# watermaker membrane cleaning?



## snokid (Oct 25, 2016)

Hi guys getting ready to buy a watermaker, but I'm going to be cruising fresh water for one more year before heading off to the ocean.
I have read that you can filter fresh water with a R/O as long at you decrease the pressure to get the flow you would get when running in salt water. ie if you get 15 gallons per hour of drinking water from salt water, then reduce the pressure till you get 15 gph of drinking water from fresh water. Seems simple enough. But I have also read that in fresh water the filters may become dirty (if that's the right word) and you would need to replace them more often.

So my daughter is a chemical engineer and worked at the plant that made the filters so I asked her she told me that you could run bleach thru them to kill any growth, but she didn't know how much fresh water would be needed to get the bleach out.

So that lead me to YouTube you can learn everything from YouTube right?





Seems like you can clean the membranes, but looking at the boating forums it doesn't seem like anyone does clean their membranes.

So for those in the know can you clean the membranes?

next related question...
pickling your filters I have seen all kinds of mixtures people use, again my daughter told me plain old vinegar would do the trick.
I'm up in the great white north so when I would need to pickle the membranes would be for the winter, I don't think vinegar freezes but I don't know.

So you northerners how do you winterize your watermakers

thanks
Bob


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## colemj (Jul 10, 2003)

First of all, stop talking to your daughter about RO membranes. I'm sure she means well, but her advice above is very bad and would ruin the membrane.

Second, please clarify whether you are talking about the filters used before the RO membrane when you discuss filters becoming dirty and needing cleaning, or the RO membrane itself.

I didn't watch the video, so don't know what they say there. However, it seems like they are talking about industrial plants, which are much different in operation than a cruising boat system.

Here is a typical general watermaker component setup: Raw water intake > strainer > filter > watermaker pump > RO membrane > Fresh water tank.

So there are filters and a membrane involved. The membrane is a type of filter, but not really discussed as such in describing components.

Bleach will almost immediately kill a RO membrane. Even a little bit at very low concentrations is harmful. Vinegar won't kill the membrane, but it won't be helpful. Since it freezes at 28F, it would kill the membrane in the winter. Neither should be used in a watermaker system for any purpose.

Fresh water won't foul a RO membrane any more/quicker than salt water. In fact, I suspect less fouling would occur. Fresh water might foul the filters faster if it has a lot more stuff in it than salt water. Often times, this is the case with fresh lake water containing algae, etc.

Cleaning filters is easy, and replacing them as needed is cheap. Carrying around a bunch of filter cartridges is normal for a cruising boat.

Cleaning RO membranes is rare, and few people carry around spare membranes. As long as the membrane is flushed with clean fresh water after each use, fouling doesn't occur much, and neither does calcification.

If the RO membrane does need to be cleaned, one would use sodium hydroxide for biofouling and citric acid for chemical fouling. Again, this is very rarely necessary.

To store RO membranes in freezing weather, just store the entire system in -100F glycol antifreeze like used in protecting boat/rv fresh water systems. This both preserves the membrane and keeps it from freezing. Alternately, you could remove the membrane, put it in a bag with a glycol solution and take it home.

But the very best way to keep a membrane from freezing is to keep the boat containing it in a nice, sunny, warm climate. 

Mark


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## capta (Jun 27, 2011)

My understanding is that even the tiniest bit of bleach can damage the RO membranes permanently. Perhaps your daughter was speaking about the prefilters.
I would suggest you contact Rich at [email protected] with any questions you might have. He is extremely knowledgeable and helpful about watermakers and their parts and will not try to sell you anything, though I have found him a great source for parts when needed.


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## snokid (Oct 25, 2016)

Raw water intake > strainer > filter > watermaker pump > RO membrane > Fresh water tank

I knew the pieces of the system I have even looked at building my own, doesn't seem very hard.

I like where you said the best way to winterize a boat is to have it in a warm place!!! my plans exactly!!!

would of thought the antifreeze wouldn't of been good for the system good old pink stuff.

my daughter said that what they did with the filters they were using, but those filters weren't a membrane even though that's the plant she worked at.

Cruise RO is top of my list if I end up buying new vs. used or building my own system.
Bob


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## colemj (Jul 10, 2003)

snokid said:


> Raw water intake > strainer > filter > watermaker pump > RO membrane > Fresh water tank
> 
> I knew the pieces of the system I have even looked at building my own, doesn't seem very hard.
> 
> ...


I didn't mean to offend with simplicity - it just wasn't clear to me whether you were talking about the filters or the membrane at various points.

It isn't difficult to build your own system, but it is time-consuming searching for good deals on parts, and fiddly getting all of the small bits and bobs together. I was going to do so, but then realized that it would take me months of searching for deals on the pump, motor, valves, and housings just to save $300-500 over a complete system. If I just ordered the parts retail, I wouldn't save any money at all.

The pink stuff isn't very good for pickling because that is the -50F antifreeze. If I remember correctly, the -100F antifreeze is blue. But then, I'm trying very hard to forget everything I know about living in Michigan winters.

We have a CruiseRO system and it is very good - it just pumps out water continually without complaining. However, it is an AC-powered system, so that requires a generator. If you want a DC-powered system, then CruiseRO would not be a good choice. The only good choice there is an energy-recovery system like Spectra (there aren't many others like this).

If you build your own DC powered system, then you will be running a generator anyway to make water, because they are power hogs that don't perform well unless the batteries are at charging voltage when running. We cruised for several years with a DC system and found we were running the generator most of the time anyway, so just got an AC system instead. The advantage is that we now make 30gal/hr instead of 6.

Mark


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## capta (Jun 27, 2011)

snokid said:


> Cruise RO is top of my list if I end up buying new vs. used or building my own system.
> Bob


Rich helped us build our own, plenty of good advice. As I said, no pressure to buy anything, but he often has some of the parts at a good price that are harder to source.
I installed a HM Digital, Inc PPM meter in the system instead of using a portable one. Battery operated (lasted 6 years & replaceable), so no wiring beyond the sensor, which goes right behind the panel. I also used Pex fittings and Pex tubing after the prefilters, for all but the high pressure lines; really simple and color coded.


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## snokid (Oct 25, 2016)

colemj just got to give my wife time to retire, or change her mind and get retired sooner!!! I keep telling her you can't take the money to the grave!!!! November 1st 2019 is when she want's to wait till. She's a teacher so she has the whole summer off so the summer after next we start our journey get as far south as we can and she flies back to work sept, oct. then back to the boat and warmth!!!

We are in a 40' mono cats like your sure look nice I really like the leopard 43's don't know might end up with one, really not sure yet.

Having refit most of the boat this last summer, in what free time I had, I was care giver for my wife's father who has since been placed in a home. So my free time was very limited, only have to finish the wiring, finish the davit's, build a dodger/bimmini, install the windlass, and get and install a watermaker and we are ready!!! Most of that I can have done before schools out for the summer this spring. 

Then we are going to live on the hook as much as possible this summer,(north channel) kind of silly but we are still paying for a slip anyways. But since we are going to spend as much time on the hook as we can I figured I should be looking at either increasing our fresh water storage or installing a water maker now. That's what got me researching watermakers and fresh water usage.



capta, thank you I will give Rich a email. This is really the start of my research. I know the system is pretty much a thru hull, a strainer, a prefilter, a pump, the membranes, couple of gauges and valves, and another thru hull for the brine. The little bit of research seems to lead to bigger is better, but with a mono space is more limited, but really it's just the membranes that get bigger so where can I stuff them? LOL I know I don't want a system that only can make 1.5 gallons per hour for sure. thinking in the 10-20 gallons per hour seems much more suitable. I have solar but I know that won't keep up with a bigger pump if I go with 12v could run the motor when making water though. going with cruise RO I would also have to get a little Honda to power it, then that means gas can's on the lifelines...

lol choices!!!
Bob


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## mitiempo (Sep 19, 2008)

The Spectra 150 gives you 6 gallons per hour with a consumption of 9 AH. There isn't a watermaker more efficient than this. Easy to run off solar as many do.


