Electrical Wire Guage Sizes, and Lights

[keithwwalker]

What is a typical guage wire to use for headlights?

I am talking the power end, not the leads for the relays.

On a side note, I noticed that some companies in Europe use wire diameter in millimeters, mm, instead of guage.

Does anyone have an equivalence chart handy?

Thanks
Keith Walker

[Will]

14ga or less is probably what you want, I'd personally go 12ga.

A 55W headlight draws about 4-1/2A@12.x V, Assuming you have two of them on the same circuit then you are drawing just shy of 9A at typical battery voltage.

Assuming 2 percent loss is acceptable, then you can get 5' of run out of 14ga or 8' of run out of 12ga.

I'd opt on the bigger side, but there is no need to drop to something crazy like 4ga.

IMO the secret to brightrer lights is twofold. First, getting a clean 12v to the bulb, which usually requires a relay. Second is to use a high color temperature halogen bulb (like the Phillips or Sylvania Super White Halogen) . Note that I'm not talking about blue, ricer wannabe HID or any other such thing, just a bright, clean 55w Halogen.

And IMO add a fusible link because when you start dealing with larger wires, they can explode your battery if they short out, rather than just smoking up the wire.

As far as a chart goes, there are a lot of variables (like the number of wire strands, etc) but you can get started with this.

http://www.mrsolar.com/Merchant2/merchant.mvc?Store_Code=MSOS&Screen=faq11

[Scott H]

A 55W headlight draws about 4-1/2A@12.x V, Assuming you have two of them on the same circuit then you are drawing just shy of 9A at typical battery voltage.

Will,
Your theory is right but the practicality isn't. It is best to keep the wiring separate for the 2 lights. Make the split in the circuit at the relay itself. Otherwise you make a mid-harness connection which is inherantly prone to failure and adds additional connection points. Make a single circuit of 14 ga to the relay. Then take 2 - 16 ga out to each light from the relay.

Also, you can not calculate amperage from the wattage of an incandescant bulb. The startup current is higher until the element reaches its operating temp.



IMO the secret to brightrer lights is twofold. First, getting a clean 12v to the bulb, which usually requires a relay.

Incandescent lights don't give a shit how clean the voltage is.



And IMO add a fusible link because when you start dealing with larger wires, they can explode your battery if they short out, rather than just smoking up the wire.

A fuse link is typically for protection above 30 amps. You will be burning a lot of wiring, connectors, etc. long before the link lets go. It is usually recomended to go about 25% above the steady state current load for fuse size. Use a 15a fuse on the supply to the relay.


As far as a chart goes, there are a lot of variables (like the number of wire strands, etc) but you can get started with this.

*Gage* is not a rating of the diameter of the wire. It is the cross section of the conductor material. A 16 ga solid wire caries just as much current as a 16 ga multistrand wire.

The multi strand wire gives flexibility. The more strands, the more flexibility. The diameter of the individual strands is critical. It is really hard to find good quality, high strand count, large gage wire. Also, the larger wire will be subject to greater movement because of the mass of the wire. That is why I like to use the smallest wire possible.

Carry on Will :)

Scott

[Will]

Scott;
With all due respect:

a) Whether you split before or after the relay(s) unless you are making two home runs to the battery you will be drawing amperage for both lights through the same wire. So yes, you need to size the wire for the combined load(s).

b) "Incandescent bulbs don't give a shit how clean the voltage is". Yeah, well I do because I don't like my lights dimming if I decide to, say, turn on the heater or something. Try turning your wipers on and watch your lights. Personally, I'd rather draw from a clean (battery or major i.e. cutoff switch) source rather than taking my light supply wire off of some other circuit that's got other stuff on it and is going to be subject to intermittant voltage drops. To a lesser extent, even electrical noise like ignition noise will marginally affect an incandescent lamp's efficiency.
In your own post, you wrote that they draw more when they are turned on because the element is heating. While this is a fraction of a second and DOES NOT affect the wire size needed, if you have a very electrically noisy circuit, the fluctuating voltage will cause more of the energy to be produced in the infrared (heat) spectrum rather than visible light. This is not a significant factor, I'm only mentioning it for semantics.

c) I use a 20A fuse link for my lights, but even if you use a 30A fuse link you are probably quite safe from blowing up the battery. I'm quite aware that wire size is not a rating for it's current per se, but combined with the wire length and composition, you get the wire's resistance. This determines how much current it can pass.
Even relatively small wires can carry pretty significant transient currents before they burn up. A fusible link ensures that this number cannot exceed what can safely be delivered by the battery. It's not designed to protect your low-current wires at the lights. It's designed to keep you from accidentally turning your battery posts to slag. BTDT with a fresh battery once and you don't want to try it. A fuse at the relay is another option and I'd also recommend that, but at any rate you should have something between the battery and the relay- preferably AT the battery if possible.If this is the Scott H I know, I'm surprised you'd advise AGAINST a fusible link and also that.....

d) Apparently you are unaware of this(?), but electrons travel on the outside of the wire, along the surface. Yep, that's right. What this means is, that a stranded wire has a lower resistance and can pass current more easliy with less heat loss than a solid wire. And yes, stranded wire does flex more easily and with a greater number of cycles before fatigue failure, but practically any wire you find in an automotive application will be stranded with a few rare exceptions like some thermocouple wires, etc.
There are numerous places you can confirm this if you don't believe me, or if you simply refuse to accept it then that's your prerogative.
Regarding number of strands, more is better- but only up to a point. I like to solder my connector ends and very small strands make it a little tough to get a good sloder flow since the heat conducts away from the joint so fast. The result is that even with a 100w gun, by the time you get the business end of the wire hot enough the PVC jacket is starting to look like it wants to crawl up the wire. Unless you want to strip back 3/8" or more and then use a heat sink clamp, it's easier to stick with conventional automotive stranded wire, commonly referred to as "primary" wire. The upgraded version of this has a "crosslinked" jacket and moderately higher temperature rating and chemical resistance. It also apparently does not like to be marked with ball point pen, which I find acutely annoying.

