Amp reading for Superformance

ralpherickson · #1 (**permalink**) 06-17-2017, 11:00 AM

I just installed a new alternator and it seems to be putting more amps at idle then the previous one. It was a direct replacement so I was not expecting a difference. At idle the new reading is about 25 amps. Is this correct? Thanks in advance for any help.

Mark IV · #2 (**permalink**) 06-17-2017, 11:59 AM

Is this a "one-wire" alternator or are you using the supplied voltage regulator?

Is the replacement alternator new or a reman? These will all affect the idle output of the alternator.

ralpherickson · #3 (**permalink**) 06-17-2017, 12:58 PM

It is a one wire and the alternator is new and an exact duplicate of the the one I replaced. After driving it for about 25 miles the amp meter is showing about 12 amps vs the 25 amps before. I am thinking the battery was not fully charged (due to bad previous alternator) and the increase in amps was the new alternator trying to bring the battery back up to full charge. I now have the battery on a charger and will try again tomorrow after a full charge. Should have thought of this before I bothered people with this post.

cycleguy55 · #4 (**permalink**) 06-17-2017, 05:19 PM

While ammeters are traditional and probably more 'period correct', voltmeters are the way to go, IMO. Apparently I'm not alone: Ammeter vs. Voltmeter: Which is Better? - Hot Rod Network

patrickt · #5 (**permalink**) 06-17-2017, 06:21 PM

Quote:

Originally Posted by cycleguy55

While ammeters are traditional and probably more 'period correct', voltmeters are the way to go, IMO. Apparently I'm not alone: Ammeter vs. Voltmeter: Which is Better? - Hot Rod Network

Ammeters get an undeserved bum's treatment from the internet car sites. Except for when the battery is recharging right after you fire her up, a properly laid out wiring harness has very little amperage going through the ammeter when you're driving it. Plus, better ammeters don't run the entire wire full of current through the gauge itself, only a portion of it is shunted through it. If you know your car really well, then either a volt meter or an amp meter is going to tip you off if something is amiss. So it's really just a matter of personal preference.

ralpherickson · #6 (**permalink**) 06-17-2017, 08:36 PM

Follow up to my original post - after charging the battery fully the amp meter show about +3 or 4 during normal running, just what I expected. The culprit was the old alternator - it was the original , 10 years old and since I live near the beach I think the salt air had corroded some of the internals. I will know more when I take it apart.

Moto One · #7 (**permalink**) 06-17-2017, 08:43 PM

Well this answers why the amp gage is on or near Zero.

Mark.

pgermond · #8 (**permalink**) 11-19-2018, 03:39 PM

A question for an old thread.......... what voltage should I see on a volt meter with a single wire (transpo) regulator?

patrickt · #9 (**permalink**) 11-19-2018, 04:00 PM

Quote:

Originally Posted by pgermond

A question for an old thread.......... what voltage should I see on a volt meter with a single wire (transpo) regulator?

Single wire/three wire/externally regulated/built in/built out/happy/sad it really doesn't matter. Regardless of what it is, or what your load is, I like to see high thirteens or low fourteens on voltage with your revs up past two grand.

tortuga · #10 (**permalink**) 11-20-2018, 06:33 AM

Question: the SPF comes with a voltage regulator bolted to the left fwd engine bay, with a "1 wire" alternator is it actually doing anything? (No obviously) Can it be removed?

Mark IV · #11 (**permalink**) 11-20-2018, 08:27 AM

Quote:

Originally Posted by tortuga

Question: the SPF comes with a voltage regulator bolted to the left fwd engine bay, with a "1 wire" alternator is it actually doing anything? (No obviously) Can it be removed?

No and yes.