Changing to Halogen headlights

[SteveSpitfire1500]

Hi, one of my original headlights has blown, so I just ordered these http://www.ebay.co.uk/itm/360621766779

Do I need to do anything else or are they just a straight swap? I know I will need to blank off the sidelight to make them fit my 1500, but other than that is all the old wiring etc ok? Thanks

[WIMPUS]

The really best thing to do is put relays inbetween the headlights .. then you can't have a burned out dash switch ..
(my uncle had that in his TR6 in the late 70's , just after he changed to halogens)

But i've heard from guy's that running halogens and have no problem  :)

You also say to blank of that side light .. maybe wire it also up with your other side lights  :)

Then everyone will notice you more  :P

[SteveSpitfire1500]

Hi there, thanks for the reply, is there an article anywhere that explains how to wire in relays? I'm ok at following instructions but I'm not an expert in these things, this is my first old car, so trying to learn!

[SteveSpitfire1500]

Actually a quick google and there seem to be ready made kits, should I buy one of those?

[Velocita Rosso]

If I were you I would do what we did....buy all the bits separately eg headlights and lamps
The lamps we bought were Nightbreakers....far better than standard

[SteveSpitfire1500]

Hi, thanks for the reply, I've already ordered the headlight units on ebay  http://www.ebay.co.uk/itm/360621766779, but the wiring loom on my car seems a bit fragile, thing it had an alarm fitted at some point so there's wiring all over the place that I intend to tidy up over the winter when the car is off-road in the garage. I started to read about relays, maybe I need to find a wiring diagram, I've got a soldering iron and that plastic shrink stuff so I could probably do it if there's an idiots guide to what I need to do :)

[thehanko]

Std Relay pins are:

30 high power supply (thicker cable)
85 switched positive eg old light power supply. So when light switch is turned on its telling the relay to turn on.
86 earth
87 to head light. (Thicker cable)

Note 85 and 86 can be swapped it doesn't matter which way they go.


Basically when power flows through 85 to 86 to earth it turns the relay on and connects 30 and 87. The result is that the old wiring and dash switch only needs to supply enough power to turn on the relay. Once the relay is one the lights load is solely supplied by the thicker cable.

You can get relays which provide 2 x 87 outlets which are handy for head lights as you need only 2 instead of 4.

Note that if your relay has an. 87a it will be the opposite of 87. Eg when one is live the other is not and vice versa.


HTH

[junkuser]

See what John had to say in technical section "Two types of relay?  Really?  Yes" in case you are sold the wrong type.

[Dannyb]

This is my wiring . Might help

[SteveSpitfire1500]

I did an A level in physics in 1987 :) so will give this some proper thought and maybe give it a go! Thanks for all the info. Shame they don't just make all this in a kit? I found one but it's from a seller in the US, $37 I think it was, might check if they are happy to ship back to UK?  Hopefully a US kit will fit a UK car????

[thehanko]

Mate if you get that stuck give me a holler, I could knock up a loom for it for a few pounds worth of materials. But realistically you can do it.

2 relays with dual 87's

A box of wire connectors

Some wire

And ten minutes looking at the pic and descriptions here and you will be fine.

[nang]

Only thing I have done differently, a seperate fuse for high and low beams. That way if you blow a fuse you've still got dip or high,
Tony.

[thehanko]

Yeah nice, could get fused relays which would stop any additional clutter.

[Don Cook]

I just swopped the headlights over...nothing else. That was about 6 years ago, no problems at all.

[bodders1]

4526 wrote:

The really best thing to do is put relays inbetween the headlights .. then you can't have a burned out dash switch ..
(my uncle had that in his TR6 in the late 70's , just after he changed to halogens)

I've never really understood this piece of received wisdom.
A 55W quartz-halogen bulb draws exactly the same current as a 55W tungsten bulb so the current passing through the switch is the same.  So why does the change to halogen bulbs necessitate adding relays to the circuit?


