Generator quandary.

[john_morris_uk]

Left field
One of the quietest generator set ups can be the faithful 1kwHonda suitcase plonked onto the rubber floor of the dinghy ..
cheap enough , easy to sell on..
across an anchorage you can hear tappit like noises but that’s it . Proven tech, great when you need to fix something on deck or when aground ( no cooling water ) or on the beach. ( etc etc )

Understood. We had a Kippor generator but the hassle of another fuel supply (and it being petrol) vs the built in press and play of a diesel generator has won me over. I've used a diesel generator in a silencing enclosure in the past and they've been very convenient and effective. It's just a matter of which one...

 

[john_morris_uk]

Don't know much about these generators but I would assume that if an engine is running at "R" RPM at "X" load it will use "Y" fuel. If the load increases to "XX" it will require "YY" fuel to maintain "R" So variable sped may be a bit of a gimmick?

However that's not how a diesel engine works. IIRC the speed is governed and you set the desired speed with the throttle and the governor meters the fuel to supply the revs. High revs under no load uses not much fuel. Put a load on and the governor tries to maintain the revs by supplying more fuel... Of course power out is also a function of rpm hence the need to vary the speed. You don't save a huge amount of fuel, but you do gain quietness and less wear at the reduced revs.

 

[geem]

Left field
One of the quietest generator set ups can be the faithful 1kwHonda suitcase plonked onto the rubber floor of the dinghy ..
cheap enough , easy to sell on..
across an anchorage you can hear tappit like noises but that’s it . Proven tech, great when you need to fix something on deck or when aground ( no cooling water ) or on the beach. ( etc etc )

But won't run a watermaker as the OP wants or the immersion heater.
Not sure about the interpretation of quiet. They always seem loud when some guy puts it on his sugarscoop when anchored near you so he doesn't have to listen to racket whilst everybody behind him does.

 

[Zing]

I would work on making do with solar if possible. Top up with the engine in a long cloudy spell. Ultimate silence and reliability. Cheap too. Zero maintenance. You may need to maximise energy use to enable this. Maybe an energy recovery watermaker. They use less than 4Wh /lt. Insulate the fridge more if you can. Improve seals. It’s the biggest consumer usually. Get max No of panels. Use multiple MPPT controllers and diodes to maximise output and to minimise shading losses.

If you are going to get a genset look at Polar Power. It is DC, so you save charger losses, plus extremely small, light and simple. Should be reliable, but it will break though sooner or later, everything does, so less is more. If you have the room, Northern Lights or a similar simple 1500 RPM unit would be my next option.

 

[Graham376]

Not if it's built into an acoustic box inside a yacht. You wouldn't know the difference

Maybe quiet for those on board but on anchor we often hear generator exhausts as well as water peeing out.

 

[Alex_Blackwood]

However that's not how a diesel engine works. IIRC the speed is governed and you set the desired speed with the throttle and the governor meters the fuel to supply the revs. High revs under no load uses not much fuel. Put a load on and the governor tries to maintain the revs by supplying more fuel... Of course power out is also a function of rpm hence the need to vary the speed. You don't save a huge amount of fuel, but you do gain quietness and less wear at the reduced revs.

Sorry John, I thought that was what I said?

 

[geem]

Maybe quiet for those on board but on anchor we often hear generator exhausts as well as water peeing out.

Quite possible. There are differing levels of installation. Even so compared to a petrol generator on deck they are more often far quieter. Ours doesn't make an exhaust noise but you do hear the water splash as it discharges.

 

[Zing]

Quite possible. There are differing levels of installation. Even so compared to a petrol generator on deck they are more often far quieter. Ours doesn't make an exhaust noise but you do hear the water splash as it discharges.

I have a water separator with a below the waterline discharge and there is no splashing. My genset is virtually silent (outside). Fumes and global warming guilt and shame are another issue.

 

[geem]

I have a water separator with a below the waterline discharge and there is no splashing. My genset is virtually silent (outside). Fumes and global warming guilt and shame are another issue.

