Gen Sets .

[Gordon]

We are evaluating the pros and cons of installing a genset into a new catamaran. We will be running watermaker(12v - 60ltr/hr ) two frigde and one freezer, a washing machine, microwave, various 240v appliances, and two chart plotters radar and an autopilot over legs of up to three weeks.
The unit I have been looking at is the Hybrid Genverter GV7i by Whisper Power, does anyone have experience with this unit.Also of interest is the new hybrid gen. by Mastervolt the GPX 6.

Cheers Gordon.

[Captain Bill]

If you are going to get the genset don't get the 12volt water maker unless you have more solar and wind power than you can possibly use. My 12 V water maker takes uses so many amps I have to run an engine or the genset to use it and which means I have to run it all day to fill the tank. Our washing machine uses 14-22 load gallons per which is 2-3 hours of genset time. I recommend an AC water maker that you can use while topping up your batteries. They are available at prices near the bottom of the 12volt systems but putting out up to 40 gallons per hour.

[jeremiason]

Originally Posted by Captain Bill

I recommend an AC water maker that you can use while topping up your batteries. They are available at prices near the bottom of the 12volt systems but putting out up to 40 gallons per hour.

I sorry, but I disagree with installing an 120 volt AC water maker, only because if your generator fails you can't make water. With a 12 volt watermaker, if your GenSet fails, you can still make water and charge your batteries with your engine alternator.

We have a Spectra Newport 400 Watermaker and produce about 17.5 gallons per hour using about 22 Amps per hour or 1.25 amps per gallon of water.

As far as the Generator.... We have a Fischer-Panda Mini 8, which in my opinion is the quietest GenSet on the market right now, especially when combined with an Aqua-Lift Muffler.

Over the years, I found the FP GenSets tend to be like anchors, their owners either love them or hate them... I happen to love mine and have had no problems in the last six years.

You didn't mention it, but are you considering Solar as well?

[Capn Morgan]

Several other threads on this subject will provide you with more info. For us, Northern Lights was the solution. Have a look at this:

http://www.cruisersforum.com/forums/...tem-29667.html
http://www.cruisersforum.com/forums/...set-50139.html


Cheers!

[Gordon]

Thanks for the input, and yes we will have solar, four 120w panels and 600 Ah of house AGM batteries. Also considering installing a wind generator possibly an Air Breeze. Also with the watermaker have been considering the Aqua Base XA223 90 ltr/hr and dual voltage 12v/ 230v. Ac.

[Tellie]

Originally Posted by Gordon

Thanks for the input, and yes we will have solar, four 120w panels and 600 Ah of house AGM batteries. Also considering installing a wind generator possibly an Air Breeze. Also with the watermaker have been considering the Aqua Base XA223 90 ltr/hr and dual voltage 12v/ 230v. Ac.

I rarely deal with Aqua Base units on small craft so my information may be dated. The ads can be misleading. Unless they've come up with something new the voltages are specific not either or. The XA223 90 is only a 115/230 Volt unit. It is not built for 12Volt. If as in your first post you are referiing to the 60 liter per hour unit it is the XA223 60 which only comes in 24 volts at 25 amps. The largest Aqua Base 12volt unit I'm aware of is the XD122 at 50 liters per hour at 31 amps. Not really efficient enough for a 600 amp battery bank. That being said, running all the other equipment you mentioned I'd say a generator is definatly a required add on.

[colemj]

I agree with Captain Bill on getting a high capacity AC powered watermaker. If you get one that makes 20-30 gal/hr, the AC draw will be reasonable enough to run it off an inverter with the engines charging the batteries, or you could buy (or borrow) a small honda generator if your main generator breaks.

A DC based system only runs well when the batteries are around charging voltage, which usually means running the engines or generator to provide water along with normal charging needs.

The Spectra systems are great at conserving power, but they are very expensive. An AC watermaker system by CruiserRO or Echotec plus a diesel generator is not much more expensive than a competing Spectra system alone. Running off a honda, they are considerably cheaper.

Mark

[Gordon]

Boy, you guys have thrown open another area for me to look into. We have eight months to get this sorted before boat handover. Now I am researching AC water makers, this will be on another thread. Still unsure what would be the best option re the gen set. We will be running 230/240 v and 50Hz. And being a catamaran want to keep weight to a min.
Thanks for the input, it all helps and experience counts. We have only been coastal cruisers and managed on our previous boat with solar, 600Ah house bank and a Victron Pheonix 3.0Kw inverter/charger and no where near the extra power requirements.
Cheers Gordon.

[sailorboy1]

I know nothing about the genset you asked about. But everything I've read over the years suggests that you get the highest capacity watermaker you can support, so if you have a genset why would you get a 12V watermaker?

[sailinglegend]

Originally Posted by Gordon

Thanks for the input, and yes we will have solar, four 120w panels and 600 Ah of house AGM batteries. Also considering installing a wind generator possibly an Air Breeze. Also with the watermaker have been considering the Aqua Base XA223 90 ltr/hr and dual voltage 12v/ 230v. Ac.

With your setup then a 12 volt watermaker would be very good. Ours takes 22 amps and produces 70 litres an hour. We only make water when motoring as most anchorages have some unpleasant things floating around!!!! Make sure your batteries are getting well up first so that the alternator will not have to work too hard when you switch on the watermaker. You could do with a 150 amp hot rated marine alternator - and one more battery would be better - oh and research DC gensets - our FP charges at 280 amps max.

