5KTQ Headlight Wiring

[Livolsi, Stephane]

I understand what you are saying but a while ago, hunting down an electrical
gremlin I put my multimeter to some of the fuses and I got 12V..dead on,
while the car was running.  This leads me to believe that somewhere between
the battery and the fuse block is a 'decent' voltage regulator which knocks
the voltage down while the engine is running.  Once the engine is shut off,
you would only have 12V because it's coming from the battery only, and not
the alternator.  Like I said before, I am not sure about all this but it's
what appears to be correct from my experience.


Stephane

> ----------
> From: 	Ameer Antar[SMTP:ameer at snet.net]
> Sent: 	November 6, 2000 11:33 AM
> To: 	Livolsi, Stephane; Audi Quattro List
> Cc: 	bullitt at cybertours.com
> Subject: 	RE: 5KTQ Headlight Wiring
> 
> I thought about that too, but the battery, and even the rest of the 12V 
> wires in the car should be at 13.8V as well. You get 14.4V w/ no load, but
> 
> as long as the battery [batt. has internal resistance] and the car's load 
> is attached, that voltage goes down under that load. The regulator in the 
> alt. is a simple diode circuit and does change under load. The only way
> for 
> the batt. to be lower voltage than the alt. is for a large resistance 
> between the two. Since there's a 4 or 8 ga wire between them, and not a 
> resistance wire, the voltages are about the same. You have to remember
> that 
> the whole car has a poor regulation system. It can go from 11V-14.4V [most
> 
> car amp manuf's spec 11-14V].
> 
> With the stock setup and their thin wires, I once measured 10V across my 
> high beams. So there was a 2-3V drop from system voltage, but that's b/c 
> they used 20 ga. wire. By using thick gage wire and hooking to a direct 
> source, you give the bulbs the full power from the car. But even if you
> ran 
> a fat wire from the batt. directly to the new bulb circuits, it'd be the 
> same as getting power from the alt, since they are connected w/ a fat
> wire.
> 
> In any case, I think the stock bulbs last longer than they were designed 
> to, since they run under lower voltage. But the relay setup gives the full
> 
> voltage, which is part of the performance increase, which may cause the 
> bulbs to live shorter than stock lives. But I bet they still meet there 
> life expectancy. I bought decent H4 bulbs, and they've been fine now for 
> several months.
> 
> One thing about using the stock bulb connector is that it's different than
> 
> the H4 setup. If you wire it exactly the same way, you will constantly run
> 
> both high and low beams [that is for 2-filament bulbs]. The difference is 
> just switching a ground w/ one of the other wires. They sell H4-to-sealed 
> beam adaptors, but there's no need, since you'll be using relays and
> wiring 
> it yourself. You can find lot's of info here: 
> http://catalog.com/susq/other/headlamp.htm
> 
> an multimeter will help too. good luck.
> 
> -ameer
> 
> -ameer
> 
> At 01:13 PM 11/6/00, Livolsi, Stephane wrote:
> >I am not quite positive on the details but this might lead to shorter
> bulb
> >life.  I imagine the headlamps are rated 12V but if you get the power
> from
> >the alternator you will be getting more than that, all the time (isn't it
> >13.5 or 14 V output at the alternator?)  I think the underhood battery
> >terminal is also unregulated, isn't it?
> >
> >
> >Stephane
> > > ----------
> > > From:         Ameer Antar[SMTP:ameer at snet.net]
> > > Sent:         November 6, 2000 9:16 AM
> > > To:   Jack Gagnon
> > > Cc:   quattro at audifans.com
> > > Subject:      Re: 5ktq Headlight Wiring
> > >
> > > At 06:28 AM 11/6/00, you wrote:
> > > >I just converted my 87 5ktq to the older quad headlight set-up in an
> > > attempt
> > > >to get decent lighting.
> > > >
> > > >I temporarily put in some over the shelf Sylvania cool blues that are
> > > much
> > > >better than the stock aero lights, but I am going to get some Hella
> H4's
> > > >with 50/100 bulbs.
> > > >
> > > >Does anyone know if I need to install relays and heavier wire for
> this
> > > >combo?  I would assume so.  I think I need new plugs also since the
> Audi
> > > >ones are pretty wimpy.
> > >
> > > I also upgraded my quad lights, but as long as the wires for the plugs
> are
> > >
> > > short, you'll be ok. In truth current capacity doesn't only depend on
> wire
> > >
> > > gage, length is just as important. A 20 gage wire can handle maybe
> 100A if
> > >
> > > it's a foot long, but after 10ft, it cannot handle much more than a
> few
> > > amps. So keep the plug wires short, and splice them into 16-14 ga.
> wire to
> > >
> > > connect to the relays.
> > >
> > >
> > > >I was thinking that I could tap the jump start wire located near the
> air
> > > box
> > > >and use the existing headlight wiring to activate the relay.
> > > >
> > > >Does anyone have a recommended setup for this?  I need to know where
> to
> > > get
> > > >the relays, how many are needed, wire size and where to buy the
> plugs.
> > >
> > >
> > > I actually got power for the lights directly from the alternator w/ an
> > > inline fuse. Either way is fine, but it was just easier for me, cuz
> all I
> > > needed was a ring term. to connect to the alt. output post. I used 4
> > > relays...one for each bulb. It's not necessary unless you use high
> power
> > > bulbs, b/c the left and right headlights always need to be on at the
> same
> > > time. But if you use 2 bulbs on one relay, it must be able to handle
> the
> > > bulb current *2 which could be ~20A for 2 100W bulbs.
> > >
> > > I think the key to good lighting is a good lens w/ a decent pattern,
> and
> > > decent bulbs. Hella is a decent choice for both bulb and lens. High
> > > wattage
> > > bulbs offer more light, but aren't really necessary if you have a good
> > > pattern. good luck.
> > >
> > > -ameer
> > >
>