Haha, yep, I know you have talked about lots of solar. We live off solar completely except for the watermaker. About 100 litres of diesel per year. Considering whilst we are on the boat for most of the year we don't drive a car or have a heating or electricity bill then I suspect our carbon footprint will be incredibly low compared to the average?
We do use a small amount of diesel on the main engine but negligible

 

[john_morris_uk]

I would work on making do with solar if possible. Top up with the engine in a long cloudy spell. Ultimate silence and reliability. Cheap too. Zero maintenance. You may need to maximise energy use to enable this. Maybe an energy recovery watermaker. They use less than 4Wh /lt. Insulate the fridge more if you can. Improve seals. It’s the biggest consumer usually. Get max No of panels. Use multiple MPPT controllers and diodes to maximise output and to minimise shading losses.

If you are going to get a genset look at Polar Power. It is DC, so you save charger losses, plus extremely small, light and simple. Should be reliable, but it will break though sooner or later, everything does, so less is more. If you have the room, Northern Lights or a similar simple 1500 RPM unit would be my next option.

I’m looking at solar but we’re really struggling to find space to fit any, let alone lots. I will fit some but how much is a moot point.
Agree re the energy recovery water maker and that’s on the shopping list.
I’ve already rebuilt the fridge and it’s so well insulated and efficient that if you accidentally knock the thermostat it will turn the whole fridge compartment into a freezer and freeze down the entire contents. Many the time we’ve had frozen milk, frozen wine, frozen everything because we’ve knocked the thermostat as we’ve got things in or out of the fridge. As I think I’ve already mentioned the condenser is also water cooled making the fridge extremely efficient.

 

[Zing]

I’m looking at solar but we’re really struggling to find space to fit any, let alone lots. I will fit some but how much is a moot point.
Agree re the energy recovery water maker and that’s on the shopping list.
I’ve already rebuilt the fridge and it’s so well insulated and efficient that if you accidentally knock the thermostat it will turn the whole fridge compartment into a freezer and freeze down the entire contents. Many the time we’ve had frozen milk, frozen wine, frozen everything because we’ve knocked the thermostat as we’ve got things in or out of the fridge. As I think I’ve already mentioned the condenser is also water cooled making the fridge extremely efficient.

It can be hard to find space, assuming a monohull. Most people with solar have an arch, or above davits, or a frame above the bimini or everything. Sometimes flip out units on the guard rail, semi flexible units on the fore-deck maybe. My plan is for a fixed bimini.

If you have your power use minimised in the way you say, you should find it a small jump to do without the genset. Have you measured your power use?

 

[vas]

I also have a generator and 600W of solar. Indeed with halfdead Trojans 4X6V last year I had to resort to using generator for around an hour every couple of days for the watermaker (two on board).
Now with 304Ah@24V LifePO4 I'm pretty sure I'll be okay with no generator.
You need enough solar, but you also need batteries that are happy to be taxed for an hour or so. Watermaker in my setup is 80A@24V, Multiplus 3000 is happy to provide that, at 12V it's going to be circa 150A which is a bit tough on cabling...

 

[jwfrary]

I would work on making do with solar if possible. Top up with the engine in a long cloudy spell. Ultimate silence and reliability. Cheap too. Zero maintenance. You may need to maximise energy use to enable this. Maybe an energy recovery watermaker. They use less than 4Wh /lt. Insulate the fridge more if you can. Improve seals. It’s the biggest consumer usually. Get max No of panels. Use multiple MPPT controllers and diodes to maximise output and to minimise shading losses.

If you are going to get a genset look at Polar Power. It is DC, so you save charger losses, plus extremely small, light and simple. Should be reliable, but it will break though sooner or later, everything does, so less is more. If you have the room, Northern Lights or a similar simple 1500 RPM unit would be my next option.

Polar power look nice units and compact! But I heard a little tricky to get ahold of?

 

[geem]

I’m looking at solar but we’re really struggling to find space to fit any, let alone lots. I will fit some but how much is a moot point.
Agree re the energy recovery water maker and that’s on the shopping list.
I’ve already rebuilt the fridge and it’s so well insulated and efficient that if you accidentally knock the thermostat it will turn the whole fridge compartment into a freezer and freeze down the entire contents. Many the time we’ve had frozen milk, frozen wine, frozen everything because we’ve knocked the thermostat as we’ve got things in or out of the fridge. As I think I’ve already mentioned the condenser is also water cooled making the fridge extremely efficient.

