Engine and devices grounded to hull?? This looks weird.

[clendee]

Hi folks,

 

I really need your advice here.  I still consider myself new to boating and am learning every day.

I've read many places that electrical circuits on a boat should NEVER be grounded to the hull.

 

I think some of my circuits are grounded to the hull, see attached picture. 
Should I remove this immediately and replace with a suitably amped bus bar?

 

I welcome your thoughts,

 

Many thanks.

Edited April 22, 2023 by clendee

[PaulD]

The 12v negative should be connected to the hull in a single point. Whether this is the correct place is difficult to judge from the photo.

[Tony Brooks]

What you think about grounding is not quite true. If there is no negative to the hull bond and a positive shorted to the hull, the result would be that no fuses would blow or circuit breakers trip and the whole hull would become live. That could easily cause excessive hull corrosion.

 

So although all the equipment should be fitted with their own negative leads back to the negative bus bar and battery negative, there should be a single 25mm sq mm CCSA bond between the battery negative and the hull. Normally the engine and domestic bank negatives are linked with similar cable so the one bond serves both batteries. As most NB engines are mounted on rubber mounts, typically a negative would run to the engine block/starter with an extension to the hull bond.

 

To answer your question, I would want to know about all the bonds to the hull and where the negatives for each piece of equipment went.

 

At this time, I think you may have a more problem than a possible double earth bond. It looks like a single alternator, twin battery bank boat and the split charge relay that allows one alternator to charge both banks without one discharging into the other is not working. The negative cable for the coil has been disconnected. It might be that the relay is redundant or used for something else.

Just now, PaulD said:

The 12v negative should be connected to the hull in a single point. Whether this is the correct place is difficult to judge from the photo.

 

Often stated as fact but with flexible engine mounts and flexible fuel pipes you increase the chances of a control cable burning out as it takes the starter currant to the hull. I would suggest the majority of inland boats with flexibly mounted engines have one bond to the engine that is extended to the hull.

[clendee]

Thank you for your input on this.  I apprecate the time you took and the explanation.

Yes you are correct in that my alternator is not working.  I have 2 x 12v 100AHr batteries in parallel for the 'House' part of the boat and a single 12v starter battery.

I have been having trouble with my alternator and replaced both the alternator and the relay.  I need to look further and see what is happening with that.

The negative from the relay is disconnected as it was affecting other functionality on the panel.  My alternator just does not seem to be charging my battery.  I understand that the relay is present to stop the alternator being connected to the battery when there is no current from the alternator (again, Im not sure if this is true or not).  I don't think it is a full split charge relay system as the batteries are not connected together.

 

Whats intersting is that the alternator is connect to the 'house' battery bank.  I'll probably try and connect it to my starter battery as the house batteries are charged by solar.

 

 

Edited April 22, 2023 by clendee

[Tony Brooks]

10 hours ago, clendee said:

Thank you for your input on this.  I apprecate the time you took and the explanation.

Yes you are correct in that my alternator is not working.  I have 2 x 12v 100AHr batteries in parallel for the 'House' part of the boat and a single 12v starter battery.

I have been having trouble with my alternator and replaced both the alternator and the relay.  I need to look further and see what is happening with that.

The negative from the relay is disconnected as it was affecting other functionality on the panel.  My alternator just does not seem to be charging my battery.  I understand that the relay is present to stop the alternator being connected to the battery when there is no current from the alternator (again, Im not sure if this is true or not).  I don't think it is a full split charge relay system as the batteries are not connected together.

 

Whats intersting is that the alternator is connect to the 'house' battery bank.  I'll probably try and connect it to my starter battery as the house batteries are charged by solar.

 

 

 

For a boat, the alternator to domestic bank is generally considered the best way because it minimises the current passing through the relay contacts. Altering it as you suggest may reduce the life of the relay. Unless the starter battery of the engine is faulty, the start battery spends most of its time fully charged - unlike the domestic battery.

 

I think that there is something more wrong with your electrical system for the relay coil positive to cause the panel to malfunction. This may well be why a new alternator is not working, and I think it is far more urgent than your original question. The worst it might do with the normal connection is require the engine to be revved a bit more to get the alternator charging, but that is not so common.

 

If you want help with this, please describe this "panel misfunction", what and when. Also will you post a photo of the back of the alternator that you have altered to show the connection i.d.s on the alternator case if we can't see them (B+, D+, W etc.) and where you think each cable comes from.

