Another high amp wiring thread

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BlackBrick

BlackBrick

The Cult Mechanicus
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I know, I know, you guys see this question all the time, but I have a few questions about installing a high amp alternator in the Brick. :banghead:

In the very near future (hopefully this coming weekend) I will be adding 2 audio amplifiers to the Brick. Current plan, because of lack of amperage output of the system, is to leave the subwoofer amp unpowered until I can increase the amperage output in the system.

Currently, I am running a stock style alternator, presumably a 65 amp, since the car came with some of the elctronic goodies that were offered way back when.

In looking at the instructions here: http://www.allpar.com/fix/alternator.html

I have bypassed the amp gauge as per the instructions for MAD enterprises, but did not wire in a new ammeter or a volt gauge, just soldered the wires from the ammeter, and added the fusible links at the relay.

In order to add a 100+ amp alternator, I need to run a 6 gauge wire from the alt to the battery (or lug on the starter relay), 10 gauge fusible link inline with that (I plan to use the Tuff Stuff 100 Amp model from Summit). This is mostly to prepare for the inevitable "more amp using" installs down the road (electric fans etc)

My question is, will the 6 gauge wire be solid enough to run from the Alt to the starter relay going around the stock wiring position?

I saw a post here somewhere about the need for a larger gauge wire the longer the cable (current planning is about 8 feet-ish, with the 6 gauge wire)......

And do I need to re-wire, with heavier gauge wire, for the field wires and upgrade the voltage regulator?

I am trying to get the ducks in a row so there are no surprises to the wife and no burning of the Brick because of bad wiring decisions.
 
No6 should be fine

No need for larger field wires BUT. If you look up some of my threads, voltage drop in the ignition harness is becoming an issue. This path is:

battery -- fuse link -- through bulkhead -- through ammeter circuit -- to ignition switch connector -- through switch -- back out switch connector -- back out bulkhead -- to ignition loads, regulator, alternator field.

If this circuit develops a drop, usually in the bulkhead connector or switch connector/ switch, the output voltage feeding the ignition AND MORE IMPORANT the regulator IGN terminal will be LOW as compared to the battery, and will ADD this amount of drop to the regulator setpoint. This causes OVER voltage at the battery

(Before I reworked my Dart, I had more than a 1 volt drop in this circuit, charging at 15.5)

One way around this, as long as you are upgrading, is to remove as much loads as possible through the bulkhead connector, and the switches and connectors

So install a relay/ fuse panel under the hood, and run your heavy loads from relays.

I used a junk Voyager relay box, but Bussman makes some boxes that you can configure yourself.

My junkyard relay box, relays for ign/ charging, fuel pump, hi and lo beams, security, and space left over. Mounts on the left apron between the battery and washer bottle

image.php




Some ideas on converting ammeters to voltmeters


http://www.forabodiesonly.com/mopar/showthread.php?t=119480&highlight=ammeter+conversion
 
Since the battery and alternator are the source of juice and the alternator does most the work, like you said, having a heavy gauge direct wire to the battery or start relay post (load termination terminal) will be good.

The thing is, you really need a nice little distribution block instead of running 8 load terminations off (connected to) the starter relay or battery terminal.

6 gauge from alternator to battery (to load) is more than adequate in 8 feet to negate voltage drop. You loose .64 V at 100 amp load, which your alternator will be glowing, so you will probably only want to draw 75% of max from your alt continuously. So using the calc, 75 amp load with 8 foot of 6 gauge =.48 V drop, then add in a couple tenths here and there for connector loss too.

Your alt will be running about 14.2V or so during cruise. I am probably going to run a modern delco type alternator (though I hate their appearance). We have a 1 wire 100 tuff stuff mopar on the Jensen and it is not the hot ticket that's for sure. It has slightly better idle V droop but still is inherently anemic at idle and low rpm. We show 13.8 on the V gauge at cruise. This is a stock Jensen electrical system so it has some V loss like factory mopar.

So, I suggest, run from alt to terminal block, terminal block to starter relay (or batt) positive post and use terminal block to feed the relays which feed your high draw accessories.

You could run appropriate amp fuse(s) or fusable links btw terminal block - positive post and alt - terminal block.

http://www.supercircuits.com/resources/tools/voltageDrop

This is a great little calc for V drop. Also, use the calc when planning high load runs like fans, head lights, ignition, fuel pump, stereo, amps...

Buy or borrow an amp meter if you are really interested in testing all your various components for their actual amp draw.

