Usual location of generator on a monohull

[Jammer]

Where are these things usually installed on a 37-42' monohull? Inside below decks somewhere? A lazarette?


Thinking in terms of the Northern Lights 6kw unit or others of similar size.


Related question, do people buy the sound shield for it from Nothern Lights, or install without, or make their own sound reduction system?

[Singularity]

I've got a 6kw NL, came with the boat, mounted beside the main engine with genny oriented fore/aft.

It's got 4 hours on it with the sound cover from NL.

I do not think I would install an AC genny at this point in history on a monohull <50 foot. My largish inverter charger can only put 125amps/hour to the LFP. A DC generator can put closer to 200 amps/hour with a smaller engine and footprint. Recall that LFP can safely discharge all the energy you would ever need whenever you need it, as much as the AC genny you're looking at.

If this makes sense, you start to look at the AC generator as a less efficient means converting diesel to usable electricity than the DC genny option.

[Jammer]

Thank you, Singularity. By a DC generator, do you mean another unit attached to the diesel engine used for propulsion? Or a separate genset with its own diesel engine?


I have been unable to find any DC gensets (engine plus generator/alternator) that are well engineered. They all look like science projects. Have you seen some that are promising?

[newhaul]

Originally Posted by Jammer

Thank you, Singularity. By a DC generator, do you mean another unit attached to the diesel engine used for propulsion? Or a separate genset with its own diesel engine?


I have been unable to find any DC gensets (engine plus generator/alternator) that are well engineered. They all look like science projects. Have you seen some that are promising?

http://www.cruisersforum.com/forums/...kw-124095.html
Here are some ideas

[Jammer]

Originally Posted by newhaul

http://www.cruisersforum.com/forums/...kw-124095.html
Here are some ideas

Thanks. I sent Polar Power a note and will see if I hear back. They had disappeared from the internet for a while and seem to have resurfaced. They appear to be oriented towards custom builds and I am skeptical of their interest in a "quantity one" sale. We'll see.


The other solutions are science projects, that is, experiments. It's hard to get this stuff right and build something reliable that will run hundreds or thousands of hours without a lot of fiddling. All the more so if it has to fit in a small space.

[newhaul]

Originally Posted by Jammer

Thanks. I sent Polar Power a note and will see if I hear back. They had disappeared from the internet for a while and seem to have resurfaced. They appear to be oriented towards custom builds and I am skeptical of their interest in a "quantity one" sale. We'll see.


The other solutions are science projects, that is, experiments. It's hard to get this stuff right and build something reliable that will run hundreds or thousands of hours without a lot of fiddling. All the more so if it has to fit in a small space.

how small a space? There are several options

[Singularity]

Originally Posted by Jammer

Thank you, Singularity. By a DC generator, do you mean another unit attached to the diesel engine used for propulsion? Or a separate genset with its own diesel engine?


I have been unable to find any DC gensets (engine plus generator/alternator) that are well engineered. They all look like science projects. Have you seen some that are promising?

I am referring to one of the science project looking contraptions, typically water cooled single cylinder Kubota diesel that turns an alternator and/or water maker and/or refer plate pump and/or bilge pump and/or hydraulic pump. Last I checked the basic MyTGen with a 150 amp alternator was like $4200. With 30 gph water maker about $9000.

At this time I would rather have a little kubota turning a large alternator that could be the same model alternator as on the main engine. I constantly think redundancy, failure odes, etc. The AC genny by all accounts is reliable, but it is also $10k worth of unique parts that can be large and heavy. The little Kubota contraptions look they could be disassembled and carried as checked luggage by paying a little extra fees (if/when parts are needed).

By all accounts the DC gensets work as well as AC, though the fact of the matter is most anyone can rig a DC genset, poorly, resulting in bad outcomes that tarnishes the entire concept.

[a64pilot]

I keep harping on this, but I see no real advantage of a DC generator, conversion of AC to DC or the other way is so easy and efficient now that there just isn’t the need.
Comparing a NL generator to any “science project” is just nuts, the quality of a NL is pretty much second to none and will likely run thousands and thousands of trouble free hours.
Science project? Not so much.

However the day that NL or similar quality generator begins mass manufacturing of a DC genset, well then I may change my mind.
It’s trouble free operation, availability of parts that I’m after, not what flavor of power it makes.

Where to mount them is easy, wherever there is room, for me that was the lazarette, others may have room elsewhere, but me there wasn’t anywhere else.
I went with the factory soundshield, and double isolated mine, meaning that the generator sits on engine mounts inside of its sound shield, then I put the sound shield on its own set of engine mounts, the same as the ones internally as engine mounts are often selected for the weight and vibration frequency of the engine.
No way could I have built a sound shield anywhere near the quality of the factory one.

