Water maker comps

[john61ct]

The dichotomy is not AC vs DC. It is

low AH consumption/gal, running longer hours, may or not be a mostly-solar boat

vs

high gph output, running fewer hours, usually primary power from a motor


.
I see this more fundamental distinction as paralleling refrigeration.

Some have fridge / freezers with holding plates, usually a motor providing the "charging" power, running say 1-3 times per day.

while evaporator systems need to cycle on and off 24*7, and are low-current enough that solar may provide most of that power.

That said, besides the difference in up-front expense which is there in both arenas, there are different decision factors at play.

Noise is less an issue with refrigeration.

And you have to charge a eutectic system more frequently and regularly, can't get away with just a few times a week for an hour or two.

[SSgtPitt]

We’re also currently in the market for a water-maker. We’ve got a 1982 36’ Cape Dory, not a lot of room on this one with it’s narrow beam and low freeboard and there’s only two of us. No kids, no relatives, no friends, no one else but us......WhooHoo!!
We’re moving onto the boat in a few days so we can get her ready go. So our experience is limited and what we buy or do is influenced by CF and others.

I’m really leaning hard to the AC CruiseRO or the AC Rainman. I like the CRO because of the high output, no dealer specific parts, all consumables can be bought anywhere and the customer service. Plus he gives away a ton of info here on CF and actually answers the phone when you call.
The Rainman though is super portable, no hard install, so it can be offloaded very easily and taken ashore if needed and I can’t find a bad review anywhere but I also don’t want any dealer specific consumables.

I have 400w of solar in process, 2KW inverter, 450A in 4 - 6v Trojans and the Honda generator. I’m hoping to be able to use a combination of the solar/batteries/inverter and then the generator as needed when we’re using it for something else.

If this is considered “hijacking the thread”, I apologize, but we need some more experienced cruisers recommendations.

[travellerw]

Originally Posted by rom

@travellerw: in Martinique you should now get enough juice from your 900W solar panels to supply the WM without a genset ? I was there last year and my 1300W panels would ouput 100+A while my 100l WM (Dessalator brand, not particularly efficient) draws about 50A@12VDC. I am not saying you're wrong but I do not understand the choice for AC WM when you have so much solar (& batts I guess).

WOW.. you have a pretty efficient system. 100+a for 1300w is just over their rated production (assuming 13.5V for bulk voltage). Although my panels will go over their rated production (we sometimes see 68-70A), they definately don't stay over that number for very long. Our system will put out about 62A at the peak of the day for 2-3 hours. We do better in the spring and summer months as there is much less cloud cover. Even today, there is many high clouds that reduce our production.

I'm guessing you don't have 3 kids aboard? 3 kids that use laptops (about 40W each) for homeschool. 3 kids that have other various electronics. 3 kids and a wife that like to have hot water (which we make on solar). 3 kids and a wife that require MUCH more food (leading to longer and harder runs on fridge and freezer). Me, that likes my cold beer (again more fridge). Hell if it was just my wife and I with 900W we would have TONS of power.

There are also other issues.. Rainman doesn't support running their AC watermakers off an inverter. However, it does work and could be used in emergencies, but draws 90A@12V (roughly 1250W). Even if it was supported, I don't think I would bother trying to balance our life around a 90A draw every couple of days. With homeschooling the kids, maintaining the boat and enjoying the islands I need some convieniences. 1 1/2 hours of generator every 3 days is a nice convienience for us.

[rom]

Originally Posted by travellerw

WOW.. you have a pretty efficient system. 100+a for 1300w is just over their rated production (assuming 13.5V for bulk voltage). Although my panels will go over their rated production (we sometimes see 68-70A), they definately don't stay over that number for very long. Our system will put out about 62A at the peak of the day for 2-3 hours. We do better in the spring and summer months as there is much less cloud cover. Even today, there is many high clouds that reduce our production.

