cooky6983

No electrics with engine running

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G'day all,

Firstly, I am loving this site. It's so good to find a place like this with so much good information.

Anyway, the issue that I have is that I have just done a rewire on an old 4.9m fibreglass runabout, with a Merc 90 on the back. 

Having done a heap of research on how to do the wiring I was pretty proud of myself when everything worked the way it should when the switch was flicked...at least I thought so.

The problem that I'm having is that everything works beautifully when it's just me and the boat sitting on a trailer in the drive. However, when I turn the key to the acc position (the one just before the engine kicks over, I lose it all. Turn the key off, everything comes back. 

Obvioulsy I'm missing something in the wiring that goes to the key so if anyone can help me I'd appreciate it. I've got a marine mech who can do it and an auto elec that I can contact as well, but I'd really like to try to get this solved just so that I know as much about the boat as possible.

If anyone has some ideas I'd be most grateful. I'm happy to send pics of my wiring if you need them.

Cheers

Cooky

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Hi Cooky,

That's very interesting.

The fact that it all works before turning on the ignition makes me think you have the earth for your accessories on a relay or something along those lines that cause once you power up the ignition the relay would become a positive connection depending which connection you have it connected to if this is the case, had a similar issue on my boat.

There is probably suitably qualified people on here that may disagree with what I am saying but honestly best not to jump to conclusions just work through the problem from the very beginning.

To be on the safe side we would need to look at the diagram before jumping to any conclusions.

Upload a picture of the wiring so we can understand it a bit better.

also when you put the key into ignition I would carry out a test using a test light in the following way.

Before using the test light connect it directly to the battery to ensure it works, sounds silly but a quick check to make sure your device is working will only take a few seconds!!!

Connect the Negative wire directly to the battery, then with the positive wire on the test light try the connections on the switch panel or switches depending how you have wired it, if the light turns on you have positive at your switch so the problem is with your negative, once you have established which circuit is turning off then you need to determine where its connected and work your way through it.

The main thing you need is patience and no interruptions when your working through these issues. every-time I have had to do stuff like this I will make sure the Wife and Daughter are well aware to stay clear of me or encourage them to go out for a few hours, you will be very happy with yourself once you have it nutted out.

 

Best Regards,

 

Nathan 

 

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A picture would be helpful. I'm guessing that it should be an easy fix.

 

cheers

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As crazy as it sounds, make sure you run your motor wiring (including via the switch you mention) direct to the battery.

Don't use any buss bars or link other +ve or -ve wiring. Just get it straight to the battery, with its own fuse of course.

Cross over current from motor to other electrical is cause of many issues.

Did you run a dual Battery set up? If so, check the wiring through the battery switch.

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35 minutes ago, Ah Me Ting said:

As crazy as it sounds, make sure you run your motor wiring (including via the switch you mention) direct to the battery.

Don't use any buss bars or link other +ve or -ve wiring. Just get it straight to the battery, with its own fuse of course.

Cross over current from motor to other electrical is cause of many issues.

Did you run a dual Battery set up? If so, check the wiring through the battery switch.

Yep did the same thing as I did not want to mess with any wiring that has anything to do with the Motor, your switch panel only requires one positive feed as the switches piggy back off each-other well that is how mine is anyway. I did however install a sealed earth terminal block which has not given me a single issue so far. I am very interested in seeing Cookies wiring diagram. 

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On 4/26/2019 at 10:54 AM, beginner said:

Yep did the same thing as I did not want to mess with any wiring that has anything to do with the Motor, your switch panel only requires one positive feed as the switches piggy back off each-other well that is how mine is anyway. I did however install a sealed earth terminal block which has not given me a single issue so far. I am very interested in seeing Cookies wiring diagram. 

Guys thank you so much for your replies. I will get straight on to what you’ve suggested, the first being the diagram. Awesome fellas. Thanks. 

Cooky 

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Good Luck with it Cooky,

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Hey guys,

I've attached a diagram of what I've got so hopefully you'll understand what I've got.

The black and yellow wires that I've circled are connected to the negative side as per the instructions that came with the switch panel. I've also used two bus bars, a pos and a neg.

I have not used a fuse block as I'm relying on the fuses that are part of the switch panel. 

As far as power to the bus bars goes, I've taken the existing pos and neg cables coming from the battery. These went to the original switch panel. I decided to replace the old one as it was poorly positioned and was pretty old and tired.

Looking forward to your replies ( I think :) )

wiring diagram 1.pdf

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On 4/26/2019 at 10:11 AM, Ah Me Ting said:

As crazy as it sounds, make sure you run your motor wiring (including via the switch you mention) direct to the battery.

Don't use any buss bars or link other +ve or -ve wiring. Just get it straight to the battery, with its own fuse of course.

Cross over current from motor to other electrical is cause of many issues.

Did you run a dual Battery set up? If so, check the wiring through the battery switch.

Hey Ah Ming, thanks for that. I will disconnect the bus bars as you suggested. I'd already used them prior to posting my query.

Cheers

Cooky

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2 hours ago, cooky6983 said:

Hey guys,

I've attached a diagram of what I've got so hopefully you'll understand what I've got.

