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Brighter Headlights


redhouse53

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Check the volts at the bulbs with engine off. Should be exactly the same battery volts. If not your wiring is dicky.
Check earth continuity to battery (via the body). Should be very low  - 0.1 ohms.
Any volts drop or high resistance will degrade the light output.
Install a relay so that the bulbs are powered direct from the battery (or thereabouts) (using thicker cable) with the relay being activated by the light switch.
Fit Halogen bulbs as stated above

Roger

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Hello Roger,

I would doubt that many on here have a meter capable of measuring fractions of an ohm accurately, better to measure the voltage drop with everything switched on. I don't know practically what volt drop to expect on a good connection, but 0.1 ohm gives a volt drop of 2 volts with 20 amps flowing, which sounds far too much, I would like to see >1 volt?
Certainly, by far, the best upgrade is to fit a relay with decent sized cable and ensure the earths are good.

Alec

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Hello Sam,

"Any standard multimeter will measure to 2 decimal places"

It will not be accurate at low levels of resistance, you need a ductor to measure such levels of resistance. This works with four prods, two voltage and two current and are hugely expensive.

Alec

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I know I shouldn't however if you wish to be picky,  you would want to use a safety ohmmeter. I'm an aerospace electrician by the way ...

Note, the ductor test measures to a milli watt (x10 to the power of negative 3) The same as a fluke being operated by a competent individual.

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junkuser wrote:
As a heavy wire is being run from battery to lamp via relay for the switched side of the circuit, would it not be a good idea to do the same for the un-switched side to the lamp holder/plug?


No point as the load will only be for the relays which is small

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junkuser wrote:
As a heavy wire is being run from battery to lamp via relay for the switched side of the circuit, would it not be a good idea to do the same for the un-switched side to the lamp holder/plug?


No that's the whole point of using relays. The on/off switch has very low current passing through it as it only switches the relay coil on/off hence the switch doesn't burn out and lasts longer. Check your modern car fuse box, it will have loads of relays exactly for that reason.

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Interesting responses!
I did not refer to the relay wiring, the heavier wire suggested was for the side of the circuit to the lamp originally supplied via the bodywork and various intermediate connections.

I avoid referring to this side of the circuit as either +ve or -ve as this depends on which way the car is wired and "earth" is somewhat inappropriate.  Frame side is accurate but some misunderstand what this means.

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Hello Junk user,

yes you have a point but generally the return wire to the body is very short so the gain would be much less.

Sam, I don't know if we are at cross purposes as to what a Ductor is but the ones I've used are specifically for low value resistance. There is a voltage prod to provide a current and current probes to measure the actual current and hence the meter computes the value of resistance, nothing to do with power.

Alec

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4058 wrote:
There is also the crystal headlights!
They give a nice bright beam. (various makes, but go for a good one, for example wipac)


Anyone in the UK with these fitted had any issues at MOT time?

I fitted a pair of Crystals (Wipac 6072) and Chic Doig reported that the MOT man was having problems measuring a beam pattern on his equipment. They did get it to register something on his tester eventually by randomly fitting different bulbs - but it all seemed a bit odd and I didn't have a lot of time to chat about it when I collected the car.

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Thank you Piman, but the point is that wherever there is a join there is a possibility of resistance, particularly in aged cars as these are.
Battery conductor to body and connection(s) of body to the lamp socket.

Many posts on here saying "clean the earth connections".  This also applies to headlamps.

Just felt that if a heavy conductor is being run for the switched side (via a relay) it would not be much more work to run an equivalent conductor with it to bypass any original connections in the unswitched side and take it right to the headlamp sockets, or as close as practicable.

Personally I find standard sealed beams on original wiring and switch are adequate on my 1962 vintage Spitfire4.
I certainly prefer them to the lamps in my "modern" which have the flat topped low beam.
Everything within the illuminated area brightly lit but you can see very little beyond as pupil size is adjusted to the brightly lit area.

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Further savings in cost and conductor resistance could be achieved by simply attaching the heavier conductors directly to the alternator instead of the battery.

Assume an alternator would be fitted by anyone chasing higher light output as it would decrease the likelihood of dimming and battery drain at low engine speeds such as idling or in traffic.

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Hello Junkuser,

I think you are going beyond what is really practical and chasing the law of diminishing returns? E.g.,  why would you want that fraction extra output when the car is idling, indeed there is probably a good argument for reducing the output in slow moving traffic?
Alec

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I'm just playing with the ideas of possibilities Pieman.
Seems a few people have posted that they want brighter headlamps and turn to higher wattage ones.
I'm happy with the standard setup.

The alternator suggestion was for those who spend time in traffic using their lights.
If they fit higher wattage lamps a dynamo may well not keep up with the power consumption at the prolonged lower engine speeds whereas the output of an alternator comes to higher levels at lower engine speeds than a dynamo, so less likelihood of lowering battery charge level.

If people are going to the effort of running a heavy conductor and switching by relay for the switched side and have an alternator, may as well simplify things by running from that instead of all the way to the battery.

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  • 2 months later...

On my 2500, I ran heavy cable from battery to fuse to relay, then rewired  from  relay to individual lights and same gauge wire from lights to earth. With halogen bulbs got great lights that even the testers comment on.
With the Spitfire again heavy cable to relays but left the original wires from relays to lights and earth, still good lights but probably not quite as good as the 2500.
Tony.

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