Generator or No generator, that is the question

[Kropdad]

Ultimately the batteries lose out in every solar system, fact of life. A generator just makes sense as they afford redundancy and help extend the life of the batteries.

[Beach Panda]

There is a lot of really good & valuable insight here.

I used to do Rescue/Releif work and modified a Military LMTV for deep water service (5' 8" deep) without worry to the engine or cab.

Military trucks dont come w/ AC but I took a regular Split A/C system and swapped out the starter with a low voltage starter so my battery bank & inverters wouldnt blow. I had already upgraded the Alternator (CAT 3116 engine) to a 400w system.

It worked great & I could he deployed for days at a time, staying off grid & not needing to check into a hotel w/ FEMA.

I ran a hot plate, water maker, A/C, small fridge, SAT Phone, Police Scanners, HAM Radio, and Spot Lights.

Yes... the engine ran 24x7, but I Carrie's extra fuel... no solar... not enough room for gear on the cab roof.

My recommendation, in short, convert you A/C's to use Slow (low voltage) starters

May you have tight lines, full sails, and following seas

Enjoy

[Simi 60]

Originally Posted by Amapola

Generators make life so much easier unless you are a marina Queen.

Solar, perhaps you've heard of it?

We haven't seen a marina in 5 years
Run extensive AC electrics, mostly on solar.
Genset for backup

[Redcoat]

When you get all the hard luggage off the boat . You will find the room for a Honda EU 3000. . And one day when your whole system goes down and you're in the middle of nowhere . You be glad you brought it onboard.

[wingssail]

Being the contrarian I have to offer an alternative:

No Genset and no massive solar/lithium/inverter system AND keep the AC!

We wanted light and simple yet we wanted comfort of home.

We wanted a boat with excellent windward performance and lively performance on every point of sail.

We wanted to diminish the maintenance hours spent keeping complex items running and we wanted high uptime percentages while cruising away from docks and marine services.

The solution for us is efficient refrigeration (including freezer) and AC which we can put away (8000BTU) which is sufficient for our vessel even in the tropics and moderate solar 280watts (with little windage, no arch) and a large alternator on the main engine.

We only run the AC at the dock (when shore power is available).

The solar keeps up with everything else as long as we are in colder water which reduces the refer load.

We use the main engine to recharge the batteries when needed.

This is cheap, reliable, light, and does the job. And the boat is still a high performance racing boat in which we have circumnavigated.

One can be as comfortable as home for a lot less than most of the recommendations in this thread, just so long as the home you are comparing to is not a seven room all electric condominium in Florida.

Instead of that, we chose to live on a sailboat and live a simple life.

Photo: You don't need a 7 room condo will full time AC to enjoy life on a boat

[theBigKahuna]

Just realize that if you don't have a genset, you will have times (few or many) when you're 'outta juice'. Even as a backup, a generator is very handy.

[wingssail]

Originally Posted by theBigKahuna

Just realize that if you don't have a genset, you will have times (few or many) when you're 'outta juice'. Even as a backup, a generator is very handy.

Mr Big Kahuna, If you decide to carry everything which might become handy (sometime) you have to carry it 100% of the time.

In my view you go light, you go simple, and you develop a contingency plan for when the "bad things" happen.

Like when you are outta juice, you turn on one of the two engines you have and get more juice, OR you put up the sails and sail to a port with a dock and shore power.

[SOLAR SUPPORT]

It is the right time to talk about SOCat, (Solar Only Catamarans). SOCat is the nickname of an Electric Propulsion Sea Vessel that looks like a catamaran without a mast.

Catamarans are widely used like summer houses, especialy during the pandemic. Particularly for a group of People who like to live, cruise anywhere in their comfortable houses. Those People will probably like this Environment Friendly Concept which offers also paying nothing for fuel to cruise and daily energy costs to live. Catamaran builders should consider the needs of this type of living style.

If they come in to the market, their prices won't be too high when compared with the conventional Catamarans. I did not make a search yet, but will do as soon as I finish this article.. ;-)

Large area of a new design Catamaran called SOCat, is a perfect base for a big solar energy plant. The new, solar integrated roof design covering the boat's whole top is a must. Ignoring to put a big mast and riging on to the boat also brings too much savings to the production cost of the SOCat. Diesel engines are also replaced by electric motors. So their costs can be ignored. Diesel engines are more heavy, noisy and expensive than electric motors. Electric motor's transmission gear is also shrinked or not even exist when compared with diesel engines.

Electric energy Storage capacity required for this kind of a catamaran is the main cost that can be reduced by integrating a small diesel generator to work together with the batteries which is only required to work during very long or night time cruising that is not ever so often needed.

Expanding electric powered car industry enables big amount production of high performance batteries, motors and controls at considerable costs, that brings the competition with petrol based systems. We, Mariners can have more advantages with this renewable solar source in our entire Marine life for free.

An average sized catamaran approximately has 100 metric square area which can be used as a solar energy plant, that can produce 20.000-25.000 Wp capacity of electric power. This Solar plant can power SOCat to cruise at 4-5 knots during the midday without any extra energy support from batteries or a generator.

When Electric Motors compared with Diesel Engines by means of efficiency, weight, volume, balance, power, maintenance, sound, cost, Electric Motors are the winner for each perspective with huge advantages. New design electric motors have very high efficiency around %95. They can run at full power continously.

