Headlight Volts

[Classic49]

Hi all

Having got bored with modern cars that just get you from A to B, I (or nostalgia) decided to change to a car with character and personality. I did own a Triumph Herald 1200 once among other cars now counted as classics but I decided to go for a Stag. Consequently, I picked up my new Mk 1 Stag on Saturday. Its only done 27000m and the body work is in pretty good nick (apart from duff door locks) which, for me, was the most important factor. Also, that it runs (albeit a little sluggish) and sounds good.

Anyway, my question is about volts to the headlights. Having checked out a non working inner lamp, I discovered that it was only reading 8.7v compared with 11.7v at the battery. I fitted a new earth wire which brought it up to 9.5v. Is there an intentional reduced voltage feed to the headlamps or is it just a result of 39 year old wiring?

Simon

[jleyton]

Hi Simon,

Welcome to the Forum and to Stag ownership, which I hope you'll find as infectious as almost all of us do

As for your wiring, the lights are 12v and so that drop can only be due to the wiring or the switches etc. I guess age catches up on all of us

The only things I can think of in the Stag that don't run on 12v are the coil (with a ballast resistor in line) and the instruments with their 10v voltage stabiliser. I reckon simplicity is one of the many beauties of an old car compared to today's with their multiplex wiring and computerised systems.

Cheers

Julian

[KOY 23]

Welcome to the forum.
The headlamps should get full battery voltage. I would replace all the bullet connector sleeves and clean up the bullets in the supply and earth. Also worth checking the fuse connectors and replacing the fuses as they often have poor internal connections.
John.

[richardthestag]

The only things I can think of in the Stag that don't run on 12v are the coil (with a ballast resistor in line) and the instruments with their 10v voltage stabiliser.

And the rear lights if you have a night dimming relay fitted to you mk1 stag. My Mk2 1973 export model had one fitted and was hastily bypassed.

Welcome also to Simon

[djw113uk]

re: uprated lights

If the car is for daily use - including winter then I reccomend upgrading to HID lamps. They use far less power, but are MUCH brighter. There is an SOC member who sells them too, rather than risking ebay!

I fitted 2 dip and two main, and even compared to my modern car the stag has the best lights of the lot

David

[Classic49]

Thank you all for the warm welcome and the guidance. I suspected poor connections would be the case but the prospect of working my way through the wiring system didn't appeal too much.

[Arbman Al]

Hi Welcome to the forum

Your battery voltage looks to be bit on the low side at 11.7v
I would check this as well.

As for HID headlights, you may have trouble getting hold of the seller as he is a bit koy.

Cheers....Al

[KOY 23]

Hi Welcome to the forum

Your battery voltage looks to be bit on the low side at 11.7v
I would check this as well.

As for HID headlights, you may have trouble getting hold of the seller as he is a bit koy.

Cheers....Al

......... and if you need your trees doctored speak to ........Al

[DJT]

Hi, and welcome. If your existing lights are showing signs of old age then I can recommend H4 type lights and a relay kit as sold by EJ Ward. You get 4 lights on dip and main beam (perfectly legal) and the kit improves the voltage too. The result is excellent lights which are comparable to, or better than many modern cars.

[V Mad]

The reading of 11.7 volts is extremely low for a battery. This should read over 13 volts so it needs investigating.

The drop in voltage to the headlights is also unacceptable. No pint in fitting uprated lights until that is resovled. The bullet connectors behind the front valance is usually the main culprit; pull apart the connectors, then fit new female connector parts; clean the male (bullet) ends with wire wool or a dremel wire brush until all corrosion is removed. This should fix the problem. Get elec. parts from Vehicle Wiring Products (VWP).

[KOY 23]

Dave.
Do you find that you get flashed because oncoming drivers see 4 lights and assume that you are on main beam? 4 H4 halogens will draw around 18A, compared with 2 H4 HID's taking 7.5A and still giving more light. But Wards will also sell you an uprated alternator.
It's good to have choices.

John.

[DJT]

Dave.
Do you find that you get flashed because oncoming drivers see 4 lights and assume that you are on main beam? 4 H4 halogens will draw around 18A, compared with 2 H4 HID's taking 7.5A and still giving more light. But Wards will also sell you an uprated alternator.
It's good to have choices.

John.

Not had that problem yet John. I did make sure that all 4 headlights were aligned using my local garage's MOT beam tester, so they don't dazzle. You are correct about the benfits of HID lights, but as my car already had 4 virtually new H4 lights, this was the most cost-effective way to go. I have found that the lights are now far superior to other Stag headlights and when on main-beam light up the road very well indeed.

[Peter]

Simon,

Welcome to thirty year old electrics!!! I would address the battery voltage first, this should be 13.2 volts fully charged, you need to start from a sound base. If the battery is OK make sure the altenator belt isn't loose and the charging system is working. Are the lights dim at idle and get brighter when you rev the engine? Do you get a higher voltage at the lights with the engine running? Checking the fuses is a good idea, alsw work the switch on an off a few times (may clean the contacts for you).

Remember this sort of issue is what makes a classsic "interesting"!!!

Peter

[Classic49]

The reading of 11.7 volts is extremely low for a battery. This should read over 13 volts so it needs investigating.

The drop in voltage to the headlights is also unacceptable. No pint in fitting uprated lights until that is resovled. The bullet connectors behind the front valance is usually the main culprit; pull apart the connectors, then fit new female connector parts; clean the male (bullet) ends with wire wool or a dremel wire brush until all corrosion is removed. This should fix the problem. Get elec. parts from Vehicle Wiring Products (VWP).

Thanks Chris. I've added it to my ever extending to-do list, lol.

[Classic49]

Simon,

Welcome to thirty year old electrics!!! I would address the battery voltage first, this should be 13.2 volts fully charged, you need to start from a sound base. If the battery is OK make sure the altenator belt isn't loose and the charging system is working. Are the lights dim at idle and get brighter when you rev the engine? Do you get a higher voltage at the lights with the engine running? Checking the fuses is a good idea, alsw work the switch on an off a few times (may clean the contacts for you).

Remember this sort of issue is what makes a classsic "interesting"!!!

Peter

Thanks, will check this out, I had been checking out the lights without the engine running, so the drop might be reasonable. When running the Volt meter looks healthy so I think the alternator is probably ok. All fuses check out ok so will systematically work back. As said elsewhere, I need to get full voltage at the lights before considering an upgrade.