 

There are generic wiring diagrams and fault-finding procedures in the electrical notes on my website. tb-training.co.uk

 

Edited to add. If you have a multimeter then the voltage across the engine battery and domestic battery might help. As may a photo of your batteries showing the connections.

Edited April 23, 2023 by Tony Brooks

[Tracy D'arth]

I find it odd that these new posters often don't  tell us where they are. Somewhat rules out anyone going to help them.

[Tony Brooks]

11 minutes ago, Tracy D'arth said:

I find it odd that these new posters often don't  tell us where they are. Somewhat rules out anyone going to help them.

They also don't very often give us a bit of history. I suspect this is a new boat for the OP, and he has found a number of things that are, at present, beyond his understanding. But we can't help as well as we might without as much info as possible.

[David Mack]

36 minutes ago, Tracy D'arth said:

I find it odd that these new posters often don't  tell us where they are. Somewhat rules out anyone going to help them.

I think that's a little unfair. I suspect it never occurs to a new poster that somebody on the forum might be willing to visit a complete stranger to sort out a problem.

[Tracy D'arth]

5 minutes ago, David Mack said:

I think that's a little unfair. I suspect it never occurs to a new poster that somebody on the forum might be willing to visit a complete stranger to sort out a problem.

Its their decision.

 

But it is part of the profile when you sign up, not that it is compulsory but it would possibly help them get a resolution to their problem.

 

Any road up,    

[clendee]

Hi folks, I am based between Sharpness and Gloucester.  It never occured to me that anyone would be physically willing to help with my issues. 

 

I went out to my boat today to have a look at the alternator and see if I can document the current state of affairs.  It looks completely mis wired to me.

The positive post is not wired to anything.  The negative post is not wired to anything.  I've added some more pictures.  Im sorry to even put this mess on here, my starter battery is currently not charged by the alternator, it's charged by a manual switch on my solar array.

 

I have inherited these problems, but I'd love to get my alternator working properly and charging my starter battery.
 

Some history : I purchased this boat a few years ago and the alternator was never working.  There is not a complete circuit wired to the alternator, so it is not doing anything.  A friend looked at it 6 months ago and we didn't figure it out then either.

 

The panel malfunction:  I'll have to get back to you on this, it previously made the alarm speaker to emit constant tone.  Its been disconnected so long, I'd need to check if this is still the case.

 

Thank you for the link to your site Tony, I have come across your site and appreciate your feedback.

 

Here is some more info I gathered today:

Alternator is a Paris-Rhone 14V - 50A   A 23N1M - F2 - L

It has a - post, + post, 61 post and a W post

 

The 61 post currently has the positive wire, the panel wires and the relay wires attached.

 

This is how I think it should go, please correct me if Im wrong:

+ post -> positive feed to the relay - then from other side of relay to starter isolator switch

- post -> negative feed to the (relay and engine?)

61 Post -> back to the panel

 

Perhaps Im way out of my depth here, or its wired so wrong theres a lot to correct.

 

The next day Im out at the boat I'll devote some decent time to the alternator situation, at least beginning with wiring the relay to the starter isolater rather than the leisure isolator.  Apologies if there are still bits of information missing from this post.

 

The thing is I really interested, but also a little overwhelmed.

 

 

 

 

Edited April 23, 2023 by clendee

[Tony Brooks]

Thanks, that looks like a Bukh engine but don't know which one. Regrettably I no longer have my DV36 manual but I easily found one in an online manual for the DV10/20 by Google. Bukh diagrams are not the easiest to read because they are small and you have to "work through" the multiway connectors but, from memory.

 

Alternator positive to the load side of the domestic master switch (to comply with the BSS) or to battery side or  domestic positive terminal.

 

W feeds pulses to the rev counter if you have one

 

61 is connected back to the charge warning lamp and may well also feed the relay coil (blade terminal) positive. This wire may well run back to the diode pack I explain below. If you do not want a warning buzzer you do not need the diode board but it will need a larger warning lamp bulb or a parallel resistor.

 

If you have a negative or B- terminal that connects to either a mounting bolt or to engine battery negative at any convenient point (possibly the back of the starter motor case).

 

The engine and domestic battery NEGATIVES are linked with a 25 sq mm CCSA cable.

 

The split charge relay main terminals (nut & stud) can most easily be connected to the load side of the master switches. one terminal to one switch and one to the other.

 

The split charge relay negative (small blade) runs to any convenient negative.

 

You probably have a diode board associated with the warning lamps and buzzer. These can go faulty in several ways over time, this may help you. The constant tone may well result from a wiring fault here.