The black and yellow wires that I've circled are connected to the negative side as per the instructions that came with the switch panel. I've also used two bus bars, a pos and a neg.

I have not used a fuse block as I'm relying on the fuses that are part of the switch panel. 

As far as power to the bus bars goes, I've taken the existing pos and neg cables coming from the battery. These went to the original switch panel. I decided to replace the old one as it was poorly positioned and was pretty old and tired.

Looking forward to your replies ( I think :) )

wiring diagram 1.pdf

What brand / model switch panel?

Can you get up some pics of the actual wiring on your boat?

I suspect there is an overload when the engine is switched on and it draws power away from the other parts of the system. Does it actual set off any of the fuses? Or just 'dies' and comes good once the key is turned off the 'acc' position?

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One fuse two devices is not a good idea, your diagram looks a bit confusing, what devices have you got connected, and how are they wired?

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Another thought, because you know sometimes the simplest things ... What size battery, and was it fully charged?

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15 hours ago, noelm said:

One fuse two devices is not a good idea, your diagram looks a bit confusing, what devices have you got connected, and how are they wired?

Hey Noelm,

Yes I agree that the shared fuse isn't the best and will be changed. All I have connected are my nav lights, a fish finder at this stage. I will be adding a VHF radio, a bilge pump and some LED strip lighting in the cabin.

Wiring is basically from the battery to the bus bar and from there to the shared fuse and then on to the device. The only thing that confuses me a bit is the additional yellow wire going to the negative bus bar as well but I'm just following the wiring instructions that came with the switch panel.  

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At the bottom where the positive meets the negative, what exactly is that doing?

By how I understand it you have ran directly to the bus-bars from your battery so there should be no interference on your ignition circuit, I will have another look at home tonight but I would try disconnecting that and seeing what happens as it does not look right to me. 

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I'm no expert but when I rewired my boat recently I took a different path to your diagram.  I have a 2014 merc 150hp 4 stroke for reference.  The pos & neg wires from the motor run directly to the pos & neg terminals of my battery.  From there the pos goes to a 1, 2, both main battery disconnect switch.  From the switch the pos goes through a circuit breaker or fuse big enough to carry the loads of all the accessories you will be installing.  Also making sure the pos wire is big enough to carry the loads.  The pos wire goes from the switch to the pos break out terminal at the helm.  The neg wire goes from the motor, through the battery to the neg bus bar at the helm.  Each individual load ie. radio, sounder etc is fused depending on the size of the load, and wired to the pos break out terminal via a switch and neg goes to the bus bar.  Hope all that makes sense!  

 

I found a U.S. site called new wire marine, they have some very easy to follow tutorials and diagrams which I found very useful.  Good luck and hope you work it out.  Cheers.............

Dave

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18 hours ago, cooky6983 said:

Hey Noelm,

Yes I agree that the shared fuse isn't the best and will be changed. All I have connected are my nav lights, a fish finder at this stage. I will be adding a VHF radio, a bilge pump and some LED strip lighting in the cabin.

Wiring is basically from the battery to the bus bar and from there to the shared fuse and then on to the device. The only thing that confuses me a bit is the additional yellow wire going to the negative bus bar as well but I'm just following the wiring instructions that came with the switch panel.  

I'll be surprised if the yellow wire is anything more than the negative loop for the illumination of the switches. What brand, model is the switch panel? 

I suspect wiring motor and ignition direct to battery will resolve your issue IF the battery is not the issue (ie if battery flat or under sized for crank needed for motor).

Would be good to see actual pictures of the wiring. Wouldn't be the first, nor last, time what someone thinks they did isn't what has actually been installed! (yes, I'm speaking from experience, unfortunately)

PS: Fusing each circuit is ideal but not necessary. Just spread the load with heavy draw items like bilge pump, live bait pump or deck wash pump on different circuits. Then add low draw items like nav lights, cabin light, etc. Think about what will be used when and with what usually. I'll try and remember to take a picture of mine and post up. I have Sounder + Anchor Light, Bilge + Nav lights, Live Bait pump + cabin lights on my 3 fused circuits running off a 6 switch panel. Works fine. 

 

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Hey Ah Me,

Well, I've had a few goes at it and so far what I've got is this. Main cables coming from the battery being Red and Black and wired to the bus bars. As I mentioned, everything from the bus bars on work with no problem except when the key is turned. 

What I then found is that a cable that is wired to the throttle assembly, when disconnected (as in the photo's) I lose electrics again. I've finally given in and have someone coming to look at it next week, but I'd love to know what's going on. I will ask him and once I've got an answer, I'll post it here for you.

As an explanation of the photos, the first one is just the cables going to each bus bar and the next two show that I've got power going to the switch panel when the cable is together and no power to the switch panel when the cable is disconnected.

Thanks all

Cooky

 

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Wow that's some mess you have under there, it's doing my OCD electrician head in, I wouldnt  be able to leave that like that would be ripping it out and starting fresh & neat.......honestly I would be starting at the 2 bus bars and sorting out what's going on from there as I can't make heads or tails of your wiring from that, plus sort that bare solder cable joint out and the bare wire just hanging round. 

Sounds like you have a dead short in your ignition circuit somewhere, my guess it's in that bird's nest, good luck with it hope it's something simple

 

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