be uniform with respect
to direction.

No, that was one of the 'worries', compared with the frosted
incandescent 'globe' that is in there now.

More light from the side than the end.

That shouldn't be a problem (and might even be an advantage), given
there is a basic reflector in there.

In a car light assembly, the reflector and diffuser
fix this.

This one has a reflector (of sorts) but no diffuser, relying on the
lamp in the std design.

- the lamps with LED filament chains might be no more
robust than an incandescent, when you drop your
inspection light. The product above appears to use
discrete LEDs which are likely sitting on a flat
substrate.

Agreed.

A proper datasheet for a product like that, should
stretch to about 30 pages in the PDF.

Well, I just need to know a few bits of info and you would have
thought 'fundamental' points, re how it was wired might be a one of
them? ;-)

Something that has since come to mind though ... a 'what if' ... ;-)

The lamp holder is fairly substantial metal (not needed as such as the
connection is just via the base connections) and on an even more
substantial metal disk that sits in a groove in the clamshell
'handle'.

The two contacts to the lamp base are made by nicely engineered screw
terminals ... so, if I was to use an easier-to-find dual filament lamp
(say a stop tail) then I could re-wire the unit so that the ground is
on the lamp base (as normal by drilling and tapping for a small
machine screw or a small nut / bolt though the flange with a
pear-shaped-tag) and re-wire the lamp holder to give the 5W on all the
time (when connected to 12V) and then the 21W on (as well) when it's
turned on at the rocker switch.

Or ... replace the SPST switch with a SPCO, so I can swap between lamp
sides (21/5W), if that might make the lamp last longer if both 'sides'
aren't on at once (you would normally only have the side lights on
continuously and the stop occasionally) or if I can get a SPCO with
centre off, have a filament on each side of the switch and could also
turn it off with the switch (a bit like a dual heat hot air gun)?

You could go further and mount some SM LEDS / Cree modules directly to
the disk but I'd like to keep it as standard as possible. ;-)

Cheers, T i m

On Wed, 14 Oct 2020 14:03:20 +0100, "Dave Plowman (News)"
wrote:

snip

Is it a P21W / R335 as that doesn't seem to help or is there a more
common name for them please?


Sounds like a standard car SBC. Although more commonly single contact as
with a indicator bulb. Twin contacts usually twin filament.

They've probably done that to force you to buy spare bulbs from them,
rather than 2 for a quid at Halfords.

Possibly. ;-)

Although cars are now 19w rather
than the older 21w - 24w not common.

No, I'd not seen one before?

Much older cars sometimes did have two contact SBC single filament bulbs.
But LED replacements for them not common, I'd guess.

Ok.

Possible to remove the base from your old bulb and fit a suitable led
cluster to that? Or change the bulb holder?

Well, as I've replied to Paul since, I had a 'what if' along those
lines and assuming the pin spacing / orientation is 'stock'. for
something more common, I could re-wire it so that the base is earth
and then could feed the two filaments as you might with a stop / tail.

So it's just a matter or finding a suitable (LEDS facing straight out
and sideways) LED lamp and giving it a go.

Would you think running stop / rail together would impact the life
span much Dave?

Cheers, T i m

p.s. I'm thinking with a LED lamp, this could be an inspection light
and a general purpose emergency light that could be attached to one of
my several 12V LA batteries. ;-)

On Wed, 14 Oct 2020 14:16:07 +0100, T i m wrote:


But it still wasn't clear if there was a code that described that base
(with two connectors and one filament) exactly?

B15d, aka BAY15d, as in

https://www.amazon.com/dp/B004VSG858/

and there the spec drawing of the base.


Thomas Prufer

In article ,
T i m wrote:
Possible to remove the base from your old bulb and fit a suitable led
cluster to that? Or change the bulb holder?

Well, as I've replied to Paul since, I had a 'what if' along those
lines and assuming the pin spacing / orientation is 'stock'. for
something more common, I could re-wire it so that the base is earth
and then could feed the two filaments as you might with a stop / tail.

Assuming the holder makes it possible to wire to the base. It could be
plastic (or a brass sleeve in plastic)

So it's just a matter or finding a suitable (LEDS facing straight out
and sideways) LED lamp and giving it a go.

Most car replacements are like that, as the original tungsten made use of
a crude reflector.

Would you think running stop / rail together would impact the life
span much Dave?