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## john61ct (Jan 23, 2017)

Recent Practical Sailor article on 12V units

https://www.practical-sailor.com/issues/24_1/features/4384-1.html


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## mitiempo (Sep 19, 2008)

john61ct said:


> Recent Practical Sailor article on 12V units
> 
> https://www.practical-sailor.com/issues/24_1/features/4384-1.html


Recent? From last century. A lot has changed since 1998.


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## john61ct (Jan 23, 2017)

That's funny, google showed a date about two weeks old 

So who makes 12V makers that put out 20+ gph? 

Not from batteries, assume 200+A available

And fewer proprietary parts the better, similar to CruiseRO's approach?


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## outbound (Dec 3, 2012)

Will agree with Mitempo. Have spectra Cape Horn extreme. Routinely run it on wind/solar without noticeable decrease in production. Thing is I start at full charge and turn it off and back flush when I get to 80%.
For first time winterized it with -100. Hopefully goes well.
With-100 said no fouling nor freezing. I don’t pickle as I have the Z ion system which seems to work well. Spectra sells a pickling solution which should work for you while you’re in fresh water. RO systems like to be run. More often they’re used less troubles you have. Given you don’t have that option would probably pickle it and change the pickle solution every 6 months. 
I put a carbon filter in front of the membrane. Some say this decreases risk to the membrane. They are wicked expensive so be careful. No making water if any chance of oil or other petrochemicals in feed water. I don’t put ANY shore water in my tanks. No risk of contamination so don’t need to put bleach in them. Remember you back flush with your fresh water. Seen people screw up their RO systems by back flushing with shore water containing HCL.


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## capta (Jun 27, 2011)

snokid said:


> capta, thank you I will give Rich a email. This is really the start of my research. I know the system is pretty much a thru hull, a strainer, a prefilter, a pump, the membranes, couple of gauges and valves, and another thru hull for the brine. The little bit of research seems to lead to bigger is better, but with a mono space is more limited, but really it's just the membranes that get bigger so where can I stuff them? LOL I know I don't want a system that only can make 1.5 gallons per hour for sure. thinking in the 10-20 gallons per hour seems much more suitable. I have solar but I know that won't keep up with a bigger pump if I go with 12v could run the motor when making water though. going with cruise RO I would also have to get a little Honda to power it, then that means gas can's on the lifelines...
> 
> lol choices!!!
> Bob


To the best of my knowledge, there are only 2 sizes of membranes for regular RO (not Spectra) systems. It is the pump size that determines the output. We use a single 42" membrane (others have double 24"s side by side) and we can produce about 40gph when everything (water temp, clean filters, etc) is just right. Normal production is 30 to 35.
Keep in mind that the system should not sit unused for more than 3/4 days if you want maximum life from your membrane, though really, the membranes are pretty cheap compared to the cost of some of the other components. That might lead you to believe that a lower production rate might do, but honestly, if you are going to have a watermaker, you really are going to want to use water for silly things like several cool showers on a hot sticky day, or washing the stainless once in a while, after sailing. So stick with the 'bigger is better' principle, as I think it's just plain silly to invest all that money and the expense of running a watermaker, and still have to be conservative with your fresh water. SPLURGE!
What I did was shop for the pump/motor first, which took several months, but paid off. A $2200 pump/motor for $900 and change. Then I built the system to suit the pump. I've not done much research into 12 volt units, but our pump motor is rated at 17 amps of 110 vac. That would translate into a whopping 172 amps of 12 vdc. Using your main engine just to make water is a bit of overkill, and energy wasteful, so if you don't have a generator installed, you might want to consider a good portable gas unit, which would also be a good source of back up power for extra bilge pumps (we carry 4, ½hp, 2500gph submersible pumps as emergency bilge pumps), power tools, etc, anyway.


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## snokid (Oct 25, 2016)

john61ct said:


> That's funny, google showed a date about two weeks old
> 
> So who makes 12V makers that put out 20+ gph?
> 
> ...


these people do but 80amps at 12v
Watermakers / Desalinators for Yachts - 12 V DC / 24 V DC


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## snokid (Oct 25, 2016)

outbound said:


> Will agree with Mitempo. Have spectra Cape Horn extreme. Routinely run it on wind/solar without noticeable decrease in production. Thing is I start at full charge and turn it off and back flush when I get to 80%.
> For first time winterized it with -100. Hopefully goes well.
> With-100 said no fouling nor freezing. I don't pickle as I have the Z ion system which seems to work well. Spectra sells a pickling solution which should work for you while you're in fresh water. RO systems like to be run. More often they're used less troubles you have. Given you don't have that option would probably pickle it and change the pickle solution every 6 months.
> I put a carbon filter in front of the membrane. Some say this decreases risk to the membrane. They are wicked expensive so be careful. No making water if any chance of oil or other petrochemicals in feed water. I don't put ANY shore water in my tanks. No risk of contamination so don't need to put bleach in them. Remember you back flush with your fresh water. Seen people screw up their RO systems by back flushing with shore water containing HCL.


something to think about only going to get 4 months of use out of it before I would have to winterize it for the first year. We will be living on the boat 24/7 mid june to sept, couple of weekends then hauled out for the winter. So I think I could skip the pickling for next summer anyways.


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## snokid (Oct 25, 2016)

capta said:


> To the best of my knowledge, there are only 2 sizes of membranes for regular RO (not Spectra) systems. It is the pump size that determines the output. We use a single 42" membrane (others have double 24"s side by side) and we can produce about 40gph when everything (water temp, clean filters, etc) is just right. Normal production is 30 to 35.
> Keep in mind that the system should not sit unused for more than 3/4 days if you want maximum life from your membrane, though really, the membranes are pretty cheap compared to the cost of some of the other components. That might lead you to believe that a lower production rate might do, but honestly, if you are going to have a watermaker, you really are going to want to use water for silly things like several cool showers on a hot sticky day, or washing the stainless once in a while, after sailing. So stick with the 'bigger is better' principle, as I think it's just plain silly to invest all that money and the expense of running a watermaker, and still have to be conservative with your fresh water. SPLURGE!
> What I did was shop for the pump/motor first, which took several months, but paid off. A $2200 pump/motor for $900 and change. Then I built the system to suit the pump. I've not done much research into 12 volt units, but our pump motor is rated at 17 amps of 110 vac. That would translate into a whopping 172 amps of 12 vdc. Using your main engine just to make water is a bit of overkill, and energy wasteful, so if you don't have a generator installed, you might want to consider a good portable gas unit, which would also be a good source of back up power for extra bilge pumps (we carry 4, ½hp, 2500gph submersible pumps as emergency bilge pumps), power tools, etc, anyway.


Yes the 42" membrane's are huge to fit on 40'er, I'm sure I could find room, but 2 24" make it a bit easier. From what I read getting the 2521 membranes is the best bet. Seems like the whole price of the system is pretty much the pump/motor.

I have around a 100 gallon fresh water tank so I don't want a system I have to run all day if my first mate gets nuts with water usage...

Speaking of my first mate she want's us to have a generator ie. Honda 2000 watt unit. I have been pushing back, it's more crap to store, another gas can, more maintenance, that's why I was thining a 12v unit even if I have to run the motor to keep up with the current draw. Depending on how you do it I think if you plan on making water early in the day you could run the motor about half the time, then let the panels charge the batteries the rest of the way up.
17 amps at 110 vac would be putting a good load on the little generator...


