Alternator conversion question

Mnethercutt · May 22, 2020

Sorry for asking a question that's probably been asked 100 times but I'm having trouble finding what I'm looking for. I'm planning to convert to a one wire alternator on my JD 1010 and I'd like to wire it so that the indicator lamp still works. Does anyone have a link to a wiring diagram or can explain how that would wire up? I've found links with how to install the alternator and how you'd do it with a three wire but nothing on a one wire. Thanks!

Ultradog MN · May 22, 2020

To have your indicator light work I think
you can only use a 3 wire setup.

DeltaRed · May 22, 2020

Throw the 'idiot' light away and put an amp gage in it's place.

Mnethercutt · May 22, 2020

I'd love to do that but I don't have a spot on the dash for it. Is it normal for three wire alternator to have a cover on the two smaller posts? The one I have I got off another engine and just put it in the shop and forgot about it, but it's got what feels like a rubber cover where the posts would be on a three wire.

Thanks

Russ from MN · May 22, 2020

Or better yet a voltmeter!

Butch(OH) · May 22, 2020

If your talking about a 10SI Delco why
not just run the 3 wire? You have to run
your idiot light wire either way same
with the charging wire, only additional
wire would be a short jumper.

Steve@Advance · May 22, 2020

Someone was asking the same question a while back. I don't think they ever followed up with the results or if they ever tried to connect a light.

The suggestion was to pry the rubber cap out and see if there were terminals under the plug.

If so, and the #1 terminal showed battery voltage when running, then it could be used to operate a charge indicator light.

But... There are conditions where the alternator could be failing to produce a satisfactory charge and still not set the light.

I would consider a volt meter over a light.

PS, just found this, never tried one, but it's a low voltage sensor that sets a light when the voltage falls below 11 volts. That sounds low to me, it probably wouldn't start at that low voltage, but it would tell you to take action before finding out the hard way.
Voltage Monitor

Janicholson · May 22, 2020

I agree, the circuit that creates the indicator lamp is the excite circuit. in the alt. That is what is disabled to make it one wire. A volt meter, or a 3 wire are reasonable options. Remember the only part of a 3 wire system that is beyond the alternator is the indicator lamp circuit. And the lamp is the the part that keeps it from running after shutoff. Jim

John M · May 22, 2020

A 3 wire would work just fine. You already have the light, just wire it in instead of another light.

Gambles · May 22, 2020

"Or better yet a voltmeter!"

^This. The voltmeter can tell you just about everything you need to know about your charging system.

Ray IN · May 23, 2020

I just had the 10SI alternator off my 4020 diesel. Took it to the electric shop because the post was loose and not charging. He
fixed it up and confirmed that it was a one-wire. I wired up up as a three-wire because I wanted to be able to see the light go
off. It seems to be working fine, just like a three-wire would. And it had been on there for years wired as a one-wire.

Mnethercutt · May 23, 2020

Thank you for all the fast replies. I'll see if that little cover comes off and if it does then I'll definitely wire it as a three wire. If not then I found a volt meter at tractor supply and I'll put that on and 3D print a new gauge cluster mount. I'll keep y'all posted with the results.

Mnethercutt · May 23, 2020

Got the cover off and its now running as a three wire with the idiot light. Took it a minute to start charging when I first cranked it but it will charge at idle so that's nice.

Now I have an unrelated electrical issue. The whole reason I converted to alternator was to add in an electronic tachometer from Datcon. I've got it wired up and working, but when I hook it to the negative side of my coil it kills my spark. The tach will read the correct cranking RPM but I can't start it since the spark is dead. Anybody have any ideas or know who I could contact? I haven't been able to find a Datcon website for help.

Janicholson · May 23, 2020

THough I do not know the correct way, It is wired incorrectly (I assume the negative side of the coil goes to the
distributor) Jim

Alternator conversion question

Mnethercutt

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Ultradog MN

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DeltaRed

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Mnethercutt

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Russ from MN

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Butch(OH)

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Steve@Advance

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Janicholson

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John M

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Gambles

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Ray IN

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Mnethercutt

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Mnethercutt

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Janicholson

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