Self Exiting alternator

[Nathan35]

Hi folks , I’ve replaced the alternator on my campervan for a more powerful self exiting one , now that the exciter connection is unplugged it throws the red low voltage dash lights up even tho it’s charging properly and no low voltage on the van , is there a way to get around this and connect the exciter lead from the van to something so my dash lights go off , any help appreciated thanks

 

[BrendanC]

would be helpful to have a make year and model aswell as the new alternator OEM fitment.

 

[Nathan35]

would be helpful to have a make year and model aswell as the new alternator OEM fitment.

It’s a Vauxhall Movano 2.3 diesel 2014 , this is the alternator that came off I’ve been told it’s Bss coms , the new one is a 300 amp self exiting so doesn’t need the exiter wire the pics are the old alternator , thanks

 

[zzyzzx]

It's a self exciting alternator. As in:

Self excitation alternators are a type of electric motor that uses self-generated electricity to power the machine. This type of motor is different from a regular alternator in two main ways: First, self-excitation alternators use a permanent magnet to create a field that causes the rotor to rotate.

As a reference it has less wires going to it, or maybe even only the one wire output.

 

[mk378]

I think if you connect the ignition wire to the light wire (i.e. jump together the two wires in the small plug) it will simulate the stock alternator working properly and the light will stay out.

 

[ripcord]

You could connect your alternator light wire to a switched 12v source. By "switched" I mean one that has voltage only when the ignition is on.

 

[supton]

So the alternator is working properly...

Not 100% sure on how this works but it sounds like, the idiot light is what supplies a small current to the exciter coil, then the alternator, when working, will backfeed 12V to the line. The light gets 12V across both sides and so it doesn't light up. Link. So if you just connect 12V to this now unused wire, good to go.

Do you have a voltage meter? If so, then all is fine. If all you have is the idiot light, then I would want to make a circuit that would only apply 12V when more than 13.4V (?) is present.

 

[Nathan35]

It's a self exciting alternator. As in:

Self excitation alternators are a type of electric motor that uses self-generated electricity to power the machine. This type of motor is different from a regular alternator in two main ways: First, self-excitation alternators use a permanent magnet to create a field that causes the rotor to rotate.

As a reference it has less wires going to it, or maybe even only the one wire output.

It just needs the B post and earth , it doesn’t need the ignition wire plugged in , but because it’s not plugged in it throws the red low voltage light , need a way of bypassing the ignition exiter wire

 

[barryh]

In a wound rotor alternator the charge lamp comes on before starting the engine because it has battery voltage on one side of the lamp and the other side is earthed via the alternator rotor winding which will be just a couple of ohms. After the engine starts it then sees the charging voltage on both sides and therefore it goes out. The lamp served a purpose in passing current to the wound rotor to kick start the magnetic field. Now it has no purpose so why not simply remove the bulb.

 

[Nathan35]

In a wound rotor alternator the charge lamp comes on before starting the engine because it has battery voltage on one side of the lamp and the other side is earthed via the alternator rotor winding which will be just a couple of ohms. After the engine starts it then sees the charging voltage on both sides and therefore it goes out. The lamp served a purpose in passing current to the wound rotor to kick start the magnetic field. Now it has no purpose so why not simply remove the bulb.

I haven’t removed the bulb because it’s not only the red battery bulb , there’s a red stop sign bulb and all the other dash info goes blank , like mileage, mpg ,time .. it would be better for me to find a way to trick the exiter wire into thinking it’s connected somehow ( not sure that’s even possible hence the post )

 

[MolaKule]

@Nathan35 "the new one is a 300 amp self exiting so doesn’t need the exiter wire"

What brand is the new one so we can look at the wiring? I think you're going to need an isolation diode somewhere in the circuit in order to get the light to extinguish.

Other than the + post to the battery and ground, what other connectors does it have?

You're also going to have to decrease your wire gauge (increase cable size) depending on length.

 

[Nathan35]

@Nathan35 "the new one is a 300 amp self exiting so doesn’t need the exiter wire"

What brand is the new one so we can look at the wiring? I think you're going to need an isolation diode somewhere in the circuit in order to get the light to extinguish.

Other than the + post to the battery and ground, what other connectors does it have?

