Headlight Loom Upgrade

[California Dreamin]

As I mentioned in an earlier reply...this loom has only two H4 female bulb connectors so wouldn't fit a 4 lamp version. I suppose it could be modified but then the wiring would need uprating as well to cope with 'double' the amperage on full beam (4 lamp versions bring on all four lights on full beam so 240 watts/20 amps)

Martin

[Sir Brixalot]

Thanks for clearing that up. I initially thought your reservation were load related. I can see now that there are not enough connectors which rules it out for me. The bulb upgrade will have to do for now it is a vast improvement already although a bit more light on dip would have been good.

[lloydy]

Do you really need to run all those extra cables? I (and many others) just fitted the relays like this link
http://www.thesamba.com/vw/forum/viewto ... ay+upgrade" onclick="window.open(this.href);return false;
takes hardly any time at all and works very well

[California Dreamin]

But uses tired old crusty and over populated earth crowns. Tired old barely adequate feed wires to the bulbs themselves....other than than

Martin

[lloydy]

I've got no complaints with the light output of my lights? i suppose if you have bad wiring anyway you should look at fixing that. The existing wiring going to the lights is more than man enough. wasn't trying to poo poo the way your doing it, just that there is another way that is simple and works.

[California Dreamin]

I've got no complaints with the light output of my lights? i suppose if you have bad wiring anyway you should look at fixing that. The existing wiring going to the lights is more than man enough. wasn't trying to poo poo the way your doing it, just that there is another way that is simple and works.

Absolutely.....the message here is get it done whichever way..

The link you posted is the simplest method, its neat and will improve things without a doubt.
The method in the WIKI is more complicated and will put many off, however, it does eliminate long earth return runs to the crowns and replaces and uprates all the wiring right to the bulbs. Necessary or not, this all but eliminates voltage drop, which if you hadn't already realized, is the main aim of this upgrade.
Voltage drop is the enemy and the drop in light output is not linear, it is exponential

QUOTE
The Europeans consider output at 13.2v to be 100%, When operating voltage drops to 95 percent (12.54v), headlamp bulbs produce only 83 percent of their rated light output. When voltage drops to 90 percent (11.88v), bulb output is only 67 percent of what it should be. And when voltage drops to 85 percent (11.22v), bulb output is a paltry 53 percent of normal!

My advice would be to check it out for yourselves with a lamp detached but connected: Run the engine, turn on your lights (full beam) on the 20 volt DC scale, measure across the starter battery recording your results. Now do the same test at the lamp (full beam feed, directly on the inner halogen bulb and clean chassis) what was the difference? Voltage drop.

Martin

[CovKid]

I still can't help feeling that if the relays are to help counteract the voltage drop between battery and dash, it makes sense to upgrade the feed to start with. I did this on mine, running a chunkier cable to the front which terminates in a terminal block. From there I can supply voltage where its needed with (I would have thought) less chance of any drop. I'm not saying the relays are not needed (any reduction in load on switches is a good thing) but it does help if you have a good cable to start with. Certainly on mine, there was evidence of connectors at the fusebox that had got warm in the past and if you look at most modern vehicles they have fuseboxes that specifically apply to the circuits they're meant to handle. Its not uncommon to find a main fusebox for all the heavy stuff. Then another for headlights, fans etc, and another for low-draw stuff. You just get the one on the T25.

The T25 wiring was designed for minimal accessories and clearly most of us run more items than the existing fusebox was designed for. Plus most of the connectors are spade terminals which are notorious for becoming resistive through corrosion, not unlike that found at the earth crown. Screw type ring terminals seem to fare better in my experience. I keep meaning to replace the earth crown with something more substantial.

[scottbott]

what about these people https://sites.google.com/site/vanagonhe ... elays/home" onclick="window.open(this.href);return false;, andhttp://www.headlightplugs.com/" onclick="window.open(this.href);return false;

[California Dreamin]

I still can't help feeling that if the relays are to help counteract the voltage drop between battery and dash, it makes sense to upgrade the feed to start with. I did this on mine, running a chunkier cable to the front which terminates in a terminal block. From there I can supply voltage where its needed with (I would have thought) less chance of any drop. I'm not saying the relays are not needed (any reduction in load on switches is a good thing) but it does help if you have a good cable to start with. Certainly on mine, there was evidence of connectors at the fusebox that had got warm in the past and if you look at most modern vehicles they have fuseboxes that specifically apply to the circuits they're meant to handle. Its not uncommon to find a main fusebox for all the heavy stuff. Then another for headlights, fans etc, and another for low-draw stuff. You just get the one on the T25.