Interesting point. Things like rear fogs can use a 19 watt SBC, and they
could be on for quite a time, rather than stop lights, etc. You'd expect a
tail light to have a good life.

--
*Xerox and Wurlitzer will merge to market reproductive organs.

Dave Plowman London SW
To e-mail, change noise into sound.

T i m wrote:
On Wed, 14 Oct 2020 08:26:12 -0400, Paul
wrote:

snip

So, whilst it is all up and working, I think I'd like to look for an
LED lamp replacement, basically to save power but am having difficulty
pinning down what that might be.

It's a 15mm diameter, non-offset pin, twin contact (that's the bit
that seems to make it more complicated), bayonet lamp and I'd like an
LED that has 'all round' illumination like the original incandescent
lamp, so you get a nice general light, rather than a beam.

I think I have found a suitable lamp:

LED Lamp S8 BAY15D (MCS8Y15D16NS30DCW) ... but they seem quite
expensive and often from

snip

https://en.wikipedia.org/wiki/Bayonet_mount#Light_bulbs

I looked though this one:
https://en.wikipedia.org/wiki/List_o...ght_bulb_types

But it still wasn't clear if there was a code that described that base
(with two connectors and one filament) exactly?

If you need a better price, pump that part number into Google.
I know in the past, those LED replacement bulbs had ridiculous
pricing.

Yeah, I did that but didn't find anything (other than the one I linked
to) and as you say, often quite expensive. Well, I found one that was
affordable but the P&P from the USA wasn't. ;-(

Try a local auto parts store, and check the
"ricer aisle" for LED bulbs like that.

Trying to avoid bricks-n-mortar places atm (but I would normal do as
you suggest). ;-)
The datasheet I got for your part number, isn't exactly very good.
But that's all I can find for it.

http://www.farnell.com/datasheets/1564831.pdf

Noted.
- the LED might overheat, if there is a globe cover over
the whole assembly.

I was thinking that most 'car lamps' are running in a similar sized
enclosure?

For the number of service hours this
application will receive, it won't matter.

Hopefully.

- the light output might not be uniform with respect
to direction.

No, that was one of the 'worries', compared with the frosted
incandescent 'globe' that is in there now.

More light from the side than the end.

That shouldn't be a problem (and might even be an advantage), given
there is a basic reflector in there.

In a car light assembly, the reflector and diffuser
fix this.

This one has a reflector (of sorts) but no diffuser, relying on the
lamp in the std design.

- the lamps with LED filament chains might be no more
robust than an incandescent, when you drop your
inspection light. The product above appears to use
discrete LEDs which are likely sitting on a flat
substrate.

Agreed.
A proper datasheet for a product like that, should
stretch to about 30 pages in the PDF.

Well, I just need to know a few bits of info and you would have
thought 'fundamental' points, re how it was wired might be a one of
them? ;-)

Something that has since come to mind though ... a 'what if' ... ;-)

The lamp holder is fairly substantial metal (not needed as such as the
connection is just via the base connections) and on an even more
substantial metal disk that sits in a groove in the clamshell
'handle'.

The two contacts to the lamp base are made by nicely engineered screw
terminals ... so, if I was to use an easier-to-find dual filament lamp
(say a stop tail) then I could re-wire the unit so that the ground is
on the lamp base (as normal by drilling and tapping for a small
machine screw or a small nut / bolt though the flange with a
pear-shaped-tag) and re-wire the lamp holder to give the 5W on all the
time (when connected to 12V) and then the 21W on (as well) when it's
turned on at the rocker switch.

Or ... replace the SPST switch with a SPCO, so I can swap between lamp
sides (21/5W), if that might make the lamp last longer if both 'sides'
aren't on at once (you would normally only have the side lights on
continuously and the stop occasionally) or if I can get a SPCO with
centre off, have a filament on each side of the switch and could also
turn it off with the switch (a bit like a dual heat hot air gun)?

You could go further and mount some SM LEDS / Cree modules directly to
the disk but I'd like to keep it as standard as possible. ;-)

Cheers, T i m



It's possible the two pins are (+) and the shell is (-).
You have to current steer, or current share, or do something
with the two pins, to drive the chains of LEDs and
give a pleasing light pattern.

One mystery with some of this stuff, is what is the
semiconductor other than the LEDs and resistors for ?