However you need in my opinion to decide the duty of the generator. If your planning on running it a hundred hours a week or so, then by all means spend the bucks and weight on a NL.
However if it’s just a few hours a week, possibly consider a Nexgen and save a lot of money, size and weight.

[Singularity]

A tale of 2 boats. Both have 1kw solar ($2000 or less). Neither has batteries, generator, inverter.

Boat A adds 10kw LFP ($4500), big inverter ($2000), DC generator ($4500).

Boat B adds 10kw AGL ($2500??), moderate inverter ($1000), 6kw NL AC genny ($10000).

Boat A has more usable Kw on tap, costs less to procure, requires fewer hours run time to charge the LFP (and that much fewer hours run time than stepped AL charging).

What is the benefit of boat B?

The only advantage I see for the AC genny is if cabin air con is expected (even then a DC genny would work). I'm not suggesting that the DC units are on par with NL, rather that the NL doesn't offer greater utility, it has to run more hours, takes more space, costs more money)...

[boatpoker]

Originally Posted by Singularity

A tale of 2 boats. Both have 1kw solar ($2000 or less). Neither has batteries

So they lose all power when the sun goes down ?

[newhaul]

Originally Posted by Singularity

A tale of 2 boats. Both have 1kw solar ($2000 or less). Neither has batteries, generator, inverter.

Boat A adds 10kw LFP ($4500), big inverter ($2000), DC generator ($4500).

Boat B adds 10kw AGL ($2500??), moderate inverter ($1000), 6kw NL AC genny ($10000).

Boat A has more usable Kw on tap, costs less to procure, requires fewer hours run time to charge the LFP (and that much fewer hours run time than stepped AL charging).

What is the benefit of boat B?

The only advantage I see for the AC genny is if cabin air con is expected (even then a DC genny would work). I'm not suggesting that the DC units are on par with NL, rather that the NL doesn't offer greater utility, it has to run more hours, takes more space, costs more money)...

boat A can run air conditioner off Lfp bank on the inverter. 12k btu marine system uses 10amps at 120 v AC off inverter. So uses 100 ah per hour so run in sleeping cabin for an hour before bed. Not sure without more data but 1k solar should support the vessels power needs with Lfp bank.

Boat B needs the AC generator to run air con.
And to charge batteries daily. Or every 2 days

AC unit I'm using for numbers https://www.mmair.com/marine-divisio...00-btu-system/

[Singularity]

Originally Posted by newhaul

Boat B needs the AC generator to run air con.
And to charge batteries daily. Or every 2 days

What I am thinking is that both boats with a larger inverter can run a cabin air con, just that the LFP boat can run it for more hours before recharging and/or have a longer reserve capacity in case of cloudy weather. Neither boat likely needs a genny at all, unless cabin ac will be used routinely. If this occurs, the DC genny is still the least expensive way to convert Dino juice into electrical juice (unless I'm really missing something).

[newhaul]

Originally Posted by Singularity

What I am thinking is that both boats with a larger inverter can run a cabin air con, just that the LFP boat can run it for more hours before recharging and/or have a longer reserve capacity in case of cloudy weather. Neither boat likely needs a genny at all, unless cabin ac will be used routinely. If this occurs, the DC genny is still the least expensive way to convert Dino juice into electrical juice (unless I'm really missing something).

not much missing except the agm batteries won't support running a 100amp continuous load for long. The numbers have been run on here numerous times.
The Lfp will not even sneeze at it .
With 1kw solar thru mppt you will get approx 80 to 85 ah per hour which mean's just over an hours solar to sleep comfortably with no dyno juice used. And the rest of the days output to charge the rest of the Lfp bank. The hypothetical setup will produce between 350 and 600ah per day. To recharge the bank. Or most of your entire battery banks capacity.
10kw is approx 750ah if my math is right.( from memory) and that's slipping.

[Sailmonkey]

Originally Posted by Jammer

Where are these things usually installed on a 37-42' monohull? Inside below decks somewhere? A lazarette?


Thinking in terms of the Northern Lights 6kw unit or others of similar size.


Related question, do people buy the sound shield for it from Nothern Lights, or install without, or make their own sound reduction system?

Usually the generators are installed in the hull, between the bow and stern.

Most commonly in the lazarette if there is room, followed by the engine space if there is room. However I’ve seen several and installed several myself in other various spaces. Such as beneath mid-salon islands, beneath Pullman berths, and any other space that the machine can be wedged.

[svHyLyte]

Regardless of what system you choose, the three most important things to keep in mind for the installation are: Access, Access, and Access. Absent these, maintenance and up-keep will suffer, repairs will be difficult or impossible, and the machine will be a disappointment, irrespective of manufacture. BTDT.

FWIW...