On my conversion I went with the two 10 gauge wires and used 50 amp circuit breakers on both wires. Click on the red link below and you can see them by the battery.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

You really only need one wire between the alternator and battery if you can run a 6 gauge wire. It's only slightly less capacity (5 amps) than a pair of 10 gauge wires. I'm comfortable fusing only at the battery end myself. Car stereo shops have some nice stuff as do marine supply stores.

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Joshua

Wow, thanks a lot for all the great info guys it's very helpful. Electrical has never been my forte. But with you guys guiding me and all the good info on here I can proceed forward with confidence.

Ted, I've studied your pics and your setup looks great on the alternator upgrade. Reading your posts and pics is what influenced me to switch to an aluminum intake and I made an aluminum heat shield almost identical to yours. I'm gonna have to start getting some pics on here so I can show how it looks.

Joshua, I like the idea of a single 6ga wire that would simplify things. I'm still not sure wich one is better in this situation fuses or breakers or if it is just a matter of personal preference.

So I've got a new not rebuilt Remy ND style 120amp unit on the way. I found it on Fee-Bay for $99 free shipping, no core no tax. It was the best overall deal I could find. I can't wait to get started on it. Hopefully this weather will warm up in the next few days cause I'm doing this without a garage right now.

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1975 Dodge D100 2wd Reg.cab 225/6, 727auto, 3.55 gears, Cat delete with 2.25" Thrush Exhaust, Dist recurve by DI, 9.1 comp, Factory aluminum 1bbl intake with heatshield, 63 Jet, Delete ballast with Pertronix Flame Thrower 3ohm coil

DC circuit breakers in the 100 amp size are not going to be cheap. I would use a commonly available Maxi Fuse. I like to grab these from the wrecking yard when I'm there as I hate paying retail for those things. You can grab an under hood power distribution panel from a later model vehicle and get the maxi fuse and holder along with relays for headlights and whatever else you could want.

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Joshua

Thanks Joshua, that's a great idea! That gives me another great excuse with the wife to go to the Pull A Part. Lol

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1975 Dodge D100 2wd Reg.cab 225/6, 727auto, 3.55 gears, Cat delete with 2.25" Thrush Exhaust, Dist recurve by DI, 9.1 comp, Factory aluminum 1bbl intake with heatshield, 63 Jet, Delete ballast with Pertronix Flame Thrower 3ohm coil

They also make circuit breakers that are replacements for maxifuses.........

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

This might be a dumb question but I was wondering if I have a 50amp fuse between the battery and a 120amp alternator what happens when the alternator tries to put out more than 50 amps? Will this not blow the fuse?

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1975 Dodge D100 2wd Reg.cab 225/6, 727auto, 3.55 gears, Cat delete with 2.25" Thrush Exhaust, Dist recurve by DI, 9.1 comp, Factory aluminum 1bbl intake with heatshield, 63 Jet, Delete ballast with Pertronix Flame Thrower 3ohm coil

Slanted Trucker: This would depend if there are two current paths to battery from alternator. Having said that, do you have a direct wire to battery bypassing the bulkhead connector that carries all recharging duties, or is the original charging path running from alternator to bulkhead connector to Amp gage, and back out through bulkhead still connect to battery as well as the direct alternator to battery conductor?

If you have two paths to battery than some of the amp load could be directed to whatever electrical load is in use such as headlights, heater fan, ignition circuits etc. via the factory path, and the balance flows through the new shunt between alternator and battery fused at 50 amps.

The short answer is it is possible to blow that 50 amp fuse, and or it is also possible to melt the factory fusible link as well.

This is one reason I don’t like parallel conductors, or paths to carry an electrical load, and another is back-feed problems. If you are still utilizing the factory charging path you don’t have any over current protection above Chrysler original low amp output alternators (~60 amps max) utilizing original wire sizes. One risks melting portions of the original harness when a dead short happens in that side of unprotected factory charging loop (black conductor). Remember the factory fusible link is located in the battery to dash side of the charging loop (red conductor) protecting from a massive battery high amp draw.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Wjajr, I havent wired this up yet, just trying to fully understand how it works but it is my understanding the way everyone has been doing this is to "bypass" the original ammeter charging path by running the direct wire with 50amp fuses to battery from alternator. My question with only this path for current to travel from 120amp alternator to battery wouldnt the 50amp fuse blow if alternator went above 50amps in output if prompted by demand from turning alot of accessories on?

