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Old 12-10-2019, 12:43   #16
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Re: 12v Watermaker - Experiences for article?

We recently completed an eight-and-a-half year circumnavigation using a 12-volt Spectra Cape Horn water maker. Not only did we put thousands of hours on the unit without any problems but it made delicious water that we enjoyed drinking (especially important when cruising in the tropics). Whereas we could have ran the water maker from the power from our solar panels, we chose to run it whenever our genset or auxiliary engine was running.

Fair winds and calm seas.
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Old 12-10-2019, 15:19   #17
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Re: 12v Watermaker - Experiences for article?

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Originally Posted by northcave View Post
Hi all... I'm writing an article on sustainable / green boating for a sailing magazine. Unfortunately we still have a 240v watermaker run from our Genset but I'd like to hear from someone that lives aboard and has a 12v watermaker that they use regularly from the batteries and have plenty of solar or wind to top up the batteries.

Don't quite see why you are concerend about the voltage. 12v DC or any A/C voltage is avalable via ether a genset or wind/solar. Why is a 120/240v watermaker powered from solar via an inverter 'less green' than a 12v DC one. Shurly the issue should be the availability of renewable electrical energy sources.
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Old 12-10-2019, 16:09   #18
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12v Watermaker - Experiences for article?

With a good, properly sized inverter you lose about 5% to 10% by inverting DC to AC, so people assume they really need to run DC direct. However just as an example that $1,000 DC electric motor one poster spoke of will buy a Honda.
You can easily run a 30 GPH watermaker off of a Honda generator, but itís going to be real tough to do so off of Solar.

With an AC motor you gain flexibility, I can run mine through the inverter off of Solar and batteries, or my alternator and a little Solar, or off of a generator.
If it were DC, then you need a rather large source of DC, which is your bank of course, but itís going to be real tough to make significant water and charge your batteries too.
That is when a Spectra comes into its own, it uses so little power that you can make significant water, and charge you batteries too.

To run a DC watermaker off of Solar you need to be very efficient, or use so little water, than maybe you donít need a watermaker.

DC and AC are so easily converted back and forth now that except for arguments on paper as to efficiency there isnít a need to spend lots of money to stay one or the other.
Now thatís not to say that you should use your 3000W inverter to charge your toothbrush, you shouldnít. That is inefficient.
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Old 12-10-2019, 17:04   #19
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Re: 12v Watermaker - Experiences for article?

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With a good, properly sized inverter you lose about 5% to 10% by inverting DC to AC, so people assume they really need to run DC direct.......
The 5-10% is the fairly minor inverter inefficiency. The much bigger inefficiency is the difference between an AC unit and an efficient DC unit. On a 20gph CruoseRO the boost pump alone uses 8amps 12v DC, along with 9.3amps @120v or approx 83amps DC(it isn't clearly stated if this is a start current or running current. Either way, it is a much, much higher draw than an efficient DC system). A Spectra Cape Horn at 15gph uses 18amps DC. The Spectra is practical to run off solar, as it also has a single pump mode that uses 8amps DC.
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Old 12-10-2019, 17:23   #20
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12v Watermaker - Experiences for article?

You canít compare a Spectra with a Cruise RO for efficiency and state itís because itís DC powered, being DC has nothing to do with it, it would be just as efficient if it were AC.
Yes the Spectra is orders of magnitude more efficient than a Cruise RO, because it has an energy recovery pump, where the Cruise RO doesnít.
However all that efficiency comes at a cost $$$ wise and complexity, the Cruise RO gives up efficiency and gains simplisticy and less expensive.
The Cruise RO isnít supposed to be efficient, itís supposed simple and easy to repair, the Honda will supply more power than it needs and it was designed to be run from a Honda.
The consumption numbers are optimistic, meaning it doesnít draw quite that much power and the new boost pump is variable speed and doesnít draw that much power either, and it makes usually well more than 30 GPH too.
I know cause I have one.
Rich is smart enough that he understands that if his products out perform his stated numbers, then people are very happy, but let one produce just slightly less than spec and that happiness evaporates, and they donít want to hear that water temp and salinity will vary output, they bought a 30 GPH watermaker, and they expect 30 GPH.
Same identical watermaker with just a bigger motor and HP pump makes 40 GPH, but itís just a bit too much for the Honda.

