Huge spark at alternator positive terminal

[sailboatliving]

I got a huge spark at least 1 inch when I started to unscrew the positive on the back of my Balmar K6 120 amp alternator, the engine and alternator was off. It left a mark on the tool.


Is this a short? I had only had the boat for 2 months and would not have been able to identify an alternator 2 months ago

The eyes on the cables are not touching the alternator chassis or the engine.

There are two positive thick battery cables on the alternator and one is connected to the engine and then battery switch on its way to the starter battery, The other which I think caused the spark is going to an 150 amp ANL fuse then to battery switch for house. I removed the cable on the ANL fuse (with just a minor spark) and then there was no spark at the alternator connection point.

A few days ago I removed the negatives for house and starter but the spark was still there.

My external regulator is not working so I was trying to hook up a wire for the internal regulator to work. But it is not charging, I connected the ignition wire and sense wire.

The alternator was (over) charging the batteries with the defect regulator (Balmar 614) connected.

I'm at sea of Cortez, far from nearest town and they will not have a marine alternator anyway.

Second question, what should I disconnect to run the engine without the alternator involved? The positive red cables? I can't remove the belt. The solar give just enough energy for the batteries if I ration

 

[Sandy]

Was the battery turned on? You may have accidentally touched the engine, part of the negative side, with the screw driver that was on the positive side of the alternator.

There is no such thing as a marine alternator, there is only an alternator.

In theory, it is not something I have ever done, you can run the engine with out an alternator attached, but make sure you remove it AND consider how you are going to start the engine after you switch it off.

Good luck.

 

[sailboatliving]

I turned off both battery switches before I did anything.

I'm pretty sure I didn't touch the engine or anything else with the adjustable wrench. The negative terminal is far away, so I definitely didn't touch that. It happens every time, not just once.

 

[Supertramp]

The real question is why it's live if everything is "off". Something must be wrong!

Do you have a test meter so you can test for dead (or live). Appreciate that may not be easy where you are!

You can also check the charging voltage with it if you don't have volts monitoring in place.

I would make sure my solar was disconnected when running the engine (and testing things) as there is some discussion on other threads about alternators/regulators getting confused by the solar charging voltage. I have an isolation switch on the +ve feed from the solar panel.

I have had my regulator trip out on overcharging, but only when everything is fully charged and the voltage rises to 14.8 or so. I have in the past bypassed the regulator as the alternator has a built in regulator (don't know if this the case with Balmar). You will need a wiring diagram to follow but it's straight forward and reversible if you use existing connectors and make up bits of joining wire. The positive does not need changed, only the smaller wires.

If you disconnect the alternator, your engine will run for ages provided you start with a fully charged engine battery. It should also give you plenty of starts - I have run for 2 days intermittently like this.

Much easier to do this at anchor or docked rather than while sailing!

 

[lynnx22]

Firstly, if you disconnect ALL wires from the alternator it will simply be a pulley - no load in = no load out.
Saves finding another belt that is shorter, and then you can run the engine. If its a diesel then it will consume no power whilst running.

Sound like your house battery switch is not working or you have an "extra" connection somewhere. Old boats have had many fingers in the pie - who knows whats connected where!
If you have a alternator with 3 terminals (one small, two big) then you probably have a self regulating alternator and should not need an external regulator.
The small one is for the sensing wire and should be connected starter solenoid +/ignition switch/warning lamp/alternator.
The lamp acts as a resistor and the resulting voltage is what excites the alternator - no lamp ,no charging.

Other than that, without a circuit diagram or look see ........ Good Luck!!!

 

[Beneteau381]

Was the battery turned on? You may have accidentally touched the engine, part of the negative side, with the screw driver that was on the positive side of the alternator.

There is no such thing as a marine alternator, there is only an alternator.

In theory, it is not something I have ever done, you can run the engine with out an alternator attached, but make sure you remove it AND consider how you are going to start the engine after you switch it off.

Good luck.

There is such a thing as an alternator without negative ground which is used on marine engines. Mostly Volvo Penta where they don’t like the engine to be grounded.

 

[Sandy]

I turned off both battery switches before I did anything.

I'm pretty sure I didn't touch the engine or anything else with the adjustable wrench. The negative terminal is far away, so I definitely didn't touch that. It happens every time, not just once.

As others have said you must have a live circuit from somewhere.

You should find a large negative wire running from the battery to somewhere on the engine. Finding the positive might take a bit of time.

 

[sailboatliving]

The real question is why it's live if everything is "off". Something must be wrong!

Do you have a test meter so you can test for dead (or live). Appreciate that may not be easy where you are!

You can also check the charging voltage with it if you don't have volts monitoring in place.

I would make sure my solar was disconnected when running the engine (and testing things) as there is some discussion on other threads about alternators/regulators getting confused by the solar charging voltage. I have an isolation switch on the +ve feed from the solar panel.