The T25 wiring was designed for minimal accessories and clearly most of us run more items than the existing fusebox was designed for. Plus most of the connectors are spade terminals which are notorious for becoming resistive through corrosion, not unlike that found at the earth crown. Screw type ring terminals seem to fare better in my experience. I keep meaning to replace the earth crown with something more substantial.

The WIKI diagram takes two feeds 'directly' off the starter positive battery terminal (petrol models/front mounted battery) Diesels could use the leisure battery as long as the split changing circuit is heavy enough.

Martin

[Sir Brixalot]

I did like the accessibility of the Samba Thread, the step by step photographic demonstration is much easier for me to understand than the wiring diagrams and debates on here for the twin upgrade

[scottbott]

I agree easier for me to follow as well,my mind glazes over when I see a big complicated wiring diagram

[lloydy]

Scott, that link is a relay kit for the way in the samba link. He does good stuff.

[ghost123uk]

Re the "full" upgrade =

Necessary or not, this all but eliminates voltage drop, which if you hadn't already realized, is the main aim of this upgrade.
Voltage drop is the enemy and the drop in light output is not linear, it is exponential

QUOTE
The Europeans consider output at 13.2v to be 100%, When operating voltage drops to 95 percent (12.54v), headlamp bulbs produce only 83 percent of their rated light output. When voltage drops to 90 percent (11.88v), bulb output is only 67 percent of what it should be. And when voltage drops to 85 percent (11.22v), bulb output is a paltry 53 percent of normal!

My advice would be to check it out for yourselves with a lamp detached but connected: Run the engine, turn on your lights (full beam) on the 20 volt DC scale, measure across the starter battery recording your results. Now do the same test at the lamp (full beam feed, directly on the inner halogen bulb and clean chassis) what was the difference? Voltage drop.

Martin

Definitely worth doing that test !

I have just been "playing" at discovering voltage drops and despite my penchant for doing wiring properly, and noting that all my wires and connectors, old and new, are heavy duty and in good nick, I was a bit surprised at the results (posted here)

Not a problem here, after all, electricals is my best subject, but thought it worth posting my findings.

Voltage at the alternator output with no load (except the ignition circuit) = 14.1 Volts (new(ish) 14 Volt regulator/brush pack)
Voltage at the starter battery (under same load conditions) = 13.8 Volts.
Voltage into the split charge relay = 13.7 Volts.
Voltage out of the split charge relay = 13.6 Volts.
Voltage at the leisure battery = 13.3 Volts
Voltage at input to fuse panel = 12.9 Volts

As I say, no real problem here, it just shows how every bit of wire and every connection degrades the performance of the circuit (this is well known in Amateur radio circles regarding aerial connectors). I intend to fit a separate feed from the alternator to the split charge relay, and likely swap the relay for a better one, to get a better charge to the leisure battery.

Good job I have the headlight relay conversion, feeding off the starter battery live terminal, goodness knows how low it would drop at the lamps without it )

Yup, voltage drop can be quite an issue for both headlights and leisure batteries (and powerful "ICE" installs too)

[Tinium]

Fitted the Paddocks loom over the weekend - it's almost as if they had the T25 in mind, was pretty much inch-perfect (or, at least it was the way I did it!).

Took about an hour, most of which was trying to work out the best way to route the +ve supply from the battery to the front. In the end, I settled for putting the relays just below the drivers side headlamp (as these are at the light end, rather than the battery end of things), running the +ve wire down to the horn (near the drivers feet on my van), then across to and back along the radiator pipes, then up into the battery compartment (under the drivers seat) using existing grommets. There's an earth connector for each lamp, so simply put these under the screws holding the lamp mounting frames in place, and that gave a good earth.

Impressions from driving home on Sunday (I've also fitted Osram +100% bulbs) was that the light is finally the nice white light you see on all those strange modern cars = Far more relaxing to drive. The dip was the best improvement, now has a definite cut-off on the horizon, picking up cat's eyes and street signs for a good distance beyond that, and was far nicer for the 3 hours in rush hour traffic on the M5. Full beam was previously not too bad, but now gives far greater range. Lovely.

The only thing I'd possibly change is that the supplied fuse is at the relay end of the +ve wire - So I'll probably add another in the battery compartment just to be sure that nothing goes too badly wrong if the wire gets nicked for whatever reason between the battery and the lights.

But for £30 (and £12 for the bulbs on Amazon) a good investment for the winter I think

[ghost123uk]