Hi it’s a specially made alternator by D2U alternators in the uk , there’s the B post and a single pin on a connector on the alternator , the old alternator Also had a single pin connector and the b post , the new one doesn’t require the single pin so that connector doesn’t even need to be plugged in and doesn’t do anything if it is , there is a single wire going into a connector that comes from the ecu I’m guessing that fits into that connector on the alternator , so I need something that connects to the wire from the ecu and makes it think there’s voltage so the lights go out and the dash info comes back , thanks for the reply

 

[MolaKule]

Hi it’s a specially made alternator by D2U alternators in the uk , there’s the B post and a single pin on a connector on the alternator , the old alternator Also had a single pin connector and the b post , the new one doesn’t require the single pin so that connector doesn’t even need to be plugged in and doesn’t do anything if it is , there is a single wire going into a connector that comes from the ecu I’m guessing that fits into that connector on the alternator , so I need something that connects to the wire from the ecu and makes it think there’s voltage so the lights go out and the dash info comes back , thanks for the reply

For the warning light to be extinguished, there has to be the same voltage on each side of the light terminals (no current flow).

For the light to shine, you must have a current flowing; so on one side of the light a positive (Bat+) voltage from the ignition switch must be present, and on the other side you must have a ground or near ground. So why is the light glowing? Something on the other side is grounding the low side of the light. So something else is pulling the low side of the light to ground. Could it be the PCU? You're going to have to look at your vehicle's wiring system to find out.

JEGS says: "NO WARNING LIGHT Note that a 1-wire alternator does NOT permit the use of a charge warning (idiot) light. Most hot rodders and muscle car enthusiasts prefer the use of a voltmeter or ammeter to monitor charging. However, certain JEGS alternators noted below have terminals that may be used for a warning light. To wire a warning light using one of these alternators, simply remove the terminal plug cover and connect the R (Left terminal, looking from the back of the alternator) to the warning light wire."

 

[mk378]

Is this same alternator used on any car that was sold in the USA that many of us could look up a diagram? Does the stock alternator have an internal voltage regulator, or does the PCM regulate it?

 

[MolaKule]

Is this same alternator used on any car that was sold in the USA that many of us could look up a diagram? Does the stock alternator have an internal voltage regulator, or does the PCM regulate it?

@Nathan35 In my experience, for a single-wire self-excited alternator, there has to be an internal voltage regulator that regulates to a constant voltage for the battery. It senses the voltage between the single output post and ground.

The self-excited alternator samples (senses) the battery voltage to start creating enough magnetism in the rotor poles (magnetic field windings).

 

[LvR]

Caution here - even though only a single wire, most all modern alternators in modern vehicles run on a type of LIN bus to tell the alternator if, when and how much to charge - the instructions come from a BMS/BSS or equivalent in the form of either pulse width signals or a varying constant voltage on the single wire going to the alternator.

So - do NOT go connect that plug to ignition - chances are you will blow/damage the ECU/BMS/BSS or whatever drives that charging instruction and you will end up with a Christmas light show on the dash.

I reckon you may have to write the alternator out of the BMS/BSS and/or DASH module configuration to solve the dash light thing (if that is even possible)

 

[Nathan35]

Caution here - even though only a single wire, most all modern alternators in modern vehicles run on a type of LIN bus to tell the alternator if, when and how much to charge - the instructions come from a BMS/BSS or equivalent in the form of either pulse width signals or a varying constant voltage on the single wire going to the alternator.

So - do NOT go connect that plug to ignition - chances are you will blow/damage the ECU/BMS/BSS or whatever drives that charging instruction and you will end up with a Christmas light show on the dash.

I reckon you may have to write the alternator out of the BMS/BSS and/or DASH module configuration to solve the dash light thing (if that is even possible)

Thanks for the reply , yes I’ve come to thinking there’s no real way around it , if I want the big alternator ( I’m going up to the arctic this winter and need plenty of umph for charging my leisure batterys offgrid) I’m going to blank the lights off under the cluster , the electrical system works perfectly apart from the lights and it turns off the mileage mpg etc after about 15 seconds ( I’d rather have the extra alternator power than that info ) for this trip anyway , I can always put my old alternator back on after the trip if I want , many thanks again for the reply’s

 

[LvR]

You can try removing the old alternator regulator from the alternator and plugging the exciter wire into that - make sure you have battery 12v and ground going to the appropriate points on THAT and it should kill the dash moan too - isolate the lot in a plastic case and you may get lucky that way

 

[Nathan35]

You can try removing the old alternator regulator from the alternator and plugging the exciter wire into that - make sure you have battery 12v and ground going to the appropriate points on THAT and it should kill the dash moan too - isolate the lot in a plastic case and you may get lucky that way

Ok thanks , I’ll have a go at that and see if it works , fingers crossed then

 

[Nathan35]

So if this was the rectifier ( it will be similar) the exiter wire obviously goes to the plug input , do I need another 12v feed going into it too ? And does the earth go to the prongs ? Thanks