I have had my regulator trip out on overcharging, but only when everything is fully charged and the voltage rises to 14.8 or so. I have in the past bypassed the regulator as the alternator has a built in regulator (don't know if this the case with Balmar). You will need a wiring diagram to follow but it's straight forward and reversible if you use existing connectors and make up bits of joining wire. The positive does not need changed, only the smaller wires.

If you disconnect the alternator, your engine will run for ages provided you start with a fully charged engine battery. It should also give you plenty of starts - I have run for 2 days intermittently like this.

Much easier to do this at anchor or docked rather than while sailing!

Balmar has a internal regulator. No way I would touch the positive terminal with a multimeter, it will probably fry it right away

 

[sailboatliving]

I was able to make the pictures small enough now.

The second positive cable is not visible on the picture.

I also tried to connect the stator and field into one cable with a butt crimp and then I installed it on the positive terminal as shown in the picture. It didn't not go well. The cable starter smoking as soon as I started the engine.

 

[penberth3]

I turned off both battery switches before I did anything.

I'm pretty sure I didn't touch the engine or anything else with the adjustable wrench. The negative terminal is far away, so I definitely didn't touch that. It happens every time, not just once.

I'll guess your battery switches isolate everything beyond the batteries, you still had a live connection from Alternator to Battery.

Did you check there was no voltage at the Alternator terminal? You should have done that before you started with the tools.

I get the feeling you don't have much experience of electrics. I would stop now, get some hands-on help before you do serious damage.

 

[BobnLesley]

The real question is why it's live if everything is "off"...

This

 

[VicS]

Balmar has a internal regulator. No way I would touch the positive terminal with a multimeter, it will probably fry it right away

You need to learn how to use your multimeter.

Testing with the multimeter before you start working on things will help you avoid incidents like this .

.

 

[Supertramp]

Balmar has a internal regulator. No way I would touch the positive terminal with a multimeter, it will probably fry it right away

It will measure the voltage, not fry.

 

[rotrax]

Balmar has a internal regulator. No way I would touch the positive terminal with a multimeter, it will probably fry it right away

EEERR - Really?

The Balmar Alternators I have experience of have both had external regulators. Perhaps Balmar do make one with an internal reg, but I have not yet seen one.

I also cannot imagine a multimeter, used correctly to measure voltage, 'Frying' anything. I have been using multimeters for 60 years, starting with an Avo and finishing with the modern pro job I have in the electricical tool box. Used it today to check an earth on a Suzuki outboard CDI ignition.

Just sayin..............................

 

[rotrax]

Getting back to the OP, I suspect the alternator pos is always live. Often the Starter motor solenoid is too. Better not to have the heavy cables switched for less current drop and reliability.

 

[KompetentKrew]

I'll guess your battery switches isolate everything beyond the batteries, you still had a live connection from Alternator to Battery.

+1

No way the battery switches isolate the alternator because that would allow you to disconnect the alternator from the battery, which would kill it if you started the engine.

Well, it's possible if you had a particularly bad PO.

 

[sailboatliving]

EEERR - Really?

The Balmar Alternators I have experience of have both had external regulators. Perhaps Balmar do make one with an internal reg, but I have not yet seen one.

I also cannot imagine a multimeter, used correctly to measure voltage, 'Frying' anything. I have been using multimeters for 60 years, starting with an Avo and finishing with the modern pro job I have in the electricical tool box. Used it today to check an earth on a Suzuki outboard CDI ignition.

Just sayin..............................

Well Balmar technical support and their web site says it has an internal regulator.

I use my multimeter daily on the boat but I'm not touching that positive terminal with a metal rod from a multimeter after seeing the marks it left on my adjustable wrench

 

[PaulRainbow]

EEERR - Really?

The Balmar Alternators I have experience of have both had external regulators. Perhaps Balmar do make one with an internal reg, but I have not yet seen one.

The one the OP has does have an internal regulator, although Balmar recommend using an external one.

 

[PaulRainbow]

+1

No way the battery switches isolate the alternator because that would allow you to disconnect the alternator from the battery, which would kill it if you started the engine.

Well, it's possible if you had a particularly bad PO.

It's actually very common for the engine battery isolator to disconnect the alternator. Typically, the battery positive goes to the isolator then to the starter solenoid and the alternator B1 is connected to the solenoid too. Turn the switch off with the engine running and it usually blows the diodes in the alternator.

 

[VicS]

I was able to make the pictures small enough now.

The second positive cable is not visible on the picture.

I also tried to connect the stator and field into one cable with a butt crimp and then I installed it on the positive terminal as shown in the picture. It didn't not go well. The cable starter smoking as soon as I started the engine.

You joined the "field" (blue) wire and the "stator" (white) wire together and connect both to the positive output terminal ? Why on earth did you do that? It is NOT what is shown in the diagram!

You appear to have no understanding of what you are doing. Please stop messing with it before you do irreparable damage or worse.