If I hadnít from the beginning bought into the desire to have a generator, then I would have a Spectra, but I decided in the planning phase that I wanted a generator.

The 9.3 amps is running current, the start up is actually not all that high due to the pressure being turned all the way down, all the way down is still pretty high though over 100 PSI anyway, but 800 PSI of course takes more power.
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Old 12-10-2019, 17:34   #21
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Re: 12v Watermaker - Experiences for article?

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Originally Posted by a64pilot View Post
You canít compare a Spectra with a Cruise RO for efficiency and state itís because itís DC powered, being DC has nothing to do with it, it would be just as efficient if it were AC.
Yes the Spectra is orders of magnitude more efficient than a Cruise RO, because it has an energy recovery pump, where the Cruise RO doesnít.
However all that efficiency comes at a cost $$$ wise and complexity, the Cruise RO gives up efficiency and gains simplisticy and less expensive.

The Cruise RO isnít supposed to be efficient, itís supposed simple and easy to repair, the Honda will supply more power than it needs and it was designed to be run from a Honda.
The consumption numbers are optimistic, meaning it doesnít draw quite that much power and the new boost pump is variable speed and doesnít draw that much power either, and it makes usually well more than 30 GPH too.
I know cause I have one.
Rich is smart enough that he understands that if his products out perform his stated numbers, then people are very happy, but let one produce just slightly less than spec and that happiness evaporates, and they donít want to hear that water temp and salinity will vary output, they bought a 30 GPH watermaker, and they expect 30 GPH.
Same identical watermaker with just a bigger motor and HP pump makes 40 GPH, but itís just a bit too much for the Honda.

If I hadnít from the beginning bought into the desire to have a generator, then I would have a Spectra, but I decided in the planning phase that I wanted a generator.

The 9.3 amps is running current, the start up is actually not all that high due to the pressure being turned all the way down, all the way down is still pretty high though over 100 PSI anyway, but 800 PSI of course takes more power.
Except the price isn't really much different. The CruiseRO is usd$4,650 plus say $1,000 for a Honda 2000 = $5,650. A Cape Horn will cost you around usd$6,500.
Yes, the CruiseRO watermaker is simpler, but you do add in the maintance on the Honda.

Either way, having a good watermaker on a cruising boat makes life a lot nicer. Owners will be happy with AC or DC systems.
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Old 12-10-2019, 17:45   #22
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12v Watermaker - Experiences for article?

The Honda was going to be there anyway, remember, that is why I said the decision to have a generator drives in my opinion which watermaker.
Although I suspect people that buy a generator just to run a watermaker will find that they run it other times too.
Lots of things can be DC, but many times better quality products are available for less money if AC, things like toasters, vacuum cleaners, even blenders etc. my hookah was cheap with an AC compressor, DC not so much, Portable ice makers if AC are $99. Tell me what dc powered ice makers cost now, I know as we had them on our Sportfishermen and they are high buck and break often it seemed.

Honda maintenance is very minimal, a quart of oil will change it three times I think, and how long will a spark plug last?
The guys in Alaska living off the grid say they last for thousands of hours, and on a boat they never breathe dust, so I wonder how long the things will last?
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Old 12-10-2019, 17:59   #23
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Re: 12v Watermaker - Experiences for article?

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Originally Posted by a64pilot View Post
The Honda was going to be there anyway, remember, that is why I said the decision to have a generator drives in my opinion which watermaker.
Although I suspect people that buy a generator just to run a watermaker will find that they run it other times too.
Lots of things can be DC, but many times better quality products are available for less money if AC, things like toasters, vacuum cleaners, even blenders etc. my hookah was cheap with an AC compressor, DC not so much, Portable ice makers if AC are $99. Tell me what dc powered ice makers cost now, I know as we had them on our Sportfishermen and they are high buck and break often it seemed.

