Ammeter to Voltmeter Conversion -- Existing Wire Question

[Crackedback]

Original was 68 rr with ac. This one is 70 RR 383 bone stock. Have replaced or replacing all harnesses. Thanks again!!!
Updated to put in the listing of current car. Got it from another member after a lot of negotiation back and forth. Great member!
SOLD - 1970 Roadrunner | For B Bodies Only Classic Mopar Forum

All those kit parts will work on the 70.

I'm not a fan of the mad electric approach, it works, but I prefer to not cut the oem harness if possible.

 

[mrmolding]

Don't know how much it really matters, but Mark at MAD Electrical has changed his recommendation as far as wiring a bit. He hasn't got around to redoing the website yet. He is saying a guy should run the wire from the alternator to the starter relay unfused, but instead add a fuse link to the smaller red wire going from the battery positive to the starter relay. He thinks this is far better than his previous picture shows.

Thanks! That sounds like exactly what I got from Crackedback so...

 

[mrmolding]

All those kit parts will work on the 70.

I'm not a fan of the mad electric approach, it works, but I prefer to not cut the oem harness if possible.

So am I just back to putting your wire in place, getting the voltmeter conversion by Redline, and leaving the rest alone? Everything else is brand new from M&H (YearOne). I will say, it took me three years to find another car and I held on to your harnesses since I was so impressed with the work!

 

[72RoadrunnerGTX]

And the myth of the spontaneously combusting ammeter is perpetuated once again courtesy of Mad Electrical.

 

[diesel_lv]

Don't know how much it really matters, but Mark at MAD Electrical has changed his recommendation as far as wiring a bit. He hasn't got around to redoing the website yet. He is saying a guy should run the wire from the alternator to the starter relay unfused, but instead add a fuse link to the smaller red wire going from the battery positive to the starter relay. He thinks this is far better than his previous picture shows.

I did that w 4ga and thought it was enough for 2 high amp draw electric fans, fuel pump, fuel injection n 3 stereo amps. Melted quite a bit. Thankfully fused link saved it. Changed to 2ga from alternator directly over to battery positive, then the battery to the starter relay. No issues at all anymore. But this doesn't work w an ammeter, only a voltage gauge.

 

[mrmolding]

And the myth of the spontaneously combusting ammeter is perpetuated once again courtesy of Mad Electrical.

I'm new-ish here. It was bound to happen. But, I have a family friend who actually used to drive a 70 satellite doing county inspection work. He said that when they outfitted for CB and other equipment the battery always died. He said eventually they upgraded the wiring and alternator to handle the load.

 

[hunt2elk]

I did that w 4ga and thought it was enough for 2 high amp draw electric fans, fuel pump, fuel injection n 3 stereo amps. Melted quite a bit. Thankfully fused link saved it. Changed to 2ga from alternator directly over to battery positive, then the battery to the starter relay. No issues at all anymore. But this doesn't work w an ammeter, only a voltage gauge.

Yes, the rest of his original bypass is still done, only changing the placement of the second fusible link. I really don't understand which way is better or safer, and why. I did the conventional MAD bypass on my Road Runner and his new recommendation on my Super Bee.

 

[RJRENTON]

And the myth of the spontaneously combusting ammeter is perpetuated once again courtesy of Mad Electrical.

SAY......AMEN...AMEN.....someone once said: "a little bit of knowledge is a dangerous thing".....perhaps this addage could be applied to this instance. "We, the unwilling, lead by the uneducated, can accomplish anything using nothing"..... may also apply...
BOB RENTON

 

[Dave6T4]

I am adding Vintage Air and power seat to my '64 Polara, so have upgraded my alternator to 90 amp. unit. I have also upgraded alternator circuit wiring to 8 ga. passing it through the firewall through grometted holes, rather than the factory bulkhead connector. Rather than solder the red and black wires together under the dash, can I just nut them together on one of the posts of the bypassed ammeter, along with the power wire for my electric clock? I will be adding a voltmeter under the dash.

 

[diesel_lv]

I am adding Vintage Air and power seat to my '64 Polara, so have upgraded my alternator to 90 amp. unit. I have also upgraded alternator circuit wiring to 8 ga. passing it through the firewall through grometted holes, rather than the factory bulkhead connector. Rather than solder the red and black wires together under the dash, can I just nut them together on one of the posts of the bypassed ammeter, along with the power wire for my electric clock? I will be adding a voltmeter under the dash.

That's what I did, bolted them together.