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1975 Dodge D100 2wd Reg.cab 225/6, 727auto, 3.55 gears, Cat delete with 2.25" Thrush Exhaust, Dist recurve by DI, 9.1 comp, Factory aluminum 1bbl intake with heatshield, 63 Jet, Delete ballast with Pertronix Flame Thrower 3ohm coil

SlantedTrucker:
[quote]My question with only this path for current to travel from 120amp alternator to battery wouldnt the 50amp fuse blow if alternator went above 50amps in output if prompted by demand from turning alot of accessories on?[/quote]

Yup it will pop that fuse if the original factory charge path leading to amp gage using black 10 gage wire is disconnected when alternator exceeds 50 amp output; poof.

Run one new 6 gage or two 10 gage wires from alternator output stud to stud on starter relay; install a fuse at the starter relay end of this wire. There should be a short length of 6 gage connecting starter relay stud and battery + terminal.

Disconnect factory’s black 10 gage charging wire that runs from alternator to bulkhead connector; this wire passes through bulkhead connector and attaches to amp gage. This eliminates the secondary path to battery.

Now you should beef up the conductors feeding the dash (10 gage red) between starter relay and fuse block, and also use a higher current handling fusible link, or fuse to protect form over current. The only time 120 amp alternator will output more than stock 60 amps is when the battery is drained & recharging at a high rate, and the combined electrical load downstream is high such as when headlights on, heater on, brake lights on, high draw modern stereo on, etc. Battery and or alternator will match power demand, and no more except if there is a short, or voltage regulator fails driving alternator to full 120 amp output. The battery will absorb a lot of amperage, and acts like an electrical shock absorber for lack of a better term.

Look at the Mad [url=http://madelectrical.com/electricaltech/amp-gauges.shtml]charging circuit bypass[/url], and [url=http://madelectrical.com/electricaltech/remotevoltagesensing.shtml]remote voltage sensing[/url] method to stabilize charging rate, and voltage levels; and [url=http://madelectrical.com/electrical-tech.shtml]other topics of interest[/url].

I have performed the amp gage bypass, and power ignition circuit with a relay, and use remote voltage sensing at starter relay post. I also run headlights via relays powered from battery utilizing 10 gage conductors, and have a 60 amp 1970’s stile square back alternator and don’t experience dimming of lights at idle… These alterations have eliminated voltage drop that caused high charge voltage.

I have to disclose that my engine idles at 1100 rpm in “Nâ€￾, and in gear about 800 rpm due to a big lumpy cam. The car has normal A Body stock electrical loads, and no big aftermarket stereo.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Wjajr, Thanks a ton for the info, this Mad article addresses all my concerns on the power distribution side I was concerned about and is definitely the route I need to take to ensure all will work good with this upgrade. One question I have immediately is 50 amp fuse at relay sufficient or should I go larger going this route? And also what size fusible link should I use for power feed into bulk head connector? Or can I use a fuse there and if so what size? Author of Mad article says 16 guage fusible link but he doesnt say what amp alt he is installing. I'll be studying this over before I start so bear with me. Thanks!! Sam

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1975 Dodge D100 2wd Reg.cab 225/6, 727auto, 3.55 gears, Cat delete with 2.25" Thrush Exhaust, Dist recurve by DI, 9.1 comp, Factory aluminum 1bbl intake with heatshield, 63 Jet, Delete ballast with Pertronix Flame Thrower 3ohm coil

Fusing has to be calculated taking into account existing wire size, and load. Which relay are you talking about?

If you stay with stock wire harness and loads probably the factory's 14 gage fusible link will handle the load, as the bypass will shunt heavy charging directly to battery. Does a 14 gage fusible link equate to a 50 amp fuse, I can't answer that as both devices work and respond to over current conditions differently. One is slow to react, the other pops as soon as it sees 50 amp flow of electrons. You may have to start at 50 amps, and up size until one size can handle the nominal load without over taxing the factory's borderline under sized harness.

