One wire 6 volt alt.

[Don]

I know you have to increase rpm to get alt started charging on start up. Sometimes I forget to race engine on start up and alt will not start charging even going down the roAd at 20 mph.Is there a way to get it started charging or is there a problem.Have a new optima battery??? Even with lights on ,no charge,battery never goes down. Bad amp meter?????

[Mike V. Florida]

You have alternator problems if it does not start charging if you are driving 20mph. Rolling down a hill with the engine at an idle ok, but not driving.

[BRENT in 10-uh-C]

Well, remember the regulator only tells the alternator to charge when the battery actually 'needs' it, --not just because there is an opportunity to charge. As for a way to excite the regulator, there is a headlight relay available from NAPA that has a diode built into it that I have used where I connected a wire from the stop light switch to the field of the alternator. As soon as the brake pedal is pushed, it energizes the field coil and the alternator begins charging (--if needed).

[stewwolfe]

If you are a person who shifts at slow speeds you could get into third gear at 20 MPH without energizing the alternator! but once you get up to cruising speed it should energize. If I notice that I'm not charging at idle I generally pump the gas pedal once and it kicks in. If I don't notice I'm not sure what happens, but I've yet to have a dead battery since installing the alternator, so I must assume that it eventually kicks in and starts charging.

[BILL WILLIAMSON]

When starting your car, you're supposed to "ROAR" it up, to attract ATTENTION!
Insecure Bill W.

[Smog Tech]

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One wire alternators are self energizing. They must run above idle speed before they start charging. Once you do this they will continue to charge at low RPM’s. Alternators factory installed are energized by power from the ignition switch. They start charging immediately.

[Don]

Anyway to energize the alt, with a push button sw .number 3 post above was using the brake sw but not clear on connection to alt,

[BRENT in 10-uh-C]

Originally Posted by Don

Anyway to energize the alt, with a push button sw .number 3 post above was using the brake sw but not clear on connection to alt,

Yes, you can energize it by momentarily placing a powered lead onto the #2 terminal on the alternator. Looking at the backside of the alternator, this is the blade terminal on the Right side. My suggestion above was to use the brake light switch to momentarily power/energize the regulator by running it thru a NAPA AR274 diode switch.

[Mike V. Florida]

Originally Posted by Smog Tech

One wire alternators are self energizing. They must run above idle speed before they start charging. Once you do this they will continue to charge at low RPM’s. Alternators factory installed are energized by power from the ignition switch. They start charging immediately.

But he says that he has to get the car running faster then 20 mph to get it to charge.

[Smog Tech]

I think there is a problem with the alternator if you must go 20 mph to charge. Could be loose fan belt.

[hardtimes]

Originally Posted by Don

I know you have to increase rpm to get alt started charging on start up. Sometimes I forget to race engine on start up and alt will not start charging even going down the roAd at 20 mph.Is there a way to get it started charging or is there a problem.Have a new optima battery??? Even with lights on ,no charge,battery never goes down. Bad amp meter?????

Hey Don,
Sounds that you have a ONE wire alt, no ?
If a one wire is in use, as said, sounds like you have a problem with alternator. I have one wire that has worked flawlessly for 10 years. Upon startup, just a slight rev (maybe 1000)above idle (500rpm) starts/excites the system. Two things: the charge almost immediately shows needle at middle when battery is full/near full..it just fills up / charges that used to start up engine; and be sure fan belt has no more than a inch deflection +/- a little

[machine girl]

hardtimes is right a tap on the petal should start charging, have been building one wire alternator kits for over 20 years, no need for diodes etc. the correct rectifier and regulator on a 6 volt pos. ground system must be the right ones. do not jump the regulator, you will most likely short it out .

[tbirdtbird]

by his own admission this only happens if he fails to rev the motor up after he first starts it. (obv. a one-wire alt.) You could conceivably not have the revs up enough if you are a slow driver and only got up to 20 mph (this was already said).

Rather than fiddle around with a whole bunch of relays, diodes, switches, etc that are not needed and may harm something, wouldn't it be easier to just rev up the motor before you start out? Every time? You need about 1500 rpms for these babies to kick in.

That is what most of us 1-wire boys do....

In any case, Terminal 1, the excitation terminal, should only have momentary 6V, NOT constant 6V. If constant, the alt. will peg at full output and you will destroy it.

Just rev it to 1500 every time, done.

[Keith True]

What I can't figure out is why anybody should care if it charges or not right off the bat.You can drive it for hours with a slight discharge,and it will still start.The battery is not going to run down in the time it takes for you to get up to speed and start charging.There is just no reason for it to HAVE to start charging as soon as you start it.Well,there may be a reason,but I've just never heard one.I don't like revving a cold engine either.As soon as you get rolling it will charge,starting to charge a minute,or five,or ten later makes zero difference.I think I would just enjoy it.

[jrelliott]

I have the information of how to convert the one wire alternator to a 3 wire so the alternator will energize as soon as you start the engine. It only requires a diode, some wire, a few connectors and the DA plug available at auto parts store. If you would like the info please send me an email to [email protected]. Contrary to what tbirdtbird says this mod will not cause the alternator harm or electrical system harm. It is a mod that is sold by reptuable suppliers at a cost of about $15.00, but I figured out what they had done and will relay on the info for free.

[Don]

Don't know if problem or not,today start up and rev engine ,starts charging,20 seconds later goes to 0 charge raise rpm ,no charge,turn on lights shows discharge.go on and drive 20 miles to house ,no charge even with lights on.,Raise rpm ,still no charge

[Tom Wesenberg]

Originally Posted by Don

Don't know if problem or not,today start up and rev engine ,starts charging,20 seconds later goes to 0 charge raise rpm ,no charge,turn on lights shows discharge.go on and drive 20 miles to house ,no charge even with lights on.,Raise rpm ,still no charge

But, does it show discharge, or stay on 0?

[Don]

Shows discharge.

[tbirdtbird]

Regardless of anything above, please know that there are 2 very distinct types of GM 10si alternator regulators.

1. standard or non-self-exciting (also known as the 3-wire alternator). This type requires voltage to the number 1 terminal at all times the engine is running, if you want it to charge. If you set this up for key-on, then the motor will not turn off when you turn the key off because it will back-feed. This is solved very simply using a 1 dollar diode in the wire you run to the #1 terminal. You do not need relays, etc.

2. Self-exciting (also known as 1-wire). On a brand-new install, you may need to momentarily connect voltage to terminal 1 to get it to charge. This is a one-time event. Otherwise, once revved to 1500 it will self-excite. If you have voltage going to this terminal at all times, you will peg the alternator to full output at all times and ruin something. If you do not believe this, try it and get back to us.

The point is the two regulators are very different, and behave differently. You cannot interconvert a 3-wire to a 1-wire without a change of regulator or vice-versa.

Another point that I am sure some "expert" will challenge me on is that with the so-called 3-wire system you do NOT have to have a wire connected to terminal 2 at all. You can connect it to the main output terminal if you wish but this is not necessary

I agree with a poster above who wants to know why everyone insists the alternator kick in instantly but that is a different story.

OK, since this IS the Fordbarn, I expect a multitude of inexperienced users to tell me how wrong I am about all this. Despite that I work with both types of alternator setups day in and day out.

[w.michael]

tbird,

I have the one wire 6v pos ground. Of course, I have to rev it up a bit to get it to charge. I don't care that it doesn't start to charge immediately. But am I doing any damage to the alternator if I continue to run it for a period of time at low rpm's and with no output? That is, does it matter if I don't rev it up fairly quickly? I just don't want to damage my alternator.

W. Michael