Headlamp Modifications

[electrokid]

Actually there is no need to buy separate LHD headlamps cos the ones you have can be modded.

Hmmmm - interesting. I tried this on a spare headlamp off the car today but I couldn't see any difference in daylight so I looked at it again this evening by fitting a pair of modded bulbs to the car.

Not ideal circumstances - I used a pair of old bulbs which have some greying of the glass inside - this tends to happen over time so it's worth replacing headlamp bulbs every 3 years or so - and I wasn't about to crop the tab off the relatively new xenons for the experiment. And since the new spheres have been fitted the ride is a bit softer so under power the back is down just a bit making the headlamp aim perhaps a couple of degrees too high.

I found with the nearside headlamp I was able to adjust the bar of light (part of which forms the upwards pointing area to the left which needs to be cropped for driving on the right) from it's normal slanting position to being level. This, as you say, should be fine for driving in France. In the late 60s / 70s when buying a new F**d you could chose the option of 'dip left' or 'dip centre' headlights - dad always chose 'dip centre' so modding for France was simply a case of yellow headlamp paint.

Having set the NS to level (centre dip is fine for the UK as well of course) I went for a drive along some country roads - found that the illumination of the verge was actually better because the light normally aimed at road signs (and blinding you as a result) was now lower and more useful.

Tomorrow, time willing, I'll modify the xenons and re-fit and see what result I get then.

BX lights are a bit weak

I've always thought they were quite good. Many years ago I had a friend and neighbour whose BX always seemed to pass its MOT despite having headlamps with reflectors that almost got duller and duller as you were looking at them. He thought that his eyesight was the reason he was having difficulty driving at night and put off replacing the headlamps because he was thinking of changing cars. We will never know - sadly, he died at the wheel in his BX though that was in broad daylight.

Tomorrow (weather willing) I'm going to try and wash the inside of a spare headlamp - primarily to make sure the solvent doesn't eat anything important. If successful I'll try it on the ones in the car to see if that removes any film and improves them.

[MULLEY]

I found that by fitting some higher quality & output bulbs along with new headlights, the view at night was miles better. Also found quite a big difference in just standard bulbs, one set were like candles compared to some others. I'd try the 30+ or 50+ or even the 70+ higher output bulbs to see if that makes a difference. Supposedly the wiring is the weak link, i think there may be some posts about replacing it.

[KevR]

Supposedly the wiring is the weak link, i think there may be some posts about replacing it.

It's true that old wiring and connectors can cause a serious voltage drop under load (and lose a volt at the bulb connector and you lose something like 20% of the light from a Halogen bulb). But rather than replacing the wiring, fit relays near the headlights instead. Then you're only using the original wiring to trigger the relays so there's very little load on it - the actual power for the light comes from a shiny new wire straight back to the battery. Easy to do, costs virtually nothing - especially if you use the green relays from a scrap BX's fusebox. I've just used three of them on my BMW bike!

[electrokid]

They are all valid points for sure. I got a lot done today - let's see how far I can get with this post.

It's true that old wiring and connectors can cause a serious voltage drop under load (and lose a volt at the bulb connector and you lose something like 20% of the light from a Halogen bulb).

Take the 12v lighting used in homes - the voltage to get the ideal light output is 11.6 - that's what the bulbs are designed for - run them on 11.0v and the light output will be noticeably lower and slightly less 'white' with a tad more red in the output. If you run them on 12.0v or over the bulb life will be very much shortened.

Also found quite a big difference in just standard bulbs, one set were like candles compared to some others. I'd try the 30+ or 50+ or even the 70+ higher output bulbs to see if that makes a difference.

There will be, due in some cases to poor quality control. It must also be difficult for the bulb manufacturers to know exactly what voltage spec will work best - some vehicles will have substantial wiring and relays close to the power source -

But rather than replacing the wiring, fit relays near the headlights instead.

- this works well but might shorten bulb life... and some vehicles will have wiring that is only just adequate - unfortunately the BX is close to this description.

I suspect that the 'up to' +50%... +70% more light bulbs may be designed for a slightly lower voltage than 'standard' - if there is a standard - there's much variation in vehicle electrics design so while the voltage range is bound to be quite large, the voltage at the bulb is quite critical.

