Volt meter vs. amp meter & 1 wire alternators

[mjhcobra]

I am about to put the dash together and find that this is a hot topic. I want the original look of the amp meter, but don't want flames under the dash.

I also want to use an external voltage regulator again for the original look, but I see lots of single wire alternators.

I currently have the original Smith gauges with the amp meter.

what do you guys suggest?

[Ron61]

Personally I used the volt meter as I like them more than an amp gage. But I am also not interested in making my cars look as original as possible. You could always use the amp gage and just not wire it but I think that would mess up your attempt to make the dash look original. I used a 100 Amp alternator, again not original looking, and didn't go with the one wire type. Either way, you will have a good looking dash and should be able to make the rest look close to original. Good luck and I hope that everything works out the way you want it to.

Ron

[RICK LAKE]

mjhcobra MJ I have gone to the Volt meter. SW gauges has the match in a classic chrome ring and black backing with white needle. I don't like the idea of running 100 amps through a 60 amp gauge and having to rely on small plastic insolators to protect the whole car. I am using the PAperformace setup Heavier wiring, with a master fuseable link, regulator and complete easy instructions on how to install. If you are not running alot of power ideas the 70 amp is fine for most cars. I have 2 fuel pumps, 3 cooling fans for motor, 2 for other locations. FI system and MSD. Mt gauge is in the middle of all this power useage and gets hot. Voltmeter just taps into the charging system. You have 3 wires to install to gauge 1 power from anywhere there is a battery hot wire, 1 for ground, the other is for dash lighting. Just make sure of good connections and having a clean ground to the external regulator. I hooked my charging cable to my starter soleniod on the battery side. ONly ran it for 2 minutes found no problems. reading about 13.9 volts. Rick L.

[Blas]

Mjhcobra,
They make a replacement Volt Meter that matches the original AMP Meter for the Smiths Gauges. It blends right in seamlessly. I have a few complete sets of extra gauges at the house but no Volt Meters or I would attach a photo. Here is one source to purchase one, you have many supplier choices.
VOLT METER (52MM) PART #ABV2220-07C WWW.GAUGEGUYS.COM
If properly installed, the AMP meter will serve you well. Both gauge types have their pros and cons. A properly installed master fuse, CB or fusible link will protect your electrical system. From what I have seen, your choice in the style of crimped wire end connectors will be the weakest point of any non-factory wiring installation. If you use those wire end connectors with the blue, red or yellow plastic tips over the crimps that are commonly available, even with the proper tool, they have often been the source of many problems. Why? You can’t SEE the final crimp…And the colored plastic ends are more wire gauge indicators then replacements for stiff heat shrink tubing. The more expensive crimp on wire connectors require a special tool to properly install. Usually $50 to $150 just for the crimping tool. But they have two sets of fingers, one that attaches to the wire making the circuit and the other set of fingers wrapping around the wire insulation. Add to that a heavy gauge heat shrink tubing and we’re talking “Space Shuttle” quality connectors.

[madmaxx]

The amp meter is a Lucas not a Smith. Always a good conversation piece to explain why the Lucas is there and not a Smith. I have the Lucas amp meter and love it, if wired properly you will not have any issues!!!!

[mjhcobra]

You are right, it is made by Lucas. How do you properly wire it? It seems that the volt meter is simpler and safer, especially with a higher rated alternator around 100 amps.

[mjhcobra]

Originally Posted by RICK LAKE

mjhcobra MJ I have gone to the Volt meter. SW gauges has the match in a classic chrome ring and black backing with white needle. I don't like the idea of running 100 amps through a 60 amp gauge and having to rely on small plastic insolators to protect the whole car. I am using the PAperformace setup Heavier wiring, with a master fuseable link, regulator and complete easy instructions on how to install. If you are not running alot of power ideas the 70 amp is fine for most cars. I have 2 fuel pumps, 3 cooling fans for motor, 2 for other locations. FI system and MSD. Mt gauge is in the middle of all this power useage and gets hot. Voltmeter just taps into the charging system. You have 3 wires to install to gauge 1 power from anywhere there is a battery hot wire, 1 for ground, the other is for dash lighting. Just make sure of good connections and having a clean ground to the external regulator. I hooked my charging cable to my starter soleniod on the battery side. ONly ran it for 2 minutes found no problems. reading about 13.9 volts. Rick L.