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## Minnewaska (Feb 21, 2010)

snokid said:


> ....Speaking of my first mate she want's us to have a generator ie. Honda 2000 watt unit. I have been pushing back, it's more crap to store, another gas can, more maintenance........


These are popular units, but have a couple more downsides. They don't make friends, when making noise running on deck in an anchorage. You have to manage where the exhaust is going as well, so you don't asphyxiate down below. That said, they are very reliable and inexpensive for what you get.


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## mitiempo (Sep 19, 2008)

snokid said:


> these people do but 80amps at 12v
> Watermakers / Desalinators for Yachts - 12 V DC / 24 V DC


Terribly inefficient compared to a Spectra. As I posted the 150 gives 6 gallons @ 9 AH with 12 volts. The next model up is even more efficient. One of the better Spectra models is the Cape Horn which is the one Outbound has. 15 gallons per hour @ 19 amps. It is a dual pump watermaker - you can use one pump for less output and less power consumption.

https://www.spectrawatermakers.com/us/us/11125-cape-horn-extreme-330

https://www.spectrawatermakers.com/...eets/cape-horn-extreme-330-specifications.pdf

Unless you need 30 - 40 gallons per hour you don't need an AC watermaker and the generator to run it. I also doubt the Honda 2000 can run a 17 amp AC watermaker.


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## john61ct (Jan 23, 2017)

Well I will be burning dino juice to make water, wasn't planning on feeding that from batteries anyway. 

Recharging the LFP bank takes just an hour, may have 300+A available, so efficiency doesn't matter

And a higher gph rate would be good to keep overall runtime per month down.

If I decide to do engine/holding plate refrigeration that'll be a different story, but currently that's unlikely. 

No plans for AC power.


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## mitiempo (Sep 19, 2008)

john61ct said:


> And a higher gph rate would be good to keep overall runtime per month down.


Watermakers should be run every 4 or 5 days.


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## john61ct (Jan 23, 2017)

Yes but I meant total runtime hours per month or year, nothing to do with frequency of use

Can also call it average per day 

At 25 gph may mean average one hour per day vs 8gph results in three hours per day


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## outbound (Dec 3, 2012)

Different people have different life styles. Don’t know yours. But will note we usually are on the boat and don’t leave in the evening except for the occasional evening on someone else’s boat or dinner out. So turn on the WM before starting dinner. Turn it off when we retire to bed. That means 4-6 hours of run time. With loss of 1/2h of production from a good back flush still get enough with 2 or 3 runs per week for multiple daily showers, cooking and washing and flushing with fresh. If we have company with the TV on for sports or a movie or solar/wind hasn’t been productive may run the 4K genset briefly. But this is rare. 
Usually at least one day a week is snorkeling around the boat, just hanging out on the boat or a maintenance project. Then thing may be on all day. Then may not be run for awhile. One of the reasons I picked the Cape Horn is it’s quiet. It’s in our workroom and with the door closed noise is a total non issue. We have 200g of fresh so with just the 2 of us there has yet to be an occasion I’ve asked the bride to restrict water usage. Even with a visiting couple for a week or two this has been a non issue. 
Wonder if you should take a critical look at your actual water usage. As said these things are kind of like diesels. Do better if run hard and often. So think you may be over sizing stuff unnecessarily. Think the AC v DC v engine or genset thing is determined by lifestyle. Think hourly output is the same. Hate going in. Can bring food out to the boat but not fuel. So for us DC made sense.


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## outbound (Dec 3, 2012)

Another thing to think about is the ambient water temperature. Don’t understand the physics of this and would appreciate a explanation but if set up correctly for warm water only they produce more per hour. Friends on a sistership went with a 200T. We went with a Cape Horn which is a 150 as we are in cold water on occasion in the summer. What water temperature do you envision seeing when you move on the boat?


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## Minnewaska (Feb 21, 2010)

Out, do you think it could be variable salinity, rather than temperature?


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## aeventyr60 (Jun 29, 2011)

Salinity, temperature, water clarity all play a part. Time between filter changes/cleaning and battery voltage as well. Just restarted mine after a 30 day break in service with just a fresh water storage. 250 ppm after 5 minutes of run time. So all good on this low out put water maker.


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## outbound (Dec 3, 2012)

Really don’t know but do know manufacturers talk about output with first stating water temperature and make them to function within a set temperature range so suspect it’s temperature. May be someone here knows more about it than I do. What I don’t understand is why temperature would effect change in output.


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## colemj (Jul 10, 2003)

capta said:


> I installed a HM Digital, Inc PPM meter in the system instead of using a portable one.


We just installed the same one recently. Got the dual probe so it can measure both the product water diverted to waste during startup, as well as the product water going to the tank during running. Much better than the stick probe in a cup thing.

Mark


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## colemj (Jul 10, 2003)

outbound said:


> With-100 said no fouling nor freezing. I don't pickle


You did pickle it. -100 antifreeze is also a pickling agent, in that it kills and prevents growth (which is all a pickling agent does).

Mark


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## colemj (Jul 10, 2003)

outbound said:


> Really don't know but do know manufacturers talk about output with first stating water temperature and make them to function within a set temperature range so suspect it's temperature. May be someone here knows more about it than I do. What I don't understand is why temperature would effect change in output.


It is simple thermodynamics, where osmosis rate is temperature dependent. I don't know what the difference is between the Spectra 200T and the 150, but generally systems are spec'd at a standard temperature (70F?). If Spectra uses a fixed regulating valve, then perhaps that is the difference, with all other parts being the same.

On other systems with a variable regulating valve, pressure is always controlled regardless of temperature, and the output varies with temperature. For example, we get 30gph in 65F water, but 35gph in 80F - with the pressure regulated to 800psi in both conditions.

Mark


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## outbound (Dec 3, 2012)

Thanks C that makes sense. Mystery solved. Believe spectras do attempt to maintain a constant pressure. But still note a very slight drop in production when batteries are a bit down and increase if run with genset running.


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## outbound (Dec 3, 2012)

C it maybe semantics but I realize-100 is cidal over time. However think pickling means using a pickling solution designed for that purpose. Was under the presumption pickling solutions may not protect from freezing at the temperatures we see in New England during the winter.


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## colemj (Jul 10, 2003)

outbound said:


> C it maybe semantics but I realize-100 is cidal over time. However think pickling means using a pickling solution designed for that purpose. Was under the presumption pickling solutions may not protect from freezing at the temperatures we see in New England during the winter.


I believe Spectra's "special" pickling agent is -100F propylene glycol. I know they recommend the RV stuff if you don't have theirs.

Metabisulfite is the usual pickling agent for most other watermakers. It is harmful to Spectra's Clark pump, so they warn against it. If in freezing weather, metabisulfite will freeze, and -100F propylene glycol is recommended by those manufacturers.

All manufacturers also spec their systems at a voltage, as well as temp. This is almost always 13.8V, which is why you experience more production at charging voltages than just running on batteries. It is one of the dirty secrets about DC powered watermakers - to meet specs, you need to be charging. They really should spec them at something like 12.5V, but that would make the specs look bad.

An interesting experiment is to plot your output over a range of voltages at the WM terminals. You will find that it is constant at 13.5V+, but falls off linearly below this. At 12.5V, it is a lot less. At least our previous Village Marine was 20% less at 12.5V.

Mark


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## snokid (Oct 25, 2016)

I just looked up the blue -100 antifreeze I have only ever seen the pink stuff at the stores around here.

is there any benefit to using the -100 stuff over the -50 pink stuff?

