I've got a Yanmar 3QM30 with a old 55-amp alternator and an old aftermarket Motorola solid-state regulator attached to it. After spending the night on the boat, I inadvertently left the battery switch on, but every DC breaker and the bilge pump was turned off. Four days later the batteries were completely dead.
With the battery switch on (and ignition key turned off) something was pulling 2 amps. It turned out to be the Alternator/regulator. The regulator instruction sheet says to attach the regulator "red wire" to the "AUX" post. Instead it is on charging post (right on top of the wire to the battery). So whenever the battery switch is on, power is flowing to the regulator, which in turn is apparently energizing the alternator field and drawing 2 amps.
My brain goes all wobbly on me concerning electrical stuff, so forgive my ignorance, but here goes:
1) Does the AUX post always have voltage, or only when the alternator is spinning? (I don't even know if this alternator has an AUX post...) If the AUX post is only energized during rotation, then hook the regulator to the AUX post, problem solved. If not, same problem.
2) Hooked to either the battery or AUX post, does the regulator "sense" the alternator's rotation (if present) and then "turn it on the field"? If so, the regulator is faulty, but this seems like a bad setup. The regulator would be pulling amps out of the batteries even at anchor.
3) If the existing setup is correct (at the alternator) should the battery wire be switched through the ignition switch somehow? That doesn't seem right, because turning off the ignition switch would cause a voltage spike similar to turning off the battery switch while the engine is running, thereby causing a voltage spike and blowing the alternator diodes.
4) Interconnected with this conundrum is the starter solenoid and engine panel. I want to set up the boat with a dedicated cranking battery and charge the house bank "first" (and charge the starting battery via a Xantrex Echo Charge). Should the alternator circuits be isolated from the rest of the engine panel? Or should the solenoid and engine panel be isolated from the starter (starting battery connected to the starter, and starter solenoid connected to the house bank). (Problem: A dead house bank would prevent the starter solenoid from closing.)
Phew.
BTW I - I do have Nigel Calder's book and I have yet to find this situation either addressed in text or in schematic (probably because it is too basic a question).
BTW II - The house bank is comprised of two 115 aH batteries in parallel, for a total of 230 aH. Starting battery to be determined.
If you read all of this, Thanks!
If you respond, THANK YOU!!!!!!!!!!!!!!!!!!!!!!!
Bob
Alternator pulling amps with engine shut down
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bcooke
- Master of the Arcane
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I think an easier way to answer your questions is to briefly describe how the alternator works. I will try to keep it short. Bear with me.
First it helps to explain that an electric current is generated by passing a conductor (wire) through a magetic field. In just the opposite way, a magnetic field is created whenever an electric current is past through a conductor. The two always go together.
Now, an alternator generates current by turning a magnet past lots and lots of wires (also known as windings). To save weight though the 'magnet' is not the hunk of rock (usually magnetite) that you played with in school. The magnetic field in the alternator is created by passing an electric current through a smaller set of windings (lots of wires) in the rotating part. The electric current passes through the rotating part which creates a magnetic field, which because it is spinning, effectively passes across the big windings that are attached around the rotating part against the sides of the case. These big windings are connected to the "+" and "Ground" terminals on the alternator which is where the generated power comes from. Sometimes the "Ground terminal is eliminated and the entire case (which is connected to the rest of the engine and by various paths back to the battery) becomes the "Ground" terminal.
The other terminal is usually called "Field" (short for "magnetic field") . This other terminal is what the rotating element is connected to. Power output from the alternator is controlled by varying the power to the "Field" terminal which is what the regulator does. More power to the "Field terminal results in a higher magnetic field in the rotating part which induces a larger current in the main output. The regulator senses the output voltage and varies the current to the "Field" to maintain the preset system voltage.
In your case the instructions state that you should connect the regulator wire to the "Aux" terminal. If there are only two terminals on the back of the alternator and one is marked "Aux". then I would use it. If, on the other hand, there is a terminal marked "Field" or maybe simply "F", then this is the proper terminal to use to connect the regulator to the alternator. There is some confusion between the naming of the terminals, I don't know why. The sure fire way to make sure is to call the alternator manufacturer. They will tell you instantly which terminals should be used (I have done this in the past). In my own experience, I have never seen an Aux terminal used for anything. I think they are a throw back to an old monitoring sytem that isn't used in today's technology but I am just guessing here.