Sounds like the simple solution, I am just have to going to get past the look of the volt meter. I am running 1 fuel pump, 1 to 3 fans for the engine, and maybe another fan for the driver-that's it. Maybe I can get away with a 70 +/- amp alternator but I don't want to shortcut myself in this department.

[Blas]

AMP Meter gauge wiring is very simple. All of the cars power users should have their power routed thru the AMP Meter, if not, you won't be getting a true reading on the gauge. One large wire in and one large wire out of the gauge (excluding lighting)and if you install the in & out wires backwards, the gauge reads backwards. i.e. Headlights "use" power not "make" power - the needle should move towards negative when the lights are turned on.
Regarding the alternator sizing, Do you have any big power users car? Your cooling fans are your biggest users, then headlights, parking lights, etc. The MSD box uses very little power, the fuel pump (if electric) usually between 2 and 4 Amps (i.e. Holley red-blue-black) Most wiring systems on these cars are not even sized for 100Amp service. Even on factory built cars.
3 fans for engine cooling? Check their Amp usage...progressive activation I assume?

[madmaxx]

Blas is dead on, last I read was SPF wiring is sized for 50 amps.

[mjhcobra]

The trick is going to make sure the harness I get is built this way for an amp meter. I am looking at a Ron Francis kit and they are anti amp meters and use a single wire alternator. I have sent them my car specs and am waiting for a response to see if they can make one this way. If not, on to the next guy.
Any thoughts on the single wire alternator or harness manufacturer?

[mjhcobra]

Ron Francis said no way on the amp meter-my assumption is that the rest of the harness makers agree due to the gauge not being able to register more than a 50 amp charge. Seems stupid unless I use a 50 amp alternator, which again will not work. Final decision - 100 to 125 amp alternator with volt meter.

Still trying to decide on the single wire vs external regulator - any pros or cons????????

[DAVID GAGNARD]

Originally Posted by mjhcobra

Ron Francis said no way on the amp meter-my assumption is that the rest of the harness makers agree due to the gauge not being able to register more than a 50 amp charge. Seems stupid unless I use a 50 amp alternator, which again will not work. Final decision - 100 to 125 amp alternator with volt meter.

Still trying to decide on the single wire vs external regulator - any pros or cons????????

my 2 cars are both 65 Mustangs,street car and a race car, I use a volt gauge on both with the "old style" Ford alternator converted to a one-wire unit......Simple $40.00 conversion, takes about 1 minute and you only have one wire from the alternator to the battery side of the starter seloniod,clean and simple....the way I like it, simple is always better for me....

Personal prefrence is a volt gauge, accurately tells you what your alternator is doing or not doing...I don't worry about the amps, just make sure your alternator is not overloaded amp wise.....I would add up all the amp useage your car could pull at any given time and use an alternator that can supply that + 40%........if your total amp useage would be 40 amps you should have a 56 amp alternator, a standard 60 amp Ford unit would be sufficent......

I run a standard 60 amp old style Ford unit on both car and never have had any problems......idle speed, volt meter shows 12 volts, 1,000 to 1,500 rpms or more, volt meter shows between 13 and 14 volts...

David

[mjhcobra]

Thanks David for the insight. I saw on a previous post where somebody added up all the power that are drawn on an alternator. I will use it as a guide if I can find it. I guess originality is second to safety on this issue.

[DAVID GAGNARD]

Originally Posted by mjhcobra

Thanks David for the insight. I saw on a previous post where somebody added up all the power that are drawn on an alternator. I will use it as a guide if I can find it. I guess originality is second to safety on this issue.