 

[mrmolding]

I am adding Vintage Air and power seat to my '64 Polara, so have upgraded my alternator to 90 amp. unit. I have also upgraded alternator circuit wiring to 8 ga. passing it through the firewall through grometted holes, rather than the factory bulkhead connector. Rather than solder the red and black wires together under the dash, can I just nut them together on one of the posts of the bypassed ammeter, along with the power wire for my electric clock? I will be adding a voltmeter under the dash.

I would love to see pics of that when you are done or maybe what diagram you used. Just got brake pedal and heater box out so looks like I’ll be back to this in a few weeks. My 68 RR had a retro fitted vintage air system when I got it and all original harnesses to ammeter. It didn’t seem to have charging issues but who knows long term.

 

[72RoadrunnerGTX]

I am adding Vintage Air and power seat to my '64 Polara, so have upgraded my alternator to 90 amp. unit. I have also upgraded alternator circuit wiring to 8 ga. passing it through the firewall through grometted holes, rather than the factory bulkhead connector. Rather than solder the red and black wires together under the dash, can I just nut them together on one of the posts of the bypassed ammeter, along with the power wire for my electric clock? I will be adding a voltmeter under the dash.

What am I missing here? If you are buying into the myth that a well-maintained ammeter, ammeter insulators, and wiring/connections in good condition, will someday spontaneously combust, or “arc” to the cluster frame for no reason at all, how does connecting everything to one ammeter stud alleviate your fears? The ammeter and both studs would still be energized.

 

[Nacho-RT74]

Don't know how much it really matters, but Mark at MAD Electrical has changed his recommendation as far as wiring a bit. He hasn't got around to redoing the website yet. He is saying a guy should run the wire from the alternator to the starter relay unfused, but instead add a fuse link to the smaller red wire going from the battery positive to the starter relay. He thinks this is far better than his previous picture shows.

Wow, it seems finally is correcting SOME of their WRONG statements... but still with another WRONG statement.

The fuse link must be between starter relay and cab. THERE IS NOT OTHER CORRECT PLACE FOR IT. More can be added if wished like MaMopar did on later cars with more electrical accesories and the later shunted ammeter design, BUT NEVER GET RELOCATED THAT ONE. It can't be between batt and starter relay because that wire feeds also the STARTER MOTOR SOLENOID throught the relay. Anything of the starter motor must be fuse protected due the load they suck, either the motor itself nor solenoid.

If you look closelly, the wire between batt and starter relay is 10 gauge, while after the relay becomes 12 gauge ( with the fuse link in the middle ). The extra gauge on the batt-relay wire section is just right to hold the solenoid load.

 

[Nacho-RT74]

And again, once more about the amm-volt replacement.

When you get a flat tire you don't replace it with a chariot wheel to forgett about take care of the air on tires. You inflate the tire, fix or even replace with ANOTHER tire.

Get the charging system mantenienced just like you service your brake pads a call it done. Don't pretend after 50 years and million miles run your brake pads will be perfect. Electrical system is the same. Add a voltimeter if you want, but ammeter doesn't need to be replaced due the GREAT info you get from it.

You don't replace an oil guage with an idiot light! You in fact add an oil gauge when your car gets an idiot light for the oil warning system.

 

[hunt2elk]

What am I missing here? If you are buying into the myth that a well-maintained ammeter, ammeter insulators, and wiring/connections in good condition, will someday spontaneously combust, or “arc” to the cluster frame for no reason at all, how does connecting everything to one ammeter stud alleviate your fears? The ammeter and both studs would still be energized.

By connecting both the red and black wire to one stud on the ammeter, you are eliminating the ammeter from the circuit. Same thing as just bolting the 2 wires together and insulating the connector.

 

[Nacho-RT74]

By connecting both the red and black wire to one stud on the ammeter, you are eliminating the ammeter from the circuit. Same thing as just bolting the 2 wires together and insulating the connector.

yes BUT making it on that way the ammeter is still hot on both studs and its internal shunt. You will be saving just the load going throught. SO, if the insulators are still broken or stud is loosen isnide you can get still in short the main electrical system. Ammeter needs atention before take any random decision.

once again, OUR CARS JUST NEED THE CORRECT MANTENIENCE AFTER 50 YEARS AND A MILLION OF MILES ON ELECTRICAL SYSTEM TOO, just like we service the fuel system, brakes system and upgrade our engines and trans!!!

NO NEED TO REPLACE THE AMM FOR A VOLT, just because the ammeter failure choir being predicated.

You can add a voltimeter if you want, but we don't need to delete the ammeter. The info coming from it is really valuable. Just like an oil gauge againts an oil light.

 

[hunt2elk]

Wow, it seems finally is correcting SOME of their WRONG statements... but still with another WRONG statement.