Hope that helps.
-Britton
First it helps to explain that an electric current is generated by passing a conductor (wire) through a magetic field. In just the opposite way, a magnetic field is created whenever an electric current is past through a conductor. The two always go together.
Now, an alternator generates current by turning a magnet past lots and lots of wires (also known as windings). To save weight though the 'magnet' is not the hunk of rock (usually magnetite) that you played with in school. The magnetic field in the alternator is created by passing an electric current through a smaller set of windings (lots of wires) in the rotating part. The electric current passes through the rotating part which creates a magnetic field, which because it is spinning, effectively passes across the big windings that are attached around the rotating part against the sides of the case. These big windings are connected to the "+" and "Ground" terminals on the alternator which is where the generated power comes from. Sometimes the "Ground terminal is eliminated and the entire case (which is connected to the rest of the engine and by various paths back to the battery) becomes the "Ground" terminal.
The other terminal is usually called "Field" (short for "magnetic field") . This other terminal is what the rotating element is connected to. Power output from the alternator is controlled by varying the power to the "Field" terminal which is what the regulator does. More power to the "Field terminal results in a higher magnetic field in the rotating part which induces a larger current in the main output. The regulator senses the output voltage and varies the current to the "Field" to maintain the preset system voltage.
In your case the instructions state that you should connect the regulator wire to the "Aux" terminal. If there are only two terminals on the back of the alternator and one is marked "Aux". then I would use it. If, on the other hand, there is a terminal marked "Field" or maybe simply "F", then this is the proper terminal to use to connect the regulator to the alternator. There is some confusion between the naming of the terminals, I don't know why. The sure fire way to make sure is to call the alternator manufacturer. They will tell you instantly which terminals should be used (I have done this in the past). In my own experience, I have never seen an Aux terminal used for anything. I think they are a throw back to an old monitoring sytem that isn't used in today's technology but I am just guessing here.
Hope that helps.
-Britton
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bcooke
- Master of the Arcane
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- Joined: Sat Oct 04, 2003 10:55 pm
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Now to the questions:
#1 As I understand it, the Aux post usually is just an auxiliary connection to the main power output so it is only powered when the alternator is spinning and power is being applied (via the regulator) to the field windings.
#2 The regulator senses the output of the alternator by sensing the voltage in the system. If the voltage is low then the regulator will try and send more current to the field windings. The regulator is usually disabled by breaking the connection between it and the field windings of the alternator. I believe this is normally done through the ignition switch but it could also be done by the accesories switch (both are on the key switch - different positions of the key activate the two switches). I have seen the wiring done through either switch but I am pretty sure the ignition switch is the "preferred" way. Maybe I have that backwards, I guess I should look that up and get back to you.
#3 ... oh, I think I get it now... Your regulator is suppsed to sense the system voltage through the Aux terminal. The + and Aux are connected to the same windings so you can use either one. The fact that yours is connected to the + terminal at the moment shouldn't be a problem except that now you have a stack of wire connecters piled up on a single terminal. Since you are getting a current draw that means the regulator is not shutting off. Trace its power wire back to where it is picking up its power. It should be the key switch but someone may have wired it directly to the battery either intentionally or perhaps by connecting the terminal end to the wrong terminal on the key switch. With a direct connection to the battery the regulator won't turn off until the battery is dead.
#4 I really can't help you there. Your first priority I believe should be to recharge the engine start battery since it takes a big wallop every time you crank the engine. To then connect a house bank you can use a manual switch, automatic switch, or a fancy charging box that has the multi-stage/multi bank/ multi complex features. There are too many options to go over that I don't know enough about yet.
-Britton
#1 As I understand it, the Aux post usually is just an auxiliary connection to the main power output so it is only powered when the alternator is spinning and power is being applied (via the regulator) to the field windings.
#2 The regulator senses the output of the alternator by sensing the voltage in the system. If the voltage is low then the regulator will try and send more current to the field windings. The regulator is usually disabled by breaking the connection between it and the field windings of the alternator. I believe this is normally done through the ignition switch but it could also be done by the accesories switch (both are on the key switch - different positions of the key activate the two switches). I have seen the wiring done through either switch but I am pretty sure the ignition switch is the "preferred" way. Maybe I have that backwards, I guess I should look that up and get back to you.
