Two Evils - Please Help Me Decide

[anjou]

Im trying to decide on the best design option for live aboard electrical options.

Im planning on having a 4 cyl, 70hp main engine for propulsion and hot water via a calorifier, plus possible option of 2 x 24v alternators feeding an inverter/ batt bank to supply 2 ring mains round the hull, one being 12v and the other being 220v.

Only the washing machine, macerator, microwave, vacuum, hairdryer etc will be 220v, the rest being 12v, ie, engine room, galley, heads extractor fans, all lighting, tv, radio.

So, ........is it better to spend the money on a large bank of batts and large inverter, OR
go for a stand alone diesel genny, one for sale is 8kva, marinised in a sound box, and have a smaller inverter and not put such demand on the batts.

I anticipate most time will be spent moored and it doesnt make good sense to run a larger engine for a few hours per day just to charge batts (hot water is a by product). Diesel cost, bore glazing etc is downside for an engine which is well oversized for making some electric.

I could just run the jenny when washing and vacuuming needs doing and go for a smaller inverter to just run the microwave which needs @1200w and the toilet macerator @800w. Macerator will only run 15 seconds with each flush, maybe 5 mins with a shower.
Microwave only needed maybe 15 mins a day. The jenny can be set up to auto start on demand.

With the 8kva capacity, more than enough to run washing machine and heat calorifier via immersion element at the same time, OR, convert the heat exchanger to heat the calorifier.


Which is the lesser of these two evils?

[Ram]

Sounds complacated, have you considered solar, the price has come way way down, quiet, clean, no fuel or break downs, easy to install-

[anjou]

Solar wouldnt even scratch the surface to provide the power required and you still have to store it, plus solar collectors dont work at night or during winter when the sun doesnt shine and it would cost thousands for panels, AND i would still need a genny backup.
Im not one of those women who wears a dress AND trousers underneath.

[imagine2frolic]

We live on solar, and a wind generator when cruising. We have a Honda 2k generator for tools, shop vacumm, clippers, etc. etc. It's quiet, effecient, portable, and very small for stowing.Maybe you should skip the hair dryer, and keep the come hither look?.........i2f

[anjou]

Originally Posted by imagine2frolic

We live on solar, and a wind generator when cruising. We have a Honda 2k generator for tools, shop vacumm, clippers, etc. etc. It's quiet, effecient, portable, and very small for stowing.Maybe you should skip the hair dryer, and keep the come hither look?.........i2f

Oh hunni, you smooth talker xxx

You lucky guys live in the sun. Up here, nearer to the top of the world, we get days and sometimes weeks when we dont see the sun enough to make electricity. Its cold, damp, dark and sunshine is a luxury, not to be depended on.
I know I live on the sunny side of the hill, but when its not sunny, im grid connected as a backup.

[s/v Beth]

Anjou, if your doing the permanent liveaboard thing, you may want to do a cost comparison of a diesel generator as apposed to just living on a slip with power. How long before your 6K pound generator saves you money? And what is the convenience of just walking out of your boat to your car worth, or do you want to dingy in the UK rain?
I ask because here in the Northwest, it is easier to just pay the slip and power fee. I recently just junked a diesel generator because it doesn't make economic sense to me. Of course, if you live at the slip, you don't need the inverter either. I have a 2k inverter for the times I am off on the hook, and yes right now I am dependent on the engine for charging during those times, or hooking up to a slip about every other day.

[Chief Engineer]

With your power requirements you would be better off with the genset.

As you are living aboard, you have shore power correct?

A 220 volt macerator? Is that for black water? or is it the British Term for Insinkerator/Disposall?

[Fuss]

Originally Posted by anjou

Im trying to decide on the best design option for live aboard electrical options.

Im planning on having a 4 cyl, 70hp main engine for propulsion and hot water via a calorifier, plus possible option of 2 x 24v alternators feeding an inverter/ batt bank to supply 2 ring mains round the hull, one being 12v and the other being 220v.

Only the washing machine, macerator, microwave, vacuum, hairdryer etc will be 220v, the rest being 12v, ie, engine room, galley, heads extractor fans, all lighting, tv, radio.

So, ........is it better to spend the money on a large bank of batts and large inverter, OR
go for a stand alone diesel genny, one for sale is 8kva, marinised in a sound box, and have a smaller inverter and not put such demand on the batts.

I anticipate most time will be spent moored and it doesnt make good sense to run a larger engine for a few hours per day just to charge batts (hot water is a by product). Diesel cost, bore glazing etc is downside for an engine which is well oversized for making some electric.

I could just run the jenny when washing and vacuuming needs doing and go for a smaller inverter to just run the microwave which needs @1200w and the toilet macerator @800w. Macerator will only run 15 seconds with each flush, maybe 5 mins with a shower.
Microwave only needed maybe 15 mins a day. The jenny can be set up to auto start on demand.

With the 8kva capacity, more than enough to run washing machine and heat calorifier via immersion element at the same time, OR, convert the heat exchanger to heat the calorifier.


Which is the lesser of these two evils?