The only thing I could figure, was a zero-bias FET
as a constant current source. But that never makes sense
because these zero bias FETS, the current flow was
way too low for usage with LED arrays. You can do
zero bias FETS with a single LED, as that's enough
for a pleasing light level with a cheap T-1 3/4 LED.

https://www.electroschematics.com/wi...age-range-led/

Your lamp product appears to have a 10V (four white LED)
to 30V range. I don't know how that's possible, while
at the same time claiming to be consuming 5W for the
lamp function. If there was any sort of current
limiting linear function in there, it would be
getting hot.

The 16 LEDs could be split as four groups of four LEDs.
And the four LEDs in a group, could have 10V across them.
OK, now, how do we connect those four chains of LEDs
together ? Four chains in parallel ? Or some other
arrangement ? And operating off a car battery, that's
not really a well regulated source as such. If you
were to jam the field winding, the automotive bus
voltage goes up to 18V. So any LED lamp has to withstand
at least 18V. The other specs for automotive situations
involve pulse patterns (load dumps) at much higher
voltages.

If the lamp was larger, we could assume there was an
SMPS in the base. That would solve a lot of problems.

Paul

On Wed, 14 Oct 2020 16:35:07 +0200, Thomas Prufer
wrote:

On Wed, 14 Oct 2020 14:16:07 +0100, T i m wrote:


But it still wasn't clear if there was a code that described that base
(with two connectors and one filament) exactly?

B15d, aka BAY15d, as in

I thought that was the case but it doesn't seem to specify the number
of connections?

https://www.amazon.com/dp/B004VSG858/

The picture seems to suggest there is only one central connector?

and there the spec drawing of the base.

Thanks for that but again, I'm not sure if the diagram is indicating
there are one or two connections on the bottom, as the view is from a
direction that would mask the second connector behind the first?

This is why I was unsure if there was a formal designation for this
base and wiring (two connections, one filament and not using the metal
of the cap as a (ground) connector).

eg, The layout of this is more like a mains powered bayonet lamp

https://ibb.co/bPstyRf
https://ibb.co/gw6wHjM

I might be able to get a single element lamp to make contact with
either / both of the two contacts or if I use a twin element lamp, run
them individually or in parallel.

Cheers, T i m

On Wed, 14 Oct 2020 16:12:36 +0100, "Dave Plowman (News)"
wrote:

snip

Well, as I've replied to Paul since, I had a 'what if' along those
lines and assuming the pin spacing / orientation is 'stock'. for
something more common, I could re-wire it so that the base is earth
and then could feed the two filaments as you might with a stop / tail.

Assuming the holder makes it possible to wire to the base. It could be
plastic (or a brass sleeve in plastic)

No, it's very (in comparison with most car lamp holders) substantial
metal Dave:

https://ibb.co/gw6wHjM

So it's just a matter or finding a suitable (LEDS facing straight out
and sideways) LED lamp and giving it a go.

Most car replacements are like that, as the original tungsten made use of
a crude reflector.

I have seen some that seem to just face back but unless the LED's were
*very* wide angle, it might work more like a spotlight.

Would you think running stop / rail together would impact the life
span much Dave?

Interesting point. Things like rear fogs can use a 19 watt SBC, and they
could be on for quite a time, rather than stop lights, etc.

Ah, good point.

You'd expect a
tail light to have a good life.

Agreed ... just that there seem to be LED lights and LED lights ...

Cheers, T i m

On 14/10/2020 20:05:06, T i m wrote:
On Wed, 14 Oct 2020 16:35:07 +0200, Thomas Prufer
wrote:

On Wed, 14 Oct 2020 14:16:07 +0100, T i m wrote:


But it still wasn't clear if there was a code that described that base
(with two connectors and one filament) exactly?

B15d, aka BAY15d, as in

I thought that was the case but it doesn't seem to specify the number
of connections?

https://www.amazon.com/dp/B004VSG858/

The picture seems to suggest there is only one central connector?

and there the spec drawing of the base.

Thanks for that but again, I'm not sure if the diagram is indicating
there are one or two connections on the bottom, as the view is from a
direction that would mask the second connector behind the first?

This is why I was unsure if there was a formal designation for this
base and wiring (two connections, one filament and not using the metal
of the cap as a (ground) connector).

eg, The layout of this is more like a mains powered bayonet lamp

https://ibb.co/bPstyRf

Which is a BA15d
https://en.wikipedia.org/wiki/Bayonet_mount

https://ibb.co/gw6wHjM

I assume the relevant fitting.

