Loss of all 12V systems!

[Woodsong]

Umph! *You know that age old advice about properly changing a boat's name and all that fun stuff? *Well...I should had taken more heed! *

New name got put on the boat this week. *I have put 125 hours or so on the main engine since I bought our Monk in August 2010 last year. *Never had a problem with her! *Granted, we did a lot of work but still- she's a good boat and runs good and literally has never let me down.
We were anchored out since yesterday early and late today decided to bring up the anchor and go for a little cruise for a bit. *Battery bank was getting low and instead of running the generator we figured why not get a nice little cruise in for a bit. *
I hit the windlass switch to pull up the anchor and it did it's job a little too good- it would not stop pulling up...kept going and going despite my frantic attempts to get it to stop. *I was at the flybridge helm so my wife ran inside to flip off the switch at the panel but anchor got to the top a few seconds before that. *I thought all was good at that point until I realized I had lost 100% of all my 12V systems...water pump, lights, electric head, VHF, and when we got back to the dock, I realized that also included the start/stop switch at the helm to kill the engine! *

*Had to do it manually with the switch just past the secondary fuel filters. *I traced all my battery lines and could not find a master fuse that i had blown so hopefully nothing major. *I've got a tech coming out in a.m. to figure out what I fried but I am mystified that the entire 12V system died as a result of this. *
Ok trawlerforum- let's hear your theories, ideas, suggestions.*

 

[FlyWright]

Sorry to hear this, Tony. Sounds like a welded windlass solenoid. Which battery bank is the windlass tied to? Were the start and house banks parallelled at the time of the incident? Does the windlass have a CB or fuse wired to it?

I'm thinking a blown fuse on the main feed from that bank, or fuses on both banks if parallelled. I'd look again from the battery connections out toward the main buss, looking for a blown fuse, discolored terminal or melted insulation. Hopefully, it's just a single point failure that caused the other systems downstream to fail. Perhaps a battery switch? A systematic probing with a DVM will find it. I hope it's an easy find and fix.

 

[FF]

Many motors are wound to a design that causes the motor to take more AMPS as the voltage drops.

That fuse someone wanted to stick in a Starter circuit , might have saved the day.

My guess is you melted something , bolt to a ground or ground line , a rotary switch (stink at heavy amps) or the tie or melted a post off one of the batts .

 

[Woodsong]

So the marina tech goes down to the boat this a.m. and low and behold...all 12V systems fully functioning! how could it possibly be that we lost all 12V power for the 20 minute ride back to the marina and for the 2 hours on the boat once there and then this morning it's all working. The windlass switch is fried which I figured (it's an odd looking thing anyway....looked more like an overhead crane control box that has been on my to-do list to swap for a new rocker switch) but how on earth could the boat loose 100% of all the 12V systems, only to regain it all the next morning? Weird! We are going to have to do a blessing of the vessel due to the name change and we removed the stuff with the old name from the boat when we left yesterday. Weird!

 

[Fotoman]

Weird indeed. Electrical systems are everything but self-fixing!

 

[bobofthenorth]

I'd say you've either got a circuit breaker that reset (unlikly at the implied amperage) or a high resistance connection somewhere.* Either way any decent electronic technician should have found the problem.* Given that your guy didn't find anything ........ you do the math.

 

[FlyWright]

Did you plug into shore power at the dock to recharge the batts? Was your alternator putting out 14V on your way back to dock? What was battery voltage on voltmeter when you reached the dock?
I'm thinking battery went so dead it couldn't excite alternator to recharge batts. then voltage dropped so low all systems were lost due to min voltage requirements. Recharging overnight could have restored voltage.

 

[Woodsong]

Flywright,
Please don't tell me you actually expected me to be prepared and have a voltage meter on board and not left at the house from another project!!! And of all the luck- to my utter surprise, basically almost every boat on our very large dock was out on the water or vacant! your theory sounds very plausable though. My house batteries were basically dead when I went to crank the motor. In fact, I had to crank the generator (isolated battery) for 5-10 minutes for the batteries to get charged up enough to crank the engine and then a minute later I started up the windlass. Engine alternator should be fine as we just had it fully rebuilt this winter as it gave up the ghost. I plan on replacing my batteries as it is time- they are from early 2008 and sat for a long time before I bought the boat and are not holding a charge as long as they should.

 

[FF]

"how could it possibly be that we lost all 12V power for the 20 minute ride back to the marina and for the 2 hours on the boat once there and then this morning it's all working."

Something got HOT and no longer passed electric . again I would check the ground side.

This is not uncommon as many builders save money in the electrics that most owners do not understand well enough to look for proper parts.

For example each and every terminal end that gets screwed to something should have a star washer , not a lock washer holding the assembly together.

The use of copper , not SS with low conductivity , is preferred for nuts and bolts .

 

[Delfin]

I like flywright's explanation. *Dead draw down of the batteries (where's the required fuse for the windlass?), voltage too low to kick in the alternator, then a slow recovery at the dock. *Either the foot switch is fused on the windalss (or hand switch if that is what you have) or the solenoid is toasted. *I would suggest that when everything is back on line you check the ampeage draw of the windlass to see if it is in spec. *I would be very suspicious that you have fried the winding on it.....

I wouldn't be so quick to change out the batteries quite yet either. *2008 isn't that old and while they may have sulfated up a bit if you put an equalization charge on them you may bring them back to capacity. *

I have no clue whether this device works or not, although Boat Electric and the testimonials say they do. I have them on my batts, and perhaps they help with sulfation...

http://www.boatelectric.com/nanopulser_testimonials.htm

 

[motion30]

Low voltage can cause a solenoid to stick

 

[Woodsong]

So I know all of this is pure guessing since I was a moran and did not have my volt meter, etc. on board at the time but....not sure I now can buy into the dead draw on the batteries as the cause. Reason being is that even if batteries were totally dead, the 12V typically draws straight off the battery charger once plugged in at the dock or the generator is turned on and this was not the case- I was on the boat for 2 hours after the incident and the 12V never came back on.

As far as fuse on the windlass- I was reminded of this item when all of this started happening when my good friend who is a very good surveyor noted to me that she needs a fuse installed for the windlass! Darn to-do list that is not done yet. This issue jumpstarted one of my to do list items though- new switch @ the flybridge helm for the windlass. As well, she never has had a windlass switch installed at the lower helm (always just had the upper helm and then the foot controls at the bow) so now I am doing the new flybridge switch and going to wire up the lower helm windlass switch as well so I can raise the windlass in a cold driving rain without setting down my coffee!

The batteries have got to be low on water as it's been a bit since I topped them off so I am going to top them off next time I am up there and see how they do after that- if they die within 24 hours of anchoring out again with just moderate 12v use I'll have to figure something else out as we like to anchor a lot.

 

[FlyWright]

You can always test your batteries' endurance safely at the slip. Disconnect shore power and run your systems for a couple hours. After a light load for a couple hours, the voltage should not drop below 12.3-12.5V after allowing the voltage to recover after a brief period at rest. If the voltage is dropping off after a short load, you have a charge or battery problem. Here's a table that might help.

Temperature: 77 degrees Fahrenheit

Percent Hydrometer Unloaded
charge reading voltage
100 1.265 12.63
75 1.210 12.30
50 1.160 12.00 (this represents a dead battery)
25 1.120 11.76
0 1.100 11.64

I try to remind myself to check the battery water levels each month that is divisible by 3, so that I never go more than 3 months without checking; Mar, Jun, Sep, Dec. (Just added to my boat list...check batts this month!)