Also to lessen amperage flow through bulkhead connector, control headlights with relays and install beefed up wire to feed them. By using a charging bypass, and feeding headlights from battery a large current load is removed from the factory harness. This is roughly the set up I currently have in my Dart that still utilizes a factory 14 gage fusible link at bulkhead connector. I have had no problems since 2008 when installed.

In preparation to making your proposed alterations it would be a good practice to clean, and or replace all brass connections as needed in bulkhead connector to eliminate any voltage drop; corroded high resistance connections equal destructive excess heat and reduced voltage. Replace any hacked up wire spliced with butt connectors, and sloppy non factory splices you find under dash to restore the wiring harness integrity and function as designed.

Dan Stern Lighting has a nice diagram illustrating just how to accomplish this lighting upgrade, and the hardware if needed. I have installed his good quality relays & sockets in my lighting circuit; they work great.

This project is probably a poster child for mission creep, not unlike changing a faucet washer in bathroom, and eventually replacing all plumbing back to the street. To keep track of this project it would be wise to photo copy an electrical diagram of your car, clip it to a clip board and mark it up as alterations are made so you don't miss anything, and can work in an orderly methodical manner. Also draw out all new circuits to be installed, and than a nice clean "as built" diagram of how it integrates into existing harness to have on hand for "future reference**".



**Trust me, your brain will love you for it a few years down the road... LOL I know my crusted corroded squash filled cranium has.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

You can definately use a single large charge wire vs. the two smaller. On mine I am using a single 4awg from the alt, across the rad support, into a 60a maxi-fuse, and then to the Pos post on the battery. (planned on upgrading to 120A but changed my mind, thats why its 4 gauge)

Keep in mind before jumping the juice to 120A is making absolutely sure the contacts in the bulk-head are good, clean, and up to the job of carrying more load (even though most of the load will now bypass the OE circuit). With that, be sure both pos and neg cables are good, and solid. Check the ground from the batt to frame, ground to engine, as well as the engine to firewall/frame. You HAVE to have a good ground return for a proper functioning electrical system. I even added grounds to mine (from batt to alt bracket, and batt to HEI module) Doesnt hurt to maybe replace the sensing wires from the regulator to the alternator as well, and voltage drop in these will trigger the alternator to run excessively. Mine your poor loocking and looked like they may have even started melting down from age and excessive heat.

Still running the 60A alt, no headlamp relays, full stereo with a 2000w amp for lows, and a 1200w for mids/highs. Get 14.8v at all times, idle to max rpm, and only drops to about 14v with headlights + heater on at idle...

Wjajr, The relay I was referring to installing the fuse in front of was the starter relay. As far as rhe connections at the bulkhead, I cleaned those awhile back while working on a ignition problem I had so they are in pretty good shape and I have also aquired some new original connectors just in case. You know, I never intended to get this far into upgrades and modifications on this old truck. My goal was to just make it as reliable and improve the driveability of it as much as I could because I wanted it to be my daily driver. But once I began doing these things, I realized to accomplish that meant going ahead with these improvements. And that's ok because I'm really enjoying doing the work myself and seeing the benifits add up with each and every one. I will as you suggest make notes and document what I've done because I'll never remember all the details a tear from now.

Oldskoolracer, Your right about the grounds I went through improving all the grounds awhile back while chasing an ignition problem. All cables and ground straps and wires are new. I added the 10Ga ground wire from regulator to alternator bracket as well as added a big ground strap from firewall to engine block.
What I'm planning on doing with this alternator upgrade is running 6ga wire from alternator then fused just before starter relay then 6ga to battery+. Then new 10ga wire behind 14ga fusible link straight through firewall with no connectors at bulkhead. Then bypassing ammeter and running new 10ga wire connected from original wiring feeding the dash back out straight through bulkhead again with no connectors and down to starter realy again. This will help eliminate any future connection issues with bulkhead.

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1975 Dodge D100 2wd Reg.cab 225/6, 727auto, 3.55 gears, Cat delete with 2.25" Thrush Exhaust, Dist recurve by DI, 9.1 comp, Factory aluminum 1bbl intake with heatshield, 63 Jet, Delete ballast with Pertronix Flame Thrower 3ohm coil

A refurbished electrical system greatly improves reliability of an old vehicle. This is time well spent for the future enjoyment of your old ride.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC