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The Official Magazine of the Bluewater Cruising Association

Getting a Charge Out of Your Boat

Don and Heather Cudmore

Hans Christian 33
February 21st, 2016

We were about to begin the second leg of our journey.  We were excited; charged up, and ready to go.  We’d been in San Francisco for a month, and now it was time to move on.  Around the corner, under the Golden Gate Bridge and twenty miles southeast, is the small community of Half Moon Bay.  It is a well-protected harbor and we dropped anchor there, just inside the breakwater.

The following day, we arose in the early pre-dawn hours. We put on the navigation lights, radar, Depth sounder, GPS, VHF radio and spreader lights, while we pulled up the anchor, and then headed out of the Bay.  Once past the channel markers, we encountered a problem.  We could not engage the Auto pilot due to low battery.  Fearing the loss of GPS and radar, we swallowed our pride and returned to anchor.

Waiting until 0900h that morning, we dinghied ashore, and inquired at the Harbor Master’s office as to a recommended marine electrician.  Dave was called pronto.  His response: “Get a slip, plug in for 3 days and call me in the morning…Oh, that’ll be Sunday, call me in the afternoon” And that is what we did.

Buenaventura entering Santa Barbara California.

Buenaventura entering Santa Barbara California.

Heather and I discussed this.  What have we done wrong?  We have relatively new batteries, installed as recently as July. We have two 60 watt solar panels. We’d just motored six hours the previous day.  How could we possibly have a battery problem? Being a low voltage electrician by trade, (telephone) I reviewed the possible problems as being one of the following:

  • the 110 charger is not charging
  • the engine generator is not charging, or we have a problem with
  • faulty wiring

After three days of being plugged into the dock, Dave arrived at the boat, carrying a 25 amp battery charger.  “This’ll get you going” he told us.

All five batteries were pulled up onto the deck, which was no small task in itself.  Using a battery acid tester, Dave determined the starter battery was completely dead and two of the four deep cycle, six volt batteries were iffy.  A new starter battery was ordered and the remaining batteries left to charge, in hopes of a full recovery.  Over the next ten days the batteries slowly recovered; however, the two iffy batteries had to be replaced. Dave recommended the battery acid levels be monitored weekly.

In the meantime, Dave replaced multiple battery cables, finding badly corroded ends and one very poor ground. He explained the old standard of soldered ends allows corrosion to creep into the wires.  So together, we replaced them with crimped and heat-shrunk ends.

Next, we tested the battery charger and found it was not working at all. Although we had plugged in at the various docks while harbor hopping down the coast, our batteries had not been recharged throughout this entire journey.  Why had we not noticed this?  I cast my mind back… the voltage indicator always read 12.5 volts and the solar panels were showing good readings.  The fridge worked well when plugged into the dock, but while at anchor, it was struggling to keep things cold.  At first we believed the fridge to be the problem.

Dave replaced the volt meter and installed an amp meter as our system was antiquated.  He was not impressed with the solar panels, citing that the further south one travels, the less effective they become.  The reason for this is shorter daylight hours, and solar panels do not work well in the heat.  It just goes to show that you cannot believe the sales person.  What they tell you borders on fraudulence.

The last item to undergo diagnostic testing was our two-stage alternator. This 50 and 80 Amp, heavy alternator tested at fourteen volts.  Hallelujah!  Many sailors feel that a three stage alternator is more effective.  According to Dave, the regulator protects the batteries by keeping the charging amperage low.  He is most certain the sales man will happily encourage you to spend the extra bucks unnecessarily.

Dave dropped little pearls of wisdom; the battery charger needed to be re-located as its current position under the cockpit was damp and therefore, invited corrosion.  After re-positioning the charger to an inside wall in the three-quarter berth, away from the damp and the cold, one of the settings we found was the ability to quiet the battery charger. This slows down the charge, so that the transformer cooling fan does not click on and off, disturbing the crew members or guests attempting to sleep. We were also informed that the battery banks should only be used for about 25%.  Therefore, our 650 Amp hour battery bank can give us 125 amp hours before requiring a recharge.  After much discussion and debate, we made the choice between a1000 and 2000 Honda generator.