I'm guessing you don't have 3 kids aboard? 3 kids that use laptops (about 40W each) for homeschool. 3 kids that have other various electronics. 3 kids and a wife that like to have hot water (which we make on solar). 3 kids and a wife that require MUCH more food (leading to longer and harder runs on fridge and freezer). Me, that likes my cold beer (again more fridge). Hell if it was just my wife and I with 900W we would have TONS of power.

There are also other issues.. Rainman doesn't support running their AC watermakers off an inverter. However, it does work and could be used in emergencies, but draws 90A@12V (roughly 1250W). Even if it was supported, I don't think I would bother trying to balance our life around a 90A draw every couple of days. With homeschooling the kids, maintaining the boat and enjoying the islands I need some convieniences. 1 1/2 hours of generator every 3 days is a nice convienience for us.

ok understood.

90A for a 120l/h WM is a lot ! I guess that includes about 10% losses in the inverter but still way less efficient than my Dessaltor, let alone the spectra. So I think it is an interesting number for those considering a WM.

In case it was not clear my thinking is that an AC WM runs on the inverter with losses or on a genset with noise. A DC WM runs on the house battery, straight. If solar (or wind, hydro) is not enough to cover the global energy needs, it might still be "better" to use a DC WM in (relative) silence, and start the genset to recharge the battery (@full power) once in a while. It doesn't seem to work for you but I think people buying a "high" ouput WM should do the math.

[john61ct]

Originally Posted by rom

A DC WM runs on the house battery, straight. If solar (or wind, hydro) is not enough to cover the global energy needs, it might still be "better" to use a DC WM in (relative) silence, and start the genset to recharge the battery (@full power) once in a while.

If a genset (AC or DC), or HO alt setup off the propulsion engine, is pumping out hundreds of amps for a few hours

to me that's the best time to run your high gph watermaker (whether AC or DC)

reduce both unnecessarily cycling the bank

and consolidating the noisy-time factor.

For me, running during quiet time, off batt storage, should only when necessary, with slower, energy efficient makers whose runtimes exceed that spent burning dino-juice.

[DotDun]

Originally Posted by rom

ok understood.

90A for a 120l/h WM is a lot ! I guess that includes about 10% losses in the inverter but still way less efficient than my Dessaltor, let alone the spectra. So I think it is an interesting number for those considering a WM.

In case it was not clear my thinking is that an AC WM runs on the inverter with losses or on a genset with noise. A DC WM runs on the house battery, straight. If solar (or wind, hydro) is not enough to cover the global energy needs, it might still be "better" to use a DC WM in (relative) silence, and start the genset to recharge the battery (@full power) once in a while. It doesn't seem to work for you but I think people buying a "high" ouput WM should do the math.

The math needs to include the upfront cost also. AFAIK, high output 12v WMs are ~2 times the cost of high output AC units.

[daletournier]

Originally Posted by rom

ok understood.

90A for a 120l/h WM is a lot ! I guess that includes about 10% losses in the inverter but still way less efficient than my Dessaltor, let alone the spectra. So I think it is an interesting number for those considering a WM.

In case it was not clear my thinking is that an AC WM runs on the inverter with losses or on a genset with noise. A DC WM runs on the house battery, straight. If solar (or wind, hydro) is not enough to cover the global energy needs, it might still be "better" to use a DC WM in (relative) silence, and start the genset to recharge the battery (@full power) once in a while. It doesn't seem to work for you but I think people buying a "high" ouput WM should do the math.

It's not about the math for me (power efficiency). It's about making as much water as possible on the shortest amount of time.... OK it is about the math, just different math.

[robert sailor]

Originally Posted by SSgtPitt

We’re also currently in the market for a water-maker. We’ve got a 1982 36’ Cape Dory, not a lot of room on this one with it’s narrow beam and low freeboard and there’s only two of us. No kids, no relatives, no friends, no one else but us......WhooHoo!!
We’re moving onto the boat in a few days so we can get her ready go. So our experience is limited and what we buy or do is influenced by CF and others.