At least, IMO.

[Wallace]

Just to stick my oar in - on the serries two euro monte, all the car's juice (except the starter) goes through just one cable and a rather nasty connector underneath the fuse box . . .and the connector gets hot when passing current, looses any spring tension it had, gets even hotter and melts the holder . . .

The cure ? divide the two fuse box into two seperate circuits (easy to do - there's a linking wire between them) and feed from two seperate feeds from the alternator. you can then use a copule of better connectors as well.

[bjmarsh]

Will Wrote:
Apparently you are unaware of this(?), but electrons travel on the outside of the wire, ....There are numerous places you can confirm this if you don't believe me

Not entirely accurate, you are probably thinking of the "skin effect" where current flow occurs on the outer boundry (skin) of the conductor. This is an AC (alternating current) phenomena. For low frequencies the skin effect is negligible. At DC (direct current) the distribution of current across the conductor is essentially uniform. This is a minor issue at power line frequency (60HZ) but very signifcant at microwave frequencies.

Barry

[Will]

Not entirely accurate, you are probably thinking of the "skin effect" where current flow occurs on the outer boundry (skin) Barry

Ok, not exactly what I was taught, but since this is an automotive forum rather than a physics or electronics forum, let's simplify:

IS THERE ANY reason to NOT use commercially available primary wire? Yes, I know you could use other stuff- in fact, I've temped stuff on my car in THHN just because I've got a few hundred feet laying about at any given time, and I have to get primary wire on dinky spools at the auto parts store, so I haven't always got a bunch around.

But why not use Primary wire? Why not fuse (or fusible link) at the battery? Why not use a dedicated circuit that does not pass through the ignition?


If anybody doesn't want to follow this way, don't- and I'll go do something more productive. My lights are bright as hell anyway, I was just trying to help the next guy get to where I was. The water is here in the trough, his option.

:)

[DJ]

Uuuhh, Will.

I suppose you already know that you're lecturing an Electrical Enginer, eh?

Just in case you didn't know. All I know is how to keep from getting myself shocked (most of the time. 8O

Cheers,

DJ

[keithwwalker]

Thanks for the advice Will, most of it confirms what I have been reading on the web.

This is somewhat related to my Lancia Ypsilon headlights (just managed to track down the proper tyco/amp connecters), and also to the fact that I am currently designing a headlight/electrical system for a supermotard street legal bike.

All theory aside, guess the best way to go for myself, is to go with 12ga wire, a SPST relay (for the car - a SPST relay with a double output, so both lights will be lighted by one relay), a separate relay for the high beams.

The fusible link is one that I haven't thought of but will incorporate, though I once was riding in a Camaro in Lake George NY and the fusible link blew, killing the entire car and leaving us all stranded and wondering what the hell happened!

Keith Walker

Postscript, my Scorpion lights are a Euro H-4 conversion. The light output and pattern is awesome! They are relayed, but I can tell that the PO tried to go without relays as evidenced by the mass of melted insulation underneath the steering column!

some useful links I have run across:
Hella, good relay catalog:
http://www.hella.com/produktion/HellaPortal/WebSite/Internet_usa/ProductsServices/PDF/ElecProd1.pdf

Parallel Battery Cable:
http://order.waytekwire.com/IMAGES/M37/catalog/218_005.PDF
I forget whether the Monte/Scorp runs both cables to the engine compartment for the starter, or whether there is a grounding strap back there???


14ga or less is probably what you want, I'd personally go 12ga.

A 55W headlight draws about 4-1/2A@12.x V, Assuming you have two of them on the same circuit then you are drawing just shy of 9A at typical battery voltage.

Assuming 2 percent loss is acceptable, then you can get 5' of run out of 14ga or 8' of run out of 12ga.

I'd opt on the bigger side, but there is no need to drop to something crazy like 4ga.

IMO the secret to brightrer lights is twofold. First, getting a clean 12v to the bulb, which usually requires a relay. Second is to use a high color temperature halogen bulb (like the Phillips or Sylvania Super White Halogen) . Note that I'm not talking about blue, ricer wannabe HID or any other such thing, just a bright, clean 55w Halogen.

And IMO add a fusible link because when you start dealing with larger wires, they can explode your battery if they short out, rather than just smoking up the wire.

As far as a chart goes, there are a lot of variables (like the number of wire strands, etc) but you can get started with this.

http://www.mrsolar.com/Merchant2/merchant.mvc?Store_Code=MSOS&Screen=faq11

[Will]

The fusible link is one that I haven't thought of but will incorporate, though I once was riding in a Camaro in Lake George NY and the fusible link blew, killing the entire car and leaving us all stranded and wondering what the hell happened!

So then use a fuse, but by all means use SOMETHING! The fusible link is the same thing as a fuse, it's just sealed up better than the so-called "waterproof" inline fuse holders. I find that over time, the inline fuse holders can get rather cruddy, although I'm sure somebody's got to make a good, reliable one somewhere. I reckon you could grease pack it too, there's some special schmutz that's made for LV lights that I have, but regular old grease or white lithium might work just as well. I'll let one of the engineers fill ya in on that one.

[keithwwalker]

Here's a good sealed weather resistant fuse housing for something 'under the hood' (closer to the lights and battery) as opposed to in dash:

http://order.waytekwire.com/IMAGES/M37/catalog/218_062.PDF
http://order.waytekwire.com/CGI-BIN/LANSAWEB?WEBEVENT+L0A06702C87C48000B2DA061+M37+ENG

It comes with 12ga. leads.