#3 ... oh, I think I get it now... Your regulator is suppsed to sense the system voltage through the Aux terminal. The + and Aux are connected to the same windings so you can use either one. The fact that yours is connected to the + terminal at the moment shouldn't be a problem except that now you have a stack of wire connecters piled up on a single terminal. Since you are getting a current draw that means the regulator is not shutting off. Trace its power wire back to where it is picking up its power. It should be the key switch but someone may have wired it directly to the battery either intentionally or perhaps by connecting the terminal end to the wrong terminal on the key switch. With a direct connection to the battery the regulator won't turn off until the battery is dead.
#4 I really can't help you there. Your first priority I believe should be to recharge the engine start battery since it takes a big wallop every time you crank the engine. To then connect a house bank you can use a manual switch, automatic switch, or a fancy charging box that has the multi-stage/multi bank/ multi complex features. There are too many options to go over that I don't know enough about yet.
-Britton
Well, I think this is the problem. The + leads straight to the positive battery post (through the A-both-B switch), so the regulator is always "powered up" and it is always sensing the system voltage. With the engine off, it is sensing 12.25 volts (at full charge) or less, so it is turning the field on (I guess) and then drawing 2 amps. The regulator has three wires, black (ground), green (field), and red (to AUX, but in this case it is hooked to +). Nothing is switched. If AUX and + are the same, then yes, it doesn't matter - but it will have this problem. If the AUX and the + are the same, I could connect the red regulator wire to the ignition switch to sense system voltage - then it is sensing the starting battery voltage unless they are in parallel (either through the battery switch or through an automatic battery combiner).bcooke wrote:Now to the questions:
#3 ... oh, I think I get it now... Your regulator is suppsed to sense the system voltage through the Aux terminal. The + and Aux are connected to the same windings so you can use either one. The fact that yours is connected to the + terminal at the moment shouldn't be a problem except that now you have a stack of wire connecters piled up on a single terminal. -Britton
If AUX only has power when the alternator is spinning, then that is the solution. The AUX should power the charging idiot light/voltmeter and perhaps the tachometer. Maybe I just answered my question - connect it to AUX. (This is the problem - I can't see if it has an AUX terminal, and the Yanmar manual that came with the boat describes an internally regulater alternator, with E B and L terminals - Ground, Battery, and Lamp, respectively.)
I just looked at the wiring diagram for a Balmar regulator. It has a special wire running to the ignition switch.
Mr. bcooke, thank you for your help!
Bob
Problem fixed, for now.
Here's the story:
New regulators have multiple wires, among these are Ground, Field, Battery or +, and Ignition. The regulator doesn?t work until switched on by the ignition system.
My ancient regulator has three wires, green, black, and red. Green for Field, Black for Ground, and Red should be hooked to AUX on the alternator. The alternator doesn?t have AUX, so the previous owner hooked it to the output post on the alternator. This wire supplies power to the regulator and the regulator senses the state of the battery through the same wire.
I moved the red wire to the ignition switch, so that it is now sensing the battery state there and is only ?powered up? when the key is on. No more 2 amp draw.
That solves the problem for now and for a long time. Thank you Britton for your help!
Stop reading now if you want...
If I decide to add an additional starting-only battery and eliminate the dreaded A-B-Both battery switch, then I have to rewire. I want to charge the house bank first, and siphon off juice to charge the starting battery (using the Echo Charge device).
The ignition switch takes its power from the starter post that is connected to the battery. Therefore the regulator will always sense the starting battery, even if the + side of the alternator goes to the house bank.
A hot wire leads from the battery cable on the starter to the keyed ignition switch. On the other side of the ignition switch is a wire that leads to the pushbutton start switch. A wire on the other side of the starter button leads to the solenoid. Push the button and current flows back down to the starter solenoid, pushing out the plunger to make a connection between the starting battery cable and the starter motor.
I think I can I use another power source (the house bank) to energize the solenoid. It seems that the solenoid is only a coil (it can?t be interconnected to the starting battery somehow, can it?) - energize it and the plunger moves forward making the cranking connection.