I’m really leaning hard to the AC CruiseRO or the AC Rainman. I like the CRO because of the high output, no dealer specific parts, all consumables can be bought anywhere and the customer service. Plus he gives away a ton of info here on CF and actually answers the phone when you call.
The Rainman though is super portable, no hard install, so it can be offloaded very easily and taken ashore if needed and I can’t find a bad review anywhere but I also don’t want any dealer specific consumables.

I have 400w of solar in process, 2KW inverter, 450A in 4 - 6v Trojans and the Honda generator. I’m hoping to be able to use a combination of the solar/batteries/inverter and then the generator as needed when we’re using it for something else.

If this is considered “hijacking the thread”, I apologize, but we need some more experienced cruisers recommendations.

Your solar and battery size is very similar to ours. We are using the Spectra 150 and get around 7 gallons per hour which for the 2 of us is just perfect. In normal sunny conditions we can put the watermaker on around 1 pm as our batteries are topped off and run it for an hour or an hour and a half and our battery bank hasn't been touched. The two keys are a very efficient fridge which uses less than 30 amp hours in a 24 hour day and reasonable care in freshwater use. No need for genset of any sorts. Even though the portables are small they still take up room and on your boat you should be watching this carefully. If you don't empty the fuel tank between use you have to be careful where you store it. There are certainly days when it's cloudy and we have to run our main engine, but not that often here in the tropics.

[john61ct]

Originally Posted by DotDun

The math needs to include the upfront cost also. AFAIK, high output 12v WMs are ~2 times the cost of high output AC units.

Interesting.

So for a boat currently without any AC, I suppose those savings would pay for a big quality inverter.

[rom]

Originally Posted by DotDun

The math needs to include the upfront cost also. AFAIK, high output 12v WMs are ~2 times the cost of high output AC units.

Dessalator provides them at the same price:
DessalatorÂ* l Â*Developement of unique systems for the desalination of sea waterÂ* l Â*Price listÂ*

I would not understand why DC would be more expensive than AC. the DC motor is somewhat the same as those of my windlass & winches, cost is about 500 EUR. My WM costs close to 10000 EUR ...

[john61ct]

Demand and supply?

High amp loads running for hours at a time have traditionally been powered by AC.

[DotDun]

Originally Posted by rom

Dessalator provides them at the same price:
DessalatorÂ* l Â*Developement of unique systems for the desalination of sea waterÂ* l Â*Price listÂ*

I would not understand why DC would be more expensive than AC. the DC motor is somewhat the same as those of my windlass & winches, cost is about 500 EUR. My WM costs close to 10000 EUR ...

You just confirmed what I thought! Your WM was 2 times the cost of mine!

30 GPH Marine Water Maker by Cruise RO Water & Power

[travellerw]

Originally Posted by rom

Dessalator provides them at the same price:
DessalatorÂ* l Â*Developement of unique systems for the desalination of sea waterÂ* l Â*Price listÂ*

I would not understand why DC would be more expensive than AC. the DC motor is somewhat the same as those of my windlass & winches, cost is about 500 EUR. My WM costs close to 10000 EUR ...

Wowzer... $10K EUR... Holy smokes that over double what I paid for my Rainman including the Honda 2000. I knew the Specta's (and Schenkers) were really high priced. I didn't realize the other 12V brands were priced that high.

[john61ct]

Originally Posted by rom

I would not understand why DC would be more expensive than AC. the DC motor is somewhat the same as those of my windlass & winches

And if it were that easy to just slot in a DC version of that motor, I bet Rich would be offering that option, rather than turning business away.

He does also sell the ones that power directly off your own motor's PTO too, but reckons they're not worth the headaches.

[robert sailor]

Originally Posted by travellerw

Wowzer... $10K EUR... Holy smokes that over double what I paid for my Rainman including the Honda 2000. I knew the Specta's (and Schenkers) were really high priced. I didn't realize the other 12V brands were priced that high.

These types of things are not cheap in Europe...No body sells these types of products cheaper than in the States. Boats yes, but not watermakers