Thread: Headlight Wiring Upgrade Kits

I have no business affiliation with Drivesafe or Traxide...... just a very satisfied customer.

6 months ago I fitted one of these kits - anyone considering it may want to read this thread - including before and after pics:

http://www.aulro.com/afvb/showthread...ight=headlight

Money really well spent I'd say....

Thanks again Tim.

Mark

I ordered a combo kit of Tim a few days ago so look forward to fitting it and the IPF's i scored off an AULRO forumite, should make my night drive to Adelaide next week a bit brighter - i just hope it arrives in time.

Just out of interest, on a Defender, can you take the power feed from the alternator to save running back to the seat box with the power wires?

My thinking is while the engine is running, you'll get full alternator voltage (I'm fittign HID's as well), and when off, you should still get battery voltage over the alternator charge cable for things like dim-dip (Assuming 1994 Aus cars have that, as I've never bothered checking!)

Originally Posted by jik22

Just out of interest, on a Defender, can you take the power feed from the alternator to save running back to the seat box with the power wires?

My thinking is while the engine is running, you'll get full alternator voltage (I'm fittign HID's as well), and when off, you should still get battery voltage over the alternator charge cable for things like dim-dip (Assuming 1994 Aus cars have that, as I've never bothered checking!)

I've always been told that this is not a good idea Jeff. While you will get the voltage at the alternator (output is usually around 14V) it's the amperage that you want to power lights. I'm not really sure of the exact reasoning, but ab auto sparky told me that it is always better to power accessories directly from the battery. I'm running HID's (Hella Predators) on the Disco and about to install a Hi/Lo HID conversion kit in the headlights, and taking all power sources from the battery. Admittedly, this is easy in the Disco with the battery sitting just behind the right headlight.

Originally Posted by BMKal

I've always been told that this is not a good idea Jeff. While you will get the voltage at the alternator (output is usually around 14V) it's the amperage that you want to power lights. I'm not really sure of the exact reasoning, but ab auto sparky told me that it is always better to power accessories directly from the battery. I'm running HID's (Hella Predators) on the Disco and about to install a Hi/Lo HID conversion kit in the headlights, and taking all power sources from the battery. Admittedly, this is easy in the Disco with the battery sitting just behind the right headlight.

The alternator provides all the current you use while the engine is running anyway, so your reasoning does not make sense. Your sparky was talking about the advantage of not overloading existing wiring, but in fact for accessories that are normally run only when the engine is running, such as headlights, since the current they use comes from the alternator, it is better to have the current taking the shortest route (and hence minimum voltage drop) direct from the alternator rather than from the alternator at the front of the vehicle then back to the battery and forward again to the headlights next to the alternator.
For the Disco with the battery at the front there will be no significant difference, but for a Defender with the battery under the seat the difference in voltage will make a significant improvement to the brightness of the Q-H lights, although I doubt it will make any difference to the HID lights, as I suspect they are designed to give the same light output regardless of voltage (within reason).
In any well designed electrical system, however, the wiring size will be large enough and the connector quality good enough that the difference will be minimal, and probably undetectable - but using the term "well designed" for anything from Joseph Lucas is a bit shaky to say the least.

John

I don’t know the exact reason for not sourcing power for the headlights at the alternator but when you consider that auto makers will do just about anything to save money yet even though many in many vehicles, the distance from headlights to the alternator is shorter than the distance to the battery, I only know of one specific vehicle that has come out with the power for the headlights being sourced at the alternator.

Back in the 80s, VW golfs started coming out with the headlights being power from the alternator. This only happened for a short while and VW went back to powering them from the battery.

This is just a guess but as the battery also acts as a big spike suppressor, having everything come of the battery, allows the battery to give the alternator some protection.

Cheers.

Originally Posted by drivesafe

I don’t know the exact reason for not sourcing power for the headlights at the alternator but when you consider that auto makers will do just about anything to save money yet even though many in many vehicles, the distance from headlights to the alternator is shorter than the distance to the battery, I only know of one specific vehicle that has come out with the power for the headlights being sourced at the alternator.

Back in the 80s, VW golfs started coming out with the headlights being power from the alternator. This only happened for a short while and VW went back to powering them from the battery.

This is just a guess but as the battery also acts as a big spike suppressor, having everything come of the battery, allows the battery to give the alternator some protection.

Cheers.

The battery acts as just an efficient spike suppressor via the alternator - battery wiring, which has negligible inductance. I would also point out that in the 110, and I suspect the Defender, although I have never checked, the only lead to the battery is from the starter solenoid, and all other power is taken from there - which is actually closer to the alternator than it is to the battery, although probably about the same as the wire goes.

I suspect the main reason why headlight wiring goes from a more central point such as the starter rather than the alternator is simply for ease of design and assembly.

John

I suspect that the major reason

Last time you had this conversation, drivesafe and JDNSW, (about 12 months ago?) I went to the trouble of doing a circuit diagram. Everything is still in the loop - alternator, battery, lights - whether you wire from the alternator or from the battery. It's just which end of the alternator-battery wire (or in the middle?) that you attach to.

If there was an issue with what was "nearest" to the current draw, surely it would be the negative side of the circuit that should be considered, being the electron donor?