The fuse link must be between starter relay and cab. THERE IS NOT OTHER CORRECT PLACE FOR IT. More can be added if wished like MaMopar did on later cars with more electrical accessories and the later shunted ammeter design, BUT NEVER GET RELOCATED THAT ONE. It can't be between batt and starter relay because that wire feeds also the STARTER MOTOR SOLENOID through the relay. Anything of the starter motor must be fuse protected due the load they suck, either the motor itself nor solenoid.

If you look closely, the wire between batt and starter relay is 10 gauge, while after the relay becomes 12 gauge ( with the fuse link in the middle ). The extra gauge on the batt-relay wire section is just right to hold the solenoid load.

Nacho, I am trying to understand what you are saying here. First, I understand that you are adamant about keeping the stock ammeter, but some of us are not. I for one saw first hand the damage caused when my Grandpas 1970 Satellite burned up in 1984. Started at the ammeter.
Second, I value your opinion and do agree with your thinking, it is just not what I want on my cars. Everybody can have their own opinion, correct?
I want to make my cars as safe as possible. At this point, I have removed the ammeter from all 3 of my cars and am not going back.
In the original circuitry, a #16 fusible link protects everything on the car, and is easy to do because it is in series with both the small red battery to starter relay, alternator feed, and all other wiring.
Now, when doing the original MAD bypass, A #16 protects the car wiring, and another fuse link also protects the alternator to starter relay bypass wire (size determined by the gauge of wire used). The problem with this is that the #10 red wire from the battery to starter relay is not protected. And if I am reading your above post correctly, you don't think this is necessary?
Like I said before, I just want my cars wired the safest they can be as I have way to much time and money invested to lose one to a wiring fire that could have been prevented.

 

[RJRENTON]

What am I missing here? If you are buying into the myth that a well-maintained ammeter, ammeter insulators, and wiring/connections in good condition, will someday spontaneously combust, or “arc” to the cluster frame for no reason at all, how does connecting everything to one ammeter stud alleviate your fears? The ammeter and both studs would still be energized.

I concur wholeheartedly with your supposition. The resultant re-iteration that follows your origional posting, is strictly, putting it mildly, lot of "bio-degradable agricultural slag", professed by others, who shall remain nameless, that have no real knowledge of the professed subject.....just suppositions and meaningless analogies.......and I'll leave it go at that.....
BOB RENTON

 

[Nacho-RT74]

Nacho, I am trying to understand what you are saying here. First, I understand that you are adamant about keeping the stock ammeter, but some of us are not. I for one saw first hand the damage caused when my Grandpas 1970 Satellite burned up in 1984. Started at the ammeter.
Second, I value your opinion and do agree with your thinking, it is just not what I want on my cars. Everybody can have their own opinion, correct?
I want to make my cars as safe as possible. At this point, I have removed the ammeter from all 3 of my cars and am not going back.

Sure! is at each own decision but allways based on the correct statements and proceedments ;)

In the original circuitry, a #16 fusible link protects everything on the car, and is easy to do because it is in series with both the small red battery to starter relay, alternator feed, and all other wiring.
Now, when doing the original MAD bypass, A #16 protects the car wiring, and another fuse link also protects the alternator to starter relay bypass wire (size determined by the gauge of wire used). The problem with this is that the #10 red wire from the battery to starter relay is not protected. And if I am reading your above post correctly, you don't think this is necessary?
Like I said before, I just want my cars wired the safest they can be as I have way to much time and money invested to lose one to a wiring fire that could have been prevented.

between batt and starter relay? No need for that, The only EXTRA/ADDED protection with a fuse link there is the wire between starter relay and solenoid aside the solenoid itself. The load for the solenoid could be variable depending on solenoid conditions, so you could burn the fuse link just cranking the engine if using th wrong fuse link rate... and if you use an oversized fuse link, you are keeping away from the protection in case of a larger short somewhere into the car. No need for that. How many times have you seen a solenoid wire burnt by a short ? they get burnt by headers or manifolds/pipes, but honestly I never have seen that wire burnt by a short to really need a fuse link between batt and starter relay to really change the location of the fuse link before the starter relay. The main fuse link must be out of any of the starter motor circuitry.

BTW, that wire keeps hot just while cranking... so why move the fuse link from its original location ?

 

[Dave6T4]

Looking at the wiring diagram on Post # 7, the red wire appears to be a redundant parallel circuit. The red and black wires are terminated together under the dash, and again at the starter relay. For simplicity's sake, could this red wire be eliminated altogether as it is no longer needed to complete the ammeter circuit? Am I missing something here? Per another post, I now realize that terminating both wires on an ammeter post is not a good idea, so I will not be doing that.