I'm in Michigan so they sell the pink rv antifreeze year round so getting it to pickle your watermaker would be easy. But how about down south or around the world how hard is it to find antifreeze?

Bob


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## john61ct (Jan 23, 2017)

colemj said:


> All manufacturers also spec their systems at a voltage, as well as temp. This is almost always 13.8V, which is why you experience more production at charging voltages than just running on batteries. It is one of the dirty secrets about DC powered watermakers - to meet specs, you need to be charging. They really should spec them at something like 12.5V, but that would make the specs look bad.


I see making water a bit like running aircon.

They pull a lot of amps, and need to run for a long time, I can't really see feeding them from battery power without a charge source running. What would be the point?

Even with a solar-only setup (how many boats? ), the watermaker is the one thing that should be run during peak production, ideally from "free excess" solar in the afternoon.

In any case volts will be high.


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## colemj (Jul 10, 2003)

snokid said:


> I just looked up the blue -100 antifreeze I have only ever seen the pink stuff at the stores around here.
> 
> is there any benefit to using the -100 stuff over the -50 pink stuff?
> 
> ...


The -50 isn't a high enough concentration to act as a biocide pickling agent. Also, it is more prone to freezing if it gets diluted with water during the storage process.

It is very difficult to find any propylene glycol antifreeze in the South US and particularly anywhere in the sub/tropical world.

Mark


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## Minnewaska (Feb 21, 2010)

-50F antifreeze is a very misleading label. It actually freezes at +12F. It should not expand and burst a pipe until -50F. As mentioned, if it’s accidentally diluted with any water, during the winterizing/pickling process, these temperatures rise quickly. 

-100F antifreeze, by comparison, doesn’t actually freeze until -60F. Huge difference in protection. Even diluted, it should still protect far below winter temps in any popular sailing grounds I know of. 

I don’t know if just being frozen is a problem for a watermaker, but it certainly wouldn’t surprise me. I’ve long since realized that my float switch doesn’t want to be frozen. It never survives a winter, if left beneath the anti freeze in the bilge. For me, mast ingress water does freeze, when mixed with the antifreeze I leave in the bilge. It just doesn’t expand and pressure the ribs and stringers..


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## outbound (Dec 3, 2012)

When I winterize. Drain all water. Put bucket with -100 at feed. Run until comes out exhaust. Refill bucket with -100 put exhaust and feed in bucket. Run >10 minutes. Believe given closed system and prior -100 flush dilution isn’t that great so it remains cidal. My understanding is -100 isn’t immediately cidal rather it takes awhile to sterilize so winterizing results in killing the biological growth. However OP referred to cleaning the membrane. Spectra markets products just for that. C do you know what’s in them and if it’s cidal? Spectra doesn’t sell a sterilization solution they just say use -100. C do you know how long the system must sit in -100 to kill the bugs.
BTW when cruising we are usually in bed (hopefully not asleep) close to nightfall. Don’t run the WM in the dark nor if wind is below 15kt without genset. We have 1020 in the lifelines so think we’re not hurting the batteries running the wm the way we are. Drop in production makes sense. There’s a gauge for production but it varies a bit as the thing cycles. Best I could do for production v voltage would be to look at water tank gauges. But voltage also varies given draw and amount I’m getting out of the wind. Solar varies but much slower. So can only estimate. Estimates are totally consistent with output falling as voltage drops. Don’t know if it’s 10% in the beginning and 20% at the end.


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## snokid (Oct 25, 2016)

Well I just picked up a used system for a good price I guess it's the best of both worlds it runs on ac or dc, it has two motors. 
Dessalator* l *Developement of unique systems for the desalination of sea water* l *AC & DC DUO Watermakers*

draws a bit on DC 30 amps but 60l an hour shouldn't have to run it long.
Bob


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## mitiempo (Sep 19, 2008)

snokid said:


> Well I just picked up a used system for a good price I guess it's the best of both worlds it runs on ac or dc, it has two motors.
> Dessalator* l *Developement of unique systems for the desalination of sea water* l *AC & DC DUO Watermakers*
> 
> draws a bit on DC 30 amps but 60l an hour shouldn't have to run it long.
> Bob


On DC that is about 15 gallons @ 30 amps. For comparison Outbound's Spectra Cape Horn produces the same 15 gallons @ 15 amps.


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## john61ct (Jan 23, 2017)

I'm not questioning whether or not Spectra's fantastic, but electrical efficiency is not an important distinguisher for me, since I would not be trying to run my watermaker off batteries. 

I suppose it would be important for someone with lots of solar, maybe timing their usage to make use of "free" excess after their lead bank is at 85%.


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## mitiempo (Sep 19, 2008)

john61ct said:


> I'm not questioning whether or not Spectra's fantastic, but electrical efficiency is not an important distinguisher for me, since I would not be trying to run my watermaker off batteries.
> 
> I suppose it would be important for someone with lots of solar, maybe timing their usage to make use of "free" excess after their lead bank is at 85%.


I think efficiency is important for any watermaker, as well as any other device that either consumes power or creates it. At least on a sailboat. With a DC watermaker any power used has to be replaced. The less you consume the less you have to replace.

With an AC watermaker how long the engine or generator has to be run to make the water you desire also makes a difference.


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## john61ct (Jan 23, 2017)

With anything consuming that much, I would be burning dino juice while it's running. Ideally also doing other things, but quite possibly just for that one purpose. 

And yes since that's the case, it's a high gph rate that is important as you say to minimize engine/genny runtime, not the amps consumed.


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## mitiempo (Sep 19, 2008)

john61ct said:


> With anything consuming that much, I would be burning dino juice while it's running. Ideally also doing other things, but quite possibly just for that one purpose.
> 
> And yes since that's the case, it's a high gph rate that is important as you say to minimize engine/genny runtime, not the amps consumed.


Agree, a different aspect of efficiency.

For a sailboat in the tropics with good solar (and optionally wind gen) and careful battery management there should be no need to run an engine or generator for daily electrical needs - including with a watermaker. That is where its DC efficiency really counts. The magic number at this time is 1 AH per gallon of water. Massive water volume is not necessary - if you run the watermaker every 4 or 5 days a simple fresh water flush is all that is regularly required.


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## john61ct (Jan 23, 2017)

mitiempo said:


> For a sailboat in the tropics with good solar (and optionally wind gen) and careful battery management


I agree, but there are many boats for which that does not apply.

With a big LFP bank and 200+A charging on demand I'm not worrying about efficiency nor supply issues much, just keeping runtimes down to a few hours a week.


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## colemj (Jul 10, 2003)

mitiempo said:


> Agree, a different aspect of efficiency.
> 
> For a sailboat in the tropics with good solar (and optionally wind gen) and careful battery management there should be no need to run an engine or generator for daily electrical needs - including with a watermaker. That is where its DC efficiency really counts. The magic number at this time is 1 AH per gallon of water. Massive water volume is not necessary - if you run the watermaker every 4 or 5 days a simple fresh water flush is all that is regularly required.


That is definitely not a general rule. For example, we are in the tropics, have 700W of solar (kind of small nowadays), and 360Ah of lithium batteries.

We run our 30gph AC watermaker 90% of the time off the inverter/batteries. At times we run the water heater off them just to use the power.

200W more solar and this would be 100% of the time.

Lithium batteries change things dramatically, and for these, a high output watermaker is what allows the efficiency to run an AC system off batteries. Lead batteries require low current, lower output systems to match them efficiently, and most of one's charging output must be dedicated to charging lead batteries. Lithium is about the opposite of that.

Mark


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## capta (Jun 27, 2011)

mitiempo said:


> On DC that is about 15 gallons @ 30 amps. For comparison Outbound's Spectra Cape Horn produces the same 15 gallons @ 15 amps.