Listed or rated amp and actual amperage draw are wildly different usually on electronics. For example, high cfm electric fans will pull 50 amps on start up and taper down within 10 seconds to 25 A during run..
.
 
67Dart's fuse box / relay / distribution just covers it all in one swoop.

I bought this similar unit, cause I was not up to the challenge of finding a suitable salvage donor.
Bottom of page, universal fuse - relay box.

http://wagongear.com/WiredWagon.html

If I had it to do over, after seeing 67Dart's I would go his route. Looks like more channels too. Not sure how they (the relays) are triggered, positive vs. neg.

Hey, 67Dart, does your relay box have a single common + main input?
Do you trigger your relays with + or - or like did you tailor each channel independently?
 
You should add over current protection located close to alternator’s power lug to new conductor attaching to battery. This will prevent a total melt down of harness if a dead short should happen. The 100 amp alternator output is not the issue, but the 700 to 1000 available amps stored in battery is what one needs to interrupt when a harness melting dead short occurs.

As stated previously, it is good practice to eliminate as many amps flowing through bulkhead connector as possible for two reasons: first the wiring and its related connections were undersized from the factory, and time has not enhanced its ability to carry a designed load practically headlight circuit; secondly if adding additional long duty cycle high amp draw accessories (killer sound system) a direct bulkhead connector bypass feed is needed for these items.

Establish some sort of secondary power distribution point under hood providing individual over current (fuse, breaker) protected circuit feeds to high draw components such as headlights, electric cooling fans, electric choke, and sound system etc. Any of these devices located in cockpit should have their own direct circuit from new distribution point directly feeding device bypassing bulkhead connector. This wiring method will insure steady voltage and current delivered to device with no voltage drop and damaging heat generated in forty year old connections.
 
Rice Nuker said:
67Dart's fuse box / relay / distribution just covers it all in one swoop.

I bought this similar unit, cause I was not up to the challenge of finding a suitable salvage donor.
Bottom of page, universal fuse - relay box.

http://wagongear.com/WiredWagon.html

If I had it to do over, after seeing 67Dart's I would go his route. Looks like more channels too. Not sure how they (the relays) are triggered, positive vs. neg.

Hey, 67Dart, does your relay box have a single common + main input?
Do you trigger your relays with + or - or like did you tailor each channel independently?
Click to expand...

I had to do some reworking of the relay coils, which is easy, as it's all wire, not PC board under there. For me, it was "low budget" but works VERY well. Has some fuses in there, and I reconfigured a couple of them as I wanted. I the photo, the two studs in the bottom of the photo are the infeed buss.
 
Rice, I think your calc's might be off. I came up with .42 ohms/ k ft for no 6 automotive wire, is that not .00336 ohms at 8 ft? (I'm assuming the ground is "perfect" as opposed to a two way circuit of no6 wire. This would then be a drop at 100A of only .34V
 
The power dist. box like 67Dart273 mentioned is the way to go. I used a Ford one in my last project years ago, largely because finding the terminals for it so you can avoid a crap load of splices was simple. Mine was from a 93 4x4 Ranger with a 4.0 in it. Had more than enough fuses/relays to suit what I needed....
 
When hunting for a junkyard fuse/relay box make sure to get one that does use wire not circuit board. The wired ones can be reconfigured, but the circuit board ones can't be reconfigured and you likely will never find a diagram of how they are set up.
 
Also, I found one, wish I remember "whut." IT was sort of modularized, and very difficult to re--work. So look them over carefully. The Voyager ones (95?) are nice and easy to reconfigure
 
My 3 cents,

If it ain't broke, don't fix it. I mean the alternator. How do you know the current 65 A alternator isn't sufficient? You can't just add up name plate currents like the electric fan, since those are often just starting currents. I would use a cigarette lighter voltmeter ($5). If >14 V in normal driving, with most loads on, your alternator is fine. Another test is to put the battery on a charger every few days or each weekend and see how long it takes to recharge. If <10 min, the alternator is keeping it charged. The exception is if your battery is getting old and can't hold a charge, but you can have it load tested at Autozone for free.

For comparison, I have the original round-back alternator in my 65 Newport and it keeps the battery charged w/ TBI, AC, and electric fuel pump. Normal stereo amps don't draw much power, but sub-woofers are a different story. Bypass the bulkhead connector and run a thick dedicated wire for that. Use a table for "appliance wiring" which is ~2x the overly conservative ratings for residential wiring.

