12 volt watermakers, which one?

[SV THIRD DAY]

Originally Posted by a64pilot

I am not bad mouthing AC watermakers, I have one, just I accept that they are enormously inefficient compared to a Spectra, but that’s OK with me, cause my generator has power to spare.

Ahh....but that's the rub and I think the false comparison people make.

It's a wrong metric to use AH/GAL when it comes to an AC water maker.
It's like measuring MPG on a sports car or SUV comparted to a Toyota Prius. Yes they are both cars....but they are made with a completely different engineering design criteria in mind.

DC energy recovery water makers are designed around what a battery bank can do...while AC piston pump water makers are designed around the concept that you have power from a generator....and if you have it already you might as well use it.

[a64pilot]

Originally Posted by SV THIRD DAY

Ahh....but that's the rub and I think the false comparison people make.

It's a wrong metric to use AH/GAL when it comes to an AC water maker.

Understood, I was trying to illustrate why putting a DC motor on one is a bad idea, that if you want to run a Watermaker off of your batteries, don’t go with one without an energy recovery pump.

Why I said way back that a non energy recovery Watermaker (although I didn’t call it that, couldn’t remember what to call it)
Is for people that have bought into the idea of having to use a generator anyway, as I did so we could wash clothes, fully charge batteries, equalize batteries, make ice etc. may as well make water too.
I needed and had a generator before the Watermaker, and even if I had a Spectra, I’d want a generator.
Maybe I could get by if I had a Lithium bank, but that is another discussion

[mitiempo]

Originally Posted by Falbala60

Thank you for the hint, as the noise is mainly from the feed pump 2X water 1/2 the time but 2X the noise ? I will think about ... We will have a Lucia and I don't know the available space.

An other question ... why is the MPC so expensive ? 2000$ to 3000$
Is it because the valves are automatic ?

The feed pump on a Spectra Cape Horn is quiet - at 80 psi not much more powerful than many water pressure pumps on today's boats. And quite quiet as well.

The advantage of the Cape Horn is flexibility. 15 gallons/hr @ 19 amps or half that @ half the power consumption. And if there were a problem with one pump you are still in business. Totally manual and as Laika stated easy to use. The MPC is not an option on a Cape Horn.

As far as space I can fit one on my 27' CS so you should have the space as well.

With good solar and the batteries accepting less current in late afternoon there is easily enough excess solar power to run a Spectra.

[Falbala60]

Originally Posted by a64pilot

...
I am not bad mouthing AC watermakers, I have one, just I accept that they are enormously inefficient compared to a Spectra, but that’s OK with me, cause my generator has power to spare.

Thank you again a64,
I... we ... are now as much knowledgeble in WM than if we had one since 1 year.
OK I go with a 12VDC recovery system, automatic because my wife want to be able to operate herself, but to reduce the cost, I will take it smaller.

I understood from others comments that 6-7 gal/hour is OK for 2-3 run of 2 hour per week.

I am eng. machinery and product designer (30 prototypes until now), but buying "intelligently" a catamaran, taking care of all aspects, electrical, genset, batteries, solar, watermaker, navigation system, GPS, AIS, AC, OH I forget ... sails, anchor, dinghy, etc. etc. plus the fact that the manufacturing quality is going down for all companies...

... I owned for 40 years 2 C&C29 and C&C5, sailed, raced in COLD St-Lawrence Gulf, chartered over 4 months in Greek Island, BVI, etc. and this is way out the most complex project I had to solve...


At the last Miami show, there was a 40' cat to visit that was just delivered to a couple that never sailed by themself before... AIE ! Manufacturing companies want to MAKE MONEY... OK ! BUT ... should have a little break to sell a sailboat to anybody... like selling a car to a 12 years old children... danger for themselves and others that will have to save them.

Like you, Cotemar, and others I thank you to HELP US on this forum ! and hope to do the same when I will have a couple years cruising on our Lucia.

[sailjumanji]

Originally Posted by SV THIRD DAY

DC energy recovery water makers are designed around what a battery bank can do...while AC piston pump water makers are designed around the concept that you have power from a generator....and if you have it already you might as well use it.

It may be a poor example - because it's a pretty sunny place - but when we spent two months in the Bahamas in 2016, we ran our Spectra DC watermaker in the afternoons, and it basically the added load was 100% covered by the solar panels and controller. And we had a pretty meager system - two (2) 120 watt panels, and a 300 amp-hr AGM battery bank. I think we could have a 100 amp-hr battery bank and it would have been enough, because it almost seems that when we started the watermaker, the battery was just sitting there idle, and the WM amp draw was coming directly from the solar panels. I know you can't always depend on sunny weather, but OTOH we only ran it every 2-3 days.

