Sweptline.ORG

Oh look Squirrel....reading the dash fire storys of the old Amp gauge I thought maybe I'll swap it out for a Volt gauge. Well like always I put a lot of effort into something I really didn't need to do? How do I get so side tracked. Anyone else do dis? I repainted the needles too.

I've taken to restoring old tube AM/Shortwave radios rather than
devoting time to completing my '61 D to W conversion.
I've promised [& threatened ] myself to get back on the
'61 this coming spring.

The Sweptline amp meters are actually quite reliable. I've never
had one go south on me. The voltage limiter is usually the weak
link that causes electrical issues. There are a few threads on this
topic.

John

I am definitely going to do this modification myself as well. Although everytime this subject gets brought up the old school fellas swear the amp gauge is fine as is and they are probably right. I have no experience in automotive wiring (yet), but I work in the Power generation and transmission industry for a living. I've had plenty of unique experiences with bad current metering circuits. Mostly I want to because I think it will be a fun project that I can lean on my experience.
I am not close to wiring yet but I am curious about what volt gauges are people using that closely matches our other gauges?

DukePW wrote: ↑

Tue Jan 05, 2021 8:56 pm

Although everytime this subject gets brought up the old school fellas swear the amp gauge is fine as is

Well..... That describes me to a T.

John

but you're right though. Some of us can't leave well enough alone.

DukePW wrote: ↑

Tue Jan 05, 2021 8:56 pm

I am definitely going to do this modification myself as well.
...
I am curious about what volt gauges are people using that closely matches our other gauges?

this is what I have (see post dated May 27, 2018):
viewtopic.php?t=41294

Great, thanks for showing what you did. I like it

Your upgrade looks very good. Yes, touchy subject the amp gauge is. Yet most of the proponents for the amp gauge have a newer daily driver that has a volts gauge. If you have seen an alternator fail in a newer vehicle, the volts gauge drops to battery voltage telling you that there is a problem. An amp gauge would go to negative telling you the same thing, neither gives better info. The advantage of the volt system is you don't need to run giant cable to the dash and back out again. It's the reason for melted wiring.

marklein wrote: ↑

Mon Feb 08, 2021 1:48 pm

...The advantage of the volt system is you don't need to run giant cable to the dash and back out again. It's the reason for melted wiring.

No, giant wire does NOT cause the melt. SMALL wire, OVERLOADED, overheats and melts. Properly sized wire for the current drawn stays cool. That's why starter wires, jumper cables and welding cables are "giant".

marklein wrote: ↑

Mon Feb 08, 2021 1:48 pm

Yes, touchy subject the amp gauge is.

To me, the advantage of an amp gauge is diagnostic: Depending upon how the needle bounces, goes negative, sits dead still at a bare discharge, or goes negative under load tells me if the problem is the alternator, voltage regulator, a possible intermittent short, or even a diode failure. The big advantage of a volt meter (besides the wiring( is being able to switch sources easily to assess the condition of multiple batteries.

I realized after I wrote that, I worded it wrong. It was generally ok until people added a bunch of different loads to the system, then the wire gauge wasn't large enough to handle the current draw. With the current demands of today's vehicles, they couldn't use an actual ammeter. Some will give current demand info in a scan tool, I have tried turning on multiple accessories and have seen constant current draw approaching 100 amps. I think some of the issues were also corrosion in the bulkhead connectors, corrosion adds resistance big time.

marklein wrote: ↑

Tue Feb 09, 2021 1:24 pm

I realized after I wrote that, I worded it wrong. It was generally ok until people added a bunch of different loads to the system, then the wire gauge wasn't large enough to handle the current draw. With the current demands of today's vehicles, they couldn't use an actual ammeter. Some will give current demand info in a scan tool, I have tried turning on multiple accessories and have seen constant current draw approaching 100 amps. I think some of the issues were also corrosion in the bulkhead connectors, corrosion adds resistance big time.

The contact resistance of the bulkhead connectors is simply too great that much current. Corrosion only makes it worse. An insulated stud is better for the main current feed.