High wattage headlights

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mat_fenwick
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High wattage headlights

Post by mat_fenwick » Tue Jan 24, 2006 10:11 am

I know this is a topic that has cropped up before, but I can't see anything when searching. :?
Has anyone used 100w headlight bulbs on a BX without uprating the wiring. The reason I ask is that I have aquired some 55w/100w bulbs (which won't dazzle other drivers when dipped) and I know the circuit does not have a relay as standard. In time I will fit one but I don't want to damage anything by fitting the bulbs in the meantime.

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Post by jeremy » Tue Jan 24, 2006 10:55 am

The problem is the voltage drop to the light units - what you've got at the moment probably could be much better - why not test them by simply hot wiring temporarily?

make sure the earth is good (Measure resistance between bulb earth and battery negative!) - if its good then try a direct supply from the battery to the bulb main beam terminal and see how much brighter it is. A direct comparison could be made with the normal headlamp supply by having the lights on then making the connection.

I haven't tried a larger bulb but the lamp unit looks large with no complex additional reflectors or mouldings around the bulb and so I wouldn't have thought overheating was a real problem - and in any case new units aren't enormously expensive. Also the main beams probably won't be on for that long.

Not sure about the legalities.

jeremy

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Post by Vanny » Tue Jan 24, 2006 1:30 pm

Surely given the uber aged wiring on the BX head lights (cut the wire open and you'll find its black with carbon deposits), the huge increase in current draw is not going to do the remains of the wires much good, and i suspect if it doesnt finish off the wiring it will get hot enough to do so serious damage! Try having a feel of the wires with normal bulns after an hours use, cook toast on em :D

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Post by tom » Tue Jan 24, 2006 2:05 pm

Vanny ain't joking. Try replacing the headlamp wiring with an uprated cable. THe effect is quite startling.

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Post by (CZ)enda » Tue Jan 24, 2006 2:40 pm

I raised the question recently on two different local forums dealing with two different car makes (yes, those which I own).
The results were surprisingly consistent - FORGET IT.
Reasons presented were:
a) Most of 100 W bulbs sold in DIY supermarkets, tuning shops etc. are not conforming to valid EU standards when it comes to blinding those driving on the other side of the road. Unless marked with the appropriate logo, they are NOT conforming, no matter what the sales clerk said.
b) The wiring in older cars is not rated sufficiently as it was designed for standard 55/60 W bulbs. It will burn, burn, burn.
c) These bulbs increase the temperature inside the headlamp, decreasing the life of the plastic reflector significantly.

General consent to increase the output of the headlamps was to use modern 55/60 W bulbs. This is what I did.
I bought Narva Range Power bulbs (the package says "+50% of light" or similar ad-talk) as they were the cheaper alternative to e.g. Osram bulbs.
Indeed, I must say they made a VISIBLE difference when compared with the Bosch bulbs (of unknown type) I had before!

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Post by mat_fenwick » Tue Jan 24, 2006 3:05 pm

Thanks for the replies, you might be right be right about the voltage drop, especially with the thin wires that are used. I was a bit reluctant to simply try it in case the switch and/or wiring melted (although I guess this is unlikely as there will be a safety margin).
I will probably swap one over first and see what if any brightness increase I get, although the current bulbs don’t look dim, its just that I would appreciate a little more light sometimes. It would be interesting to compare voltages at the bulb as well. If I do get an increase in brightness I will probably use them and fit a relay when I get chance.

Regarding legality, I think that anything other than 55/60w bulbs are for off-road use, but seeing as most of my night driving is now on deserted roads, and I won't be having my main beam on when other cars are around, I won't be causing any dazzle to other drivers.

M

Post by M » Tue Jan 24, 2006 3:45 pm

Dare I suggest a set of auxiliary driving lamps with 55w bulbs in? They can be quite small these days, yet make a useful difference.

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Post by Stewart (oily!) » Tue Jan 24, 2006 5:06 pm

On my Mk1 Diesel the light switches were getting hot with standard bulbs, in order to solve the problem i was advised to fit relays which I did, the difference in illumination was startling, I ended up fitting four separate ones, this is a mod which I will definitely "get around to" on my current car. it will probably be cheaper than bright bulbs and fully legal too, I hav a TZD to which i have fitted yellow renault driving lamps in place of the standard ones (french influence see) readily available from breakers and i use these on unlit narrow roads to fill in the gaps.
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Post by jeremy » Tue Jan 24, 2006 5:14 pm

I think there's a lot in marty's suggestion of auxillary lamps - and if they weree wired with relays as an optional 4 headlamp system I think they would be really useful especially as they could be focused independantly of the headlamps.

I know what you mean about the standard lights - I'm fed up with being eclipsed by a following car when using them - and must fit relays soon.

Some of the modern 'bright' bulbs do provide a legal alternative - ie higher output for the same current. I would however have expected the glass to run hotter than the standard bulbs and therefore the risk of overheating the light unit to be present. As I've said above its a big unobstructed unit so this may not be too much of a problem - and I suppose some holes could be drilled to let the air circulate and cool it.

jeremy

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Post by Stewart (oily!) » Tue Jan 24, 2006 6:07 pm

I just replaced a set of Hella blue ones with standard bulbs, the blue seemed to be at an invisible wavelength for me :x , a good clean of the glasses and stone protectors helped too, Jon I ended up fitting four relays to go along with the fusing scheme, independent for each lamp.
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Post by tom » Tue Jan 24, 2006 6:08 pm

Or if you have a couple of spare relays in a scrapper,Jon, I'll see you at the weekend...

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Post by Kitch » Tue Jan 24, 2006 6:12 pm

Mines run the same two 100w bulbs for the last 18months with no problems.

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Post by sleepy0905 » Tue Jan 24, 2006 7:51 pm

Mine runs 65/120s with no problem and has done for about 3 years.
2017 Seat Leon ST FR 2.0 150Bhp

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Mike E (uk)
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Headlamp upgrade

Post by Mike E (uk) » Tue Jan 24, 2006 10:21 pm

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.

May have to swap the bulbs at MOT time though.

Mike