The minimum order is 4, but that's $7. Small price to pay for doing it right.

Waytek has a good free catalog which is also downloadable page by page on the site.

KWW

ps:
another weathertight assy, uses up to 3 'mini' fuses, conductors up to 10ga., or you can put in mini type circuit breakers - internet shopping is fun!:
http://order.waytekwire.com/IMAGES/M37/catalog/218_032.pdf



So then use a fuse, but by all means use SOMETHING! The fusible link is the same thing as a fuse, it's just sealed up better than the so-called "waterproof" inline fuse holders. I find that over time, the inline fuse holders can get rather cruddy, although I'm sure somebody's got to make a good, reliable one somewhere. I reckon you could grease pack it too, there's some special schmutz that's made for LV lights that I have, but regular old grease or white lithium might work just as well. I'll let one of the engineers fill ya in on that one.

[Scott H]

a) Whether you split before or after the relay(s) unless you are making two home runs to the battery you will be drawing amperage for both lights through the same wire. So yes, you need to size the wire for the combined load(s) .

Will, the whole idea is to use as small a wire as possible with as few connections/components as feasible. Then make those connections at a place where it is durable. If you split before the relay, then there are 2 relays. Use 2 small wires directly from relay is all that was said.


b) "Incandescent bulbs don't give a shit how clean the voltage is". Yeah, well I do because I don't like my lights dimming if I decide to, say, turn on the heater or something. Try turning your wipers on and watch your lights. .

Noise is static. Noise does not affect an incandescent light. Loosing 3V from high circuit resistance during a large load is not noise. Running lights on 9v will dim your lights, duh. From a practical standpoint, to not wire the headlight through a fused relay powered from the battery would not be smart from a logistics and simplicity point. BUT, the reason is to reduce the resistance to allow it to have the full potential of the electrical system.



In your own post, you wrote that they draw more when they are turned on because the element is heating. While this is a fraction of a second and DOES NOT affect the wire size needed, if you have a very electrically noisy circuit, the fluctuating voltage will cause more of the energy to be produced in the infrared (heat) spectrum rather than visible light. This is not a significant factor, I'm only mentioning it for semantics. .

Ummmm, You have been reading way too much in dim lights :)



c) I use a 20A fuse link for my lights, but even if you use a 30A fuse link you are probably quite safe from blowing up the battery. I'm quite aware that wire size is not a rating for it's current per se, but combined with the wire length and composition, you get the wire's resistance. This determines how much current it can pass.

A fusible link ensures that this number cannot exceed what can safely be delivered by the battery. It's not designed to protect your low-current wires at the lights. It's designed to keep you from accidentally turning your battery posts to slag. BTDT with a fresh battery once and you don't want to try it. A fuse at the relay is another option and I'd also recommend that, but at any rate you should have something between the battery and the relay- preferably AT the battery if possible


I have never seen a 20A fuse link. Fuse links are also very slow. The protection (fuse, fuse link, circuit breaker) needs to be the weak link not the wire. You are wrong there. The idea is to protect everything; wire, relay, connectors, etc. If your wiring can maintain 20A and the fuse 30A. You will have a fire. A fusible link is too big for headlights and what should be the correct wiring for them. FWIW, 30A or for that matter 300A is not going to "blow up" your battery. Batteries get loaded to that level all the time when testing.

BTW, I just rewired my engine. It now has 2 fuselinks. They are great when used in the right method. One goes from the starter to the generator. It is there to protect that wire in case a positive diode in the generator shorts to ground. The main chassis feed was moved from the starter to the generator B+ terminal. This main feed now has its own fuse link too. It is to protect against a short in the main feed wire between the generator and fuse box.


If this is the Scott H I know, I'm surprised you'd advise AGAINST a fusible link and also that.....

Yep it is me :)
I said don't use a fuse link where it doesn't belong. I didn't say to not protect a circuit.

Who luvs ya Prez :o
Scott

[Will]

Will, the whole idea is to use as small a wire as possible with as few connections/components as feasible. Then make those connections at a place where it is durable. If you split before the relay, then there are 2 relays. Use 2 small wires directly from relay is all that was said.

Many relays have two output terminals for this purpose, but I disagree that you always want the least amont of connectors and components. Sometimes, especially in a retrofit application, you can gain simplicity of installation or redundancy of operation by using more components. For example, Chad's retrofit that I have on my car uses FOUR relays because it locates one high/low beam pair in each headlight location, allows the installation to practically just plug into the existing lighting system, has two discrete home runs to the battery and- tada- fusible links.




Noise is static. Noise does not affect an incandescent light. Loosing 3V from high circuit resistance during a large load is not noise. Running lights on 9v will dim your lights, duh.

Scott, Did I write NOISE? No... I did not. Did I intimate that stray radio signals would make your lights dim? No....I did not. I wrote "Clean 12V" i.e from a source that is not subject to voltage drops and fluctuations (insert joke here). You interpreted this to mean "noisy" and then went on to correct me predicated on the basis of your interpretation. I'm fairly certain the original intended recipient of the post would have interpreted a "Clean 12V" source as a major circuit without heavy loads on it, or the battery itself. If not, I'll clarify here: "By the phrase (clean 12V) I mean a 12v source that is not likely to be affected by other transient resistive, capacitive, or inductive loads within the electrical system of the vehicle" OK now?




Ummmm, You have been reading way too much in dim lights :)

No debate point there, guess I'll have to let that one go.






I have never seen a 20A fuse link. Fuse links are also very slow. The protection (fuse, fuse link, circuit breaker) needs to be the weak link not the wire. You are wrong there. The idea is to protect everything; wire, relay, connectors, etc. If your wiring can maintain 20A and the fuse 30A. You will have a fire. A fusible link is too big for headlights and what should be the correct wiring for them.


