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Re: Safely Wiring Accessories/Amp Gauge Re-wire [Re: jcruse64] #2714603
11/10/19 07:02 PM
11/10/19 07:02 PM
Joined: Feb 2010
Posts: 1,597
Phila. Pa.
Mattax Offline
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Mattax  Offline
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Phila. Pa.
Are you asking about the alternator ratings? That's right.
And rarely can we find anyone to give a full a proper answer about an alternator we're buying.

Whomever makes the alternator can rate the 'amperage' at whatever rpm and voltage they feel like.
Obviously most use a high rpm and low voltage to make their claim.
There's no standard. frown

This came up in a thread on speed-talk.
https://www.speed-talk.com/forum/viewtopic.php?f=20&t=41740

My takeaway is that within reason, more windings can be used to increase the strength of the rotor's magnetic field, and if the stator is matched more power is possible.
Of course more windings in the same space mean more expense and also less room for cooling....
A longer space makes a little more room for windings and cooling.
Tighter tolerances in machining and assembly can bring field closer to the stator windings.
Changing the way its wired from Y to delta will change the performance curve.
Some combination of the above accounts for the better overall performance of the squarebacks, revised squarebacks and the Denso alternators that followed the 'roundbacks.'

But the problem for us, the consumer, is we don't know if the rebuilder or aftermarket seller has matched the parts, or just improved the top end at expense of the low speed, and/or fudged the results a litle by playing games with the test voltage etc.

A couple example I can show of a higher rated alt having a drop low rpm performance are from AC Delco's catalog.
These are GM alternators but its nice they actually used to show the info.
[Linked Image]
Pay attention to the RPM and the voltage!
Being a pseudo-engineering graph, we don't know if the 12 Volts was the real test voltage or the nominal (common language) description of the alternator.
In other words this is 12 Volt Delcotron vs a 6 Volt generator.
(GM hated calling their AC generators 'alternators' like Chrysler did. laugh2 )
The other thing is the RPMs are alternator shaft speed. Usually 2 to 2.5 times the crank speed depending on the pulley set.
Here's another model.
I'm familar with these two because AMC used them both in the Jeeps. The 15SI was the preferred heavy duty unit presumably because of its good low rpm perfromance.



tas_alt_15si_curve_type100.jpg
Re: Safely Wiring Accessories/Amp Gauge Re-wire [Re: Mattax] #2714610
11/10/19 07:21 PM
11/10/19 07:21 PM
Joined: Feb 2010
Posts: 1,597
Phila. Pa.
Mattax Offline
pro stock
Mattax  Offline
pro stock

Joined: Feb 2010
Posts: 1,597
Phila. Pa.
The only complete Chrysler alternator curve I've ever seen is the one Nacho found in a box.

It shows the remanufacturer ran the test at 13.2 Volts.
But we can't compare that directly with the factory test for that alternator.
Almost always the shop manual test is done at 15 Volts, 1250 rpm (engine).
To compare, we need to know the pulley ratio, and then we can guestimate the performance curves at other voltages.
I just dotted in the 15 Volts without actually doing the math to illustrate the concept.

Nachrt74-Late-squareback-output-markup.jpeg
Re: Safely Wiring Accessories/Amp Gauge Re-wire [Re: Mattax] #2714639
11/10/19 08:44 PM
11/10/19 08:44 PM
Joined: May 2014
Posts: 156
Paducah, KY USA Earth
J
jcruse64 Offline OP
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jcruse64  Offline OP
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J

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Paducah, KY USA Earth
It's the Wild West out there, lol!!! Again, thank you for taking the time on this thread. I am learning a TON.