I might be able to get a single element lamp to make contact with
either / both of the two contacts or if I use a twin element lamp, run
them individually or in parallel.

If you google "BA15d 12V LED" the first hit:
https://bedazzledledlighting.co.uk/p...d-bulbs/ba15d/

You will have a selection of spots/lights. One I looked at worked from
10v-30v DC.

But I suspect I'm in your killfile?

On Wed, 14 Oct 2020 20:05:06 +0100, T i m wrote:

This is why I was unsure if there was a formal designation for this
base and wiring (two connections, one filament and not using the metal
of the cap as a (ground) connector).

B15d is bayonet, 15 mm, double
B15s is bayonet, 15 mm, single
(t triple, q uadruple, , p penta/five)

A is for automotive, Y yellow (though this rule seems often ignored).

And BAY15d may have different-height pins, with two base contacts and case for
ground, for double-filament automotive lights that need a single mounting
orientation (brake & running light, I think is one...)


Thomas Prufer

In article ,
Thomas Prufer wrote:
And BAY15d may have different-height pins, with two base contacts and case for
ground, for double-filament automotive lights that need a single mounting
orientation (brake & running light, I think is one...)

There are offset pins (height wise) for the older stop/tail bulb. And then
a different offset (not 180 spaced) came in for others - like amber
flasher bulbs.

--
*Save the whale - I'll have it for my supper*

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote in message
...
In article ,
Thomas Prufer wrote:
And BAY15d may have different-height pins, with two base contacts and
case for
ground, for double-filament automotive lights that need a single mounting
orientation (brake & running light, I think is one...)

There are offset pins (height wise) for the older stop/tail bulb. And then
a different offset (not 180 spaced) came in for others - like amber
flasher bulbs.

Why is is that cars always seem to use the dual-filament bulbs for
tail/brake, with a separate bulb for rear fog lights? Given that tail and
fog lights serve the same purpose, of defining the presence and width of the
vehicle as seen from behind, it would be better if clusters were designed to
have tail/fog on the dual-filament bulb and a separate light for brake.

On Thu, 15 Oct 2020 09:32:20 +0200, Thomas Prufer
wrote:

On Wed, 14 Oct 2020 20:05:06 +0100, T i m wrote:

This is why I was unsure if there was a formal designation for this
base and wiring (two connections, one filament and not using the metal
of the cap as a (ground) connector).

B15d is bayonet, 15 mm, double
B15s is bayonet, 15 mm, single

Ah, thanks for the explanation Thomas. ;-)

(t triple, q uadruple, , p penta/five)

;-)

A is for automotive, Y yellow (though this rule seems often ignored).

Ok.

And BAY15d may have different-height pins, with two base contacts and case for
ground, for double-filament automotive lights that need a single mounting
orientation (brake & running light, I think is one...)

Understood. As mentioned in my OP, the pins aren't offset (in either
orientation) but I don't know if there is also a height standard /
range for the non-offset pins?

At least that gives me a bit more info to search for options.

Cheers, T i m

In article , NY wrote:
"Dave Plowman (News)" wrote in message
...
In article , Thomas Prufer
wrote:
And BAY15d may have different-height pins, with two base contacts and
case for ground, for double-filament automotive lights that need a
single mounting orientation (brake & running light, I think is one...)

There are offset pins (height wise) for the older stop/tail bulb. And
then a different offset (not 180 spaced) came in for others - like
amber flasher bulbs.

Why is is that cars always seem to use the dual-filament bulbs for
tail/brake, with a separate bulb for rear fog lights? Given that tail and
fog lights serve the same purpose, of defining the presence and width of
the vehicle as seen from behind, it would be better if clusters were
designed to have tail/fog on the dual-filament bulb and a separate light
for brake.

At a guess, tail and brake are older and more standard. Rear Fog are
comparatively modern and therefore an extra.

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

On Thu, 15 Oct 2020 10:19:01 +0100, "Dave Plowman (News)"
wrote:

In article ,
Thomas Prufer wrote:
And BAY15d may have different-height pins, with two base contacts and case for
ground, for double-filament automotive lights that need a single mounting
orientation (brake & running light, I think is one...)