Re modern power distribution block, I used one from a 90's Grand Cherokee in my 65 Dart (see post). As 273 says, the relays have individual wires, so you can re-wire however you want. Most are standard auto relays, so terminal 85 to 86 is the coil (recall). I ground one and switch 12 V to the other to actuate. For consistency, I grounded the terminal shown on the Radio Shack bubble pack, but shouldn't matter (unless relays have a kick-back diode). The only distribution is a 12 V rail to the big fuses, which helps. I wanted to run new wires, but couldn't find the connectors. They aren't standard 57 spade terminals, closer to some Ford terminals. I bought some terminals off ebay that look similar, but didn't quite fit, so ended up splicing to the existing wires. I stripped the factory wiring and started from scratch since their interconnections didn't help.
 
As to the alternator, just replace it. You did not mention any other electronic equipment, but why run an alternator that is going to be maxed out all the time? You mentioned a 65 amp alt., guessing this is at cruise. At idle will not be enough to power every thing. Why do something twice? If you are going to put a dist. block of sorts in the car it is going to take some rewiring to put it in. Why go thru that nightmare and keep the wimpy *** oe alternator only to have to replace it when you get the amps and everything else wired. Not saying to throw a 290 amp alt at it, but something that will at least keep the battery charged would be nice....
 
Thank you all for the feedback. The current setup, under the hood, is bone stock. All of the stereo equipment, minus the accessory hot lead, are wired outside the normal wiring, using their own dedicated wiring (for the amps I am running 0 gauge from battery to trunk, then ANL fused split to 4 gauge to the amps). I have added nothing major, electronically, to the car yet, but I am planning for the future. I am going to test it out with the subwoofer amplifier powered, just to see if the alternator can keep up.

Again, planning for the future here, and want to make sure I am prepared for what needs to be done in the future to plan for a possible alternator upgrade scenario, in case it is needed.
 
If you are crazy serious about lots of output for a giant sound system you could always mount another alternator in the ac compressors location as part of a stand alone electrical system to power the amps. A completely isolated system with battery and capacitors would insure a good power supply, but is overkill for most stereos. I once saw a denso from a 1990 ramcharger throw 160 amps of output on a load tester. Densos are small compact units and that is more than enough output for an amp.
 
BlackBrick said:
I am running 0 gauge from battery to trunk, then ANL fused split to 4 gauge to the amps)..
Click to expand...


What kind of average/ RMS power are those amps supposed to be running? "We" may have underassumed what you are up to here

This sounds more like you do need big as opposed to small and do INDEED need to pay attention to what is coming and going from the bulkhead.

The problems you get into with really really big amps is not just simple DC voltage drop. Your amp changes power draw as the voice/ music going through it changes. Sort of like turning a light switch on/ off really really fast.

The causes what might be called modulation on the power leads, and the associated magnetic field can cause unintended effects in other parts of the car system.

So I ask again, just how huge is the average/ RMS ratings on your amps?
 
Good point 67Dart273. The online calc I used, and posted the link to, uhm more than likely assumes it is a two conductor to-from the load rather than having a perfect ground. Dang! Sorry about that.

BlackBrick, it sounds like from all the posts that you need to get some actual amp load assessments of all your larger items and tally them up first before planning your wiring system unless you just want to factor in undeniable overkill.

It is like planning a pluming system based on flow volume needs.





67Dart273 said:
Rice, I think your calc's might be off. I came up with .42 ohms/ k ft for no 6 automotive wire, is that not .00336 ohms at 8 ft? (I'm assuming the ground is "perfect" as opposed to a two way circuit of no6 wire. This would then be a drop at 100A of only .34V
Click to expand...
 

Rice Nuker said:
Unless you just want to factor in undeniable overkill.
Click to expand...

I prefer overkill, in almost all things, especially electrical.

Like I said, planning stages now, and I am doing the Amp install this weekend, and will test the load on the battery once all installed. I plan on doing a bit of re-wiring while I am at it, but not going with the large Amp Alt just yet, unless the wifey says go for it.

If the load is too high, I will not power the amp for the subwoofer because that is the one I know will cause the most issue.
 
Well, got the amps in, and after Joe got done tuning them to my choice of music, I am not really having a problem, very minimal headlight dimming, and the sound is fantastic. I still want to do the relay setup for the headlights because they seem to be pretty weak, and every now and then, when the sub amp hits, the headlights dim just a bit.

But I like the stuff that they have on the sites and will probably use them when I get to the headlight relay install......Was looking at the wiring to the headlights on Saturday, and looks like someone who had the car before hacked up the drivers side headlight wiring pretty bad.
 
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