That cant be answered based on the info supplied. We need to know...
does any of this setup exist already
how bigs the boat
has the boat 24v as well as 12
is a 220v system already installed
how much room is available
do you want to have gas for cooking or electric
how much solar
is there an energy budget
is there a financial budget

some things to consider...
Why would you install a 220v generator mostly just for the washing machine, it would be more worthwhile if there was more advantages like all electric cooking and no gas, but then again generators can be unreliable.
At anchor...
To get the full advantage of a generator for charging your batteries over using your engine then ...
The generator must charge the batteries in the shortest time which means that the charger must be sized accordingly.. eg 800 amps of batteries means about 150a of charger just for the batteries. If at the same time
30a is coming out for other things then you need maybe 200a of charger. Do you see many 200a chargers around... a couple of victrons linked maybe. For example, if you have an 80a charger and 20a is being used for other things then you will run your generator to power your ac charger that is only putting 60a into the batteries. If the batteries are at 70% full then it will take maybe 4 hours to charge them up to 90% full.
4 hrs of generator doesnt sound like fun.
Some batteries dont like to long periods without a 100% charge.
Generators can be unreliable devices... having them start automatically is something not to be taken lightly.
Solar can change the calculations considerably
What about a dc generator and a larger inverter and small batteries

Its worth making an energy budget and seeing if solar and wind can help.
I have all electric cooking and a 7kw ac generator which at anchor runs for 45mins a day and keeps the batteries fully charged so I know the problems.

[noelex 77]

You are setting the boat up with a very high electrical demand. While this is achievable it comes with a cost not just financial. Generators are one of the least reliable boat systems, are difficult to repair, produce heat and noise.
I have meet too many boats that spent much of the season trying to fix their generator rather than enjoying the beautiful anchorages.
You would look great with short hair.
Ditch the 220v appliances unless on shore power and you will enjoy the boat much more.
Just my 2c worth. Good luck with whatever you decide.

[anjou]

ok
The boat is still on the drawing board. Im not going to start building before I get all this sorted out as I might find I cant afford to do it.

The boat will be a barge style 50' x 10'6'' built to EU RCD cat c which means she can be sailed inshore, ie not off shore or blue water. She will be capable of crossing the English chanel so the continental canals and rivers are accesable.
Canals and rivers in the UK which are wide enough and have airdraft, have over 1500 miles of navigation to offer. Due to the massive house price hike in recent times, there has been a huge rise in canal boaters looking for an affordable home afloat, therefore, everything has become regulated and moorings not so abundant.

So, i need to plan for riverbank living where there is no shore power, or for continual cruising. Mooring in one place when not in a marina is limited to 14 days. If I found a marina where I wanted to spend more time, and there was a berth free, I might stay a while, and would plug into shore power.

Im narrowing things down slowly. Forget the genset, opt for twin 12v alternators, (output undecided, advice?) supplying an Ample Power regulator, into a battery bank, feeding a Victron V3 -12 inverter, backed up by shore power when available. I will install as much 12v stuff on board as possible, but the problem with 12v microwaves, fridges etc is they are so expensive compared to standard donmestic 220v appliances.
I will use propane for the gas hob, but thats all because the boat safety inspections get too complicated. I prefer an electric oven but rarely use one. A wok and microwave is all I use. A washing machine and steam iron is a must.

All the heads waste must go into a black tank and its rumoured soon the EU will demand all waste from basins, sinks, washing machines etc goes into a black tank.

Im not planning on using too much 220v, but think its always wise to have spare capacity for the future.

[BubbleHeadMd]

Ok, you don't get as much sun as some parts but I know you get wind. How about adding a wind turbine to that?

[Pete7]

Were is the heat coming from for the boat if we have another winter like this one? Just had two friends move off the yacht to a small flat. Even in a marina with shore power they couldn't do it, although to be fair the boat the Beneteau wasn't insulated and set up for living on board. If it had been a warmer winter they may have got away with it.

A barge then, that will be diesel fired heating with a back boiler for hot water perhaps? that should keep the boat toastie warm. Something like a pot stove and heating oil as apposed to red diesel which should be cheaper.

I am not sure I would ditch the idea of the genny though if you are tow path mooring, I can't see how you can generate enough elec without one to be comfortable.

Pete

[anjou]

Im going to install a solid fuel stove, - wood, coal, briquettes etc. It gives some independance from diesel and is too simple to go wrong.
After the steelwork is finished, I will batten out, fit the double glazed windows and then the whole hull and cabin inc roof will be sprayed with foam to 3'' thick before boarding out.
Traditional metal framed, single glazed top opening lite boat windows will cost @ £1,000 but im using fully spec'd, 28mm gap double glazed with thermal break UPVC frames for much less than that.
I hate condensation and It seems madness to fit windows that are dinosaurs.

Small wind turbines are little more than a gimmick. They make too much noise and to be effective, need to be up on a tower to escape ground turbulance. I would need to be able to dismount a turbine to enable the boat to pass under bridges. Lots of rivers and canals are bordered by trees.

[BubbleHeadMd]

I agree that you couldn't run a laundry machine on a wind turbine, but a small turbine blowing all night while you sleep would go a long way to keeping your battery bank topped off.

[sailorboy1]

I don't believe you are going to be able to serve all those electrical lods without running engine or a genset to supply a huge battery bank. So that's my vote.