Electrolysis Part 2 Now I need HELP!!

[some_fool]

OK Gents i have searched and read the posts regarding electrolysis and motors and everything, but i need some advice, i have wired up 2 boats before this without ever letting the earth touch the hull, anywhere. I bought a second hand Blue Fin a couple of weeks ago and was not happy with the electrical setup. I needed a new switch panel and some other electrical stuff run so this is where i am at on the 12 volt side of things-

Battery Positive to 6 amp circuit breaker to buzz bar to switch panel to lights,pumps, radios fish finders etc.

Battery Negative to buzz bar to lights, pumps, radios and fish finders.

The boat is also setup to charge off the motor. Obviously, once the cables from the motor are hooked up to the battery, the hull is earthed at that point.

I also found the hull earth by the fuel gauge mounting bracket.
I also found the new switch panel which has an earth wire to it for the little led lights on the switches earthed the hull also.

My question is this guys - The fuel guage mounting bracket is nothing i can make up a plastic bracket and fit that no worries.

The led on the switch panel - would it be safer to just not bother with the little lights, everything works fine without them on and that is the way i am leaning on this.

The motor is a problem, i really want to be able to charge the battery like this, is this a major problem having the hull earthed in such a fashion, and would anyone here run an anode on the back of the boat or is the anode on the motor suffice?

My last question is how many Ausfishers have put a test light or multimeter on there new boat to see if it is earthed ? I was shocked a bit with the fuel gauge bracket.

Cheers
Michael

[Noelm]

not too sure what you mean, but the - on your battery will go to an earth Point on the motor, which will in turn be earthed to the Boat via the bolts, this is a very common and necessary way to do it, but I THINK what you are getting at is the fact that the LEDS are going to operate by the hull to motor to neg terminal to complete the "loop" is that the worry?

[PADDLES]

hey fool, the hull has to be earthed but not used as a earth return so the goal is to have no potential on it. ie you need to ensure that your earthing system is completely isolated from the aluminium hull and that the only connection to the hull is the main earth from the motor (this should let your sacrificial anode on the outboard, which is also bonded to earth, protect the hull)

[some_fool]

Noelm,

Thats exactly what i'm worried about, it is the LED lights on the switch panel using the earth, when a LED is on, that would therefore mean that possibly there is that loop between the earthed hull and that positive, therefore, i would have i think what one would say "earth leakage". Thanks to paddles as from your post and other enquiries i have come to understand more about the whole charging setup and will continue to leave it setup.

What do you guys think about the connection from the motor, should i connect the two alternator wires directly to the battery as i would think, or would you run them to the buzz bar's?

Cheers
Michael

[finga]

The positive and negative wires from the charging circuit of the motor should be connected to the battery cables going to the motor in the motor.
The negative somewhere on the block near the battery negative and the positive somewhere very close to the start solenoid.
If it's not an electric start then the wires go onto the battery.
You may be able to get an earth return onto the led's
What size wire is going from the battery to CB to busbar??
6A IMO is a bit small for nav. lights etc etc.
I hope this CB is placed as close as possible to the battery terminals. :)

Don't worry about the earth connection of the motor to the hull.
Just make sure all the auxiliaries are isolated to the hull and you should be dunky dory.
Can you put a picture up of your switch panel and the location of where it is and someone may be able to think of an isolation solution for the led's.

Where are you matey??

Fun this sparky stuff hey ;)

[some_fool]

Hey finga,

Will post some pictures hopefully tomorrow morning the camera batteries need a charge. Thanks for your advice, i have run the alternator cables straight back to the battery as in your post.

In regards to the circuit breaker, what amp do you think it should be? On this boat is run 2 fish finders, nav lights, fuel gauge, anchor light, bilge pump, VHF and 2 light plugs(for 100W spottie). What are your thoughts on how much charge i will get out of the 40HP motor, it's a 50 AMP DC battery, i think it is too small, but it came with the boat.

8 gauge wire from battery to CB to buzz bar, same for the negative but no CB. Do you think suffice? The CB is right next to the battery and the buzz bars are sealed in a box right below that again so their would not be any more than 200mm of cable from battery to cb. The switch panel is located only about 200mm away again from the buzz bars

I live in Boondall Northside Brisbane. It aint that much fun finga but it beats painting and the only way to learn is to do it yourself!!!!(with a little great help from some ausfishers).

Thanks heaps mate!!!!!
Michael

[PADDLES]

michael, where are you putting this cb? is it only for your auxiliary stuff? basically add up all your load and then make sure that the breaker is big enough to cope. the purpose of the protective device is firstly to protect people who might get electrocuted and then to protect the cable. now in a 12vdc system electrocution risk is pretty minimal so the main thing you want to prevent is a fire caused by a short. a fuse will act way quicker than a cb but the down side is that when it trips you have to replace it and not just reset it like a breaker. in my opinion use fuses on a boat.