A Really Strange Wiring Problem that I need Advise on....

[blairv70]

Hi All,

So I took the plunge today a rewired the boat. I discoonected the main cable leading from the batteries to the cabin, snipped everything back and cleaned it all up.

I then recrimped the main cable and attached it to the new bus (dual bus bar) and nothing.......

Stuck the meter on the battery 12.8 volts, checked the fuse near the batteries - fine, checked the voltage on my crimps - still 12.8 volts.

So I ran the extension cord down to the boat and plugged in a 12v battery charger - everything works fine. Unscrewed everything and tested one by one - still all fine.

So ran a lead direct from the house battery (battery 2) to the bus bars - all good there to.

So it seems like if I bypass the main (existing) cable that is earthed to the boat along with the batteries by the looks of it everything is fine.

I have dual batteries with a manual battery selection switch that I guess the positive of the main cable to the front cabin is connected to. This has a 30 Amp fuse that is intact and the negative cable is wired to the hull.

Anyone have any ideas?

Can I just run another cable from the house battery straight to the main bus in the cabin and both batteries will still be okay?

Thanks for your help - this one has got me beat!

[tunaticer]

For starters, do not earth to your hull ever!!
Run an earth back to your battery.
You should have two bus bars, one for positive and one for ground, The ground one has a dedicated cable directly back to the battery. You should also have a positive from one or both of your contacts for the battery switch to the positive bus bar. From those bus bars EVERYTHING in the boat should be wired to.

Be sure both bus bars are fully insulated from the hull.

[whaler]

Sounds to me like you may have a problem with your negative return to the battery. Check it and ensure that your negative busbar is hard wired back to the battery (don't rely on the chassis).

Do you mean that you have a fuse on your main feed to the busbar? If so did you check the load side of the fuse holder to see if you are passing a voltage through that far?

Also check both sides of the battery switch as they do fail after a while.

[Shark Poker]

For starters, do not earth to your hull ever!!
Run an earth back to your battery.
You should have two bus bars, one for positive and one for ground, The ground one has a dedicated cable directly back to the battery. You should also have a positive from one or both of your contacts for the battery switch to the positive bus bar. From those bus bars EVERYTHING in the boat should be wired to.

Be sure both bus bars are fully insulated from the hull.

Cut the earth wire from the hull, NOW!

[blairv70]

For starters, do not earth to your hull ever!!
Run an earth back to your battery.
You should have two bus bars, one for positive and one for ground, The ground one has a dedicated cable directly back to the battery. You should also have a positive from one or both of your contacts for the battery switch to the positive bus bar. From those bus bars EVERYTHING in the boat should be wired to.

Be sure both bus bars are fully insulated from the hull.

I think that could be the issue. There seems to be no negative bus at the back of the boat - it seems the ground is just wired to the same area that the battery switch is and is just attached to the hull at that point - not bus or anything.

There is not voltage running through the hull - i have tested that with a multi meter.

If i redo this should I just wire bus back to one battery or both. Currently there is a cable that runs between the negative terminals. The ground from the engine is attached to battery one.

[blairv70]

Cut the earth wire from the hull, NOW!

And attached to the battery?

[blairv70]

Sounds to me like you may have a problem with your negative return to the battery. Check it and ensure that your negative busbar is hard wired back to the battery (don't rely on the chassis).

Do you mean that you have a fuse on your main feed to the busbar? If so did you check the load side of the fuse holder to see if you are passing a voltage through that far?

Also check both sides of the battery switch as they do fail after a while.

Whaler i checked the fuse and it was all good will post a diagram to help explain myself but I think you are on the money

[solemandownunder]

Hi All,

So I took the plunge today a rewired the boat. I discoonected the main cable leading from the batteries to the cabin, snipped everything back and cleaned it all up.

I then recrimped the main cable and attached it to the new bus (dual bus bar) and nothing.......

Stuck the meter on the battery 12.8 volts, checked the fuse near the batteries - fine, checked the voltage on my crimps - still 12.8 volts.

