DC electrical problem

[tjsolberg]

I recently put my boat up and the next time I took it out, nothing would work off DC power. For instance, my engine compartment blowers, water pump, toilet vacuum system, etc., which all run on DC power, will not work unless I turn on the main breaker in the main cabin power panel and the invertor breaker. I have looked at the schematics I have, and cannot identify any fuse that may have blown. Everything works fine if I turn on those breakers mentioned, but I never had to do this before unless I was running my generator or on shore power. I haven't changed anything electrical to cause the change, so I am baffled. Any suggestions of what I can look at would be very helpful and appreciated. I have a 1987 Sea Ray 300 Sundancer.

 

[tjsolberg]

Re: DC electrical problem

I recently put my boat up and the next time I took it out, nothing would work off DC power. For instance, my engine compartment blowers, water pump, toilet vacuum system, etc., which all run on DC power, will not work unless I turn on the main breaker and the invertor breaker in the main cabin power panel. Everything works fine if I turn on those breakers mentioned, but I never had to turn them on before to run things on DC power. The only time I would turn on those breakers otherwise, is if I was running my generator (ship power) or on shore power. I haven't changed anything electrical to cause the change, so I am confused. Is there a breaker/relay/fuse somewhere thats causing this? Could it be something with the invertor? Is there an accessary fuse in the DC system that may be blown? If I hook up shore power, everything works as it should. The only problem is the DC system, nothing works unless I turn on the convertor. I have no problem starting the engines or the generator off baterry power. Any suggestions of what I can look at would be very helpful and appreciated. I have a 1987 Sea Ray 300 Sundancer with OMC Chevy 350's and Cobra outdrives. It basically boils down to nothing works off the batteries except starting the engines or if I turn on the invertor. Is there a fuse on engine harness that can cause this?

 

[tjsolberg]

Re: DC electrical problem

Need to know a little more about your engine and drive set up but if its a Mercrusier it sounds like you have blown the circuit breaker mounted on the engine.

Bubba,
Is there a breaker on the engine harness that can cause this? I haven't looked at it from that point. How does that affect the rest of the DC system?

 

[sasto]

Re: DC electrical problem

Hey tj....Do you have 120 volts going to the inverter when you turn on breaker? If so, you may have a bad battery or a bad connection in the battery wiring. I am assuming your inverter is your battery charger. I am also assuming you have different battery for engines and another for house. Is this possible?

 

[tjsolberg]

Re: DC electrical problem

LTJG,
I tested the batteries with a fluke and had 12 volts on them all. I'm bringing a load tester down next weekend to test them again. I have a seperate invertor that was installed by a marine center 4 years ago. I do have four batteries, one for each engine, one for the generator, and one for the house. I checked all the wiring and everything is clean and tight. I haven't check the invertor for 120 volt input with the breaker on, but assume it's there because everything works when I turn it on. If the house battery shows 12 volts, but doesn't hold a load, would that cause this problem? The problem with that is the invertor control panel shows good green lights for battery power, also the invertor battery is jumpered with the stbd engine battery, I'm not sure why that is. Anyway, I'm listening, anymore suggestions for things to check when I go back down are all welcome. I hope I am explaining my situation well enough. Any questions, just ask and I'll try to explain. Thanks.

 

[sasto]

Re: DC electrical problem

Sounds like the problem is isolated to the house battery, the inverter/charger is supplying enough amps to your battery to run your equipment. One quick check would be to run a few of your DC circuits simultanueosly and see if they can handle the load. If not, I would concentrate on your house battery.

House battery in parallel with an engine start battery? I would think there is a switch for that. Normally, (term used loosely) the house battery is wired to the generator, which would charge house battery under circumstances if the inverter would fail.

Good Luck!

 

[tjsolberg]

Re: DC electrical problem

LTJG,
Thanks for the input. I will conduct a full load test on all the batteries and go from there. It just seems so wierd that I finished using the boat with no problems, then the next time I go to use it, nothings working right. No DC power for anything but the engines unless I turn on the main and invertor breakers in the main cabin power panel, that's after I turn on the main battery power switch in the engine compartment.

As for the house battery being connected to a engine battery, I'm going to check the wiring diagram to make sure that it's wired correctly. Thanks for the input and I'll let you know what I find out.

Any other suggestions of what to check out next weekend are greatly appreciated. Thanks.

 

[Mikes402Jetboat]

Re: DC electrical problem

Have you checked all your grounds to be they are tight and not corroded or loose. Just a thought.

Mike

 

[fish_on_the_deck]

Re: DC electrical problem

I'd start at the batteries with a multimeter and work your way out... eventually you'll narrow it down to where your lost fuse or bad connection is. You can use hte continuity tester to test for bad connections too, but only trust nagatives, as you can easily get a false positive (ie connection is intermitant, or fails with a higher load.)

 

[seabob4]

Re: DC electrical problem

tj,
Assuming you have a battery switch, what you are saying is before, you simply turned on your battery switch, and all your DC accessories worked. Now, you have to turn on the main DC breaker on the panel down below in order for the same accessories to work...

This may be a stupid question, but are you sure the main DC breaker wasn't on in the "before" scenario? I mean, equipment just doesn't switch their source of power all by themselves...