Publish Date: Wednesday, November 11, 2009
Location: Beaufort, South Carolina
Coordinates: 32° 25.675′ N 80° 40.972′ W
We have been at anchor near the waterfront here in Beaufort for more than two weeks, which has given us a well-needed break from the demands of day-to-day cruising. It also allowed Kathryn and Ayla to take a trip back to Boulder for a few days, and gave me time to do a few boat projects that I’ve been wanting to do. We’ll be here a few more days before we head south to Florida.
We prefer to be at anchor rather than tied to the dock: It’s more relaxing, and it also saves quite a bit of money. The main challenge to being at anchor, though, is managing power usage and replenishment. Like most trawlers, Three@Sea’s electrical system includes 12-volt DC components and 120-volt AC components. For example, all of the interior lighting on the boat is 12VDC, while all of the refrigeration is 120VAC.
All 12VDC power for the boat comes from our house battery bank. We have five house batteries with a capacity of about 255 amp hours each, for a total of 1275 available amp hours. This seems like a lot, but when you look at our usage during a normal day, it becomes clear that we have to charge the batteries at least once per day, and usually twice per day. The 120VAC power for the boat can come from one of three sources:
- We can plug the boat into “shore power” when we’re at a dock. Marinas usually charge extra for this, either at a flat rate or a metered rate.
- We can run our generator to produce 120VAC power. Ours is a 10 kilowatt generator, and it burns diesel fuel at a rate of about 1/2 gallon per hour (depending on the load).
- We can invert 12VDC from the house batteries into 120VAC. This is what’s normally occurring when we’re at anchor and the generator is not running.
So when we’re relaxing here at anchor, the boat is being powered entirely by the house batteries: 12VDC directly from the batteries, and 120VAC through the inverter. We have a battery monitor that tells us when the batteries are getting low enough that they need to be charged. We normally charge them when they have been discharged 40-45% (i.e., they still have 55-60% of their charge). When it’s time to charge the batteries, we fire up the generator for 2-3 hours. Unfortunately, it’s not quite as easy as starting it, forgetting it, and then stopping it three hours later. You see, the generator is a diesel engine, and diesel engines don’t like to run lightly loaded — it’s not good for them. So when we do run the generator, it’s important to keep it sufficiently loaded while it’s running.
When we first start the generator, the battery charger alone is enough to load it. Charging the batteries occurs in three phases: bulk charging, when the batteries take a flood of electrons very quickly; absorption charging, when the batteries aren’t taking in power quite as quickly, but they’re still able to absorb a reasonable amount of power; and float (trickle) charging, when the batteries are essentially full, but they’ll continue to take in electrons slowly until they reach their theoretical capacity. Bulk charging takes about an hour, and the absorption phase takes about two hours. Once you get to the float phase, you might as well shut down the generator because you’re not really charging the batteries much at that point.
So what do we do to keep the generator loaded during the three hours that it is running? We have a number of “power hungry” devices on the boat that can only be used when the generator is running, so we cycle through those:
- Do a load of laundry. We have a small combination washer/dryer on the boat, and although the wash cycle doesn’t take much power, the drying cycle uses a ton of power. This is our best strategy to keep the generator loaded late in the cycle. Unfortunately, the three of us don’t produce enough dirty laundry to do more than one load per day, so this isn’t a strategy that we can use every time we start the generator.
- Heat water. The hot-water heater uses a ton of power for about 30-45 minutes, which is another good way to load the generator late in the cycle. It also allows each of us to take a hot shower sometime during the day, which is very satisfying to the other members of the crew.
- Make fresh water. We have a reverse-osmosis water-maker on the boat that allows us to create fresh water from sea water. As long as we are anchored in a location that has good water flow from the open ocean (i.e., the water is relatively clean), we can make all the water we need. Anchored here in the river in Beaufort, we wait until the peak of the flooding tide to use the water-maker so that we’re getting as much fresh water from the ocean as possible.
- Heat or cool the boat. When it’s hot or cold outside, we can use the three air-conditioners on the boat to load the generator. They’re actually heat-pumps, so they can either heat the boat (if the water isn’t too cold) or air-condition the boat. This works great to load the generator, but it is dependent on the weather outside.
- Bake cookies. Pre-heating the oven and baking something uses enough power to make a dent in the power consumption (by the way, this is the one device listed that we can use when the generator is not running). I really like the result of this activity the best, but unfortunately it’s not a very consistent way to load the generator because the heating elements go on and off.
So that’s the drill that we go through once or twice per day while at anchor: Start the generator, cycle through the power-hungry devices to keep it properly loaded for three hours, and then shut it down. Then, when the generator is not running, we do everything we can to conserve power (“Ayla, the light in your stateroom is on again!”). Now you understand why I recently installed an LED anchor light to replace the incandescent anchor light that was up there before. Conserve, conserve, conserve… 🙂
Why not put a few solar panels on the roof and maybe a wind generator?
We live aboard our homebuilt sailboat and get all the power we need from the sun and the wind. Of course, we don’t have AC or laundry. But still, it would cut down on the use of that diesel generator.
We were anchored near you in Beaufort last week.
Good luck on your travels.
Hi Mike,
Yes, yes! I am so envious of the sailboats around us that have wind generators spinning away, capturing all of that “free” energy. When our budget allows, we will definitely install one on Three@Sea. We looked into it last Spring, but we decided on some other (expensive) upgrades first.
