Back to Mogwai’s

Well, I saw the movie, and I knew you couldn’t get the wet, or feed them after midnight.  Then again, I don’t think I got them wet or illegally fed them, but someone or something must have!

Luckily, we have exorcised the gremlins and just have started to get out of project mode and more into explore mode, though there are ALWAYS projects…

We still do not know exactly what happened, which is the most frustrating part of it all.  What we do know:

  • It only happened when the engine was running
  • I measured 28V DC behind my breaker board
  • the voltage returned to ~13V as soon as I powered off the voltage regulator.
  • The problem was not readily reproducible, but it happened twice.

What decided to give up the ghost:

  • NX2 FDX Instrument server.  (yup, no wind seed for the first leg)
  • NX2 display head.  (luckily just one, so we still have another multi, but only one now)
  • Uniden Fixd mount VHF (ended up using a handheld for the trip)
  • the red LED on one of my alpenglow light.  After looking at it, a single resistor melted down and actually unsoldered itself from the circuit board!  Hopefully I can take apart of the other ones, find the value and replace it)
  • My house batteries.  They were already 4 years old, but in okay shape before we left.  They now would drop to 11.9 volts after only about 50 Ah taken out of the 400 Ah bank.  Not good!

There was more corrosion on the positive terminals of the batteries that I would have liked to see, but boiling batteries like that can do that pretty quickly.  That also means that I could have been seeing a voltage drop from the sense wire back to the regulator, but I never was able to measure anything.

My system consisted of an Ample Power alternator and Smart Alternator Regulator v3 (SARv3).  I also have a Balmar duo charge that charges the start battery, as well as two MorningStar Sunsaver MPPT solar charge controllers feeding into the system.

Theoretically, even if the SARv3 was reading werid voltage on the sense, the is supposedly circuitry in it that would prevent it from going crazy like this.  We opened the unit up and there was nothing out of the ordinary from visual inspection, and all of the equipment lives in a locker that is VERY dry.  We also though maybe there could have been a short of the field wire back to positive.  That is still the only reasonable hypothesis we have come up with that could have made 28Vs.  (I had a marine electrician on the boat as crew believe it or not, and have talked with several others down here since then…)  Sadly, we found no evidence of that.

Since we didn’t find anything overtly wrong, but all signed pointed to the voltage regulator, we decided to replace ours with a Balmar MC-614.  You can debate on which one is better, but I lost faith in the old one, and I like the production quality of the balmar better.  Cleaner board layout, resin potted, theoretically smarter…  We also replaced the batteries with some new Deka flooded cells.  We had Dyno D185’s on the boat before had served us well, and battery chemistry also gets into religion pretty quickly.  Sadly, we use odd size batteries on the boat, but it does allow us to have about 400Ah @12VDC in the factory space which held considerably less.  I just have to be diligent now about watering them…

After removing the old batteries (something a little over 100 lbs a piece) we notices that the floor of the battery box was wet with acid.  A box of baking soda and some plywood later (did you ever make those vinegar and baking soda volcanoes when you were a kid?  This was the same thing but with sulfuric acid instead of vinegar, and hopefully no volcano!)

You can see the new box here mostly constructed.  Basically plywood and some fiberglass to make the wood more acid resistant, along with some spacers so the batteries don’t shift around.  We also replaced all the wiring that went through there, including the large 1/0 gauge stuff that goes to the positive and negative buses in the next compartment over.

We then removed the old Ample Power regulator and replaced it with the Balmar MC614 and setup all the parameters so it is happy in our system.  We also added a new fixed mount VHF on the boat.  It is nice having the increased power and tall antenna over the little hand-held.  We actually heard another boat from Seattle hailing us on VHF when we were near Cape Mendocino, but they couldn’t hear our reply from the hand-held.

Here you can see the new batteries in their home, just awaiting the connection of the temp and voltage sense wires from the new alternator.

Getting the instruments replaced was more of a chore…  We have Nexus NX2 instruments on the boat, but I love and still think are the best value proposistion out there.  Sadly, the Comnav, who owns them is in Canada, so getting parts QUICK can be a hassle, since nobody seemed to stock the server only.  Thankfully, after a few calls, Rich from NavStore.com came through and found a west coast distributor that had one and would drop ship it to us overnight.  Sadly the distributor messed up and fedex’d the package to Navstore, whom in turn overnight-ed it to us.  The new server powered up the network and all was good, though for some reason, if I connect one display to the bus (all the displays are daisy-chained together) the whole system goes down.  I also looked at the inside of that guy, and nothing obvious.  I am guessing there there is a voltage regulator/step down in it that fried with the crazy voltage was flying around.

Luckily other stuff on the boat was either not turned on, or had more forgiving voltage tolerances, but we still had to spend a few boat bucks to get everything back together again.  Luckily in my case, the king had better horses and men than in previous ages!

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Categories: S/V Piko | 3 Comments

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3 thoughts on “Back to Mogwai’s

  1. Michael Pack

    Great blog (as I would expect from you)! Interesting adventures.

  2. uncle larry

    Hey
    Had a low grade short in a battery once. It caused the system to charge hard all the time and took out the reg/alt.
    Battery could not reach charge … but did not always show short.
    Sediment in the bottom of the battery …??
    Long time ago and systems were more robust and simple.
    No damage other then Reg/alt.

    Smooth sailing
    UL

  3. kevin

    whooah –

    this is starting to get complicated.

    can we get Nigel Calder on the phone.

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