Water cooled condensers are very efficient in the UK with it's super cold sea water. In the Caribbean water cooled is less of an issue. Sea water temperatures can hit 30degC. At that point the difference in efficiency is far less significant. There is the advantage that watercooled is quite and the heat doesn't go in to the cabin.
Unless you can install a high output energy recovery watermaker (at vast cost) and enough solar to run it and the fridge and everything else there will be more times than you can imagine when you need to run the engine.
My preference is for high output 220v watermaker( circa 200-250 litres/hr), genset and solar. The genset can make hot water, charge batteries etc. For me redundancy is important. I don't want to be sat in a marina somewhere waiting for parts when I should be cruising. Good luck with your choices

 

[john_morris_uk]

Water cooled condensers are very efficient in the UK with it's super cold sea water. In the Caribbean water cooled is less of an issue. Sea water temperatures can hit 30degC. At that point the difference in efficiency is far less significant. There is the advantage that watercooled is quite and the heat doesn't go in to the cabin.
Unless you can install a high output energy recovery watermaker (at vast cost) and enough solar to run it and the fridge and everything else there will be more times than you can imagine when you need to run the engine.
My preference is for high output 220v watermaker( circa 200-250 litres/hr), genset and solar. The genset can make hot water, charge batteries etc. For me redundancy is important. I don't want to be sat in a marina somewhere waiting for parts when I should be cruising. Good luck with your choices

All good points.
The water makers I’m looking at are either the Osmosea 12volt ones or the Zen (Osmosea N12ES 12/24V Semi automatic 25-100l/hour - Sailfish Marine - Watermakers, Marine Generators, Solar Panels and more.. or Mactra Marine Equipment - Schenker Watermaker - Zen 50)
I didn’t want to go down the 220 v water maker route as if the generator packs up you’ve got no water making ability. With 12volt you’ve still got wind generator, main engine and solar potentially topping up the batteries.
50 litres an hour is enough for two of us to shower etc surely?

 

[john_morris_uk]

Sorry John, I thought that was what I said?

Sorry I’ve reread your post. My mistake.

 

[john_morris_uk]

It can be hard to find space, assuming a monohull. Most people with solar have an arch, or above davits, or a frame above the bimini or everything. Sometimes flip out units on the guard rail, semi flexible units on the fore-deck maybe. My plan is for a fixed bimini.

If you have your power use minimised in the way you say, you should find it a small jump to do without the genset. Have you measured your power use?

We continuously measure Ah in and out as well as current being drawn.

There’s a dinghy on davits on the back end with a wind generator on a big pole but there might be room for some solar panels on the Bimini being fitted next week.

I’m erring towards flip out panels on the rails.

 

[LadyInBed]

there might be room for some solar panels on the Bimini being fitted next week.

A fixed bimini made out of solar panels seems to me to be an ideal solution.
How much did you use your previous generator? I have a 2kw generator on board but I have to admit that it doesn't get much use.

 

[Tradewinds]

All good points.
The water makers I’m looking at are either the Osmosea 12volt ones or the Zen (Osmosea N12ES 12/24V Semi automatic 25-100l/hour - Sailfish Marine - Watermakers, Marine Generators, Solar Panels and more.. or Mactra Marine Equipment - Schenker Watermaker - Zen 50)
I didn’t want to go down the 220 v water maker route as if the generator packs up you’ve got no water making ability. With 12volt you’ve still got wind generator, main engine and solar potentially topping up the batteries.
50 litres an hour is enough for two of us to shower etc surely?

We had a 12v VMT Little Wonder 150 which did about 20l/hr. Two adults and two small children- was plenty for us. YMMV.

 

[john_morris_uk]

A fixed bimini made out of solar panels seems to me to be an ideal solution.
How much did you use your previous generator? I have a 2kw generator on board but I have to admit that it doesn't get much use.

The Bimini we’ve ordered and which is about to be fitted is canvas. Too late to change that now.

The main times I’ve sailed with a generator were under different circumstances and with large crews on bigger boats. On one I had a crew of 12 and on another I had a crew of 14. The generator was run every day for an hour or two and I rotated water useage and replenishment round multiple tanks. Otherwise my generator experience has been while teaching or examining on a variety of power or sailing craft in the Mediterranean. I’ve never had one on our own boat before.