[Franziska]

So, are there any reasonable priced and still reliable DC desalinators with an energy recovery similar to the Spectra around for less money?

[jmh2002]

Really very useful and interesting practical information here. Although it's interesting that there is still quote a wide disparity between different setups on different boats.

But still very good to hear about all the different options that are out there being used, not only specs on paper.

[jmh2002]

Originally Posted by Falbala60

I am eng. machinery and product designer (30 prototypes until now), but buying "intelligently" a catamaran, taking care of all aspects...

@Falbala60

You might sound a little crazy with some of your posts, but with some language difference (I think), this craziness (=stress too) is totally understandable, because even on a relatively small boat like your Lucia, setting it up from brand new is still quite a big task.

Anyone can just pay money and order a boat, but it is a totally different question to firstly try and spend that money wisely and then after to make, as you say 'intelligent' choices about the all of the systems.

Because unfortunately in most cases the builders idea of 'ready to cruise' is a bit different to 'actual real life cruising'!

[Zai]

I have 600 watts of solar, my watermaker is a Pure Water Whisper 30.

It makes 30 liters per hour and it is VERY quiet.


I bought it at a boat show and if I remember correct it cost about 3500 euros.


I have been using it for about three years now and it hasn't had any problems.


It is no problem to run it from solar and I run it just about every day.


I am a full time cruiser.

It is 12 volts and uses 15 amps.

[a64pilot]

Originally Posted by Franziska

So, are there any reasonable priced and still reliable DC desalinators with an energy recovery similar to the Spectra around for less money?

Not that I am aware of, efficiency comes at a $$$ and I believe is more mechanically complex and using proprietary parts.
When you want less expensive, mechanically simple and made from readily available parts, then you get into an AC watermaker, which if you have a generator anyway or will have one, in my opinion it only makes sense to go the AC route.
Now I can't see getting by long term without a generator, or am not willing to make the sacrifices to do so, whichever you prefer, and we don't economize on water, so then a high output AC watermaker at a fraction of the price of a Spectra of equal output makes a lot of sense to me, cause I like simple things that I can troubleshoot and fix myself.
We go through more water in a week than people without a water maker will in a month or more, I'll wash off dive equipment, the boat and even fresh water wash the anchor chain, it lasts much longer, doesn't rust and has no smell that way, but without a high output watermaker, Id not be rinsing my regulators and BC's off, nor washing salt off of my furlers etc either. A fresh water flush head is much nicer too

Plus the Wife is happier using as much water to wash dishes or shower as she wants, cause before the Watermaker, I was the water Nazi, and neither of us liked that

[LeaseOnLife]

Originally Posted by Franziska

So, are there any reasonable priced and still reliable DC desalinators with an energy recovery similar to the Spectra around for less money?

There is Schenker from Italy with similar energy recovery:

SCHENKER dissalatori watermakers desalinators dessalinisateur wassermachers


That might be an option, specifically in Europe, but I don't think you will save money. And Spectra does have (did have?) a roaming tech program, cruisers with some extra training, parts and tools, to fix you in "out-of-there" locations.

[Franziska]

Hey A64, the posting just before yours suggests another energy recovery alternative.

Still, from our perspective, I guess we will head down the AC route. Rainman modular economic model. We have a 2.6kw genset already.

For the 3000€ less we can buy a lot of fuel for the genny.
As we need the genset for hot water anyway every 2-3days, we can do both in parallel.
Wish on demand gas water heater would be legal and available in Europe too :-)

[sy_gilana]

No investigation is complete without considering eco-sistems DC watermaker, with several patents awarded.

I have installed several. Very efficient.

Potabilizadoras/desalinizadoras de agua de mar - Eco-Sistems Watermakers

Especially for boats in Europe.

[Franziska]

Another energy recovery manufacturer. Great.

Gilana & Zai could you please tell us more on the efficiency and noiselevels of the Pure Water Whisper 30 and the Splash 30?

[sy_gilana]

Hi Franziska.

Very difficult to answer this in an absolute way, I would love to say it is xx dB, but I cannot. Let me give you some comparisons.

About the same as a Hella Fan on full blast if you were 1m from the fan, and 4m from the pump.

Less than background music.


More than a mouse fart.


It is a vane type pump, that feeds the Clark/Schlenker type pump. The vane pump is driven through a speed control, so it is adjustable. (Slow it down when there is less sun on the panels etc)

If there are air bubbles in the system, you will hear it for sure...and thats good, so you can find out why.

Sorry I cant be more specific about the noise.


Power = 192 watts @ 30l/h







One Warning...NEVER EVER LET THE PUMP RUN DRY. It is water lubricated, and the dry run lifetime is about 20 seconds. Pump MUST be below waterline.