There are offset pins (height wise) for the older stop/tail bulb. And then
a different offset (not 180 spaced) came in for others - like amber
flasher bulbs.

There also seems to be 1156 and 1157 that is supposed to refer to the
pin orientation but getting all that to line up Bay15D 1156 (
supposedly non offset pins) and a single filament wired across both
terminals and not terminal to base *and* with the LEDS facing all ways
and at a reasonable wattage / light output, seems quite an ask. ;-)

I may have found such on ebay and I've asked for confirmation of fit
in general, wiring and wattage.

It sorta suggests it's polarized and if it is I can stick a blocking
diode in there or bridge (single diode less lossy), in case I or
someone connects it up backwards.

Cheers, T i m

In article ,
NY wrote:
Why is is that cars always seem to use the dual-filament bulbs for
tail/brake, with a separate bulb for rear fog lights? Given that tail
and fog lights serve the same purpose, of defining the presence and
width of the vehicle as seen from behind, it would be better if
clusters were designed to have tail/fog on the dual-filament bulb and a
separate light for brake.

Probably history, as cars had stop lights well before rear fogs. But not
all did as you say anyway - not even all Lucas.

--
*Why isn't 11 pronounced onety one? *

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
T i m wrote:
It sorta suggests it's polarized and if it is I can stick a blocking
diode in there or bridge (single diode less lossy), in case I or
someone connects it up backwards.

If a car bulb, it will already be protected against reverse connection.

--
*When everything's coming your way, you're in the wrong lane *

Dave Plowman London SW
To e-mail, change noise into sound.

On Thu, 15 Oct 2020 10:40:59 +0100, NY wrote:

Given that tail and fog lights serve the same purpose, of defining the
presence and width of the vehicle as seen from behind,

They might now but at one time a single fog light was allowed. The
rear light clusters having that single fog on the (off?) side and the
reversing light in the same position on the (near?) side.

--
Cheers
Dave.

"Dave Liquorice" wrote in message
idual.net...
On Thu, 15 Oct 2020 10:40:59 +0100, NY wrote:

Given that tail and fog lights serve the same purpose, of defining the
presence and width of the vehicle as seen from behind,

They might now but at one time a single fog light was allowed. The
rear light clusters having that single fog on the (off?) side and the
reversing light in the same position on the (near?) side.

I'd say that a single foglight on the offside is now *more* common than it
used to be. I'm not sure whether it's penny-pinching - fit as few reversing
and fog lights as you can - or whether it's a conscious decision not to pair
the reversing and fog lights, thus preventing a) both sides of the road
behind you being illuminated when reversing, and b) the fog lights acting as
high-power tail lights, defining the width of the car to vehicles coming up
behind you.

With the exception of a my first car (a Mark 1 Renault 5) and my present
Peugeot 308, all my cars (VW Golf Marks 2 and 3, Peugeot 306 x2) have had
dual foglights and dual reversing lights in the cluster, though in each
case, the car was supplied with only a bulb in the offside fog light. My
present Pug 308 (and the Renault 5) only have one reversing light (in the
nearside cluster) and one foglight (in the offside cluster) so I can't just
add the missing bulb to restore paired fog lights. When I'm reversing at
nigth, I tend to put on the fog light to illuminate the right-hand side of
my field of view so I can see *both* gateways that I'm reversing between.

I wonder if there are some countries (maybe France for the Peugeots and
German for the VWs) where it is actually *illegal* to have paired fog
lights, which is why a bulb is only fitted in the offside cluster of those
cars which have sockets in both clusters.

My feeling is that *all* lights, with the exception of the central
high-level brake light, should be paired.

On Thu, 15 Oct 2020 14:42:16 +0100, "Dave Plowman (News)"
wrote:

In article ,
T i m wrote:
It sorta suggests it's polarized and if it is I can stick a blocking
diode in there or bridge (single diode less lossy), in case I or
someone connects it up backwards.

If a car bulb, it will already be protected against reverse connection.

Well, that's what I'd assumed but ignoring old +ve earth cars, most
dual contact lamps seem to be polarised to some degree because of the
bayonets and it wouldn't be an issue with single pin lamps?

On a couple of the eBay items I saw they had + and - marked on the
base connections, but that might have been indicating they were the
'live' connections, rather than contacts to cap etc.

Cheers, T i m