Power Generation

[jddevel]

More advice please. In an attempt to ensure my nearest and dearest remains content with my ability to design and fit-out our narrow boat I`ve spent a good deal of time researching numerous aspects of this ambition especially on this forum. So to the subject of a on board generator. I realise there are some very "hardened" views on even are they needed but on the assumption it is my choice an advised size would be helpful.

4x110 amh minimum domestic (possibly larger) batteries. Mastervolt 2000 plus inverter.

T.V., washing machine,fridge, and freezer. elect. toilet (plus a cassette!!!) microwave ( for when I`m on my own!!) hair drier-and that's to start with. Obviously not all would be run at the same time with the washing machine normally whilst cruising. My leaning is towards a water cooled diesel hopefully accommodated in the engine room. With a 38hp Beta installed I`m currently having a Travel Power quoted for but believe a larger capacity alternator than currently fitted may be also a better option. Plus as I`ve yet to start other than have a bow thruster fitted with it`s own 12 volt battery should I certainly go for 24volt. If so how will this affect any solar etc I might fit. If the above should have been split into separate topics hopefully the moderator will so do. Thanks again

[Sea Dog]

Pretty close to my set up (no freezer, Beta 43 with 175a domestic alternator) and I have no problems. I'm either on shore supply or out and about stopping for only a few nights at a time though, and spending more time stopped and off grid or being a heavy user will change things a lot. You can always manage with more stored capacity, but remember that what you take out, you have to put back plus a bit.

 

The bow thruster issue is eased by having a battery sited up forward next to your unit. The supply cables then are there only to recharge. Unless you really can't drive and rely heavily on the thruster, this arrangement should meet your needs.

[WotEver]

It would help if you gave us your intended usage. Will you be cruising most days? Just some days? Only in the summer? Will you have access to shore power? How often?

 

Note that microwaves use huge amounts of power albeit only for a relatively short period of time.

[OldGoat]

jddevel, on 09 Oct 2016 - 2:53 PM, said:

More advice please. In an attempt to ensure my nearest and dearest remains content with my ability to design and fit-out our narrow boat I`ve spent a good deal of time researching numerous aspects of this ambition especially on this forum. So to the subject of a on board generator. I realise there are some very "hardened" views on even are they needed but on the assumption it is my choice an advised size would be helpful.

4x110 amh minimum domestic (possibly larger) batteries. Mastervolt 2000 plus inverter.

T.V., washing machine,fridge, and freezer. elect. toilet (plus a cassette!!!) microwave ( for when I`m on my own!!) hair drier-and that's to start with. Obviously not all would be run at the same time with the washing machine normally whilst cruising. My leaning is towards a water cooled diesel hopefully accommodated in the engine room. With a 38hp Beta installed I`m currently having a Travel Power quoted for but believe a larger capacity alternator than currently fitted may be also a better option. Plus as I`ve yet to start other than have a bow thruster fitted with it`s own 12 volt battery should I certainly go for 24volt. If so how will this affect any solar etc I might fit. If the above should have been split into separate topics hopefully the moderator will so do. Thanks again

Your power 'requirements / needs' are potentially horrendous and not very practical in what appears to be a small-ish boat (38 hp Beta)

Domestic devices - washing machine and microwave take a lot of power and to a lesser extent a hair dryer.

In a small-ish boat you don't have a lot of room for a separate generator.

Have you considered a Beta Prop gen setup instead of a travel power on the engine - it would be a lot quieter....

A 2KW inverter is likely to be too small

I would go for a 24V system anyway...

 

As I'll probably get flamed - I haven't bothered to explain my reasonings at this stage.

[Paul C]

There's 3 basic routes, 4 if you count onboard/external generator as separate ones:

 

1. Big alternator, big battery bank, big inverter

2. Travelpower

3. Generator

 

No. 1 has the advantage that its not necessarily tied to running the motor (so some could come from solar power, or you could use the loads 8pm-8am etc) but obviously there's a charging efficiency and the fact you'd be discharging/recharging the batteries too. The other two, there's not much in it all told when the costs are compared. What 2 or 3 have in differences in cost, also have in detail differences which might make a particular option appealing.

 

24V is definitely worth thinking about although I suspect it would make sense to have "24V engine electrics" and "24V domestic electrics" together, and the engine electrics might be a stumbling block eg on starter motor, gauges etc. You could do 12V engine electrics/24V domestics but then you lose a little functionality, ie you can't twin the alternators etc.

[ditchcrawler]

. You could do 12V engine electrics/24V domestics but then you lose a little functionality, ie you can't twin the alternators etc.

That is what I have

[Paul C]

That is what I have

 

So.....if your domestic alternator breaks down, you can start & run the engine ad infinitum but not charge domestics until the alternator is fixed?

[bottle]

Set up:

 

12v engine

 

24v domestic

 

Beta 43, 50 amp 12v and 80 amp 24v alternators

 

Cummins Onan 7Kw generator (12v 30 amp alternator)

 

Solar panels 400watts @ 38v (approx),(connected series,parallel) MPPT controler

 

Victron 'combi' 24v, 2Kva, 80 amp

 

Battery bank 24v 390 amp,hrs @ 20 hr rate (six batteries connected series,parallel)

 

Boat is live-aboard, continuously cruising and does not have any gas on-board

 

Works for me.