I have a few principles in life - one of which is "don't try to guess if you can measure what's going on"

One of the things I did today was to measure the voltage at the headlamp bulbs on the BX - they were as follows...

NS dip 12.46
OS dip 12.56
NS main 12.32
OS main 12.24

Nominal battery voltage with the engine running and therefore being charged is around 13.8 - it depends on many things including the state of the alternator (how many phases are fully functional and the voltage the internal regulator is set to) and the state of the battery - a poor battery will be slightly higher internal resistance and the volts-on-charge can be higher. I think my battery will need replacing this year - I flattened it the other day while working on the fan mod and I've had the car 4 years and not changed it so it's probably due - the voltages above were measured with the engine running and the battery voltage was 14.19 which is just a tad higher than one would expect.

The headlamp wiring on the BX is a bit on the skinny side but even so the voltages measured were somewhat disappointing. I think it would be just a bit more complex than just a single relay to fix it if the dim-dip facility was to be included.

This post is already 'War and Peace' so I'll add the other tests later - cleaning the inside of the headlamps and measuring the light output.

[mat_fenwick]

My plan is to rewire the headlamp circuit with relays - keeping the dim dip feature but doing away with the resistor, and using a double pole changeover relay to switch between series and parallel operation. Using a resistor seems so wasteful!
I should point out that I have been planning this mod for the last 6 years, so don't expect a comprehensive write up by tomorrow...

[Mike E (uk)]

Here is a repeat of my posting from 1995:

"I was unhappy with my headlamps too,
problems are:

The wire is too thin to start with,
it corrodes after 12 years or so,
The headlamp reflectors tarnish,
The headlamps are powered via the dashwiring, not a relay, so there is lots of unnecessary resistance.

If you simply add 100W bulbs in place of the 55W bulbs, ohms law will double the voltage drop in the wiring, so you will probably end up with little more than the amount of light you started with.

So I did this:

Fitted new headlamp units and replaced the fog lamps with new spots, from AX GT.
Fog lamps are useless anyway.

I rewired the headlamps direct to battery with a proper relay + fusing.
Fitted the headlamps with 50/100W bulbs.
Rewired the Spots to light on full beam only.
Fitted the spot lamp bulbs with 100W items.

Now I have normal, legal, but effective dip beam which will not dazzle people.

and grass verge scorching 400W on main beam.

I can see for miles, and the car looks completely standard too. "

Since then,5 years on, I still have the same bulbs fitted. So no problem with bulb lifetime.

I have the circuit somewhere, but it is very simple. I think it is on Vanny's BX project site too.

Mike

[rayfenwick]

I should point out that I have been planning this mod for the last 6 years, so don't expect a comprehensive write up by tomorrow...

Damn, now I'm disappointed

[rayfenwick]

The headlamps are powered via the dashwiring, not a relay, so there is lots of unnecessary resistance.

Another big advantage of running new cable with relays is that you're then eliminating switching a big current via the dash switches - this will prolong their life considerably. It's a (reasonably) popular mod in the XM world too, and one I'll get round to eventually, though the HID conversion in the XM has made a huge difference itself

[Mike E (uk)]

I have found my notes on the headlamp wiring.

If anyone wants a copy, pm me and I will email it.

Mike

[electrokid]

I should point out that I have been planning this mod for the last 6 years

I'm very good at planning too

I wanted to see how much the light output was affected by removable muck so I picked a headlamp out of the lot I picked up from Nick last Saturday - one which was a bit damaged and not going anywhere else. I found a spot in the workshop that was dark enough to have minimal effect on light readings and set up a 'standard' position for the headlamp.

Before any cleaning I measured the main beam light output reflected from the area - 54 Lux.

Then I poured 100ml of isopropyl alcohol (IPA) into the headlamp and swilled it around for a while then poured it out and dried with a hair dryer.

Put it on 'the rig' again and measured the light output - 74 Lux.

Full of overconfidence I decided it was time to do the same with a headlamp from the car measured the light output from that (using the same bulb as before) - 82 Lux.

Poured 100ml of IPA in as before and swilled. It didn't seem to be cleaning as well so I poured in some glass cleaner - the green stuff - as well and swilled a bit more. This is where my overconfidence smacked me in the chops - I sarted to see little flakes of silver in the mix so it was an emergency drain out and wash. I put some IPA in and swilled to assist drying.