I would suggest you add up the max amp draw of each electrical device on your car, that'll give you the most accurate amp useage for your car........then go from there.....

Either the "old style" voltage regualtor or the one wire unit both work well and do the intended job, it's more of a personal preference to me which to use....

Which ever way you go, check out this site, a lot of useful info on amps/volts/wires/wiring..........

http://www.powermastermotorsports.com/charge_wires.html

I adhere to the KISS principle, cause, I smart enough to be fairly good at few things and dumb enough to be dangerous at a LOT of things!!!!!!!!!!!!!!!!

David

[Blas]

Trans brake = 12 - 20 amps
throttle stop = 5 - 15 amps
fans = 6 - 25 amps
cdi ignition = 3 - 36 amps
hei ignition = 6 - 10 amps
nitrous solenoid (each) = 5 - 15 amps
electric fuel pump = 3 - 12 amps
electric water pump = 3 - 12 amps
instrument panel = 2 - 4 amps
brake lights = 3 - 6 amps
running lights = 3 - 10 amps
an MSD 6 or 7 series ignition consumes approximately 1 amp/ per thousand rpm.

[mjhcobra]

Thanks, that's the list I was looking for.

My car has the following:

2 front fans @ 4 amps = 8 amps
1 fan behind radiator = 20 amps
Instrument panel = 4 amps
Brake lights = 5 amps
Headlights = 10 amps
Holley Red fuel pump = 10 amps
Wiper motor = 10 amps

Assuming that I am stuck in traffic, its raining with wipers on, at night with lights on, and all fans are running-I would be maxed out at 67 amps at an idle. Add 40% more to ensure you have 67 amps at a loaded idle and you get 94 amps.

Does this sound accurate?

I want to use the original alternator and regulator rather than a single wire alternator. Sounds like 95 to 100 amp alternator should cover me with these loads. Anything I should look for in my search for the correct alternator and regulator?

Thanks for the guidance, Martin

[DAVID GAGNARD]

Does this sound accurate?

I want to use the original alternator and regulator rather than a single wire alternator. Sounds like 95 to 100 amp alternator should cover me with these loads. Anything I should look for in my search for the correct alternator and regulator?

Thanks for the guidance, Martin

Sounds accuarate to me.....I'd go with a 100a unit for your application.....I'd give Powermaster a call, they show old style/new style and chrome units in 60a/80a/100a/140a/200a........they could also give you some info on the voltage regulator and wiring.......

David

[mjhcobra]

It is interesting that there have been no comments on the part the battery plays in this issue. I got a pm from another member who brought up the point that the battery is like a box of amps and that the alternator keeps it charged.
What about the thousands of British cars that have heaters, fans, fog lights, wipers, etc and they all run with a 4 cylinder motor and a 45 amp alternator and an AMMETER.
Additionally, the big ford cars of the 60's and 70's came with 55 amp alternators and they had all kinds of power options and AC-some had ammeters, some had volt gauges, some had idiot lights. Just some thoughts on the subject.
I will still probably go with a volt gauge for the safety aspect, but still am not clear about the high amp alternator that is being suggested.

[DAVID GAGNARD]

Using a higher amp alternator is just added insurance you have enough capacity to run everything............and not maxing out your alternators output.........

With that said, I've been using a standard $19.95 Auto-Zone Ford old style 60 amp alternator on my 65 fastback street car since 1995, no problems so far............

I have in the car the following:

MSD ignition with MSD dist.
windsheild wipers
heater
headlights
turn signals/horn
cigarette lighter
am/fm radio w/cassette player
one 18" diameter electric fan off a Caddy.

Alternator powers everything fine,but, I rarely drive the car at night and never in the rain at night.........

A 60 amp for the application would most likely do the job, 100 amp would do it better by not maxxing out the alternators output.......

David

[mjhcobra]

What about the battery? I thought the power to the accessories came form the battery and as it is used, the alternator kicks on and charges is back up then shuts off until needed again? All I read is how the alternator is powering everything.....