That's 15gph under ideal/corporate testing conditions, not real world conditions. Unfortunately, I'm guessing that the actual production levels will be closer to 12gph. I wish him well, but for us, 12gph would be a case of becoming a slave to the watermaker (minimally, 3 hours of production, 3 or more times a week) to enjoy anything more than the minimal benefits of having a watermaker.


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## john61ct (Jan 23, 2017)

Since DC driven units have relatively low production rates, and I am avoiding AC as much as possible, I am considering going with an engine-driven unit.

A big advantage there is the ability to buy from Rich Boren.

My issue is I don't want to increase to a bigger engine as a result, I want to be able to take the different loads off and on as needed.

Is that straightforward to do with a pulley drive system?


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## capta (Jun 27, 2011)

john61ct said:


> Since DC driven units have relatively low production rates, and I am avoiding AC as much as possible, I am considering going with an engine-driven unit.
> 
> A big advantage there is the ability to buy from Rich Boren.
> 
> ...


One other consideration for you might be to install an engine driven generator that produces 110 vac. That way you might be able to run the watermaker and have ac for a battery charger or whatever, at other times. Probably around the same hp draw on your engine, but multi-use.


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## john61ct (Jan 23, 2017)

capta said:


> One other consideration for you might be to install an engine driven generator that produces 110 vac. That way you might be able to run the watermaker and have ac for a battery charger or whatever, at other times. Probably around the same hp draw on your engine, but multi-use.


No, as I said I am avoiding AC as much as possible.

DC is generated to charge the bank directly, at 200-300A with LFP accepting it all, only need to run a few hours a week.

By going to engine driven, hoping to get all the water we need in a similar timeframe.


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## outbound (Dec 3, 2012)

Different strokes for different folks. See the logic of all statements so do whatever floats your boat.
We run the water maker whenever the main engine comes on for more than getting out of the mooring field. Haven’t paid attention to how many hours that is. It also goes on if we turn on the AC which requires the genset. But that’s only a few hours. (AC is really not needed in the Easter Caribbean). But would note we have 2 people and 200g. The high tankage means we can pick and choose when to run the watermaker and still escape from concern about running out or need to be frugal. 
Also about once a week we don’t leave the boat. Yes occasional will peek at the dials but it doesn’t distract us from doing other stuff. So think Capta maybe a bit off the mark in how he views what degree having a DC unit is an imposition on lifestyle. Rather it’s been a huge improvement. Also appreciate not putting hours on the genset or engine. 
Seems my experience is congruent to Mitempo’s.


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## RegisteredUser (Aug 16, 2010)

Figure out what you think your needs will be. Try to be realistic.
Small boat mode.

If you don't have women onboard needing complete fresh water showers, you may not really need it.
Adding it adds to the complexity of your job - maintaining/managing da ship....

Maybe do it later...if she has really long hair...


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## outbound (Dec 3, 2012)

https://water.usgs.gov/edu/qa-home-percapita.html
Interesting to look at water usage. Average American is in excess of 100g/d. Whereas European is 53g. On a boat much of that usage doesn't exist. Things like that 1/2 shower, running the water while you brush your teeth or irrigation for the lawn and plants.
So using Capta's numbers which probably aren't far off assume 12g/h. One day of a 7h run minus a flush get ~80g. Sneak in another block of 4h get 44g. So get 124g. If we are doing pots/pans we do it salt with a fresh rinse. We do wet, soap then rinse in the shower. But beyond that don't live differently on the boat. Sorry to be so loosey goosey about numbers. The wm is sufficient so haven't been anally playing attention to this like we are about the batteries or other stuff. 
Agree Li May be life changing but doesn't make sense to flip now as there's life in the current ones and I'm waiting for lithium metal if possible.


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## mitiempo (Sep 19, 2008)

colemj said:


> That is definitely not a general rule. For example, we are in the tropics, have 700W of solar (kind of small nowadays), and 360Ah of lithium batteries.
> 
> We run our 30gph AC watermaker 90% of the time off the inverter/batteries. At times we run the water heater off them just to use the power.
> 
> ...


Do you charge solely off the solar or do you have to run the gen or engines to charge?

Yes there are many with boats depending on engine/gen time for charging. There are also many cats with enough solar to never run an engine or gen to charge. I don't think Lithium should make that much difference as far as efficiency is concerned really as you still have to return the AH's used. If you are using engine or gen for charging then by all means get an AC watermaker - it makes sense.

On the other hand if you wish to be free of the engine except for moving the boat, regardless of the battery type, efficiency is important. Solar alone (or with wind gen) can supply all needed current for daily use including the watermaker if it is planned for.

Boats with heavy electrical use - air conditioning, electric stoves, washers, etc will run their engines or gens even if they don't have a watermaker. AC high output watermaker is and should be their choice.

Lithium is still on a very small minority of boats and I think it will be that way for a while. There are many, many cruisers with lead batteries out there and will be for a long time to come.


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## john61ct (Jan 23, 2017)

What is revolutionary with LFP is that well under an hour is all you need to get even a large bank refilled.

Ridiculous CAR, and no declining acceptance as SoC rises.

And no need from the bank's POV to get to Full, in fact it prefers to sit well depleted when not being actively cycled.

So if you are regularly burning dino juice for other purposes anyway, there's no real need to bother with solar.


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## mitiempo (Sep 19, 2008)

john61ct said:


> What is revolutionary with LFP is that well under an hour is all you need to get even a large bank refilled.
> 
> Ridiculous CAR, and no declining acceptance as SoC rises.
> 
> ...


If you are not burning dino juice for any other reason it seems like a step backward to do so just for charging.


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## colemj (Jul 10, 2003)

mitiempo said:


> Do you charge solely off the solar or do you have to run the gen or engines to charge?
> 
> ............................
> 
> I don't think Lithium should make that much difference as far as efficiency is concerned really as you still have to return the AH's used.


90% of the time the entire boat is run off 700W of solar. The remaining 10% is the short daylight months of Dec/Jan if we are above 15*N, or if cloudy without rain for long periods. If rain, then our large water catchment takes care of water production, and the solar is still enough to keep some charge in the batteries.

Lithium does have a large efficiency difference in several ways. First, it accepts all the charge you can throw at it right up to full. So there is no several hours of absorption taper charging at low current to get them full; nor is there a limit on the amount of current they will accept. There also isn't a significant Puekert factor, so 100A in covers 100A out. So like John mentioned above, if the batteries are down 50% (180Ah in our case), then one hour of running the chargers or engines has them completely full again. This would easily take 6-7hrs for any type of LA battery - giving lithium a 6x charging efficiency advantage right there.

But the real advantage is that you do NOT have to return the Ah's used. Lithium is happier spending its time below fully charged, and there is no need to bring them to full charge on a regular basis because there is no harm in not doing so. LA will die quickly spending weeks or months at 50% state of charge.

A typical scenario might be that the batteries are at 80% SOC, it is cloudy for a few days so that the solar just keeps up with house loads only, we run the watermaker for two hrs to make enough water for the next 4 days, and our batteries now are at 30% SOC. They stay at 30% SOC for 2 days until the sun returns and they get up to 70-80% SOC over the next 2 days before we run the watermaker off them again.

This above scenario can cycle forever with no harm to the batteries. I suspect even the best LA batteries (excepting Oasis) would be dead within a few months of this abuse.

To recap, what makes this work as a system is a high-output AC watermaker that makes days worth of water in a couple of hours. Of course, if we are motoring or running the genset, we make water like Outbound describes because that is otherwise wasted energy regardless of batteries/watermaker. The only difference there is that we don't care if the batteries are getting fully charged while the dino energy sources are running.

