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Old Nov 21, 2014 | 05:16 PM
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Default Alternator wiring

Transplanting a 2001 LS1 into something non-GM. I'm using a Megasquirt ECU and a custom wiring harness.

The alternator plug has only one wire. Is that the exciter wire for the internal voltage regulator? That's usually controlled by the ECU. Does it need 12v? or 5v?
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Old Nov 21, 2014 | 10:50 PM
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Bob, yes that is the exciter wire. I believe that the control voltage is a range up to 5v.
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Old Nov 22, 2014 | 08:20 AM
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If it's less than 5v, I can run an output from the ECU.

If it's 6v or higher, I can use a keyed circuit and a ballast resistor. Which I like better. Alternators can be noisy, and when they start to go bad they can make nasty spikes and surges, which could damage the ECU.

Any idea on how many amps that circuit draws?
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Old Nov 22, 2014 | 01:20 PM
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Bob,
Here's an update/correction of my answer.
With the 98, I haven't seen anything over 5 volts. However, this is not the complete answer, nor does the same LS1 alternator wiring apply to every year.
Read this for more exact info, and note the discussion of a resistor, or sometimes, a ballast lamp.
Sorry, I had forgotten the particulars.

https://ls1tech.com/forums/conversio...d-voltage.html

Glenn
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Old Nov 22, 2014 | 08:50 PM
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Originally Posted by gMAG
Bob,
Here's an update/correction of my answer.
With the 98, I haven't seen anything over 5 volts. However, this is not the complete answer, nor does the same LS1 alternator wiring apply to every year.
Read this for more exact info, and note the discussion of a resistor, or sometimes, a ballast lamp.
Sorry, I had forgotten the particulars.

https://ls1tech.com/forums/conversio...d-voltage.html

Glenn
Pretty interesting; thanx.

I had read about the resistor. But I also read of some failures, and a voltage reducer was more reliable. A 12v to 6v reducer is cheap and readily available. I just don't know! By the time you read for an hour, one thing contradicts the other and it all becomes a blur.

Anybody know how many amps this circuit draws?
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Old Nov 23, 2014 | 11:30 AM
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Originally Posted by .boB
Pretty interesting; thanx.

By the time you read for an hour, one thing contradicts the other and it all becomes a blur.

Anybody know how many amps this circuit draws?
I wish I had a dollar for every incorrect part I bought, as a result of contradictions.
I didn't see an answer for the amps/milliamps question.
If need be, email John @ Speartech.com. He is the electric gooroo around here, and a sponsor.

Glenn
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Old Nov 23, 2014 | 10:42 PM
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Thanx, I'll do that.
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Old Dec 1, 2014 | 08:38 PM
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I soldered in the resistor and it works great, after frying one without it lol.

Not much time on it, though. The resistor was probably 3 dollars for a 3 pack. I'm using a Holley Dominator, might be different.

I'll ship you one of my extras for free!
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Old Dec 2, 2014 | 09:25 AM
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Thanx for the offer. I'm leaning towards the in line resistor. It's an easy modification, and I have a couple of them left over from a previous project. I think they came in a 5 pack.
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