IPA is very useful - you can put say 100ml in the diesel or petrol tank and it sorts out any water in your fuel. Folks usually say that it's because it dissolves in both fuels and water - actually is dissolves in fuel but forms an azetrope with water.

Naah - I don't really know what that means either - except that a water / IPA mix will evaporate as quickly as just IPA on it's own and it will take the water with it so it's very good for drying stuff out.

After I finally got the headlamp dry I measured the light output again - 88 Lux.

Then I put it's proper bulb (this set are xenons 'up to 70% more light') and checked the light output - 97 Lux.

Haven't got the aim right yet so no specific conclusions - except perhaps that the cleaning process is never going to be 100% so it might be worth investing in a new set every now and then.

[mat_fenwick]

Interesting stuff, I had noticed an (unquantified) improvement in night vision after changing to a new looking second hand set but surprising how much difference a clean can make. I wonder if India Pale Ale has a similar effect?

Spurred on by my lack of progress over the last few years I have drawn up a circuit sketch using standard automotive SPCO relays (3 of them) to operate the dipped beam and dim-dip parts of the circuit. I will obviously need a 4th to operate main beam, and am trying to work out if I can get away without a 5th to operate the 'dim-dip when sidelights and ignition are on' logic.
It's all made a bit more complicated by the fact the twin filament bulbs have a common earth, so when on main beam the filaments both need a dedicated earth path rather than one earthing through the second bulb...

Watch this space!

[electrokid]

I wonder if India Pale Ale has a similar effect?

It has been know to make it harder to see at night

I have drawn up a circuit sketch using standard automotive SPCO relays (3 of them) to operate the dipped beam and dim-dip parts of the circuit. I will obviously need a 4th to operate main beam, and am trying to work out if I can get away without a 5th to operate the 'dim-dip when sidelights and ignition are on' logic.
It's all made a bit more complicated by the fact the twin filament bulbs have a common earth,

I've wondered about fitting the series / parallel arangement too but not thought about it with the BXs because it's already fitted - and it does successfully throw a small amount of light out which can be useful at times. I'm not sure what voltage the bulbs run at on dim-dip - I'll measure it in the next couple of days.

An update on the glass jigsaw puzzle that arrived from France. Now when the postie said "I'll mark it RETURN - DAMAGED" I kinda presumed that it would be sent back. Well... not entirely true - I had a letter from the local Parcelforce office saying they were having difiiculty delivering it to me ! ! !

At first annoyed with such levels of basic incompetance I thought I could turn it to my advantage.

At the counter I said "I have a complaint... and a request". So I whinged about the letter - then asked if I could see the parcel and explained the situation.

They opened the box for me - one of the headlamps was FUBAR and the other intact - one layer of secondhand medium sized bubble wrap and lots of space left in the box for them to rattle around in was clearly not sufficient.

But - I wanted to see if there was any difference between the LHD and RHD lenses (there is - a lot of difference) so that was achieved - and they are now going to try to send it back despite the 'nes pas retourne' being marked on the Colissimo label - and given me a tracking number so I can have a laugh seeing how far it gets

I'll have a think about the series / parallel - should be able to do it with less than 5 relays - and I like to try and maintain my reputation for being a smart-arse

[mat_fenwick]

I've done it in 5 - the gauntlet has now been laid down...

I've even put in a resistor to operate the dipped beam warning lamp at a reduced intensity.


The questions are:
Can you see an obvious reason why this would not work?
Can you do better?!
I feel sure that the wiring around the two relays in the top left corner could be improved, but can't get my head around how at the moment.

[KevR]

Two things...
1: It's only just occurred to me to wonder why Electrokid wants LHD headlights in the first place.
2: It's also only just occurred to me that I've probably got at least one pair of perfectly good RHD headlights mouldering in the barn if anyone wants them. I've imported three BXs to froggyland and changed the lights so presumably most of the old ones should still be lurking about somewhere.

[electrokid]

I've done it in 5 - the gauntlet has now been laid down...

Ahh - the old gauntlet trick huh

Actually I'm not sure that you have done it ! !

During dim-dip there's a path for current through the 'main' filaments of both bulbs which you still have connected together - if it's any consolation, smart-arse here is struggling with that one as well

Essential trip to the shops now - out of ciggies...

I'll be back