Mark


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## john61ct (Jan 23, 2017)

mitiempo said:


> If you are not burning dino juice for any other reason it seems like a step backward to do so just for charging.


Well if you're using 200AH per day on average that takes a fair bit of solar to replace, many don't even have room for that many panels, or would spoil the look of their boat.

A little DC genny running for an hour a few times a week, also making lots of water at the same time, seems reasonable to me.


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## mitiempo (Sep 19, 2008)

colemj said:


> 90% of the time the entire boat is run off 700W of solar. The remaining 10% is the short daylight months of Dec/Jan if we are above 15*N, or if cloudy without rain for long periods. If rain, then our large water catchment takes care of water production, and the solar is still enough to keep some charge in the batteries.
> 
> Lithium does have a large efficiency difference in several ways. First, it accepts all the charge you can throw at it right up to full. So there is no several hours of absorption taper charging at low current to get them full; nor is there a limit on the amount of current they will accept. There also isn't a significant Puekert factor, so 100A in covers 100A out. So like John mentioned above, if the batteries are down 50% (180Ah in our case), then one hour of running the chargers or engines has them completely full again. This would easily take 6-7hrs for any type of LA battery - giving lithium a 6x charging efficiency advantage right there.
> 
> ...


That all makes sense. You have a good system - I went through your blog.

I do not however think your system is anywhere close to the normal cruiser's. Most cruisers have lead acid batteries and not LiFePo4. For them efficiency is much more important.

The Cruise RO watermaker does make a lot of water in a short period of time. But efficiency is hardly its strong point. The 30 gallon/hour model uses 9.3 amps AC - about 84 amps DC through the inverter - as well as 8.2 amps DC for the boost pump. That is about 3 amps/gallon.

If ot were me I would opt for an efficient Spectra watermaker that consumes 1 amp/gallon (Cape Horn) and is quiet enough to run anytime - if I had LiFePo4 batteries or lead acid batteries.


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## john61ct (Jan 23, 2017)

I still don't see how efficiency in amps/gallon can be important if an engine / generator is running while the watermaker is running.

Especially with a limited acceptance lead bank.

Maybe if the power output is being 80-90% consumed by other loads, but that's in fact more likely with charging LFP, not less.

But usually there is excess capacity of power, the engine is running at a certain rpm regardless.

So watermaker efficiency in gph becomes the more important issue, if the owner wants to minimize runtime.

Efficiency in amps/gallon obviously is **critical** where the watermaker is running off batteries, and all/most energy input is solar. But really is that common?

In the case of the dino juice power source running for hours every day regardless for other reasons, then **neither** measure of efficiency is important.

But maybe I'm just missing some in-between scenario?


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## mitiempo (Sep 19, 2008)

john61ct said:


> In the case of the dino juice power source running for hours every day regardless for other reasons, then **neither** measure of efficiency is important.


Sounds pretty inefficient to me.

To me the goal is not to run the engine for anything except travel.

With LiFePo4 the amps comsumed by the watermaker take away from charging amps.

Those with LiFePo4 usually have large alts. Why not just a 50 amp alternator? Because efficiency is important.


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## RegisteredUser (Aug 16, 2010)

mitiempo said:


> ....Why not just a 50 amp alternator? Because efficiency is important.


I think you lose that extra ace up your sleeve...insurance.


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## john61ct (Jan 23, 2017)

mitiempo said:


> To me the goal is not to run the engine for anything except travel.


I was not talking about the propulsion engine necessarily, maybe that's an outboard, or electric propulsion, whatever.

Think generator, but in my case no AC involved, 12VDC @ 200-300A output.

Or even someone running a little eu2000i with an 80A charger, doesn't matter, call it "dino juice power source".

In most cases there's lots more Amps available anyway, than any little differences in "amps per gallon" efficiency.



mitiempo said:


> With LiFePo4 the amps comsumed by the watermaker take away from charging amps.


Total runtime for LFP charging is only 3-4 hours per week.

My point is making the water should also be in the same range, at least as low runtime as possible.

If they can both be done together within say 8 hours per week, fine. It is **high GPH** that enables that.

Low amps per gallon is (I think) only useful

where there **isn't** dino juice power on demand, and the watermaker is running off batteries.

At least I can't think of any other common one. And again, is that a common scenario?


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## mitiempo (Sep 19, 2008)

john61ct said:


> Low amps per gallon is (I think) only useful
> 
> where there **isn't** dino juice power on demand, and the watermaker is running off batteries.
> 
> At least I can't think of any other common one. And again, is that a common scenario?


Or where there is dino juice power on demand but nobody wants to listen to it.

Sure some have LiFePo4 battery banks and revel in its advantages for running high consumption items through an inverter as well as its ability to absorb 200+ amps in charge current. The majority of cruisers still have lead acid battery banks, whether flooded or agm, and want (or need) efficiency. Spectra sells a lot of watermakers. This is because of efficiency for those that need it.


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## colemj (Jul 10, 2003)

mitiempo said:


> That all makes sense. You have a good system - I went through your blog.
> 
> I do not however think your system is anywhere close to the normal cruiser's. Most cruisers have lead acid batteries and not LiFePo4. For them efficiency is much more important.
> 
> ...


I have been surprised at how many cruising boats are changing to lithium. Much more than I had supposed would do so. At the rate I've seen in the past 2 yrs, I would venture a guess that 30-40% of boats may be using lithium batteries within 5 yrs. Of course, some of these installs (and their owners) are quite worrisome, so perhaps there will be a backlash after a few failures.

Efficiency is measured in different ways depending on usage. For running off batteries, it is amps/gal. For running off engine/generator/inverter it is gal/hr. Both strive to minimize power used, but in different ways - whether it be a chemical reaction in a battery or a chemical reaction in an engine.

The part of the watermaker model spectrum I don't understand is how any of the non-energy recovery DC watermakers get sold. Using 15-20A to make 5-6gph doesn't make sense. That is the same DC "efficiency" as our 30gph AC watermaker running off the inverter.

Apparently, DC efficiency isn't high on priorities because CruiseRO sells units faster than they can make them, and they aren't the only game in town on this front - Echotec, Rainman, and others are also doing brisk business selling AC watermakers.

While lithium batteries are not yet widespread and common in the cruising community, Honda generators seem to be universal because every crowded anchorage we go to have those beasts baying on the sterns of every boat all day long.

So like John points out, if one is burning dino juice for whatever reason, pumping out a large amount of water in the same run time is more efficient than a smaller amount using less DC power.

BTW, our AC watermaker is quieter than a Spectra (I have experience with both). I understand why you might think AC systems are noisy because those using CAT or cheap pressure washer pumps do scream like banshees. But the General pump used on Echotec and CruiseRO (and maybe some others) is very quiet - the feedpump is louder than the pressure pump (and Spectra has two of those).

Mark


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## mitiempo (Sep 19, 2008)

colemj said:


> .......But the General pump used on Echotec and CruiseRO (and maybe some others) is very quiet - the feedpump is louder than the pressure pump (and Spectra has two of those).
> 
> Mark


Spectra does have 2 on the Cape Horn - you have a choice of more output with both or half the output with one. The Spectra Ventura has one. The Catalina and above have a single mag pump - very quiet.


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## mitiempo (Sep 19, 2008)

I agree that if you have LiFePo4 or an inefficient system that requires running an engine or generator an AC watermaker makes sense. Too bad they are nowhere as efficient as the DC watermakers can be. 

Most cruisers we see still use flooded or agm batteries and want efficiency. The bulk of the LiFePo4 we sell goes to rv's - seems there are many building systems on Sprinters nowadays.