So I ran the extension cord down to the boat and plugged in a 12v battery charger - everything works fine. Unscrewed everything and tested one by one - still all fine.

So ran a lead direct from the house battery (battery 2) to the bus bars - all good there to.

So it seems like if I bypass the main (existing) cable that is earthed to the boat along with the batteries by the looks of it everything is fine.

I have dual batteries with a manual battery selection switch that I guess the positive of the main cable to the front cabin is connected to. This has a 30 Amp fuse that is intact and the negative cable is wired to the hull.

Anyone have any ideas?

Can I just run another cable from the house battery straight to the main bus in the cabin and both batteries will still be okay?

Thanks for your help - this one has got me beat!

MIGHT be your problem...RIGHT there (Battery Switch/Isolator)...it is the only missing link I can think of.

AND...as been mentioned...do NOT earth to the hull.

Cheers, Ray.

[Shark Poker]

blairv70,
just in case you were unaware mate, earthing thru the hull leads to all sorts of corrosion problems.

(Apparently they do this with cars, but not boats)

Pauly

[Volvo]

If i were you i would pull out both wires from your battery switch (Pos) and neg from battery and start over again unless they are both tin and at least 7mm thick. Attatch two Bus Bars as previousely advised back of your dash panel.
One for Pos lead from your battery switch( SO you can isolate your main lead) and also attatch a fuse close to the batt switch.
Then run your negative from the battery to your negative Bus.
I presume you do have a fuse swtich panel on the dash??..If so run a pos wire same diameter as your main lead from main battery isolator from the Pos Bus to your fuse switch panel to feed your switches to variouse instruments etc.
All you should now need is to run a pos for each intrument eg sounder, GPs etc from the feed side of your fuse switch panel to each instrument .
Then the neg side of the instrument to the Neg Bus, and up to uou how tidy you want to do the job..
If ive missed something out somebody else may want to pick me up on it or may have a better suggestion..

[Shark Poker]

.
..... and up to you how tidy you want to do the job..
..

Neatness of the wiring is not only a personal choice. It helps when a fuse blows or a wire comes loose if you can find it and fix it quickly.

A 'birds nest' of wire also bounces about and encourages reliability problems.

Here is a recent set up that caught my eye....

[Jarrah Jack]

This type are very good. They have the fuses and neg and pos bar together so you can track problems easily. I got a Blue Seas one from a guy in WA.

http://www.ebay.com.au/itm/12-Way-Bl...item27c114317a

[Volvo]

This type are very good. They have the fuses and neg and pos bar together so you can track problems easily. I got a Blue Seas one from a guy in WA.

http://www.ebay.com.au/itm/12-Way-Bl...item27c114317a

Mate, you mind posting the link where you got yours from..looks spik..

[blairv70]

If i were you i would pull out both wires from your battery switch (Pos) and neg from battery and start over again unless they are both tin and at least 7mm thick. Attatch two Bus Bars as previousely advised back of your dash panel.
One for Pos lead from your battery switch( SO you can isolate your main lead) and also attatch a fuse close to the batt switch.
Then run your negative from the battery to your negative Bus.
I presume you do have a fuse swtich panel on the dash??..If so run a pos wire same diameter as your main lead from main battery isolator from the Pos Bus to your fuse switch panel to feed your switches to variouse instruments etc.
All you should now need is to run a pos for each intrument eg sounder, GPs etc from the feed side of your fuse switch panel to each instrument .
Then the neg side of the instrument to the Neg Bus, and up to uou how tidy you want to do the job..
If ive missed something out somebody else may want to pick me up on it or may have a better suggestion..

The batteries have nice hick well made cable so i think I will leave them alone. First port of call will be to get the earthing sorted out and see how it goes from there.

[Jarrah Jack]

Mate, you mind posting the link where you got yours from..looks spik..

I found it on ebay but don't see it there any more. The one I put up looks the same though.