Best way to power driving lights?

[240ZMan]

Originally posted by ozlime240z

My recommendation is to run all under bonnet after market electricals off the Positive of the alternator and fuse at that point.

I will post some photos of my set-up if anyone is interested.

Seeyas

OzLime240Z

I'd be interested in seeing a picture or two of the connections at the alternator. I agree with you that I'd like all my load + alternator on one side of the ammeter and the battery alone on the other. I don't like to "get used to" a gauge that reads somewhere other than where it should, especially since it will depend on what accesorries I am running at the moment. Of course, that's just me.:classic:

On the other topic of whether to switch on the positive or negative side of the load, I can't see any reason why it would make a difference either way on the load and hence life of the contacts. However I can see pros/cons on issues of safety vs. cost of building the car. I'll bet that those issues dominate the decisions of the automotive engineers who make these decisions. My .02. (Fun topic!)

[LanceM]

Daniel,

I reread your post and need to claify a point you made.

AHHHHHHH I never did a quote before!!! anyway you said and I quote

"In the electrical code you are allowed and is common what is called a "reduced neutral".If I run say 3 #10's (30a each) I can use one #10 as a return.Thats why if your house has a 200amp meter you have two 2/0 hots and one 1/0 return or neutral as it is called."

The reduced neutral in this case carries no current in normal operation and is there for safety reasons only. Before sometime in the 70's or earlier there was no reduced neutral. This third wire is typically attached to the metal chassie of a device, say a washer so that if a hot wire were to come loose and touch the metal chassie the chassie would not go to 110V it would instead blow the breaker. In AC all of the load is carried between the hi and low lines, the black and white wires, nothing through the green, you could remove the green and it would still work, such as a simple electric light which only has 2 prongs on the plug.

I agree that theory and reality stray at times but in my 30 years working in the electronics industry I find that they tend to follow each other pretty closely.

Daddy what do you do at work? Been designing and building things that kill people for almost 30 years, what a thing to have to tell your kids

Luckily I'm in the radio group now, the joke there is how many can you kill with a radio? One if you hit him with it, hundreds if you call in an airstrike.....

[LanceM]

To all,

You really should run all electrial items so that they go through the ampmeter, this is your indicator for your charging system and really the indicator for your whole system. If you add enough items before the ampmeter it may be showing no charge, but your battery may be needing more than is available to charge, just that the output of the alternator is being used up before it gets there.

By running everything through the meter you know that you are not exceeding the limits of the alternator, which is really what it is there for, if you are driving and have the stereo blasting, lights on and flip on the driving lights and the amp gauge drops below center you are now sucking power from the battery, you have exceeded the power available from the alternator and you need to turn something off or get a bigger alternator, otherwise enough of this type of driving will leave you with a flat battery.

[Zedrally]

Originally posted by ozlime240z

"snip"

My recommendation is to run all under bonnet after market electricals off the Positive of the alternator and fuse at that point.

I will post some photos of my set-up if anyone is interested.

Seeyas

OzLime240Z

Ozlime is correct in his method of running all these elec accessories from the Alternator, the reality of it is that you may quickly run out of space on the terminal. I did as I was running relayed low beam, high beam, 2 sets driving lights all seperatly relayed and fused. It had the potential of becoming a rats nest all to quickly.

The solution... Run the heaviest cable you can from the alternator to the starter, then use the starter terminal as a bus for all your accessories. No noticable loss of brightness in the H4 or drivers.

It's also preferable if you need to do a quick changeover in a rally due to toasting your altenator!

[Daniel]

Lance,good discussion.I'm going to try and get some documented info. today.I'll pm it so we dont take this thread.As for your washer wiring concept.The black is hot,the white is return sometimes called neutral,the green is the ground.Ground is the wire you discribed. See the three wires coming into your house.Two coated(120v each)one bare.That bare is not only a return but if it is cut or broken it will send 240 volts thru EVERY receptacle in your house.The transfomer needs that return. Thats just an FYI. oh yeah I happened to think of the simplest example.A common flashlight. It switches on the low side as you refer. After the lamp/load.

[Zedrally]

DC circuits switch after the load.

There is another thread somewhere on this site that explains it, or states it. I think it has a lot to do with the current [amps] that the accessories draw and it is preferable to palce any switching after the load.

It has created a lot of confusion at times when looking at car electricals. Maybe someone with a more experiance can help in the thread.

HIH