Many sailors recommended the 2000 generator; and I agreed, if you have a water maker, need to plug in your toaster, and have the storage space.  We purchased a 1000 Honda generator.  It will run our fridge, ceramic heater, hot water heater, and newly installed LED Christmas tree lights, as well as our new 40 Amp battery charger.  We are happy with this arrangement, even though the hot water heater and charger cannot be run simultaneously.

After consulting the battery charging graphs, I learned these sophisticated chargers initially charge at a high rate, but quickly drop off to protect battery life.  This means that a slow charge over six to eight hours provides the healthiest means of charging your batteries.  Although, the 2000 watt generator would supply more power to the charger, the charger would not utilize this power as it is sensitive to the batteries’ needs.

As a closing note, we changed the solar panel leads, from the batteries to a block of wood, with the intention of readjusting them at a later time.  Surprisingly enough, after two weeks, the block of wood is said to be fully charged! That is, according to the solar charging controller.  Do you know anybody who wants to buy a solar panel?



  1. Nick says:

    Nice article – lots of electrical challenges (there always are!) Just wanted to say our experience with solar was totally the opposite, 2x75w panels in the tropics kept everything topped up between trips and happily kept the fridge cold if we were away and running nothing else. Shorter daylight is more than compensated by more direct sunlight because the sun is overhead for longer, not low towards the horizon. It probably also offsets the 10-12% loss due to the temperature difference between BC and Mexico summers (about 1% per ‘C). Your block of wood will probably be fully charged – I expect the controller is detecting that it isn’t drawing any current and the panels are maxing out at 16v or so.

  2. Hugh Bacon says:

    The learning curve for these folks at least as far as onboard electrics are concerned has indeed been vertical. Certainly, there is little linkage between a yacht 12 volt system and a shore based telephone system as the Cudmores discovered. They were indeed fortunate to discover Dave who seems to have set them on a better track. Buena Ventura nevertheless lacks a robust electrical system sufficient for going offshore. The Honda generator is not going to do the job when under sail over a few days to weeks. As well, as most folks know, gasoline generators make unwelcome noise as many of us have noticed especially in a quiet anchorage at sundowner time.

    Once the Cudmores reach the destination of their current cruise, they will need to make further modifications to the electrics. That will be the time to redesign the system so it will fully support their needs under bluewater conditions. Especially important will be the addition of a dynamic system monitoring capability to give real time battery condition with alarms. A wind generator is a good addition and marine quality solar panels work well at any temperature and need to be carried. A higher output alternator, not a generator is essential as is a digital full spectrum voltage regulator.
    On a modern yacht with refrigeration and other high draw systems, there must be a capability to operate everything without access to shore power or a gasoline generator. Sounds like they might need a heat exchanger system as well to provide hot water from engine heat. Yes, that learning curve is not going to flatten for a while. Good luck folks

    1. Nick says:

      Good points, especially about the Honda genset. They are great for at anchor use (not at sundown please!) but can’t safely be used at sea. And the battery monitor system is essential – I am an ‘amps Tzar’ – “hey, did someone leave a light on in the heads….?! The monitor says 0.3 amps…”

      I’d say that on a 33ft Hans Christian, solar, a wind gen and a good alternator, quality charge control / external regulator / monitor system like the old Heart/Xantrex (not sure what you’d buy now) should be more than enough offshore and on. We cruised our bigger boat with that setup and found that offshore needed about an hour a day of engine run to top off the batteries – running electronic autopilot, nav system, fridge and spinning the radar up every 15 mins on the night watch, otherwise wind + 150w solar did it all. 80A alternator.

  3. Ted Simper says:

    We have 480 watts of solar on Roundabout II. This plus a Duo-Gen wind/water generator gets our batteries to full charge almost every day. The solar panels work just fine in the tropics, but the days are shorter, so you need more of them.

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