Ok you start off with an assumption "I've never seen a 20A fuse link, so Will must be referring to a bigger fuse link, even though he wrote other wise" and then you build from there.
Or you could try another approach " Will, I've never seen a 20A fuse link, is that really what you meant? where could I get one?" in which case I'd reply:

# FL-18
18ga. Fusible Link
protects 14ga. or heavier wired systems
$ 2.95

# FL-16
16ga. Fusible Link
protects 12ga. or heavier wired systems
$ 2.95

# FL-14
14ga. Fusible Link
protects 10ga. or heavier wired systems
$ 2.95

# FL-12
12ga. Fusible Link
protects 8ga. or heavier wired systems
$ 3.95




BTW, I just rewired my engine. It now has 2 fuselinks. They are great when used in the right method. One goes from the starter to the generator. It is there to protect that wire in case a positive diode in the generator shorts to ground. The main chassis feed was moved from the starter to the generator B+ terminal. This main feed now has its own fuse link too. It is to protect against a short in the main feed wire between the generator and fuse box.


You'll note I'm not correcting your use of the word "generator" three times in place of the word "alternator". Do you know why? Because AFAIK you may actually have a generator, or electronically controlled hybrid generator/alternator, or some such thing bolted onto that Toyota lump.
Plus, you used it not twice but 3 times, I think it's troll bait, I think you DO probably have a generator :)



Yep it is me :)
I said don't use a fuse link where it doesn't belong. I didn't say to not protect a circuit.

I didn't say to use a fuse link where it doesn't belong either, FWIW. I said to use one AT the battery or inside the confines of the battery compartment if possible, so that an exiting wire will be protected. There's a significant potential for a poorly installed wire (to the relay(s) ) to get pinched, worn, cut, snagged, or otherwise compromised with a resulting short to chassis ground. I'll stand by that statement, but I will concede that a fuse will do the same job provided a) you can find a suitable holder and fuse that doesn't get corroded over time, and b) your fuse is at that location, not downstream at the relay. Otherwise, you aren't protecting the big wire in the system- the one that has the potential to cause the most damage. In "absolute" engineering theory, you should use an appropriately sized fuse each and every time you step down one or more wire sizes. In your split at the relay configuration, you'd need a total of three fuses or fuse links, one at the battery for the 14ga wire, and one on each of the 16ga wires. This violates your "least number of components" rule. Otherwise, you could run the whole system in 14ga wire and eliminate the need for the two additional fuses, but this violoates your "smallest possible wire" rule. Personally, I think the latter is easier and lets you buy just one spool of wire instead of two spools of wire and two additional fuses. Either way is acceptable from an engineering standpoint, but one is just easier.



Who luvs ya Prez :o
Scott

I have a great deal of respect for you, Scott- if you choose not to accord me the same, that's certainly your prerogative. But the "corrections" you made to my post seemed to be predicated on some faulty assumptions regarding your interpretation of what I wrote, with a generally inculpatory tone (as I read it).
In my mind, you haven't made a case for the exclusion of a fusible link, merely that you've never seen an appropriate one. Ditto on the location for said fusible link or fuse protection, which I still believe should be as close to the battery as possible, not downstream at a remote relay.

I'm a little curious as to the statement that "fuse links are also very slow" as I don't really understand what makes it faster or slower. In high voltage applications, I think it's the physical construction of the fuse, I guess in automotive application it would be the fuse material? If so, isn't the speed of the fuse link determined also by what it is made of, and do we know that it's not the same aluminum alloy or whatever that a blade fuse is made out of? I know the fuse links have teflon insulation so they don't smoke up, but I just don't know what the metallurgy of the conductor is.

[Scott H]

Hey Prez
:D

You need to go take a look at the little smileys and the use of the sarcastic "Prez". I find it hard to believe that the king of the Lancia Scorpion code enforcement department has said that *I* am inculpatory. You have personally given more (possibly inculpatory) *opinions* to contradict some people who have some real results and success' with these cars. I give you a little techinical smack down and you come down with a small case of PMS (poor me syndrome :lol: ). Come on Will, where's that tough NY guy I used to bash? Allen is off huffing resins on his boat repair project so I feel you needed some...... umm, corrections.

So, first let's say that this is a hobby and life's way too short to make or take this thing as personal. None intended.

I'll hit the high points that come mind. First, I have never seen that small of a fuse link. I learned something :P . But, I would never use it. Fuse links can't be changed easily on the side of the road. They are slow. That is they are slow to blow. Common circuit protectors are resistors, when they make enough heat, they melt. The link is so long and are made of a different material so that it takes a lot of heat to make them burn through. They do handle quick surges of over current very well because they won't blow fast. Also, I have never seen a specific amp spec for them. When I delt with them last, about 20 years ago, the standard sizing recommendation was to use a link that was a couple (don't remember exact #) wires sizes smaller than the wire being protected. A bit of a SWAG to me.

The comment about reading in dim lights. Ahhh, subtlties on the intarweb. You obviously read a lot. In the statement that I put that under, I took your comment as a theory or book based observation. Not a practical one. I tossed in the dim lights because of the subject. When *I* wrote it, it was funnier than hell!! :twisted:

Ooohhh, now my favorite part. Semantics and context. Will, there are a hundred ways to do most things on a car. Some better, some not. Some are personal choice, some are a culmination of experience, education, etc. Some a balance of needs, wants, budget, and engineering trade offs. When I say it is best to use the minimun number of components, there are reasons I say that. Reliabilty is far and away the most important. Yes, you CAN add other components. It adds complexity and with each added component, quality takes a nose dive down. Since a huge majority of electrical issues arise out of connections, adding connections adds issues. The best guidline goes something like this, "The best design is not when there is nothing left to add, but when there is nothing left to eliminate". Some French engineer said that.

So yes, in this circumstance or that, it may be better to add this connection or to add that relay. When it comes to electrical, each "this" or "that" adds failures. On an Italian car, we have enough already. We were talking specifically headlights. Where I come from, any defect on that circuit is a recall. Don't read anymore into it than that.

Generator. Go out to your car and turn the key on. That big red light on the top-right of the instrument cluster. "GEN" not "ALT". Alright. I did put in that little trap and I have to say I snagged a big one 8) !!

The way I have always been told, Chrysler was the first to use the term "alternator" for their AC generator and they tradmarked it. To this day, the OEMs that I know of use the term generator to describe that part of the car. Think about it, DJ doesn't work at a nuclear alternating station does he? ...and it is AC current they make isn't it.... That being said, I know the aftermerket companies will use "alternator" and even our wiring diagrams refer to alternators. I guess that was a byproduct of some guppy Lancia translator??? It is pretty much in the public domain but the company I work for still calls all of our electrical current-makers, "generators". The hybrid generators only make AC with no internal rectification. (You would like to see the external water cooled inverter on that thing though!).

On another day, I will tell you why a fuse link or their modern replacements are still a good idea for a circuit or two. Until then, keep it very simple.

Scott

[keithwwalker]

Wow - you guys know how to go at it! :twisted:

To keep this discussion on thread, what do you guys think of using a circuit breaker instead of a fusible link or a fuse?

There are self resetting types and manual reset:

http://order.waytekwire.com/CGI-BIN/LANSAWEB?WEBEVENT+L0A2AD12A1CE50600B69A011+M37+ENG

Keith

[Will]

Scott;

The Scorpion uses an alternator, not a generator. I don't have the benefit of years of auto-specific training of a certificate from Toyota, but I do nevertheless know the difference between an alternator and a generator.

Want to know what it is?

A generator is older technology, rectification was done by commutator. They are usually bigger, heavier, and spin slower. Later, diodes were added in a Wheatstone-bridge type arrangement to rectify the output, and the overall size of the package was reduced. Thus, the alternator was born.

Here's a quick list of the other differences:

a)Alternator field and armature windings are transposed vs. a generator. Field rotates on alternator, armature rotates on generator.

b) Brushes carry full load on the generator (this is why you have to clean thre commutator and change brushes on a generator, but not an alternator)

c) Alternators are multi-pole, generators are (almost always) 2-pole.


A generator vs. alternator can also be identified by its voltage regulator, the alternator uses a much simpler design.

Advantages of alternator:
Can work effectively at higher RPM
Higher output at idle
Smaller, lighter, more compact.

[quote="Scott H"]
You have personally given more (possibly inculpatory) *opinions* to contradict some people who have some real results and success' with these cars. [ /quote]

I think that's an unfair statement. I do offer an opinion based on what I know, what can be applied in a logical, problem-solving way and what I believe is a good solution based on my limited experience- isn't that what you do?

"Real results" is funny. Since most of the "real results" guys seem to have their cars up on blocks, I find that's a tough one to quantify.

However, when I do something and suggest "you can do this", I often get a "real results" guy telling me it is impossible. Once I suggested putting a dial indicator down thru the spark plug hole in line with the bore and was told it was impossible because the spark plug hole is at an angle- I really didn't know what to say except "It works when I do it!" Now- when I do it and it goes through no problem, how is the result any less "real?"

You know, I really don't *mind* being corrected if it's supported by logic and practical. But if somebody does correct me, I like to hear a rationale for that reasoning, not something like "I've never seen that so it must not exist" "you can't do it that way because it won't work" or " you must have read that in a book- you should get some 'real world' experience".
The latter is my favorite. it makes me want to reply "Hey, maybe you should pick up a book and RTFM so you can solve your problem yourself, your 'real world' experience is great but if you turn to p127 in the shop manal, it tells you how do do that in five minutes without dropping the motor, Genius!"

Also, I may not have been working on Scorpions for the last 30 years, but I've pretty much qualified in the "real world experience" category as a hobbyist since I've done engine rebuilds, FI conversions, major electrical "reconstruction", brakes, monte lights, etc.- and made all of my own ancillary parts along the way. Oh, and my car runs :) (OK, that was maybe unfair, I'm sure your car will run nicely when you get it done)

Anyway, people that knock other people for picking up books are idiots. You can read how to do something and then go do it in a fraction of the time the "trial and error" approach takes. You usually have to replace less parts, too :)
FWIW, the differences between alternators and generators I fact-checked against Miner Brotherton's "The 12v Bible For Boats". I have had this excellent book since I worked on boats in the '80's.

PS: The # of wire sizes smaller a fuse link should be is 4. And constructive criticism is always welcome, but please support it logically or contextually, that's all I'm asking.
Example: There is no possesive of the word "success", the plural is "successes" : (m-w.com)

Anyway, regards. I'll take some Midol and report back tomorrow ;)

[Will]

Keith;

I haven't tried cicuit breakers for automobiles. I've seen 'em, just not used 'em. From a convenience standpoint, circuit breakers are certainly better than fuses, and you don't need to carry spare fuses. Except, you probably still will unless you replace ALL your fuses. I personally would stay away from an auto-resetting type unless there is some way to keep it from trying to reset itself indefinitely in the event of a short. Packaging, form factor, durability, and corrosion resistance would be features I'd look for. I'd love to see the Waytek wire links you posted, but this computer cannot display PDF files since acrobat reader does not work with my display system.

Don't worry about me and Scott- we are AOK, I know he is only stepping on my balls because I'm quick to correct anybody else that gives bad info, and in turn he knows I'm not REALLY taking anything said on any kind of internet forum to heart. Besides, exchanges like this are good at showing us how much we know about something, and yet how much we don't know about something related. It's sometimes good to get a "technical smack down" as Scott put it, to force you to examine the logic behind your statements. Besides, it provides entertainment for the rest of y'all when Jerry Springer's not on :)

[keithwwalker]

Call and ask for thier catalog: 1-800-328-2724, it's free...

Alternatively, if it works on your system, right click and save as....

k


I'd love to see the Waytek wire links you posted, but this computer cannot display PDF files since acrobat reader does not work with my display system.

[bjmarsh]

Will wrote:

..diodes were added in a Wheatstone-bridge type arrangement.... It's sometimes good to get a "technical smack down"...


Uh, sorry Will wrong Bridge!...., it's a bridge rectifier, (also known as a full wave rectifier) it has nothing at all to do with a Wheatstone bridge which is used to determine unknown resistance values.

:)

Barry (EE smack downs cheerfully provided -as needed)

[Will]

A Wheatstone bridge uses the same arrangement AFAIK, but uses resistors rather than diodes. I wrote "Wheatstone bridge type arrangement" referring to the schematic form (classical diamond shape) of the Wheatstone bridge, because I don't know of a better way to describe the schematic arrangement of a typical alternator's rectifier circuit.. I guess I could have written "four diodes in a diamond pattern...etc."

I was only trying to provide a clearer picture than "bridge rectifier" since
bridge rectifiers can have many different schematic forms (as you know).

Of course you are correct in that had I known the precise terminology, I should have used the phrase: Full-wave rectifier circuit(bridge design) as illustrated here, 6th illustration from top:
http://www.allaboutcircuits.com/vol_3/chpt_3/4.html

Please bear in mind that most of my electrical focus is domestic line level, where we are more concerned with SCR's and TRIAC dimming, humming halogen filaments and bulbs that go black from being operated dimmed all the time. (Fortunately the cure for that's just to leave them on full power for a day until the blackness disappears via the halogen cycle. )I am admittedly not good with the electronic/ circuit design aspect and will readily seek your advice on such as the need arises.

Meanwhile, I'll let you call something level when you really mean plumb, how's that for fair?
:)

KW: I will request catalog, thanks. My problem is actually that when I try to open a PDF, it opens somewhere in a window that's off the screen of my right hand monitor. The only solution I've found is to disable my left and center monitors, reboot the computer, and then it shows up on my right (boot/ primary) monitor. I think it's a windoze glitch. Anyway, if you run across a solution to that, please let me know! it's a PITA for me to hike to another machine to read a PDF since my closest networked machine that's always on is the mac down in the studio, and there's usually a large pile of sh*t enroute to the path to that one!

[bjmarsh]

Will wrote:

I wrote "Wheatstone bridge type arrangement" referring to the schematic form (classical diamond shape) of the Wheatstone bridge, because I don't know of a better way to describe the schematic arrangement of a typical alternator's rectifier circuit.. I guess I could have written "four diodes in a diamond pattern...

Nope,

RTFM and tell us how many diodes you see.... (hint see illustration #10 in your reference)

Barry

[Will]

A generator is older technology, rectification was done by commutator. They are usually bigger, heavier, and spin slower. Later, diodes were added in a Wheatstone-bridge type arrangement to rectify the output, and the overall size of the package was reduced. Thus, the alternator was born.


That's from my original post, in context.

Now, are you telling me that the first alternators were in fact multipolar, polyphase, or (substitute correct jargon here)?

That'd indeed be surprising news to me.

However, it was erroneous on my part to use the word "typical" in the follow up post, since it implies that modern alternators (typical today) aren't multi-polar (or insert correct term here) which they predominantly are, at least through the early 90's. I try not to look under the hood of any new cars, no user serviceable parts inside!

PS> Do you know why you can't use an overdrive or underdrive pulley size on the alternator on some diesels?

[bjmarsh]

Will wrote (in context)

"A generator is older technology, rectification was done by commutator. They are usually bigger, heavier, and spin slower. Later, diodes were added in a Wheatstone-bridge type arrangement to rectify the output, and the overall size of the package was reduced. Thus, the alternator was born"

Will,

The alternator was not derived from the generator, they are two different methods of producing electrical power. The Generator is atributed to M. Faraday c 1831, The "Polyphase Alternator" was Patented by N. Tesla 1891.

BTW: Tesla and Edison were at "war" in the early days of electrification, regarding the benifits of each type of power generation (kind of like some present day "flame wars"" that occur far too often)

For those who have not RTFM, there are 9 diodes in a Fiat/Lancia polyphase alternator. (including both the stator and rotor circuits).

Barry (always rembember the first rule of holes is; " don't dig")

[Will]

Sure, and a modern rifle wasn't derived from a musket, because a modern rifle uses a cartridge and isn't smoothbore, the fact that it uses nearly the exact same fundamental principle and a musket predates a rifle by hundreds of years is irrelevant, right?

That's some funky logic IMO.

The diode is old technology too but sometime in the 60's auto manufacturers started using alternators.

FIRST they were using generators, then they SWITCHED to alternators.

You noted yourself that the generator predates the alternator by some 60 years, so why didn't they start off with alternators from the get-go, i.e.why don't model T's have alternators?

I'm guessing the 60's is probably about the time the technology of the solid-state diode came along and made it possible. After all, there are no 1940's cars with tube diode rectifiers (at least not that I know of!)

This original thread was about a guy that wanted to have brighter lights. I notice nobody had anything to contribute for the first 12 hours while his post sat there. I offered him help based on my limited knowledge. If you and/or Scott want to critique the minutae of my posts, since you (clearly) know so much more than I do, perhaps you could answer the original post yourself? Quite frankly, that'd save me some typing since this thread has wandered way outside my sphere of peripheral interest.

Regards.

[betamark]

Well, getting back to the original problem. I too am interested in brighter lights for my 77 HPE, which is a daily driver. Since the wiring in this car is overly complex; it has has 13 relays (how lucky, or un is that), I do not want to break into the original wiring. I am thinking about using the stock relays and wiring to switch two additional realays, high and low, with heavier headlight wiring to them to provide more power for headlights. That and following the recomendations for wire gauge listed earlier is my solution. Also, I do not use crimp connectors without solder and shrink. After all the work of getting this car right, I don't need to hit a deer.

[Wallace]

You boys !!! I love reading all of this - anyone ever heard the expression "going at it hammer and tongs" ??? !!!

Another oar to stick in. I think the dip lights on a euro monte goes through the column switch - not a relay. Fit bigger bulbs, you melt the switch out (expensive).

You must use a relay !

[Will]

Does the 77HPE have original lamps? If so, IMO the best, simplest thing you could do is replace them with some nice modern halogen sealed beams.

You could certainly try wiring one loose (not installed in the car, but temporarily connected to the wiring) to compare light output. This is a simply, easy test that will keep you from rewiring the car only to find that it was the old lights themselves that are the culprits.

(Note that experts may warn this test may not work under laboratory conditions where the different filament resistances cause unequal quantum-vortex corialis photon-boundary reabsorption of visible spectrum light, but it works damn fine in my garage, which is admittedly low tech. )

In my response to the original post, the two points were:

a) Good, halogen, high K bulb or sufficient wattage (i.e. 55W)

b) Getting a clean 12V (or substitute "stable", "non fluctuating", "consistant" or other "proper" nomenclature here) supply to the bulb.

You can test the voltage output at your current lamp very easily, and if you hit it with your DVM and it's 11 volts or better, then you probaly want to go the bulb route and try to increase your efficiency there.

If you are only getting 10v, then you've got a problem with the existing wiring, and also your halogen bulbs will suffer. Halogens need something on the order of 10.7V (not sure of the exact number but it's 10.x) in order to work properly. The Halogen "cycle" strips and redeposits material from the filament. Too low a voltage prevents this from happening correctly and the filament gets thin in the middle, makes poor light, and the bulb burns out early. (this is simplified to "average Joe" language).

So...test voltage and bump up wire size and/or add relay until you have 11V or better at the lamps.

then....fit halogens.

My. 02, YMMV.

[Wallace]

I really don't want to start it all up again - but for "clean" read "low resistance".

Which goes back nicely to my sugggestion of having two seperate feeds for the two fuse boxes . . .

[bjmarsh]

It’s pretty easy to calculate the wire size you need for better lighting (or any other application) for example:

What wire size do I need to run my dual 55watt lights if I want no more than a 2% power drop?

V =12.8 volts (nominal Lead Acid battery voltage)
I = current drawn by the lights
Power = V x I = 55 Watts x 2 =110 Watts total /12.8volts = 8.6 amps total

(This is a series circuit so the same current flows throughout the entire circuit)

Solving for the maximum resistance the wire can have for a 2% voltage drop
2% of 12.8 = 0.256 volts (this is the voltage “dropped” across the wire)
V=IR (Ohm’s law)
0.256 Volts = (8.6 Amps) X R
R = 0.256 /8.6 = 0.0298 ohms maximum resistance.

If you want no more than 2% drop at your lights you must limit the total resistance of the wire used to 0.0298 Ohms.

Checking a wire table (various books/ web sites provide this info) yields the following:

24 gauge 0.0257 ohms/ ft or about 1 foot of #24 wire
18 gauge 0.00639 ohms/ft or about 4.6 feet of wire #18 wire
14 gauge 0.0025 ohms/ft or about 10 feet of wire #14 wire

The total length of wire you need to connect your headlight dictates the wire gauge you need to use in order to achieve less than a 2% voltage drop.
Use good quality connectors properly crimped / soldered and a good ground connection. Currents of this level should optimally be run through a relay rather than using Fiat/ Lancia switches which all seem to be of marginal capacity.

Barry

[bjmarsh]

Wire size part 2

Just double checked my numbers, I gave some extreme examples of wire size. The intent was to show that as your lines get longer, you need larger conductors.

If you were to actually use one foot of #24 gauge wire to connect your lights (not that you are likely to), it would have to be Teflon, which will take up to 10A. More commonly used PVC wire in #24 gauge has a max rating of about 7amps for a 105C temp rise. In any case a 1 foot #24 wire would get quite warm and would not be recommended for this application.

It's a good idea to double check your wire size calculation with the max current capacity for the type of insulated wire you are planning to use. Many Lancia owners will note that several wires run pretty warm because they were marginally sized from the factory.

Barry

[Will]

Wallace;

NO!!!!

For "clean" DON'T misinterpret that to mean low resistance, I am referring to the source voltage, not the conductor.

You could have the wires run in 4ga, and if that comes from a source that's down to 10V, your lights will still be dim!

Taking directly off the battery solves this issue, but adds the requirement to provide fuse protection.

Note that Barry just did the roughly same calculation I did in my first reply to the original post, and came up with the same result : 14 ga or lower.

Although, Barry states it's a series circuit, which is not how I'd wire it. If I wired it, it would be a parallel circuit. If what I know about series vs. parallel wiring is true, then a parallel circuit (the way I'd wire it) would draw somewhere close to Barry's figure, less 1/2 the resistance of one bulb added to the equation and a series circuit would draw a little less current as the resistances of both ( 2X) bulbs are added, but with a resultant reduction in light output. Feel free to correct me if I'm wrong on that, Barry.

I'm all for drawing a little more current from the battery and optimizing light output, personally. If that means 12ga wiring would be better, then I say use it. I don't see the difference in wire weight being a performance factor the way Scott does, and the cost differential is negligible.

