Powermaster One Wire Alternator Hook Up Question
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8 gauge wire is half the size needed to work with a high current alternator.
Wire size current table:
Keep in mind that the wire size in the chart is for the circuit itself, not the size of the fuse link. The packages of fuse link repair material you can get at the auto parts stores also will have a current rating on them.
See http://fordfuelinjection.com/?p=7 for some excellent tips of soldering wires for best electrical performance.
Aircraft type circuit breakers are designed for low voltage DC applications and would be an excellent choice to replace fuse links. They come as a push/pull to reset button, and range from 1.5 amps to 60 amps and higher.
See http://www.aircraftspruce.com/index.php or http://www.wicksaircraft.com/catalogDetails.php or http://www.sacskyranch.com/ for circuit breakers and other items.
There is a store local to Orlando that does electronic surplus and has all kinds of circuit breakers. See www.skycraftparts.com That's where I get most of my wiring supplies. There may be a similar type store in your area.
For a battery cut off switch, see http://www.moroso.com/catalog/categorydisplay.asp?catcode=42225
is the switch http://www.moroso.com/catalog/images/74102_inst.pdf is the installation instructions.
Use the super duty switch and the following tech note to wire it and you will
be good to go.
Use the Moroso plan for the alternator wiring and you risk a fire. The 10 gauge wire they recommend is even less adequate that the stock Mustang wiring.
There is a solution, but it will require about 40' of 18 gauge green wire.
Wire the battery to the two 1/2" posts as shown in the diagram.
The alternator requires a different approach. On the small alternator plug there is a green wire. It is the sense lead that turns the regulator on when the ignition switch is in the run position. Cut the green wire and solder the 40' of green wire between the two pieces. Use some heat shrink to cover the splices. See http://fordfuelinjection.com/?p=7 for some excellent help on soldering & using heat shrink tubing.
Run the green wire back to the Moroso switch and cut off the excess wire. Try to run the green wire inside the car and protect it from getting cut or chaffed. Crimp a 18 gauge ring terminal (red is 18 gauge color code for the crimp on terminals) on each wire. Bolt one ring terminal to each of the 3/16" studs. Do not add the jumper between the 1/2" stud and the 3/16" stud as shown it the
Moroso diagram.
How it works:
The green wire is the ignition on sense feed to the regulator. It supplies a turn on signal to the regulator when the ignition switch is in the Run position. Turn the Moroso switch to off, and the sense voltage goes away, the voltage regulator shuts off and the alternator quits making power.
The fuse & wiring in the following diagram are for a 3G alternator. The stock alternator uses a dark green fuse link wire that connects to 2 black/orange wires. Always leave them connected to the starter solenoid even if you have a 3G alternator.
Rear mounted battery ground wiring. Follow this plan and you will have zero
ground problems.
One 1 gauge or 1/0 gauge wire from battery negative post to a clean shiny spot
on the chassis near the battery. Use a 5/16” bolt and bolt it down to make the
rear ground. Use a 1 gauge or 1/0 gauge wire from the rear ground bolt to a clean
shiny spot on the block.
One 4 gauge wire from the block where you connected the battery ground wire to
the chassis ground where the battery was mounted up front. Use a 5/16” bolt
and bolt down the 4 gauge engine to chassis ground, make sure that it the metal
around the bolt is clean & shiny. This is the alternator power ground.
The computer has a dedicated power ground wire with a cylindrical quick connect
(about 2 ½”long by 1” diameter. It comes out of the wiring harness near the
ignition coil & starter solenoid (or relay). Be sure to bolt it to the chassis ground
in the same place as you bolted the alternator power ground. This is an
absolute don’t overlook it item for EFI cars
Note: The quick disconnect may have fallen victim to damage or removal by
a previous owner. However, it is still of utmost importance that the black/green
wires have a high quality ground..
Picture courtesy timewarped1972
Crimp or even better, solder the lugs on the all the wire. The local auto stereo
shop will have them if the auto parts store doesn't. Use some heat shrink tubing
to cover the lugs and make things look nice.
Starter solenoid wiring 86-91 model cars
Connect the fused 4 gauge wire to the alternator and the battery side of the starter solenoid.
Starter solenoid wiring 92-93 Model cars.
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring
http://www.veryuseful.com/mustang/tech/engine/ Everyone should bookmark this site.
Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif
Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif
Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif
Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg
Wire size current table:
Keep in mind that the wire size in the chart is for the circuit itself, not the size of the fuse link. The packages of fuse link repair material you can get at the auto parts stores also will have a current rating on them.
See http://fordfuelinjection.com/?p=7 for some excellent tips of soldering wires for best electrical performance.
Aircraft type circuit breakers are designed for low voltage DC applications and would be an excellent choice to replace fuse links. They come as a push/pull to reset button, and range from 1.5 amps to 60 amps and higher.
See http://www.aircraftspruce.com/index.php or http://www.wicksaircraft.com/catalogDetails.php or http://www.sacskyranch.com/ for circuit breakers and other items.
There is a store local to Orlando that does electronic surplus and has all kinds of circuit breakers. See www.skycraftparts.com That's where I get most of my wiring supplies. There may be a similar type store in your area.
For a battery cut off switch, see http://www.moroso.com/catalog/categorydisplay.asp?catcode=42225
is the switch http://www.moroso.com/catalog/images/74102_inst.pdf is the installation instructions.
Use the super duty switch and the following tech note to wire it and you will
be good to go.
Use the Moroso plan for the alternator wiring and you risk a fire. The 10 gauge wire they recommend is even less adequate that the stock Mustang wiring.
There is a solution, but it will require about 40' of 18 gauge green wire.
Wire the battery to the two 1/2" posts as shown in the diagram.
The alternator requires a different approach. On the small alternator plug there is a green wire. It is the sense lead that turns the regulator on when the ignition switch is in the run position. Cut the green wire and solder the 40' of green wire between the two pieces. Use some heat shrink to cover the splices. See http://fordfuelinjection.com/?p=7 for some excellent help on soldering & using heat shrink tubing.
Run the green wire back to the Moroso switch and cut off the excess wire. Try to run the green wire inside the car and protect it from getting cut or chaffed. Crimp a 18 gauge ring terminal (red is 18 gauge color code for the crimp on terminals) on each wire. Bolt one ring terminal to each of the 3/16" studs. Do not add the jumper between the 1/2" stud and the 3/16" stud as shown it the
Moroso diagram.
How it works:
The green wire is the ignition on sense feed to the regulator. It supplies a turn on signal to the regulator when the ignition switch is in the Run position. Turn the Moroso switch to off, and the sense voltage goes away, the voltage regulator shuts off and the alternator quits making power.
The fuse & wiring in the following diagram are for a 3G alternator. The stock alternator uses a dark green fuse link wire that connects to 2 black/orange wires. Always leave them connected to the starter solenoid even if you have a 3G alternator.
Rear mounted battery ground wiring. Follow this plan and you will have zero
ground problems.
One 1 gauge or 1/0 gauge wire from battery negative post to a clean shiny spot
on the chassis near the battery. Use a 5/16” bolt and bolt it down to make the
rear ground. Use a 1 gauge or 1/0 gauge wire from the rear ground bolt to a clean
shiny spot on the block.
One 4 gauge wire from the block where you connected the battery ground wire to
the chassis ground where the battery was mounted up front. Use a 5/16” bolt
and bolt down the 4 gauge engine to chassis ground, make sure that it the metal
around the bolt is clean & shiny. This is the alternator power ground.
The computer has a dedicated power ground wire with a cylindrical quick connect
(about 2 ½”long by 1” diameter. It comes out of the wiring harness near the
ignition coil & starter solenoid (or relay). Be sure to bolt it to the chassis ground
in the same place as you bolted the alternator power ground. This is an
absolute don’t overlook it item for EFI cars
Note: The quick disconnect may have fallen victim to damage or removal by
a previous owner. However, it is still of utmost importance that the black/green
wires have a high quality ground..
Picture courtesy timewarped1972
Crimp or even better, solder the lugs on the all the wire. The local auto stereo
shop will have them if the auto parts store doesn't. Use some heat shrink tubing
to cover the lugs and make things look nice.
Starter solenoid wiring 86-91 model cars
Connect the fused 4 gauge wire to the alternator and the battery side of the starter solenoid.
Starter solenoid wiring 92-93 Model cars.
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring
http://www.veryuseful.com/mustang/tech/engine/ Everyone should bookmark this site.
Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif
Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif
Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif
Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg
TexasFireman
15 Year Member
Very good info!! I knew I had seen this before and it took me forever to find it again lol.
Running the green/red wire through the small posts on the Moroso switch is exactly the solution I have been looking for. I didn't want to wire it the way Moroso instructions suggested. The other solutions I have found left the 4-gauge alt wire hot at all times because it went from the alternator to the battery side of the cutoff switch.
The only thing I'm going to change is I'm going to mount my starter solenoid in the trunk as well. I tucked all my wires behind the fender up front, and don't want the solenoid behind the fender or under the hood. I already mounted a stud like this behind the inner fender.
I'll be running a wire from the battery side of the solenoid (in the trunk) up to that post to run all of the wires to that would normally be attached to the battery side of the solenoid, with the exception of the starter cable and positive battery cable. I'm going to run 1/0 from the switched side of the solenoid to the starter, along with a 2-gauge wire (instead of 4-gauge due to the length) along with my 150 amp fuse, from the large output of my 3G alternator back to the trunk.
On this setup would I be better attaching the 2-gauge coming from the alternator to the battery side of the solenoid or the output side of the Moroso switch. It may not even matter because they will be connected with the 1/0 running from the Moroso switch to the starter solenoid anyway. Just wondered if one was better than the other.
Thanks again for the info. Someone should make a sticky out of it!!
Running the green/red wire through the small posts on the Moroso switch is exactly the solution I have been looking for. I didn't want to wire it the way Moroso instructions suggested. The other solutions I have found left the 4-gauge alt wire hot at all times because it went from the alternator to the battery side of the cutoff switch.
The only thing I'm going to change is I'm going to mount my starter solenoid in the trunk as well. I tucked all my wires behind the fender up front, and don't want the solenoid behind the fender or under the hood. I already mounted a stud like this behind the inner fender.
I'll be running a wire from the battery side of the solenoid (in the trunk) up to that post to run all of the wires to that would normally be attached to the battery side of the solenoid, with the exception of the starter cable and positive battery cable. I'm going to run 1/0 from the switched side of the solenoid to the starter, along with a 2-gauge wire (instead of 4-gauge due to the length) along with my 150 amp fuse, from the large output of my 3G alternator back to the trunk.
On this setup would I be better attaching the 2-gauge coming from the alternator to the battery side of the solenoid or the output side of the Moroso switch. It may not even matter because they will be connected with the 1/0 running from the Moroso switch to the starter solenoid anyway. Just wondered if one was better than the other.
Thanks again for the info. Someone should make a sticky out of it!!
I'm not quite sure I have envisioned the setup correctly.The one problem that I see is that you will need an additional 4 gauge wire to go up front to feed power to the fuse links and other items that attach to the solenoid.
TexasFireman
15 Year Member
Correct. In my reply I stated "I'll be running a wire from the battery side of the solenoid (in the trunk) up to that post (the one I pictured, inside the fender) to run all of the wires to that would normally be attached to the battery side of the solenoid"
Like this with the exception of the alternator
Like this with the exception of the alternator
That looks like it will work. Keep in mind that the accessory draw is everything but the starter and you will be running it about 12-15 feet. That means you'll be passing up to 80 amps through the accessory wire. The current draw will be even higher if you have an electric fan or super size stereo system.
Figure this:
Ignition system & computer = 12 amps
Fuel pump = 12 amps
Exterior lights = 15 amps
Fan (heater or A/C) = 15 amps (can run between 5-25 amps depending on setting)
Radio & instruments = 10 amps
Wipers = 10 amps
That's grand total of 74 amps for standard loads, not including anything extra you may have.
Figure this:
Ignition system & computer = 12 amps
Fuel pump = 12 amps
Exterior lights = 15 amps
Fan (heater or A/C) = 15 amps (can run between 5-25 amps depending on setting)
Radio & instruments = 10 amps
Wipers = 10 amps
That's grand total of 74 amps for standard loads, not including anything extra you may have.
TexasFireman
15 Year Member
Thats pretty accurate. Only difference is I'm running a big Magnafuel fuel pump thats straight to the battery, with relays to turn it on. I still may look at and see if I can find a good place behind the fender somewhere to mount the starter solenoid. I just don't want to mount it under the hood anywhere visible lol
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