[ditchcrawler]

 

So.....if your domestic alternator breaks down, you can start & run the engine ad infinitum but not charge domestics until the alternator is fixed?

Well sort of, but I would rather not go into that, but its still better than a single alternator when you have nowt

[jddevel]

Thank you for the contributions. To expand more. I have purchased a sailaway Bourne Hull from Swanley Bridge Marina. It already had a new Beta 38 installed which I assume is 12volt electrics. Would have had a 43 but reasonably happy as a result of contributions during a previous listed topic on engine sizing. I`m having some "additions" currently being added. A bow thruster with battery adjacent ( see previous forum topic I started recently). Side hatch. Extended domestic battery compartment Originally 3 but now 4 possibly 5. Taff rails. So 12v thruster in situ. Original as supplied alternators which dependant on advice/conclusions will be changed accordingly. Trying to evaluate Travel Power( quote due in) against water cooled diesel generator, against large alternator, inverter and solar power. My use currently will be as a Marina based during late Autumn to early Spring with myself and wife extended leisure cruising periodically the remainder with additional use by my 4 children and grandchildren. Its a 57 ft semi trad. Reading a little about a Beta Prop Generator on the forum - jury is out.

[ditchcrawler]

. Reading a little about a Beta Prop Generator on the forum - jury is out.

Surly its a bit late for that option

[Sea Dog]

Beta recommend the 38 for up to 50ft and the 43 above that, but they recommend the 43 right up to 70ft and there's many a satisfied 57ft owner standing atop a Beta 38.

 

Where you might find an issue is in the standard alternator fit. Whilst the current 43 is spec'd with 70a/175a engine/domestic alternators, the 38 is 45a/100a with a 75a engine alternator as an option, but the 175a domestic doesn't appear to be an option. They don't show a 24V option for either, although they do for the 50 and above. The travel power option for the 38 is a 3.5kva whereas the 43 can be 3.5 or 5.0kva so it appears that the 38 doesn't have as high a generation potential.

 

What that does tell you is that anything more than the Mastervolt 2kva unit would be a waste hanging off the 100a alternator! However, when it comes to charging the domestic bank, my 175a alternator might inject 3 figures very shortly after start up, but is usually well down into double figures within minutes.

 

You should be able to run a well chosen washer from the 100a alternator 2kva inverter combination whilst cruising, but bear in mind that your domestic charging will be limited whilst you're doing so and it may be best that you have reasonably charged batteries before the washer goes on. I'd be careful using the washer when you need to be in and out of tick over too, like when doing locks, because a changing heavy electrical load will really affect engine revs.

 

It may well be that, once you understand your electrical system, you can get the best from it and all will be well without adding beyond standard capacity. However, if you're lending the boat out without you there, it might be unreasonable to expect occasional users to keep on top of it with heavy loads like the washer. That said, given likely holiday lengths of working parents, they can probably manage without it easily enough. It sounds to me that your investigation into generators is worth doing though.

 

Hope some of that is useful.

[jddevel]

Certainly is Seadog. Please all keep advice coming. Regarding Beta prop generator Ditchcrawler. only just learnt of their

existence by a posting above by Old Goat and therefore obviously don't understand their requirements or whether they can be

fitted retrospectively. From your comments its a No No.

[bottle]

Not exactly a no.no but very expensive and you would need to remove existing engine.

 

Just one other thing and slightly off topic, I noted you mentioned a taff rail, please think about this very, very carefully.

 

Yours being semi-trad, why do you think you need one. (rhetorical)

 

It will restrict access to stern deck and are usually at hight designed for someone to fall over.

 

When steering you will be in front of the tiller, within the sides of the semi-trad.

 

Your boat, though.

[MtB]

The problem with taff rails is should you fall off the back, the rail tips you up so you go in head first. Should the engine be in astern you can get sucked under the counter by the water flow and into the blade.

 

I was nearby when this happened to someone and they died, so I am perhaps over-sensitive to the risk presented by taff rails.

[ditchcrawler]

The problem with taff rails is should you fall off the back, the rail tips you up so you go in head first. Should the engine be in astern you can get sucked under the counter by the water flow and into the blade.

 

I was nearby when this happened to someone and they died, so I am perhaps over-sensitive to the risk presented by taff rails.

I think its probably been one of the biggest contributors to people dying while actually boating. I can think of 3 cases and one near miss

[MtB]

And getting back on topic, with the sheer amount of electrical demand the OP lists I'd go for a inboard genny every time.

 

My mate had a 6kva genny under the tug deck and it was inaudible oustide the boat, and barely noticeable inside when running. FAR quieter than running the propulsion engine with a travel power.

[ditchcrawler]

And getting back on topic, with the sheer amount of electrical demand the OP lists I'd go for a inboard genny every time.

 

My mate had a 6kva genny under the tug deck and it was inaudible oustide the boat, and barely noticeable inside when running. FAR quieter than running the propulsion engine with a travel power.

I have a friend with a Fischer Panda which has a water cooled exhaust mounted in the engine room. We were sitting by the bow of the boat on the towpath one evening and didn't even notice him start it.