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john61ct · 08-08-2017, 13:14

I would be almost as annoyed by the noise of an electric compressor running for many hours as I would by a dino juice motor.

A huge reason I like sailing is the relative quiet.

Rumpi · 08-08-2017, 16:58

For me it's pretty clear. A 9kW generator is going to start a 1.5kW motor even under full load. Given that "Leopard is no Burger King" (still trying to get my head around this concept actually) I think the question is answered in full.

Just to be a little off topic:
I strongly suspect that the generator is sized to power the dryer. I don't know what dryer they actually install but a tipical electric residential one draws more then 1.5kW.

As for powering a dive compressor on batteries what can I say. If 1000Ah of lithiums can't power a 1.5kW motor for an hour then I guess nothing can. Replenishing that power is something else but if a 45ft catamaran can't find the space to mount at least 1000Wp of panels then the buyer should get his money back. Yes this is not a solution for someone running the compressor 5 hours a day but for the casual recreational diver it might work.

john61ct · 08-08-2017, 17:03

Especially since a powerful enough genny can replenish that LFP bank every couple hours if needed.

But fact remains if used many times a day, powering the compressor directly from a dino juice motor would be simpler and much cheaper.

Rumpi · 08-08-2017, 17:43

Quote:

Originally Posted by john61ct

Especially since a powerful enough genny can replenish that LFP bank every couple hours if needed.

But fact remains if used many times a day, powering the compressor directly from a dino juice motor would be simpler and much cheaper.

I totally agree with everything. Energy conversions should be kept to the absolute minimum possible. And when it comes to big lithium banks the question becomes: How big a generator can my boat float?

softdown · 08-08-2017, 17:45

Quote:

Originally Posted by DeepFrz

The upscale boats, like Nordhavn trawlers and larger sail boats use Outback quite a bit.

I'm a regular at a solar board occupied with mostly professionals. The only negative I have ever seen posted about Outback is by me. Their plethora of manuals can be confusing for the layman. I have their FlexPower system with all the bells and whistles. I think I got seven manuals? Programming that thing gives me the willies. http://outbackpower.com/outback-prod...one-fxr-series

Olddan1943 · 08-08-2017, 18:12

Here's my experience with large generators. My 1989 Norhavan 46ft was speced for 12kw. The original owner wanted to install a compressor to recharge tanks. He had them install a 20kw generator. I did not see any signs he made an effort to install the compressor. Given the size of the boat, I have no idea where he would have installed the compressor. All he managed to do was totally screw up the layout of engine room. IF anything happened to the outboard side of the generator, that side of the hull would have to have been opened like a can of tuna.
I also had a 8kw generator in the aft lazaret.
Now, no one has addressed the possibility of installing 2 8kw generators and installing the circuitry to parallel the generators. Not only would that give you greater flexibility on the location and weight distribution of the generators but also provide a "spare" incase one generator goes down.
Per the compressor, good luck on finding the space without sacrificing space needed for other more important equipment or storage.

**a64pilot** · 08-08-2017, 18:12

Odd, my flexmax 80 is I think very intuitive, almost as good as Garmin stuff for being able to figure out without a manual.
Now I don't have all the bells and whistles though.

Sawbonz · 08-08-2017, 18:16

Quote:

Originally Posted by john61ct

Especially since a powerful enough genny can replenish that LFP bank every couple hours if needed.

But fact remains if used many times a day, powering the compressor directly from a dino juice motor would be simpler and much cheaper.

Cheaper how, if all the same equipment is already on the boat?

Sawbonz · 08-08-2017, 18:18

Quote:

Originally Posted by Olddan1943

Now, no one has addressed the possibility of installing 2 8kw generators and installing the circuitry to parallel the generators. Not only would that give you greater flexibility on the location and weight distribution of the generators but also provide a "spare" incase one generator goes down.

Wow. Just wow. [emoji848]

Olddan1943 · 08-08-2017, 18:21

The "intuitive" part of my brain died.

**a64pilot** · 08-08-2017, 18:43

What would a 1 KW Life-Po bank even cost?
I hope one day for maybe a 400 AH one myself.

The thing I do not understand is why do boat manufacturers put generators on boats, that don't have the electric system to support them?

For instance a 30 amp boat can only use a 3.6 KW generator, a 50 amp boat can only use a 6 KW generator.
So why fit a 12 KW, do these sail boats have dual 50 amp shorepower cords and 100 amp service boxes? Cause a 12 KW generator will supply 100 amps.

downunder · 08-08-2017, 18:44

Quote:

Originally Posted by Sawbonz

I think you may be the answer I'm looking for!

If a VFD is all that's needed and is cheap to boot it seems like using one to power the more prevalent (I think) 230v 3-phase compressor is the answer. I would mind running the generator to power the compressor instead of an inverter...I just want it to work.

I'm hoping to find an electrical engineer to help draw out a plan for the specifics.

This definitely works. 3phase with variable speed drive electrical motor.

Can't find link at present but will post. Chap in Cairns, Australia ran his compressor and water maker through an inverter on a 30ft outboard powerboat with with about 100W solar. It does work. With 2x3kw inverters should be fine. Anyway if you have citron inverter chargers with boost should be fine for startup anyway.

I will try and dig up the link.

Cheers

DotDun · 08-08-2017, 18:48

Quote:

Originally Posted by a64pilot

What would a 1 KW Life-Po bank even cost?
I hope one day for maybe a 400 AH one myself.

The thing I do not understand is why do boat manufacturers put generators on boats, that don't have the electric system to support them?

For instance a 30 amp boat can only use a 3.6 KW generator, a 50 amp boat can only use a 6 KW generator.
So why fit a 12 KW, do these sail boats have dual 50 amp shorepower cords and 100 amp service boxes? Cause a 12 KW generator will supply 100 amps.

50 amp shorepower cords are 12kw (240v * 50a).

downunder · 08-08-2017, 19:05

Quote:

Originally Posted by Rumpi

For me it's pretty clear. A 9kW generator is going to start a 1.5kW motor even under full load. Given that "Leopard is no Burger King" (still trying to get my head around this concept actually) I think the question is answered in full.

Just to be a little off topic:
I strongly suspect that the generator is sized to power the dryer. I don't know what dryer they actually install but a tipical electric residential one draws more then 1.5kW.

As for powering a dive compressor on batteries what can I say. If 1000Ah of lithiums can't power a 1.5kW motor for an hour then I guess nothing can. Replenishing that power is something else but if a 45ft catamaran can't find the space to mount at least 1000Wp of panels then the buyer should get his money back. Yes this is not a solution for someone running the compressor 5 hours a day but for the casual recreational diver it might work.

Sawbones I note Brownies are supplying there yacht package compressor and yes they seem to recommend an oversized genes.

I believe a 6kva Northern Lights with a 5kw Vitron Quattro should start the compressor.

The concept of the 3 phase variable speed drive is similar to the concepts used in the modern inverter chargers. VSD means you eliminate the compressor start up loads.