Wow - that's a mess, what caused/fed the fire ?
Looks repairable, thank god it wasn't a 'modern' car.
If the wires are correctly sized, fused and secure, then there is no real benefit from reducing the current. If the devices can't dissapate the heat they generate, or the heat is an issue to thier surroundings then there is a benefit in reducing the device's consumption.
If the supply wires are too thin, change the wires.
LED's are more efficient at transfering current into light so for the same amount of light output (between incandescant and diode) there is less current consumed and less heat generated.
Up here in Scotland we need heat, to stop the buildup of snow and ice on the headlamp glass, LED's don't produce enough due to thier efficency unless we operate tham at illegal intensities.
You could fit a small heater behing the glass, like a 55W bulb for example
As long as the current draw can be safely accommodated by the supply and cabling then there is no need to reduce anything, it's only when the current exceeds the capability of the cable/device that the problem arises.
Fuses protect a circuit by being the weak point that burns out first. A 10A fuse will melt itself at a touch over 10A, the cable should be rated at least twice that (so not even get warm).
You can get thermal fuses which open when they get hot.
The really wrong thing to do is not have a fuse, then as the current exceeds the capacity of the wire is gets red hot and sets fire to the insulation that surround it and/or the material it is passing through/touching.
A car battery can supply a shedload of current, more than you can imagine even a 5mm thick piece of wire will glow like the sun if held across the terminals.
Good luck with sorting out the enginebay and electrics.
Looks repairable, thank god it wasn't a 'modern' car.
If the wires are correctly sized, fused and secure, then there is no real benefit from reducing the current. If the devices can't dissapate the heat they generate, or the heat is an issue to thier surroundings then there is a benefit in reducing the device's consumption.
If the supply wires are too thin, change the wires.
LED's are more efficient at transfering current into light so for the same amount of light output (between incandescant and diode) there is less current consumed and less heat generated.
Up here in Scotland we need heat, to stop the buildup of snow and ice on the headlamp glass, LED's don't produce enough due to thier efficency unless we operate tham at illegal intensities.
You could fit a small heater behing the glass, like a 55W bulb for example
As long as the current draw can be safely accommodated by the supply and cabling then there is no need to reduce anything, it's only when the current exceeds the capability of the cable/device that the problem arises.
Fuses protect a circuit by being the weak point that burns out first. A 10A fuse will melt itself at a touch over 10A, the cable should be rated at least twice that (so not even get warm).
You can get thermal fuses which open when they get hot.
The really wrong thing to do is not have a fuse, then as the current exceeds the capacity of the wire is gets red hot and sets fire to the insulation that surround it and/or the material it is passing through/touching.
A car battery can supply a shedload of current, more than you can imagine even a 5mm thick piece of wire will glow like the sun if held across the terminals.
Good luck with sorting out the enginebay and electrics.
dag019
Well-Known Member
It looks like it was an electrical fault as the start somewhere under the drivers wing. The thread linked at the start with the beginning of the rebuild details the fight I had with the insurance who were treating it as a modern car. It will all be repairable, I am hoping to get the replacement bulkhead built up and fitted next week. Everything is "cosmetic" there is no structural damage.
I am not as far north as you so the build up of snow and the inability to melt it is not really an issue for me. I am more looking at what you are talking about regarding ensuring the wiring can safely accommodate the current draw. The original wiring "should" be designed to cope with the current draw of a halogen bulbs (for various reasons, corrosion, etc., already discussed I know there are times when it is not capable of this) and it is of course fused to protect the wiring (again there are instances where the fuse does not, I have had headlight switches melt to the point of not making contact without the fuse blowing), but by replacing the halogen with led's what I am hoping to achieve it a much larger safety margin before problems would occur without the need to build my own uprated wiring loom.
Unless I am missing something this should achieve the same result of an increased safety margin as building my own loom, even if just headlight specific, with higher rated cabling.
High Beam is marginally better than the standard yellow candles which they replaced, so I was quite pleased - the Colour Temp is higher so it’s a crisper level of illumination. As you are going for Aux lights on High Beam they are worth a look as the low beam is very good….
We have about 4" here but am currently waiting for my PCR result so trying hard not to go anywhere...
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Nothing wrong with your logic at all, building in a margin is without doubt a good thing. If you use 1.5mm multicore wire this is rated @ 21Amps. With a 10Amp fuse in line that wire will never get hot enough to ignite cotton wool and you could run 120W of light or with a 15A fuse up to 180Watts.
LED lamps are around 35 to 40W (I seem to remember) so they will draw around 3Amps, std 55W lamps draw a tad under 5Amps.
Based on that, 1.5mm wire has plenty of margin (21 Amp rating), in fact 1mm wire will still be good enough @16Amps.
0.5mm is good for 11Amps which is over 100% margin .....
Which way would I go .... i'd examine the wiring to detrermine what size is in the loom.
If I felt I needed additional capacity on the feed to the headlamps (or aux lights, spots etc) i'd use the existing wiring to operate a relay and run a 1.5mm feed through a 10A fuse from the main fuses under the bonnet. If the lamp or cable fails/shorts the fuse will pop well before the cable gets warm. My 300tdi's loom is working and is rated to provide around 100% margin however I will be fitting relays for the lights at some point as I don't want to route the full current through the steering column switches - by just operating with a very small current I can change the current fuses to 1A giving an even greater margin againt letting the smoke out.
I just need to figure out where to put the relays etc, how to run the cables, where to fit the fuses and where to source the power. Decisions, decisions .....
I see Better Car Lighting has some rather nifty looking LED units which are a straight swap for standard H4 bulbs.
https://www.bettercarlighting.co.uk/index.php?act=viewProd&productId=833
Seeing as @v8250 has a high opinion of the proprietor I'm tempted to try some.
https://www.bettercarlighting.co.uk/index.php?act=viewProd&productId=833
Seeing as @v8250 has a high opinion of the proprietor I'm tempted to try some.
v8250
Well-Known Member
And they're fine quality units...if a little pricey. One reason I'm so enthusiastic for BLC is that they're a small British company, in a niche market, that really knows their onions. The design/build quality is superb...the side, tail/brake, fog and smaller units are build like girders. And their service...I had a tail/brake light fail, called Gil Keene who said 1. it's the first ever failure in this bulb and 2. sent out a new unit, no questions asked and it arrived next day. I've kept the faulty unit for prosperity.
dag019
Well-Known Member
I had looked at these and they are very appealing. I am now trying to work out the advantage/disadvantage of these vs a full led unit.
Thought they might be useful if seeking an original appearance but trying to keep current draw down to LED sort of levels.
Hicap phill
Well-Known Member
+1 on the original looks with the updated bulbs.
How many times have you looked at these LED headlights & thought they look wrong?
so we just now need someone to fit these bulbs & review
Or put another way ... someone daft enough to spend £130 on two H4 bulbs ....