Diesel engines in our boats labeled with their maximum power value. This is not the equal power we need to Cruise at 6-7 knots. Imagine a catamaran has two 50 Hp diesel engines runing at 2.500 rpm. They operate aproximetly at 50-60 Hp, which is nearly the half of their total maximum capacity that is equal to 36.000-43.000 Watts.

The gap between the solar energy produced by the panels and the energy demand for the propulsion can easily be met by Lifepo4 batteries and a small sized diesel generator combination that are installed in to the SOCat.

Considering the life with a SOCat, propably you won't need to cruise very long and very often, so you have enough and even more energy capacity to live in comfort when anchored. You can make tons of fresh water, operate air conditioning, washing machines, induction cooker, microwave and individual electric heaters in winter time which are the bonus of this system. Forget to run the generator when the boat is on anchor or at the Marina. You can even sell the extra energy produced onboard to other boats' energy grid in the marinas. This way SOCat effectively pay off itself in marinas.

Volkan Gorciz
MEng.

[At Peace]

You could even use air conditioning with a large lithium 24vdc battery house bank and large solar.
Here's just one example of a 24vdc A/C system: https://www.cruisencomfortusa.com/
Just need to add a 24 to 12 vdc converter for the items that need 12vdc and to recharge the engine start batteries.
There are websites that have power consumption calculators to help you figure out how large of a battery bank and how much solar you should have. As it has been stated, it depends a lot on your particular consumption, where you will be sailing, coastal or passages, and off-grid or on shore power. Having a generator has become a backup for the long periods of cloudy days.
Even for those cloudy days, you could replace the low output alternators on each engine with high output alternators and not need a generator at all.

[noelex 77]

Originally Posted by theBigKahuna

Just realize that if you don't have a genset, you will have times (few or many) when you're 'outta juice'. Even as a backup, a generator is very handy.

Many boats are set up with an electrical system that is dependent on a functioning generator, with a supplemental solar system that is only capable of supplying enough power on the better days. There is nothing wrong with this approach, although you will have the repair and service hassles associated with the generator. However, this is not the only way.

It is a mistake to believe solar panels produce no power on cloudy days. While clear blue skies are obviously the best, if you have a well designed system with enough solar, battery capacity and carefully chosen appliances, there is no reason to run out power or not enjoy the comforts when cruising the type of latitudes and seasons most cruisers frequent.

[GoneDiving]

Originally Posted by JustMurph

I tried opening all of the bleeds, but that didn't help unfortunately.
The VFD is 3kW to give it some over head, but with that nice slow 5s ramp up there's no surge to any more than full load power.

Yes, VFDs are an excellent way to reduce inrush and allow use of 3phase equipment on a battery or single phase powered boat. Just buy a VFD twice the rating of the intended 3 phase motor. Of course it needs to be 220v input not 415v. Name brands are good but expensive. Dirt cheap Chinese models are now available and reliable. I've used them for years on home based dive compressors.

I'm pulling 10 and 30kva generators from my vessel to be replaced with a large solar array and Lifepo4 pack (I'm a trawler not a sailing yacht). I'll be using VFDs to drive my 10hp electric/hydraulic anchor winch and dive compressor. My AC is a trivial load compared to these.

The OP didn't mention how often his boat will be used. If it's a weekend warrior then it can charge large batteries from the solar or shore power during the week to be ready for the weekend with no genset noise etc needed while on board.

[GoneDiving]

Originally Posted by Cpt Mark

Bauer told me a 3hp motor would not be able to run the compressor. I didn't quite believe that one and am so glad you've proved it can be done.

Not sure why they would say that. The Junior ll is 2.2kw/3hp straight out of the box. I think earlier models were also 2.2kw but at a reduced 85 lpm. The 3 phase and petrol models were more powerful and the full 100lpm.

Bauer's are great compressors. My large home unit is mid 70s and still going strong.

Apologies to the OP for the thread drift. 😁

[theBigKahuna]

Originally Posted by wingssail

Mr Big Kahuna, If you decide to carry everything which might become handy (sometime) you have to carry it 100% of the time.

In my view you go light, you go simple, and you develop a contingency plan for when the "bad things" happen.

Like when you are outta juice, you turn on one of the two engines you have and get more juice, OR you put up the sails and sail to a port with a dock and shore power.

Wingsail... not disagreeing with you. It's really a 'pick your poison' / stinkpot vs. blowhard type issue. Yes, it's a pain, but last Oct @ top of Erie canal when our genset went out and not wanting to watch engine all night... we froze our tails off... I'd have liked having the genset... but again, whatever gets (and keeps!) you on the water is the best choice.

[Wolfgang.Schau]

I have a 40' catamaran, 750W solar on the davits, acting as a roof over my dinghy, D400 wind generator, 160Ah battery, 2kW inverter. This runs everything just fine, including a small washer.

During the time up north, I had installed a secondary water loop with several radiators and 12V fans controlled by a cheap A/C controllers, a heat exchanger to tap into the engine's cooling loop, and a Webasto heater. Even at 32F, the cabin was nice and cozy and the girls enjoyed a hot shower without the engine running. I recommend a heat exchanger to isolate the engine from any problems which may arise with the secondary loop.

Now living in Florida, I added a 1000Ah battery bank and a small chiller to run cold water through my radiators to cool down the berth before you go asleep. If you don't want condensing water running into your bilge, add a drip pan under the radiators.

[john manning]

I have been 'live-aboard' both with and without a generator. Once the generator had gone we found there was much less use of things like hot water on tap, washing machine (now gone as well), water maker, and we never had aircon.

The generator was both a cost and a convenience.