I’m currently less enamored with solar panels, but that may be because our first year aboard Three@Sea has seen an abundance of wind, and not nearly as much brilliant sunshine. This may change as we cruise more in the tropic zones.
Thanks,
David
Another great informative entry, thanks Dave. Got a chuckle when I read about baking cookies. And I suppose baking brownies would probably do the trick as well. 🙂
Great info Dave…….this is better than reading “Cruising World” each month. I’m curious, why does your oven consume electricity. Isn’t it propane? If not, why would they put an electric oven on a cruising boat for ‘energy conservation’ reasons. Cruise on !
Can you remind me why it is you cannot leave Beaufort until after November 15th? Thank you.
Hi Deac,
Our oven on Three@Sea is a combination microwave/convection oven, so it is powered by electricity. You’re correct that often boats have propane ovens so they can be used without consuming electricity, but those boats don’t have the benefit of microwave oven capability. As usual, there are trade-offs.
Thanks,
David
Hi Andrea,
Because of the risk of hurricanes, our boat insurance dictates that we can not go south of Savannah, Georgia until after November 15. We visited Savannah last year, and we prefer to hang out in Beaufort, so that’s why we’re here. Different insurance companies dictate different dates (Nov 1, Nov 15, or Nov 30) and different latitudes (Charleston, Savannah, Florida/Georgia border). It’s somewhat ironic because we’ve encountered three hurricanes aboard Three@Sea, and none of them were near Florida (one in the Chesapeake Bay, and two in the Canadian Maritimes).
Thanks,
David
94 amps! Chrissakes man, put a sweater on and turn the heat off. Or was that picture taken when the blender and ice maker were running? It must be nice to live on a trawler with all that juice.
How much longer will you be in Beaufort?
Hi Dick,
LOL! That’s actually 94 positive amps because the generator is running and the batteries are being charged (no minus-sign in front of the amps). Also, I think it was actually 34 amps, but for some reason it looks like 94 in the photograph. When the generator is not running, our normal current consumption is 25-35 DC amps, which I’m sure would still draw outcries of over-consumption from you. 🙂
It is 55 degrees and cloudy outside today, and we have all three heaters running. No trouble loading the generator this morning! We’ll be leaving Beaufort for Florida on Saturday afternoon (if the weather window holds).
Thanks,
David
Thanks for the information! I always wondered about the electrical panel layout in a trawler. My dad had a 32′ Regal and I saw his but never was really taught about it. Doesn’t your boat have a propane stove top and oven? I’ve been looking at Nordhavn’s and they do but are way more expensive than a Kadey Krogen. Curious to what the price is for a wind power generator? I hope that you and the family have a safe trip south. The Nordhavn website has owner blogs and you can learn a lot about the areas that you want to cruise from them. Ken Williams writes a blog on that site and can be a great source of information on a lot of topics. Just thought that you might like the info.
Hi Dave !
Oh, those power blues… We have had both wind generators and solar panels. I personally prefer solar because they are quiet and reliable.
Last winter in the bahamas we had 2 135 watt panels which provided about 50-75 amp hrs per day through the winter, more as the days grew longer. In a winter like last year, a windmill would have been great. Remember though, It moves, it will break. I fear the spinning blades from a potential injury perspective. Also, no matter how much they tell you they are quiet, it is a constant noise that sometimes can be annoying. If you really want more energy independence, my opinion would be a combination with the majority of my money spent on solar.
And yes, that “free” energy is going to cost you a bundle !
We sure will miss cruising this year !
We miss you all !
Crew of GottaLife
Sorry about the last comment. I meant to say Kadey Krogen has blogs from owners trips that can give you some insight. Tusen Takk II is a great blog to read for heading south through the Bahamas and further south.
Hi John,
Our stove is propane, but our oven is electric (microwave/convection). We also have a propane grill outside. Kathryn and Ayla definitely make cooking choices based on whether the generator is running or not: use the stovetop (with propane) or the oven (with electricity).
We follow several of the blogs at Nordhavn. We’ll have to check out the blogs over at Krogen as well — thanks for the reference.
David
Hi Brian,
Great to hear from you. Oh how I wish we were going to see you in the Bahamas again this winter with Rio Dulce — too much fun!
I’m glad to hear that you prefer solar panels to wind generators. I will have to reconsider. I had a follow up e-mail from Mike (comment above) who said the same thing. I guess I was biased based on the terrible weather we’ve had for the last twelve months! 🙂 I like the elegance and simplicity of solar panels, but I wanted to make sure we invested in the device with the best potential for power generation. It sounds like that might be solar instead of wind, especially with the large area above our flybridge where we can install the panels. Cool!
Talk to you soon!
David
G’Day Dave,
Great info for blokes like me that havent got a boat yet but will in the future,Geez ive got some stuff to learn.Am also enjoying everyone eles coments as well.
Weather hay! its beautiful down here on the east coast of queensland,warm and sunny flat sea’s.Its PWC heaven at the moment, and were making the most of it. Love your work. PS- The light thing in the bedroom is quite standand teenage stuff,Zac;s 16 and still does it EVERY MORNING ! best of luck with that…LOL, say hi to Kathryn and Ayla,Cheers Ped
How’s the weather im watchen the weather and there saying 6 inches of rain already fisher men missing 20 ft waves. Whates going were you are I hope it’s not half of what they say. The news shows the storm from Florida the all to way to Main. I pray Psalms 91 over your family and boat God Bless
Space shuttle scheduled for lift off monday @2:28 pm. Heck of a view from Port Canaveral