TOTAL LOSS OF 12 VOLT CIRCUIT - 43

[Robert & Sandy]

With no response to my enquiry regarding the microwave door maybe you can assist with my latest, more serious query.

After returning to the yacht after a five week break away all appeared normal until I turned on the main electrical switches. There was no sign of life on any of the instrument panels including an extra battery monitor and the solar panel regulator, no pumps, radios or accessories.

A quick check of the batteries revealed they were all at max capacity and the engine started normally, without any sign of life on the Yanmar panel and no sound from the oil pressure sensor.

Is there a hidden circuit breaker or some type of fuse that could have caused this fault?.

Going nowhere just waiting for an expert SeaKnots response.

Bilgolabands

 

[Mike Brown]

Robert, yes there is a fuse that could be your problem. It could either have failed or the contact surfaces could be corroded enough to prevent current flow through it. It's a small box shaped square that sits on the Red + post of the House Battery. I believe it's rated at 300A. If you have an electrical meter check the fuse for continuity after removing it from the battery post. The fuse has a small, flat metal ring on both sides and it's these flats that you want to check with your meter. Remove the battery cable and fuse then clean the surfaces of all sides of the battery post and cable. Also do the Black - cables as well. I use a very fine grade of polishing/emory cloth on all contact points to ensure good contact, then coat all surfaces with a dielectric grease to help prevent future corrosion. If you do not have a replacement fuse and you did have continuity you can try cleaning the flat rings on both sides as sometimes that will work. If that's the case I would replace the fuse at the next opportunity as the corrosion will likely return.
Good luck and let us know how you made out.
Mike
October Moon

[Robert & Sandy]

Mike,

Thanks for the prompt response.

Sadly we do not have a square box on the pos terminal as Liberte is fitted with AGMs with the standard small (10mm) stainless bolt.

I will look further downstream for a fuse or a fuseable link carrying out the role you described..

On the microwave front the ENO unit suffered a fatal issue with the levers opening the door, more complicated than you would imagine as they ensure no power runs to the magnetron when the door in open. We replaced it with an almost perfect fit LG stainless unit for AU$129-00.

Thanks and I will go investigating..

Bilgolabands

[Mike Brown]

Robert, even if you have AGMs there should be a fuse somewhere in the circuit. I'd suggest following the Red POS lead to the On/Off switch and see if you find either a fuse or circuit breaker. If you have a voltage meter you can simply attach the Black Lead to a convenient connection. Then using the Red lead take voltage readings starting at the battery POS post and work your way along the circuit until you find your problem. Make sure both the Black GND and Red POS switches for the house batteries are turned on. It shouldn't take long to find the problem.

BTW our Microwave is a Tappan so I'm afraid I was unable to help out with that problem. Replacing the entire unit seems to be the proper thing to do.

Good luck and keep me posted.

Mike