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## outbound (Dec 3, 2012)

No genset scenario.In practice we have yet to use just one pump. Believe efficiency is increased as is production of course. Given like to run it while the suns still shining and the wind blowing so there’s ample reserve for the night. The watermaker is in the workroom so behind two doors. You can’t hear it running when both doors are closed. 
Genset scenario. Our genset stinks. It’s a high rev Lombardini and extremely noisy for a diesel genset. If going to run it while watermaking with use it to bring batteries to 100% if necessary then turn it off. Then turn it back on when batteries hit 70-80% and use it to go back to 100%. Often run it just long enough to get it good and hot. So even when using it for this function total use is <1h. Of course have wm running while genset is on. We have 1020ah so going to 80% is 200a which usually is more than sufficient to fill the tanks.
In short if you’re willing to let your batteries cycle (and put up with a shorten life) believe even if with a DC system there’s no need to put up with long genset or propulsion engine run times.


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## john61ct (Jan 23, 2017)

mitiempo said:


> I agree that if you have LiFePo4 or an inefficient system that requires running an engine or generator an AC watermaker makes sense. Too bad they are nowhere as efficient as the DC watermakers can be.


In my case no AC used at all. So I want DC, but high gallons per hour output, amps per gallon makes no difference.

Or I could go with a unit driven direct from engine, in which case maybe CruiseRO is the best?

That takes amps right out of the picture .


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## john61ct (Jan 23, 2017)

outbound said:


> If going to run it while watermaking with use it to bring batteries to 100% if necessary then turn it off. Then turn it back on when batteries hit 70-80% and use it to go back to 100%. Often run it just long enough to get it good and hot. So even when using it for this function total use is <1h. Of course have wm running while genset is on. We have 1020ah so going to 80% is 200a which usually is more than sufficient to fill the tanks.
> In short if you're willing to let your batteries cycle (and put up with a shorten life) believe even if with a DC system there's no need to put up with long genset or propulsion engine run times.


Yes reducing bank life a lot that way, you may think you're getting to 100% using dino juice, but no way by itself if your bank is lead.

Make water and charge the bank *in the morning* before sun is high, then let solar complete "the long tail" rest of the day, that's (can be) getting to true 100% (if via endAmps) and not overcycling.


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## mitiempo (Sep 19, 2008)

john61ct said:


> In my case no AC used at all. So I want DC, but high gallons per hour output, amps per gallon makes no difference.
> 
> Or I could go with a unit driven direct from engine, in which case maybe CruiseRO is the best?
> 
> That takes amps right out of the picture .


Don't think there are many very high output DC watermakers.


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## john61ct (Jan 23, 2017)

As above, 32 gallons


snokid said:


> these people do but 80amps at 12v
> Watermakers / Desalinators for Yachts - 12 V DC / 24 V DC


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## mitiempo (Sep 19, 2008)

john61ct said:


> As above, 32 gallons


With more power consumption than my windlass!


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## colemj (Jul 10, 2003)

mitiempo said:


> Too bad they are nowhere as efficient as the DC watermakers can be.


I think Spectra makes AC systems using a Clark pump that are similarly efficient as their DC units. I don't know if they make smaller ones like this, or only large commercial units.

But again, once one is looking to move to an AC unit, the measure of efficiency is gallons per hour, not amps per gallon, because an excess of power is available for a set amount of time.

Mark


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## outbound (Dec 3, 2012)

John have lifeline agms. Don’t make water everyday. On days not making water batteries get all the out put from panels and D400s except parasitic loss and pressure water pump drain. In short they are at 100% more than they aren’t. Sulfanation isn’t the issue. Rather it’s number of cycles. Big advantages of Li is greater number of cycles as well as more useable power. In my use pattern it’s number of cycles that count even though number of deep discharges is negligible.


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## outbound (Dec 3, 2012)

BTW all this talk of Dino juice makes me think of the Zappa classic dynamo hum.


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## colemj (Jul 10, 2003)

outbound said:


> Big advantages of Li is greater number of cycles as well as more useable power.


It takes a while of owning them to understand this, but the real advantage of lithium is never needing to worry about fully charging them, or using them for long periods of time in the lower range of state of charge.

Even if they had the same number of lifetime cycles as LA, this would still be a significant advantage of lithium.

There really isn't more useable power with lithium because if the bank is sized correctly, it will be a smaller bank with the same useable power as a larger LA bank. The mistake many people are making when installing lithium is to size it the same as their old LA bank. This is also one reason everyone believes lithium batteries are so expensive - they buy twice as much as needed.

Mark


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## snokid (Oct 25, 2016)

colemj said:


> It takes a while of owning them to understand this, but the real advantage of lithium is never needing to worry about fully charging them, or using them for long periods of time in the lower range of state of charge.
> 
> Even if they had the same number of lifetime cycles as LA, this would still be a significant advantage of lithium.
> 
> ...


that's what I was thinking last time I looked Lithiums were like 1500.00 per battery and I have 6 agm's....


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## john61ct (Jan 23, 2017)

If you know running your DC watermaker long enough to produce the gallons you need would seriously deplete your bank to the point you need to burn fuel anyway

then you're better off running that power source during the watermaking, and save the bank cycling

If you find that is usually the case, then you'd be better off getting a higher gph unit. 

If on the other hand, solar is meeting all your needs including making water without burning any fuel, that's fantastic, higher AH/gal efficiency is paying off for you. 

My question is, is that latter scenario actually common out there?


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## colemj (Jul 10, 2003)

john61ct said:


> If on the other hand, solar is meeting all your needs including making water without burning any fuel, that's fantastic, higher AH/gal efficiency is paying off for you.
> 
> My question is, is that latter scenario actually common out there?


Difficult to say. I know lots of people who tell me that they make water and have fully charged batteries by noon using a few hundred watts of solar only. They are also the ones buying new batteries every 2 years, so you know that story about living and dying on a battery monitor SOC function...

On the other hand, solar is ridiculously cheap and easy to install. I know lots of boats with 1000+ watts of solar (I have a friend with 2500W!), and I believe they can and do make water and fully charge batteries without burning fuel. Spectra or not, but an energy-recovery unit certainly helps.

From personal experience with 700W of solar, 6 Trojan T105's, a power usage of ~150Ah/day, and a watermaker that needed 17A to make 6gph, we struggled to run solely off solar. I believe it would have been possible with a Spectra.

Mark


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## john61ct (Jan 23, 2017)

Yes for me coddling the bank for longevity is a given, including with lead getting to 100% Full as per endAmps most cycles. 

I figure in the end over time you have to produce more than you consume anyway, procrastination is long-term expensive, so may as well do it right. 

Whole issue goes away with LFP of course, so no need for solar unless you can go solar-only.


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## mitiempo (Sep 19, 2008)

john61ct said:


> Whole issue goes away with LFP of course, so no need for solar unless you can go solar-only.


With my smaller boat if I went with LFP I would go solar only. Of course it is and will stay a low consumption boat. To me the big advantage would be not having to fully charge at any time, only replenish what is used, at least when the sun shines.

On a larger boat with more systems the high acceptance is certainly a bonus to be taken advantage of.

I would want to be as energy efficient as possible in either situation.


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## mitiempo (Sep 19, 2008)

colemj said:


> I think Spectra makes AC systems using a Clark pump that are similarly efficient as their DC units. I don't know if they make smaller ones like this, or only large commercial units.
> 
> Mark


Spectra starts with AC on the Newport 700 model. It uses 700 watts AC for 29 gallons/hr or 24 amps @ 24 volts DC.

The Newport 1000 makes 41 gallons/hr with 750 watts AC or 28 amps @ 24 volts DC.