Honda maintenance is very minimal, a quart of oil will change it three times I think, and how long will a spark plug last?
The guys in Alaska living off the grid say they last for thousands of hours, and on a boat they never breathe dust, so I wonder how long the things will last?
That's a favorite argument on CF. I'm using the Honda to charge my batteries so its free for the watermaker. If you need a good argument for battery charging you say the Honda is free because I need it for watermaking.😁

Hondas are pretty reliable. They still add to the maintance list. Oil changes, getting gas,... I remember one time anchoring in Zihuatanejo, Mex on my old boat that I had a Yamaha 1000 generator. The two other boats in the anchorage were busily trying to find the Honda dealer there to get their Hondas repaired. Like anything on a boat, its maintenance.
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Old 12-10-2019, 18:05   #24
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Re: 12v Watermaker - Experiences for article?

Quote:
Originally Posted by contrail View Post
I replaced my 110 volt Pressure pump motor and pressure pump with a $90-00, 240 volt Pressure Washer Pump That sucks water and runs the watermaker, 2300 PSI,
I also use it to pressure wash my boat,

Is your Pressure Pump Motor 12 volts, ????????

2300 PSI? That's above the limit for most membranes![/QUOTE]

No,
My Pressure pump motor is 240 volts, but runs off an invertor which runs off my 12 volt batterys,
12 volts to 240 volts,
So it is 12 volts, The primary source of power,

My batterys are charged by 500 watts of Solar panels which are 12 volt,
My wind generator is 12 volt,
My diesel Alternator out put is 12 volt,

2300 PSI is what the Pressure pump is capable of, Not the pressure I use,
I have a valve that controls a steady and constant 900 PSI to my water maker,
Which is what the watermaker runs at,
Precise pressure for the Membrane,

I also bought myself a Pure Sine Wave 3.5 KVA 240 volt Generator That I can run every thing on also, As a further Back up,

It has a built in 12 volt battery charger,
Thats a 4th method for charging my batterys,
It has a 2 year Warranty, Its a local company, I can stand there and talk to the people, This company is 40 kays from where I live,
It weighs 40 KGs,
Its quiet, so it can run for hours on my transom with out deafening me or annoying any one else,
It runs my 240 volt Pressure washer as if it wasnt connected,

At $390-00 Delivered, I can buy two of these for the price of a Honda Generator,,

Yes, It is Chinese, Built specifically to Kings requirements,
Kings are a very large 4x4 and camping company here in Australia, ,

The pressure washer is Indian, ???????????? Hahahahaha Thats worse than chinese,
It has odd sized fittings, 15mm, I had to get that fitting machined at the fitting shop as they didnt have one to fit, All fittings and machining, $30-00
But after washing my 34 foot cat with it, Using a Bucket to suck up the water from, With a hose into the bucket, The pump 3 feet above the bucket,
Approximately a full 24 hours of continuous use, Over quite a few days,
It never missed a beat, Im Impressed with it, I did expect it to crap out, Hahaha

I bought this Pressure pump as the Karcher was too big to fit where I wanted it to go, $30-00 cheaper as well,


New Generator, Invertor, Pressure pump, 240 volt Intelligent Pulse Battery charger is still cheaper than one 12 volt motor for my watermaker,
$862-00 Inclusive Versus $1100-00 USD for the 12 volt pressure pump motor,,

3.5 KVA Genny, $390-00
Invertor, $316-00
Pressure pump, $90-00
Pulse Battery charger, $36-00
Fittings, $30-00

I also bought myself a spare pressure gauge and 3 way stainless pressure valve for the watermaker,
They were $15-00 each, Delivered,

Even my 110 volt Dometic Fridge, Freezer is now 12 volt from the 12 volt batterys thru the invertor and a Transformer,

And it all works perfectly, on 12 volt from the battery,
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Old 12-10-2019, 18:56   #25
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Re: 12v Watermaker - Experiences for article?

Toasters, blenders vacuum cleaners?

Yes in that context AC def the way to go.
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Old 12-10-2019, 19:58   #26
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Re: 12v Watermaker - Experiences for article?