 

The genetic wiring diagrams on my website do not show the diodes but you do not need them if you can do without the warning buzzer or fit separate buzzers for the waning lamps.

 

This correspondence is likely to go on and on.

 

Bukh DV diode board wiring.

 

Warning lamps:

Top – ignition

Middle – oil pressure

Bottom – Temperature

 

Diode/resistor pack:

 

1 – Earths buzzer to diodes etc.

 

2 – Stop sol feed

 

3 & 4 – Live feed from ign. Sw. (58)

 

5 – Temp from light to sender (earth)

 

6 – Oil from light to sender (earth)

 

7 & 8 – liveish to buzzer, neg from ign w/l, to Ign W/L terminal.

 

 

 

Diodes D & E stop a fault on either oil or temp illuminating the other lamp.

 

Zenner F prevents the buzzer “chirping” under certain conditions.

 

Resistor C provides the buzzer earth via the alternator W/L

 

Diode B feeds the buzzer when the stop solenoid is energised.

 

Resistor A is in parallel with the Ign. W/L feed to ensure alternator energisation.

 

 

 

 

Bukh DV 36 wiring.

 

Warning lamps:

Top – ignition

Middle – oil pressure

Bottom – Temperature

 

Diode/resistor pack:

 

1 – Earths buzzer to diodes etc.

 

2 – Stop sol feed

 

3 & 4 – Live feed from ign. Sw. (58)

 

5 – Temp from light to sender (earth)

 

6 – Oil from light to sender (earth)

 

7 & 8 – liveish to buzzer, neg from ign w/l, to Ign W/L terminal.

 

 

 

Diodes D & E stop a fault on either oil or temp illuminating the other lamp.

 

Zenner F prevents the buzzer “chirping” under certain conditions.

 

Resistor C provides the buzzer earth via the alternator W/L

 

Diode B feeds the buzzer when the stop solenoid is energised.

 

Resistor A is in parallel with the Ign. W/L feed to ensure alternator energisation.

 

 

[clendee]

Thank you so much,  I will need to slowly go through this to make sure I am clear on all your suport.

 

I have a Bukh DV24 engine.

Thanks again.

[Tony Brooks]

2 minutes ago, clendee said:

Thank you so much,  I will need to slowly go through this to make sure I am clear on all your suport.

 

I have a Bukh DV24 engine.

Thanks again.

 

I think the wiring is pretty much the same on the whole range of Bukh of a given age range.

[Tony Brooks]

11 hours ago, clendee said:

The panel malfunction:  I'll have to get back to you on this, it previously made the alarm speaker to emit constant tone.  Its been disconnected so long, I'd need to check if this is still the case.

 

With the warning lamp cable on the same terminal as the main output terminal or just disconnected at the alternator, the charge warning lamp and buzzer would not work. I suspect it is disconnected. When you connect the split charge relay coil that provides a path through the buzzer to negative, so the buzzer sounds all the time the ignition is on unless the alternator is charging. When correctly wired and the alternator charging you get battery voltage on both sides of the buzzer and warning lamp, so no current can flow through them, thus no sound/illumination.

 

Further thought suggests the diode plate is probably OK unless someone has connencted the relay wire there and damaged something.

 

More info that might help.

 

The thin curly yellow cable from the regulator to B+ is the voltage sensing cable so must be connected to B+ unless you decide to convert the alternator to battery sensing. There are more important things t do at this time.

 

I am sure that you have a B- terminal that is hidden in the photos. I also have a feeling that it is insulated from the body so:

 

If you have a multimeter and know how to do a continuity test, do one between B+ and the body. If you have continuity, then you can probably ignore the B- terminal.

 

If it is insulated, then it needs connecting by a similar gauge wire to the B+ to any negative, including a mounting bolt, engine      stud/nut, starter negative terminal, battery negative terminal, or the negative hull bond point.

Edited April 24, 2023 by Tony Brooks

[Tracy D'arth]

The relay is certainly a split charging relay with one stud side connected to each battery isolator so that it connects the battery positives together when the engine is running. The spade connections are ground, negative, and the other, positive from the alternator side of the ignition warning lamp, so its  connected to 61 terminal.

 

It is not a battery switching relay as your earlier post suggested.

[Tony Brooks]

49 minutes ago, Tracy D'arth said:

The relay is certainly a split charging relay with one stud side connected to each battery isolator so that it connects the battery positives together when the engine is running. The spade connections are ground, negative, and the other, positive from the alternator side of the ignition warning lamp, so its  connected to 61 terminal.