[Florida Mike]

If you are a sailing cat you might consider getting two belt driven generators and associated hardware to mount them to your propulsion engines. You can build drive them through a air-conditioning clutch with the proper gearing to run your engines at a minimum throttle so that they’d produce enough power to run both your alternator and the generator without lugging. This will give you the redundancy to complete systems one less engine to take care of and ability to keep both engine hours equal or close to it. Just my two cents, Mike.

[capta]

"We will be running watermaker(12v - 60ltr/hr ) two frigde and one freezer, a washing machine, microwave, various 240v appliances, and two chart plotters radar and an autopilot over legs of up to three weeks."
Keeping it LIGHT????? AND you want to add a generator????
Have you considered the 1/2 ton or more of spares you should have aboard?
You should probably think a bit more seriously about your needs, not your dreams, if you want your boat to sail.
Then again, you could do what 99% of the cats here in the Caribbean do (if they are honest, anyway); run the down wind engine all the time.

[Dockhead]

Originally Posted by Florida Mike

If you are a sailing cat you might consider getting two belt driven generators and associated hardware to mount them to your propulsion engines. You can build drive them through a air-conditioning clutch with the proper gearing to run your engines at a minimum throttle so that they’d produce enough power to run both your alternator and the generator without lugging. This will give you the redundancy to complete systems one less engine to take care of and ability to keep both engine hours equal or close to it. Just my two cents, Mike.

On a catamaran, where weight is so crucially important, this is a hot tip. Probably what I would do in your place. I think the logic might be expressed something like this -- you've already got two diesel engines on board -- do you really have room for a third?

You have quite a juggling act to do between considerations of weight and your power requirements. I think you have three viable options:

1. Reduce your power appetite and install a whole lot of solar, maybe upgrade your alternators. Buy a portable Honda suitcase generator to cover the occasional power deficit.

2. Add a really big belt-driven alternator to one or both propulsion engines as suggested above. You will also need to have a large enough battery bank and a good inverter to provide AC power.

3. Put in a diesel genset. You will have to juggle conflicting considerations in choosing one. The simple low RPM continuous duty rated ones are quite heavy and bulky for their output (and expensive). But they are much more reliable and much easier to repair. I personally wouldn't have any other type of diesel genset on a boat. My favorite would be the 1800 rpm 5kW Northern Lights, which is expensive but actually quite compact for a low RPM continuous duty genset, and weighs about 190kg, quite a bit less than other continuous duty gensets (my 6.5kW Kohler weighs 266kg). A hot tip: choose the smallest one which will comfortably run your expected continuous loads, and cover any short term demand peaks (like AC startup loads) with an inverter with power boost function.

Another approach would be to buy a light weight, intermittent duty, high RPM genset, like a Fischer-Panda, one of those 3600 RPM Onans, or a Nextgen. You will save weight and money -- and the weight is a powerful argument on a catamaran. You'll have to decide for yourself whether you're willing to risk the unreliability, vibration, noise, etc. I wouldn't do it, personally. The FP gensets are quite notorious (check the CF archives), but some owners like them. For your use, the 3.2kW DC genset by FP might be worth considering -- it only weighs 175 pounds and it has a Kubota engine, rather than the crappy Farymann engines used in many other FP gensets. Before considering that, however, I would do extensive research into their reliability, and I would make sure that I have a good dealer for warranty repairs.


I agree with the posters above who suggested large capacity, simple, AC driven water makers. You don't want complexity here any more than you do with your genset. Why do you need power efficiency on a watermaker? You are best off running watermakers for shorter periods of time when you have a surplus of power anyway.

[Capn Morgan]

The approach of using the smallest possible gen set along a power assist inverter works well, but like everything, it has it's limitations. We did precisely this to be able to start a dive compressor that the little 5KVa Northern Lights would have trouble with.

However, our idea was also to use the generator only a couple of hours per day. With this approach, we replaced a 12 KVa 450kg lump with 200 kg of genset plus 4 255Ah AGM batteries. As we already had a Spectra 150T this allows for topping up the water tanks any time with little power consumption. Our fridge/freezer is AC so the inverter is left on permanently to supply it.

In theory I can run the aircon while motoring as the alternator keeps the batteries from going too far down. This is without the genset. In reality, the inverter shut off a couple of times as there was an overload when the AC compressor started. Still, for what it's worth, the system works.

[svBeBe]

I think sometimes people over-analyze things. During a large part of our circumnavigation we were friends with the owners of a Catana 43. We did not make passages together, but arrived in the same places about the same time. They had equipment as you described, but also had a 7kw 230v 50htz genset and a 160 liter per hour 230v 50htz watermaker. They had this to reduce weight.

Remember a couple of things:

• Water weighs 1 ton for 1,000 liters, or about 260 gal.
• We have an Onan MDKAV 7.5kw generator that weighs 550 lbs which is the same weight as 65 gallons of water
• Watermakers love to be run...30 minutes a day can make 80 liters...you will not use this much; with a clothes washer our average use is 50 liters a day.

Therefore it is less weight to have a genset and a 230v watermaker

Regarding another not well thought out comment..."what happens when the genset breaks..." You fix it...and when you are fixing it you will likely be in port with water.

When making off-shore passages, never have less water on hand that the required drinking water for the crew for 30 days. In the US, the reference daily intake (RDI) for water is 3.7 litres per day. (2 crew)*(3.7)*30=222liters or about 55-60 gallons.

The one thing that I did not see any comments on was your house battery bank. I think it is on the light side. We have similar equipment as you plan to have and we have 1,260ah of 12 volt batteries wired in parallel pairs for a 630ah 24 volt house. Ours is probably overkill, but if I were you, I would be looking for more.

Also, I put together an Excel model for b/e analysis on solar panels. It is an eye opener...we do not have solar.

I hope this helps.

Bill