Well when you want a toasted sandwich doing it in the oven just isnít worth it, but 30 sec on inverter is.
Wife likes frozen daiquiriís even though we havenít had one in months, and the rugs need cleaning somehow. I have a Milwaukee wet / dry vac that runs off of the same batteries that the drill I use for the winches does, but itís not nearly as good a vacuum as the little $50 Bissel is.
BTW, the drill batteries use AC to charge. I also have a circular saw that runs off the batteries, good saw, but a 110V one is probably 1/4 the cost or less.
Some things like the Hooka compressor, itís just way cheaper to do with AC
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Old 12-10-2019, 20:32   #27
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Re: 12v Watermaker - Experiences for article?

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Toasters, blenders vacuum cleaners?

Yes in that context AC def the way to go.
Those all run fine off an inverter. What does this have to do with 12v DC watermakers?
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Old 12-10-2019, 21:45   #28
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Re: 12v Watermaker - Experiences for article?

Can we just get a few facts straight?

Spectra is 2x more efficient (not order of multiples) because they use a patented energy recovery pump. They are expensive.

Regular watermakers use 3-4A per gallon. The 40E uses around 4A, the bigger watermakers use around 3A per gallon. This is DC.

While it is possible to design an AC system that is just as efficient a 12V DC system, most AC watermakers are designed to run off generators and not very efficient.

The typical piston pump is 87% efficient, the typical DC motor is 65-70% efficient, the typical AC motor is 55more efficient motors. You can design a more efficient DC or AC motor but it is costlier. So if you run an AC watermaker off the inverter you may lose up 30-35% efficiency.

If you are running any sort of a watermaker you need to budget 4A per gallon. It does not matter how you generate the the power.
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Old 12-10-2019, 21:58   #29
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Re: 12v Watermaker - Experiences for article?

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Can we just get a few facts straight?

Spectra is 2x more efficient (not order of multiples) because they use a patented energy recovery pump. They are expensive.

Regular watermakers use 3-4A per gallon. The 40E uses around 4A, the bigger watermakers use around 3A per gallon. This is DC.

While it is possible to design an AC system that is just as efficient a 12V DC system, most AC watermakers are designed to run off generators and not very efficient.

The typical piston pump is 87% efficient, the typical DC motor is 65-70% efficient, the typical AC motor is 55more efficient motors. You can design a more efficient DC or AC motor but it is costlier. So if you run an AC watermaker off the inverter you may lose up 30-35% efficiency.

If you are running any sort of a watermaker you need to budget 4A per gallon. It does not matter how you generate the the power.
T
Yes, a Spectra is typically about 2x the output per amphour than an average 12v DC system. It is many times more efficient than the typical AC units, as I showed above comparing a 20gph CruiseRo vs a 15gph Spectra.
The pricing for main stream models is higher for Spectra, but not really that much more. Compare a Village Marine vs a Spectra for example.
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Old 13-10-2019, 19:47   #30
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Re: 12v Watermaker - Experiences for article?

I would never buy a generator in today's sub $1 watt solar power market. I put 530 watts of solar on with mppt controllers & wired for about $650 and shouldn't have to touch a thing for 10 maybe 20 years. I never have to pay for or do an oil change, schlep gas, rebuild a carb or find a spark plug in Tahiti, etc... The solar is just more reliable, cheaper AND greener.. How can anyone argue a generator is more green than solar?? Show me the numbers. I think that's like saying climate change is naturally occurring.

Watermakers should always be sized to run off renewable. We knew people running Air Con off solar! Why do you need a generator? We were live aboard cruisers for 18mo, family of 4, Spectra 160 watermaker, ($5200) made 6 gal/hr, ran ~3 hours every other day. Draws about 12amps. Never had any problem with it. Only needed to run the engine to charge batteries maybe 6 or 8 times in 18months when we had several consecutive cloudy days. 450Amp-hr LA battery bank. sailed nearly 7,000 miles and total fuel consumption was ~200gal. I would not want to be in a remote area and relying on a generator for water.

Sailing is not green? How's that figured?
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