 

It is not a battery switching relay as your earlier post suggested.

 

Whilst I agree in the main, the first series of pictures do not suggest it is wired as one stud to each master switch terminal. There is a red cable that looks rather thin for the job and goes out of sight a long way from the relay.

 

As the other relay terminal looks as if it connects to the leisure battery master switch, I am hoping the thinner cable runs comes from the engine battery positive. It looks thinner than the cable on the alternator B+ (actually wrongly on 61) so there is a very good chance that is how it is wired. However, nothing is certain, seeing how the alternator has been wired.

 

If I was installing it, I would do as you suggest and connect to the master switches. Close by so minimum cable runs and obvious to anyone with knowledge who comes to fault find it in the future.

 

I am trying to get the alternator working, and will then move onto the relay, and finally the hull bonding. By then the OP should be able to trace the cables and draw a bit of a diagram.

[clendee]

Hi Tony, I won't be out on my boat until next weekend but intend to follow your instruction to the best of my ability.  I'll report back with my findings and appreciate all the feedback I have gotten so far.

3 hours ago, Tony Brooks said:

 

Whilst I agree in the main, the first series of pictures do not suggest it is wired as one stud to each master switch terminal. There is a red cable that looks rather thin for the job and goes out of sight a long way from the relay.

 

As the other relay terminal looks as if it connects to the leisure battery master switch, I am hoping the thinner cable runs comes from the engine battery positive. It looks thinner than the cable on the alternator B+ (actually wrongly on 61) so there is a very good chance that is how it is wired. However, nothing is certain, seeing how the alternator has been wired.

 

If I was installing it, I would do as you suggest and connect to the master switches. Close by so minimum cable runs and obvious to anyone with knowledge who comes to fault find it in the future.

 

I am trying to get the alternator working, and will then move onto the relay, and finally the hull bonding. By then the OP should be able to trace the cables and draw a bit of a diagram.

The relay is connected on left hand side from the alternator and the right hand side goes to the leisure battery isolator switch.

[Tony Brooks]

18 minutes ago, clendee said:

The relay is connected on left hand side from the alternator and the right hand side goes to the leisure battery isolator switch.

 

That is unusual. I would suggest that you disconnect the wire at the alternator, leaving the main charging cable in place, until we get the alternator charging. Then we can get the relay sorted.

 

I look forward to the next installment.

[Tracy D'arth]

Reflecting on this relay,

 

Could this be one of those alternators that discharges your battery when the engine is stopped and this relay is to isolate it when you turn the ignition off?

 

 

[clendee]

That is a really good call, a friend of mine (non electrician but electrically curious [you know the sort]) seemed to think the relay was for that purpose.

[Tracy D'arth]

Test it?  Connect a battery to the B+ and B- on the alternator and see if it draws any current when still. If it does, I would fit a new alternator, new ones don't do that.

[clendee]

Interesting, Im back out at the boat this weekend and will be trying to look more closely at the situation.  Ive only just replaced the alternator with a like for like, thinking my old one was broken.

[Tony Brooks]

3 hours ago, Tracy D'arth said:

Reflecting on this relay,

 

Could this be one of those alternators that discharges your battery when the engine is stopped and this relay is to isolate it when you turn the ignition off?

 

 

 

The same alternator, on my Bukh did not do that. It was a straight 9 diode machine but with the twist that the sense wire could be moved for B+ to battery+ to convert from machine sensing to battery sensing. If it is discharging the batteries with the ignition off then he has a diode problem, but he claimed (I think) that it was new.

[Tracy D'arth]

1 minute ago, Tony Brooks said:

 

The same alternator, on my Bukh did not do that. It was a straight 9 diode machine but with the twist that the sense wire could be moved for B+ to battery+ to convert from machine sensing to battery sensing. If it is discharging the batteries with the ignition off then he has a diode problem, but he claimed (I think) that it was new.

I have rarely had an alternator that drained batteries, perhaps I have been lucky. It seems odd that someone should wire the relay as the OP says it is. 

The wiring is a mess, as usual, so it could all just be wrong.

[Tony Brooks]

3 minutes ago, Tracy D'arth said:

I have rarely had an alternator that drained batteries, perhaps I have been lucky. It seems odd that someone should wire the relay as the OP says it is. 

The wiring is a mess, as usual, so it could all just be wrong.

 

It is also odd that the B+ cable was connected to 61 (D+) with nothing on B+. On the present evidence, the OP probably bought the boat from and electrical DIY numpty.