Electrical opinion

[1970FuryConv]

Hi Jim,
Another option is a solid state electronic instrument panel voltage regulator
List of cars that use IVR3, Link IVR3 Limiter List - rte

Link to buy IVR3, RTE limiter - rte

I have this company's IVR on my 1966 Dodge Coronet,
Also, the company is highly recommended on FBBO.
Ben

BTW, I think a 6 blade auxilliary fuse box run off the ignition spade of your regular fuse box is a good idea, especially if you want to add separate circuit for electronic choke or low amp circuit for actuating an electric fan relay.

 

[jmustian]

Hi Jim,
Another option is a solid state electronic dash voltage regulator
List of cars that use IVR3, Link IVR3 Limiter List - rte

Link to buy IVR3, RTE limiter - rte
View attachment 745489
I have this company's IVR on my 1966 Dodge Coronet,
Also, the company is highly recommended on FBBO.
Ben

BTW, I think a 6 blade auxilliary fuse box run off the ignition spade of your regular fuse box is a good idea, especially if you want to add separate circuit for electronic choke or low amp circuit for actuating an electric fan relay.

Another thought about electrics since I believe you know more than me on that haha. If I can't make my AT1 system work, where would I hook a wire and or switch to run the fan motor? Through the fan relay? I think direct to battery may cause problems.

 

[jmustian]

Your SYSTEM VOLTAGE is fluctuating. What sort of VOLTAGE REGULATOR do you run? Do you have a voltage gauge, instead of that damned 19th century ammeter monitoring your voltage output? If you still are running that ultra-primitive "regulator" for your instruments, an electro-mechanical breaker which continuously opens and closes to produce an AVERAGE approximating 5VDC, then know that if system voltage rises, the regulator will pulse that entire system voltage to the fuel and engine temperature sending units, both of which being simple variable resistors, will react to that pulse, averaging it's EFFECT.

The original system regulator likewise is a thermo-electric breaker, doing exactly the same thing: opening when a little resistor heats up enough and expands, thus interrupting current flow. The resistor then cools, contracts, and re-establishes the circuit, until it can't. For 30A alternators which had only headlamps and a heater motor to turn while running windshield wipers, this proved problematic, which is why by 1972 Mopar supplied a transistor (BJT) driven system regulator, though the instrument regulator would languish for more than a decade in development. Depending on the degree to which you're restoring this car, you might well have old style electro mech regulating all your circuitry.

You can obtain a solid state, MOSFET driven power supply for those instruments which will supply a steady state, flat 5VDC, regardless of whether your alternator produces 11.5 or 15 VDC. Install THAT behind your instrument panel and cruise knowing your instruments now get clean voltage to assess your vehicular condition with grreater precision.

My fuel gauge also varies depending on the vehicle's level w.r.t. the horizontal. I'm unwilling to install a modern sending unit, and live with the result, always filling the tank any time that needle touches "E" which experience has taught me with this tank and sending unit, does NOT MEAN "ENUFF!"

DON'T FUCKUP THE FUSEBOX WITH SOME COTS* generic replacement. Those old glass fuses were actually designed to a tighter specification than the modern ones. You can even pug circuit breakers into the 1.25" x 0.25" fuse receptacles. I have a Better Bypass for feeding the fusebox from the battery, eliminating the alternator charge loop from going into the passenger compartment AT ALL, enhancing safety, but again, some purists shrink in "HORROR!" from the notion of breaking Sacred Tradition.... Another thread.

*Consumer Off The Shelf

I'm only bypassing the two burnt spots/wires into a new fuse box.
My alternator and regulator are both new from napa but the reg has flat blade connectors so it's probably the old style.

 

[Gerald Morris]

I'm only bypassing the two burnt spots/wires into a new fuse box.

Cool! I can dig the rationale there. What ampacity is your alternator? By '69 47-50 amp alts had become pretty common, and the 60 was used for heavy duty stuff like cop cars, meatwagons, taxis and such.

My alternator and regulator are both new from napa but the reg has flat blade connectors so it's probably the old style.

Hmm, OK, the VOLTAGE regulator likely as not is solid state, made to LOOK like the old school stuff. Here's a fair sample of those:

I chose this brand, Regitar because it's common. One of our most redoubtable fellows in this Forum sells (or sold) one like this. Damned tariffs! Prices have DOUBLED in the past couple years....

Here's an NOS sort, the real "old school" sort, though of top quality:

I looked at what NAPA offers, and am outraged by their overpricing! Be this as it may, they're selling what looks like a faithful copy of the old school stuff. Since you got your alternator from them also, I expect it to be either a 35 or 46 amp one, IFF they advertise truthfully.

I run a 95 A PowerMaster with a solid state regulator, wired properly for the heavy current.

You should be reasonably safe if you stick with the NAPA stuff for now. Happy Moparing!

 

[1970FuryConv]

Another thought about electrics since I believe you know more than me on that haha. If I can't make my AT1 system work, where would I hook a wire and or switch to run the fan motor? Through the fan relay? I think direct to battery may cause problems.