Re: Safely Wiring Accessories/Amp Gauge Re-wire [Re: jcruse64] #2714790
11/11/19 01:16 PM
11/11/19 01:16 PM
Joined: Aug 2007
Posts: 5,636
Caracas, Venezuela, SouthAmeri...
NachoRT74 Offline
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NachoRT74  Offline
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Mattax has reached deeper into this than me. I just went to the basics, enough for me and my car. I just helped a bit. And maybe began this pro ammeter battle some years ago LOL. not because the ammeter could be the best or not, but simply because I found MOST of the ppl doesn't even know how the charging system works and how to read an ammeter.

about the diagram posted that I found, was from one of the alternators I todl you, a mids 80s replacement alt, sold under Beck-Arnley brand. I got it from Rockauto.

about those extra truck accesories and the isolation system... I'll have to learn too, LOL. Competition sound cars are on same deal.

Re: Safely Wiring Accessories/Amp Gauge Re-wire [Re: NachoRT74] #2714917
11/11/19 07:42 PM
11/11/19 07:42 PM
Joined: May 2014
Posts: 156
Paducah, KY USA Earth
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jcruse64 Offline OP
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Posts: 156
Paducah, KY USA Earth
Tested the fuel, oil, and temp gauges today, using the little hack in the latest issue of Mopar Action. Fuel gauge tested fine, but I could get nothing from the temp and oil gauges. I pulled the same 3 gauges from a '76 RC dash, and all 3 tested as working, and the needles are in better shape. I'm painting ALL the needles tonight. This truck was missing the voltage regulator for the gauge cluster when I bought it. I put one on it from Rock Auto, but those 3 gauges never worked. I've picked up one of RTE's versions of this to install.

I took the amp gauge out of the cluster for closer inspection. Both posts are solid; no movement at all in them. I'm reluctant to do any soldering, since they are still tight. I picked up some brass nuts to use for reassembly. On the back, are these black-ish squares the insulators? I have a can of Deoxit on the way. I will clean all posts, pins, and the spots of contact on the back circuit board area again, and will then reassemble everything.

Re: Safely Wiring Accessories/Amp Gauge Re-wire [Re: jcruse64] #2724030
12/14/19 05:36 PM
12/14/19 05:36 PM
Joined: May 2014
Posts: 156
Paducah, KY USA Earth
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jcruse64 Offline OP
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jcruse64  Offline OP
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Posts: 156
Paducah, KY USA Earth
Got slowed down on this project for a few weeks, but have the gauge cluster all cleaned up and back together and semi-pretty again, ready to re-install. I went with the double-post pieces that Nacho pointed out in a post, to re-route the alternator feed and amp gauge-to-starter relay out of the bulkhead connectors. Got everything under the hood in good shape and in some wire loom, to keep it safe and routed. Took the burned ignition harness connectors apart at the bottom of the steering column and made new connectors for them. I'm running the blue wire to it's own post, so I can run power from it to another spot to power a couple of future add-ons. Also repairing/replacing some bad spots in wires under the dash while it's all out, and have a question for all of you:

There is a welded splice in the harness, under the dash, for several orange wires. These are all for lighting, as far as I can tell. Mice chewed off one wire on driver side of splice, and was the reason I had no dash lights when I first got this truck. I soldered it to the splice, and got my dash lights back. I'd really like to improve my "fix" at this welded splice. I know the welded splice is much better than most other ways to make the connections with these wires in one spot, but would it be a bad idea to cut into this splice and redo it with a butt connector?

Joe

Re: Safely Wiring Accessories/Amp Gauge Re-wire [Re: jcruse64] #2724039
12/14/19 06:46 PM
12/14/19 06:46 PM
Joined: Aug 2007
Posts: 5,636
Caracas, Venezuela, SouthAmeri...
NachoRT74 Offline
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NachoRT74  Offline
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Caracas, Venezuela, SouthAmeri...
solding wires is quite enough. I'd use shrinking tube ( if you still have the chance to use it ) to seal the soldering spot, then tape everything back like it was. Nothing to worry about.


EDITING... just like this:

[Linked Image]

Last edited by NachoRT74; 12/14/19 06:48 PM.
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