Joined: Aug 2017 Posts: 691 Threads: 37
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Location: The Scottish Border
Hi folks,
There seems to be a million types of LED
bulbs available , but finding a LED headlamp bulb that is 6v,
Fits a BA15 socket, is negative earth and offers
Full and dip beams seems be the one type that just
now anyway is not available?
Or has anyone else located a source of these?
Ideally one that does not look like a “ pineapple” !
For fitting into new old stock 1925 CAV headlamps
which have clear glass lenses which reveal all.
Regards
Bill G
(Aka AllAlloyCUp)
Based near the Scottish Border,
Joined: Aug 2017 Posts: 309 Threads: 56
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Good afternoon. I would contact Peter at "Classic Regulator and Dynamo Restoration" in Lincoln one of our Cherished Suppliers.
Regards from Staffordshire - the creative County.
Stuart
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Location: Monmouthshire
I would very much agree. Peter at CRDR seems to have developed a full range of LED lights for Sevens, with good instructions for either positive or negative earth. The light is not quite like a row of Hella spots bolted on to the front bumper, but an improvement on the original. Even more encouraging for night rallying or long distance touring is the low amperage needed, 3 to 4amps all lit up. This both allows a low third brush setting and saves having a spare battery behind the front seat for the midnight swap.
Joined: Aug 2017 Posts: 691 Threads: 37
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Location: The Scottish Border
Thanks
Stuart and Steve
I’ll give them a call.
Happy motoring!
Bill G
Based near the Scottish Border,
Joined: Aug 2017 Posts: 882 Threads: 48
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Location: North Wiltshire
Car type: 1927 Chummy, 1938 Big Seven 1/2 a Trials Chummy
My understanding is that LED "bulbs" for scuttle headlamps are not currently available. A few people have tried the LED replacements that are used in R47 units but these do not sit in the correct place to focus the beam in the early, small reflector.
If anyone knows any different, please shout! My chummy is stuck with stop tail bulbs at the moment.
Joined: Aug 2017 Posts: 309 Threads: 56
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Good morning. Since my previous reply I have been reflecting (no pun intended) on whether the fitting of main and dip bulbs would achieve the desired outcome. The reflectors fitted to CAV and the later Lucas R510's were not designed to be so used - reflectors with a main/dip function place the main beam filament at the focal point of the parabolic reflector and the dip filament 'offset' so the light beam is reflected downwards. This is why the bulbs in early dipping headlamps had to be 'focused' hence the term 'pre-focused' and inserted the right way up.
My experience of CAV and 510's suggests that they merely direct the light outwards.
Further I have recently been asked why twin contact bulb holders were sometimes fitted to these early lights - the answer seems to be that one contact was live and the other return (earth).
In an earlier posting it was explained that sidelights and headlights are achieved with single filament bulbs by switching the lamps in series to give a 3v output (sidelights) and parallel to give a 6v brighter output (main).
Regards from the creative county - Staffordshire
Stuart
Joined: Aug 2017 Posts: 3,329 Threads: 372
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Car type:
thanks Tony - very comprehensive. Do you see Stuart's comment about the series/parallel applying to earlier cars still then? It was the '25 wiring diagram that was confusing showing just one wire! I can see how a two wire system, if it were an earth return, can be changed at the switch from series to parallel through the lamps' dual filaments (always operating together, presumably) in an old fashioned bulb... but we change the method of functioning by wanting to select each side of the 21/6W?