To be clear, are we talking about a cooling system fan at the radiator or heater blower motor?
If your 1969 fuse box has these 2 spades, right side spade is ignition run. As long is it has good current, auxilliary fuse box should work OK.

 

[Gerald Morris]

Another thought about electrics since I believe you know more than me on that haha. If I can't make my AT1 system work, where would I hook a wire and or switch to run the fan motor? Through the fan relay? I think direct to battery may cause problems.

The best way to power an electric motor load, like a fan, is to locate your auxiliary overcurrent protection center (fusebox/breaker panel) near the battery, then locate the relay(s) near that. I run a separate fusible link off the battery post to my 6 circuit fuse bus, use various fuses and breakers in that bus for the loads they supply. Since my pusher fan came with an 80 amp relay specified by the manufacturer for running it, I supply that with a 40 amp breaker on the bus.

Low voltage (meaning 12, 24V) DROPS EASILY WITH CONDUCTOR LENGTH, so one MUST either keep power supply wires SHORT, AND/OR OVERSIZE THEM for length. This is ONE of my major indictments against a series circuit charge loop involving an ammeter and alternator. Even with 27 or 35 amp alternators, a 12 gauge wire very quickly drops voltage per unit length, leading to overheating, leading to further voltage drop, ad infinitum until something burns out. If you place an auxiliary fuse box anywhere, supply it with LIBERALLY LARGE CONDUCTORS!

So, battery to fuse/breaker to relay is the SAFE current path for any motor load. Stick with that.

 

[jmustian]

The best way to power an electric motor load, like a fan, is to locate your auxiliary overcurrent protection center (fusebox/breaker panel) near the battery, then locate the relay(s) near that. I run a separate fusible link off the battery post to my 6 circuit fuse bus, use various fuses and breakers in that bus for the loads they supply. Since my pusher fan came with an 80 amp relay specified by the manufacturer for running it, I supply that with a 40 amp breaker on the bus.

Low voltage (meaning 12, 24V) DROPS EASILY WITH CONDUCTOR LENGTH, so one MUST either keep power supply wires SHORT, AND/OR OVERSIZE THEM for length. This is ONE of my major indictments against a series circuit charge loop involving an ammeter and alternator. Even with 27 or 35 amp alternators, a 12 gauge wire very quickly drops voltage per unit length, leading to overheating, leading to further voltage drop, ad infinitum until something burns out. If you place an auxiliary fuse box anywhere, supply it with LIBERALLY LARGE CONDUCTORS!

So, battery to fuse/breaker to relay is the SAFE current path for any motor load. Stick with that.

Good info but no relay boxes. Gonna try and work on the AT1 later this winter after rewiring the car. It may actually start working after undoing all the bypasses and jumpered stuff.

 

[Gerald Morris]

Here's a nice pic showing how I power my automotive electrical system:

Overview at battery; total of 3 #12 AWG fusible links and starter motor power attached to battery + terminal. These protect the following branches:

1.) Alternator charge lead, visible as red #8 AWG wire attached by a bronze split bolt to the fusible link, and taped over for insulation. Charge lead measures 4' and goes DIRECTLY to the alternator, hence the fusible link to readily break the circuit should any overcurrent occur. No "loop-de-loop-poop" into the passenger compartment from the alt. The charge goes straight to the BATTERY.

2.) Dashboard fusebox. As can be seen above, the second link goes to the starter relay, terminating there and feeding another #8 wire going through a rubber grommeted hole in the firewall, terminating in two equal lengths of #12 AWG primary wire used to feed the battery supplied bus on the fusebox. Thus conductor ampacity for the load center matches that of the alternator, even though a large resistive load (the battery) lies in parallel to this center, w.r.t. the alternator. With ONE exception, I feed ONLY those circuits originally meant to be fed from that fusebox off this conductor. Many of these, such as the headlights, in fact now only feed switch relays. The exception is the pusher fan control circuit. I power the pusher relay off the switched ignition side of the fusebox. System voltage reads off the feed conductor where it enters the fusebox. I noticed when I eliminated the now useless charge loop conductors, and paralleled the fusebox feed that I picked up nearly 1 VDC. Again, conductor length and thickness (surface area) matters quite a bit at these low voltages.

3.) Auxiliary power fusebox: the 3rd link goes straight to the brass bus on the top of the 6 pole fusebox I partially opened for your viewing. Note how the yellow plastic on the ring terminal shows where the link terminates on the bus. With zooming, you might be able to see that I have breakers plugged into seveeral of those fuse slots.

Now attend to the 3 relays hanging off the little angle aluminum near the top of this picture. The two rightmost control the high and low beam headlight circuits. The leftmost one, with the relay plug in the bottom, is for the pusher fan. All 3 relay controlled circuits have their overcurrent protection at minimal distance from them, and the battery. The fusible link measures just under 6 inches, the recommended maximum length for the #8 AWG ampacity conductors I run for the main power circuits. I keep a spool of the stuff in the trunk, and have never used it since putting this car on the street 4 years ago. I supply a 100W Pioneer amplifier, and under dash cassette deck, 3 small cooling fans for passengers, and my wireless phone charger pad off the remaining poles of that 6 pole fuse bus. Everything gets good voltage and current this way.