ip485
Well-Known Member
Here are my thoughts having been through a similiar process.
Firstly, even for short term cruising, you are likely to spend a fair amount of time at anchor or on pontoons - after all surely cruising is about staying at different places, not just sailing! So, if you like hot showers and hot water your biggest demand for energy is the electric heater. (I know you can run the engine but that seems a terrible waste just to heat water never mind running it at low revs. just to make hot water at anchor). So that is where the Genset comes into its own with not much to replace it and why 240V makes sense. However big your battery bank you will do well to heat the water off an inverter.
So I can run my Genset for an hour and have a full tank of hot water.
Gensets are pretty useless for charging batteries. Why run a Genset with very little load for many hours which is required to charge a battery bank? The answer I decided is definitely a big solar array. OK, I know it is a big committment but I opted for 700W which gives me enough power to run the fridge, freezer, all the lights and keep the bank pretty much fully charged without resorting to any other power source - and its silent.
I dont care what people say about Gensets not being noisy - either they have huge yachts or tons of lead lined insulation. I genuinely can barely tell if the Genset is running sitting in the cockpit but in the saloon it is more than audible.
Then there is the aircon. Again whatever you might think it is nosiy (much noiser than the Genset) (unless I guess you have a water cooled system which is seriously costly and involved to install). In reality you will run the aircon for a couple of hours to pull the cabin temperature down for a good nights sleep. I can run the units in the cabins off the battery so I dont need the Generator for that but the main unit in the saloon pulls the batteries down far too quickly (and that is using a reverse cycle water cooled system). So if you are happy with just a cool cabin you dont need the Genset.
So, the best thing I ever did was the solar array. It means the Genset only gets used for hot water and occasional use of Aircon in saloon, which is perfect, but `i wouldnt do without the Genset becasue I like the hot water. When the Genset goes on, so does almost all the 240V systems, water heater, air con (if needed), battery charger and 6Kw proves enough and an hour (or two) does the job. If it stops working for any reason the solar array will deal with the fridge, freezer and everything else bar the hot water and take it in its stride without any noise or anything to go wrong.
To complete the analysis if you opt for a water maker then again realistically you need the 240V supply, although there are 12 / 24V systems they arent that efficient, and the 240V systems are reasonably power hungry, and a compressor for diving (if that is your thing) will not escape the need for a 240V supply. Again a short run will be sufficient for these systems to do their job.
You will probably need more than 600AH and 800AH seems to work well of battery capacity, and without doubt a soft start on the 240V supply will enable a smaller Genset to be used and yet cope with a far greater potential load.
I thought hard about replacing my FP hearing all the reliability issues, and concerns about noise. In fact touch wood it has proved really reliable. Also be very careful about the often heard claims of the lower rpm units being less nosiy - they produce a different noise (deeper), and you will not find a manufacturer that will tell you in a like for like installation you will notice any significant difference. I can tell you on the same yacht, same installation, I find the lower rpm unit more intrusive. I very nearly repalced the FP for just these reasons and am very glad I spent the £6 to £8K on something else!
I fully appreciate that we can all be a great deal more conservative, and use far less power and everything can be scaled back accordingly, but if you dont wish to I can say that combination gives you everything you realsitically need without much worry about what switch you do or dont turn on, and leaves you totally self sufficent.
Firstly, even for short term cruising, you are likely to spend a fair amount of time at anchor or on pontoons - after all surely cruising is about staying at different places, not just sailing! So, if you like hot showers and hot water your biggest demand for energy is the electric heater. (I know you can run the engine but that seems a terrible waste just to heat water never mind running it at low revs. just to make hot water at anchor). So that is where the Genset comes into its own with not much to replace it and why 240V makes sense. However big your battery bank you will do well to heat the water off an inverter.
So I can run my Genset for an hour and have a full tank of hot water.
Gensets are pretty useless for charging batteries. Why run a Genset with very little load for many hours which is required to charge a battery bank? The answer I decided is definitely a big solar array. OK, I know it is a big committment but I opted for 700W which gives me enough power to run the fridge, freezer, all the lights and keep the bank pretty much fully charged without resorting to any other power source - and its silent.
I dont care what people say about Gensets not being noisy - either they have huge yachts or tons of lead lined insulation. I genuinely can barely tell if the Genset is running sitting in the cockpit but in the saloon it is more than audible.
Then there is the aircon. Again whatever you might think it is nosiy (much noiser than the Genset) (unless I guess you have a water cooled system which is seriously costly and involved to install). In reality you will run the aircon for a couple of hours to pull the cabin temperature down for a good nights sleep. I can run the units in the cabins off the battery so I dont need the Generator for that but the main unit in the saloon pulls the batteries down far too quickly (and that is using a reverse cycle water cooled system). So if you are happy with just a cool cabin you dont need the Genset.
So, the best thing I ever did was the solar array. It means the Genset only gets used for hot water and occasional use of Aircon in saloon, which is perfect, but `i wouldnt do without the Genset becasue I like the hot water. When the Genset goes on, so does almost all the 240V systems, water heater, air con (if needed), battery charger and 6Kw proves enough and an hour (or two) does the job. If it stops working for any reason the solar array will deal with the fridge, freezer and everything else bar the hot water and take it in its stride without any noise or anything to go wrong.
To complete the analysis if you opt for a water maker then again realistically you need the 240V supply, although there are 12 / 24V systems they arent that efficient, and the 240V systems are reasonably power hungry, and a compressor for diving (if that is your thing) will not escape the need for a 240V supply. Again a short run will be sufficient for these systems to do their job.
You will probably need more than 600AH and 800AH seems to work well of battery capacity, and without doubt a soft start on the 240V supply will enable a smaller Genset to be used and yet cope with a far greater potential load.
I thought hard about replacing my FP hearing all the reliability issues, and concerns about noise. In fact touch wood it has proved really reliable. Also be very careful about the often heard claims of the lower rpm units being less nosiy - they produce a different noise (deeper), and you will not find a manufacturer that will tell you in a like for like installation you will notice any significant difference. I can tell you on the same yacht, same installation, I find the lower rpm unit more intrusive. I very nearly repalced the FP for just these reasons and am very glad I spent the £6 to £8K on something else!
I fully appreciate that we can all be a great deal more conservative, and use far less power and everything can be scaled back accordingly, but if you dont wish to I can say that combination gives you everything you realsitically need without much worry about what switch you do or dont turn on, and leaves you totally self sufficent.
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