If I power the solenoid from the house bank, I would want to put another starting switch somewhere else in the boat - a momentary switch from the starter + terminal to the solenoid (key switch probably). Otherwise if the house bank is dead the solenoid won?t engage and the connection between the battery and starter motor won?t happen, even if the starter battery is topped off. A parallel switch between the batteries would work too, basically jump starting the house bank for the sole purpose of engaging the solenoid ? but then their might not be enough power to crank the engine (assuming the dead house bank immediately sucks the life out of the starting battery).
However, if the main ignition key is in the start position, engaging the back up starting switch would parallel the batteries and might fry the skinny wires. I would have to be sure to turn off the main ignition key first (hey, if they used the same key?).
Hmm?.
The alternator is a Hitachi, externally regulated, and doesn't match what is in the 3QM30 service manual. It doesn't have an AUX terminal, but it does have an "N". I haven't been able to figure out what this is for. I think that is for the charging lamp.
Here's the story:
New regulators have multiple wires, among these are Ground, Field, Battery or +, and Ignition. The regulator doesn?t work until switched on by the ignition system.
My ancient regulator has three wires, green, black, and red. Green for Field, Black for Ground, and Red should be hooked to AUX on the alternator. The alternator doesn?t have AUX, so the previous owner hooked it to the output post on the alternator. This wire supplies power to the regulator and the regulator senses the state of the battery through the same wire.
I moved the red wire to the ignition switch, so that it is now sensing the battery state there and is only ?powered up? when the key is on. No more 2 amp draw.
That solves the problem for now and for a long time. Thank you Britton for your help!
Stop reading now if you want...
If I decide to add an additional starting-only battery and eliminate the dreaded A-B-Both battery switch, then I have to rewire. I want to charge the house bank first, and siphon off juice to charge the starting battery (using the Echo Charge device).
The ignition switch takes its power from the starter post that is connected to the battery. Therefore the regulator will always sense the starting battery, even if the + side of the alternator goes to the house bank.
A hot wire leads from the battery cable on the starter to the keyed ignition switch. On the other side of the ignition switch is a wire that leads to the pushbutton start switch. A wire on the other side of the starter button leads to the solenoid. Push the button and current flows back down to the starter solenoid, pushing out the plunger to make a connection between the starting battery cable and the starter motor.
I think I can I use another power source (the house bank) to energize the solenoid. It seems that the solenoid is only a coil (it can?t be interconnected to the starting battery somehow, can it?) - energize it and the plunger moves forward making the cranking connection.
If I power the solenoid from the house bank, I would want to put another starting switch somewhere else in the boat - a momentary switch from the starter + terminal to the solenoid (key switch probably). Otherwise if the house bank is dead the solenoid won?t engage and the connection between the battery and starter motor won?t happen, even if the starter battery is topped off. A parallel switch between the batteries would work too, basically jump starting the house bank for the sole purpose of engaging the solenoid ? but then their might not be enough power to crank the engine (assuming the dead house bank immediately sucks the life out of the starting battery).
However, if the main ignition key is in the start position, engaging the back up starting switch would parallel the batteries and might fry the skinny wires. I would have to be sure to turn off the main ignition key first (hey, if they used the same key?).
Hmm?.
The alternator is a Hitachi, externally regulated, and doesn't match what is in the 3QM30 service manual. It doesn't have an AUX terminal, but it does have an "N". I haven't been able to figure out what this is for. I think that is for the charging lamp.
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bcooke
- Master of the Arcane
- Posts: 2272
- Joined: Sat Oct 04, 2003 10:55 pm
- Boat Name: Jenny
- Boat Type: 1966 Pearson Triton
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I think the problems you suggest are the reason why you don't see the wiring system set up the way you propose I am curious. What are your reasons for setting up the electrical system this way?
If a 1,2,Both battery switch is what you want to avoid, I know Nathan and probably many others (and most likely me when I get to it) is/are using a relay that connects the two battery banks whenever the engine charging system is operating. With the engine shut down the batteries are separated, when the alternator is producing power then the relay connects the batteries so that all of them can be charging. I am sure Nathan can fill you in on the details.
-Britton
If a 1,2,Both battery switch is what you want to avoid, I know Nathan and probably many others (and most likely me when I get to it) is/are using a relay that connects the two battery banks whenever the engine charging system is operating. With the engine shut down the batteries are separated, when the alternator is producing power then the relay connects the batteries so that all of them can be charging. I am sure Nathan can fill you in on the details.
-Britton