Now, it's on the edge of my memory, what was the name of that fellow and the rules for constructive criticism? Was it Buttonwood or some such fellow c 1600's? The (excuse terms) de-constrare and pro-constrare? That first it the attack (refuting the original premise) and then the alternate, constructive solution put forward to move the discussion in a positive direction? Hey, I'm going back 20 something years , so the recollection is dim as those original beta headlights! And also well into the second bottle of chianti, and you know I only buy the family size bottles :)

[bjmarsh]

Will,

In re-reading my earlier post, "This is a series circuit so the same current flows throughout the entire circuit" I realize it is very poorly phrased on my part

The two headlights are in fact wired in parallel just as you stated. The connecting wire is basically a low impedence resistor that is in "series" with the lights. The same current that flows through the lights also flows through the connecting wire, allowing you to easily calculate the voltage drop. Thanks for pointing out the ambiguity. You don't want to wire your two lights in series with each other. If you do wire the bulbs in series they will certainly last a lot longer, they will also put out a lot less light! :)

If we ran ten feet of #12 wire instead of #14 we would get a voltage drop of only .144 volts (8.9amps x .0162 ohms) so then we would have 98.9% of the battery voltage available to the lights vs, "only" 98% with #14, either would work fine. Use what you have available.

Like all things in Lancia-land, it comes down to choice, the "lightweight" #14 solution with a wimpy 98% light output or the "high output" 98.9%, #12 solution at a performance reducing weight penalty of an extra 1.2 ounces!

While we are speculating on how big your wire needs to be, remember that the "return circuit" is chassis ground. #14, #12, or even #00 won't help if you have a poor ground connection. The typical Fiat/Lancia ground is a small lug attached by a rusty screw to a corroded spot on the chassis. it does not take much in the way of resistance due to corroded contacts, or poor grounds to drastically reduce your light output.

Barry

[Will]

Barry, no problem...in fact, I thought you were trying to mess with my head when I read that, bacause there's no way I thought an EE would set the headlights up in series :)


My feeling is is if you use either #12 or #14, as your feed to the relay, and you use the same gauge for the lamps, even though that makes the lamp wire heavier than it needs to be, that you can then protect everything with one fuse link,er...fuse at the battery. This'd go along with Scott's "least number of components rule".

The other way, two relays, I feel works best as two individual circuits that have individual fuses where they meet the battery.

But, really, don't you think the big issue here (assuming your existing wiring isn't hot to the touch and you are getting 11V or better at the lamps) is the lamps themselves ?

My Zagato had lamps that somebody had replaced with something that looked a whole lot like a PAR VNSP, it had the front reflector spot and all, like a PAR lamp, and it threw about a bazillion candlepower half a mile down the road. It had stock wiring(at least, the headlights did).


Also, there might be some benefit IMO to simply replacing the existing relays (in the cse of the guy with the HPE) because although some relays like the bosch ones appear to be hermetically sealed, some are just crimped cans. I'm not an expert on corrosion, but the way I figure it is that the actual switch in the relay has got to crud up over time and that the resistance of the relay itself probably goes up significantly over time, more so if it is in the "open" position for long periods of time- just the way it would be if you were a typical Lancia owner and rarely drove the car at night.

I'm not sure if even the sealed ones don't get carbon buildup or something, although I've never cut one open and checked it out. I do know that I have some equipment here that spent its whole life in a computer installation that was close to a clean room, had air scrubbers and full climate control, and while they do not have dust on them, the grilles are blackened with some sort of carbony soot. It would not surprise me to find a 25 year old relay was internally pretty poor, I think I'll put that little experiment on my "to do" list; measure the resistance through the switch of a couple old relays, cut them open and give 'em a visual.

I have to admit your point regarding the ground is a very good one that I had overlooked. AFAIK the correct test for this is measuring the resistance between the battery (-) and ground side of the headlight connector, what would be a target resistance, around .1 Ohm?

[bjmarsh]

Will wrote,

"AFAIK the correct test for this is measuring the resistance between the battery (-) and ground side of the headlight connector, what would be a target resistance, around .1 Ohm?"


Or even lower! Since we just put in a big primary feed wire (let’s use your favorite #14) we are only dropping 0.144 through the cable but the V (Drop due to ground) = I x R = 8.9 amps * .1 ohms = .89 volts

So even with a ground resistance of “only” 0.1 ohms we now have only 12.8 - .144 (cable voltage drop) -.89 (ground voltage drop) = 11.76 volts = 92% of our original voltage at the lights. If you rewire your system with monster wire but neglect the grounds, it’s a lot of wasted effort.

At these current levels, bad grounds create many old car “Illumination problems” The entire circuit consists of the lights, the connecting wire and the return circuit which is via the ground lug through the chassis to the – terminal on the battery. Adding bigger lights pulls even more current which drops even more voltage. The poor illumination of many older Fiats/ Lancias is probably “contact” related. If your grounds are bad, adding bigger lights, upsized primary cable etc. is not going to help.

Relays in a high power lighting circuit are an absolute must, because running 9 amps through the steering column switch is OK only if you like the smell of melting plastic. The choice of 1 relay vs. 2 can be argued either way, splitting the circuits use less current which allows smaller wires, multiple relays can also provide some redundancy in case of failure, (and also provide more parts to fail) 1 relay is a simpler solution, etc. Whatever solution you choose it’s important that both your grounds and your primary wire are of suitably low resistance.

Now that we have (hopefully) finished this topic, everyone on the list can get a good laugh the next time you see somebody with a “killer stereo” with battery cable sized wire for the primary side and a little bitty #22 wire for the ground return!

Barry

[Wallace]

Last word on the subject - but funny.

You do have to watch doddgy earths. Read in a Flight mag a few years ago about one near miss when a loose earth conection on a two engined plane back fed and feathered both props when the undercarage was raised just after take-off. Luckily the pilot managed to put it down in a field ok but I bet his pants were a funny colour . . .