There *are* other good reasons to add relays such as
1) doing a lot more night driving (e.g.  RBRR) when the headlights will be on for considerably longer periods than normal
2) putting higher wattage bulbs into the lights (of questionable legality in Britain but quite a lot of people have done it (whistle) )
3) adding additional spotlamps on the main beam circuit.

bodders1

[CHRIS211083]

Mk2 spitfire, used as main transport for two years constant. lighting switch blew on the third time of being used after installing the h4's. I was suppose to be heading to the RBRR edinburgh meet to wave the cars by. I replaced with a second hand switch which also blew on the way back from the meet. Thank fully I used the high beam flash and held it in place till I got home. That was one year in. I then installed relays and the head lamps were alot brighter and no killed switches.

I have been told that the later modern switches are rated high enough but why take the chance if you will be driving at night???

Chris.

[uksnatcher]

To go relayed is not REALLY needed when going halogen but highly recommended and brighter lamps, yes i also blew an old switch or 2 before fitting the relays.

Resistance in old wiring and switchgear coupled with aged earths can potentially drop headlamp voltage down to 10volts at the bulb.

Adding new dedicated relayed and fused main/dip feeds, thus putting a full running voltage (upto 14.5V) at the bulbs and new earths back to the battery and use the old wires to only trigger the relay, doing this will transform even the old sealed beam headlamp performance plus removing any excessive amps on the dash switch, stalk and block connectors.

[SteveSpitfire1500]

TBH I rarely drive it at night, just one of the old lamp units has blown so I'll have to get it fixed for MOT time, couldn't find anything other than halogen units to replace it with hence the reason I bought them. If it's true that it only draws the same supply then maybe I'll just do a straight swap for now?

[thehanko]

bodders1 wrote:

I've never really understood this piece of received wisdom.
A 55W quartz-halogen bulb draws exactly the same current as a 55W tungsten bulb so the current passing through the switch is the same.  So why does the change to halogen bulbs necessitate adding relays to the circuit?


There *are* other good reasons to add relays such as
1) doing a lot more night driving (e.g.  RBRR) when the headlights will be on for considerably longer periods than normal
2) putting higher wattage bulbs into the lights (of questionable legality in Britain but quite a lot of people have done it (whistle) )
3) adding additional spotlamps on the main beam circuit.

bodders1

your right, the system will handle the same draw, the problem is that the lights are a high draw circuit running through a crap switch - when this switch corrodes along with the wires after say the 4th decade (or 4th week is more likely  :'( thanks lucas! ) the resistance increases and so does the heat.

The benefit in the relay system is lack of voltage drop resulting in much much better lights - doesn't matter how good the new halogens are if they are getting poor supply, they will perform poorly. Running relays on lights is good practice regardless of the wattage of your bulbs.

However if raising the wattage as alot do changes it from good practise to 'crazy not to'.

[Dannyb]

When I got my spitfire 11 years ago it has halogens fitted with no relays. No problem as I selden went out at night and if I did it was not for lon. But when I entered the RBRR and adding extra spots I changed to relays.
One for the headlights and the other for the spots. I could not believe the difference the relays made  with a direct power source straight to the lights rather than going through the switch.
At least I knew th switch was not going to burn out after 8 hrs or so continuous use.

[oil_on_the_carpet]

bodders1 wrote:

I've never really understood this piece of received wisdom.
A 55W quartz-halogen bulb draws exactly the same current as a 55W tungsten bulb so the current passing through the switch is the same.  So why does the change to halogen bulbs necessitate adding relays to the circuit?

bodders1

Except that the light output from Halogens is designed around a set high voltage for the chemistry to do it's halide thing.
If you get any significant voltage drop, the light output falls far more than with a standard filament bulb.

[Docman]

I've done the straight swap, and although they are still an improvement from sealed beams, I know their output will be much higher with relays.

Just not at the top of my priorities at the moment