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## john61ct (Jan 23, 2017)

mitiempo said:


> With my smaller boat if I went with LFP I would go solar only. Of course it is and will stay a low consumption boat.


To me low consumption rules out a watermaker, fridge etc.

My point is that with lead you **need** solar and to try to reduce runtimes, the conventional wisdom has become a mix of both.

But once you have both LFP **and** decent dino-juice charging, there is little **financial** reason to put in solar, since a few genny hours a week is enough for even a high-consuming batteries-only boat.

Then the high-gph watermaker also makes sense, to fit into the few-hours per week paradigm.

While I completely agree solar-only (no dino juice charging) is the ideal and a fine goal, especially if you can completely eliminate the genny HO alts from the design, it's just not always possible/practical, suitable etc for many boats/owners.


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## john61ct (Jan 23, 2017)

> 41 g (155 l) every hour on DC

Bingo!

So nice to have choices.


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## outbound (Dec 3, 2012)

John you make the best decisions for yourself but will note once you get away from easy access to marinas with high turnover of CLEAN and dry diesel it maybe quite awhile between access to reliable fuel. Even with racors and Baja filters before the tanks problems can arise. Cleaning injectors and bleeding the high pressure side truly sucks. Eastern Caribbean isn’t much of a problem if you ask around first and put some in a clear jar to look at it but other places can be sketchy. Even got bad fuel once in Norfolk VA. No biggy has just switched tanks and serviced the racor. Fortunately no fouled injector. Also to needing to relocate once you found that perfect spot just to get fuel is onerous. Don’t understand if you’re not switching to Li why you’re adverse to a system that can run on alt energy.


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## john61ct (Jan 23, 2017)

outbound said:


> diesel
> &#8230;
> if you're not switching to Li why you're adverse to a system that can run on alt energy


I never mentioned anything about diesel. 
I do use LFP, whole basis for the system design variables discussed above.

And I do think solar's fantastic, especially as stated if low total consumption allows for 100% solar, no need to install a genny or rely on alt charging.

I lived off-grid, no other sources of electricity for many years in the 70's and 80's, experimented with methane production at a pig farm, I doubt many here have a lower total carbon footprint these days.

But **if** you have LFP **and** already need to regularly generate power from dino juice

then there is no rational reason to put in more solar than you think looks nice on the boat or makes you feel acceptably green.

Strictly functionally / economically, the only reason to add solar to a genny-equipped boat is to accommodate **lead** banks' trailing amps, their need for a long tail.


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## Paul_L (Sep 16, 2004)

john61ct said:


> .......
> 
> But **if** you have LFP **and** already need to regularly generate power from dino juice
> 
> ...


That might be true in the higher latitudes, but dumping genset heat into a boat in the tropics sux.


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## john61ct (Jan 23, 2017)

Again, I'm talking about when running any motor is already required, getting LFP full is only a few hours a week. 

If solar alone is enough, then yes that is ideal.


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## Paul_L (Sep 16, 2004)

john61ct said:


> Again, I'm talking about when running any motor is already required, getting LFP full is only a few hours a week.
> 
> If solar alone is enough, then yes that is ideal.


Sounds like a circular argument. You are saying if using a genset works then there is no need to add additional solar unless it is to feed your ego. I gave you an example where even if the genset works, your live abroad life would be much nicer if you choose to add more solar and eliminate most running of the genset. It's a quality of life thing - no noise, no cabin heat, no oil changes, no going to the fuel dock, no cursing at a broken genset.


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## john61ct (Jan 23, 2017)

One more time: 

if you are already burning fuel regularly for other purposes. 

The tiny time required by LFP will not be significantly reduced by solar. 

And again, many people feel a lot of panels reduces the attractiveness of their boat. 

I'm just pointing out facts others may not have been aware of before. 

Obviously we all do what we like with our own setup. 

I'll stop now.


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## Paul_L (Sep 16, 2004)

john61ct said:


> One more time:
> 
> if you are already burning fuel regularly for other purposes.
> 
> ...


What use do you have for extensive genset running if it's not for battery charging? No cruising boat does this except perhaps the electric cooker ones.


john61ct said:


> then there is no rational reason to put in more solar than you think looks nice on the boat or makes you feel acceptably green.


This is just not a fact. There are many reasons to add solar to reduce genset run time and they apply to lead or Li battery powered boats.


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## Minnewaska (Feb 21, 2010)

Paul_L said:


> What use do you have for extensive genset running if it's not for battery charging? No cruising boat does this except perhaps the electric cooker ones......


That's not true. We run ours at least once per day. It makes hot water to shower, air conditions the stateroom for getting out of the shower, refreezes the ice maker, runs the coffee maker, toaster and microwave. Of course, we could live without all of these, but it's just not that uncommon to use a generator for some or all.

If we cruised to very remote places, we would obviously prefer to conserve diesel. But most don't. I estimate we burn 1.0 to 1.5 gallons of diesel per day in the genset. $3-$4 maybe. Easy vig for all that comfort, less than the first beer at the bar.

I do want to put the semi-flexible solar panels on my coach roof one of these days. The ones that have built in non-skid that you can walk on. Zero aesthetic issues, very cool. We only have 400 ah of battery capacity withe a very power hungry boat. Part of me thinks I'm better off keeping less capacity well charged, than just having more capacity that requires more charging.


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## mitiempo (Sep 19, 2008)

Minnewaska said:


> We only have 400 ah of battery capacity with a very power hungry boat. Part of me thinks I'm better off keeping less capacity well charged, than just having more capacity that requires more charging.


More capacity will not need more charging. You will only have to replenish what you use as you try to do now. If you are engine charging you only have 140 AH usable now. I would double the bank.


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## Minnewaska (Feb 21, 2010)

mitiempo said:


> More capacity will not need more charging. You will only have to replenish what you use as you try to do now. If you are engine charging you only have 140 AH usable now. I would double the bank.


I'm going to start a new thread. This is interesting.


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## john61ct (Jan 23, 2017)

Paul_L said:


> What use do you have for extensive genset running if it's not for battery charging? No cruising boat does this except perhaps the electric cooker ones.


Note I was not only talking genset, motoring counts as well with a robust alt setup, same as a genset for my argument. And I see lots of cruisers motoring more than a few hours per week.

Making water is another example, actually supposed to be the topic here 

Freezers, aircon, heating/dehumidifiers, many high-amp loads where battery power may not be enough.

And many people have higher-draw kitchen appliances these days.

In any case my statements are "if this, then that".

> **if** you have LFP **and** already need to regularly generate power from dino juice

If your situation doesn't fit, never mind.



Paul_L said:


> This is just not a fact. There are many reasons to add solar to reduce genset run time and they apply to lead or Li battery powered boats.


 **All** your electric needs taken care of with 2-3 sessions per week, of about an hour's runtime each. And you get to choose any convenient time. That's what LFP does for you.

Say that was a total of 1000+AH.

How much runtime would you be saving from say $1000 worth of panels? Maybe 20 minutes per week? Likely less.

Now with a Lead bank, you don't have anything like that, completely different paradigm.

Assuming your goal is to get to 100% Full, those three charging sessions must be at least 6 hours each. Ideally 4+ of that would be from solar, but putting in more solar doesn't really reduce your dino juice runtime.

As I said, if your usage is small enough that solar covers your needs 100%, to the point you don't need to buy and maintain any genset, then Bob's your uncle, more power to you.

If not and you stick with lead, then you need genny runs many mornings, or you murder your bank.

But with LFP and a high-amp charging genny, there's little point to solar at all, the need for solar comes from lead's "long tail".


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## aliquidlife (Feb 16, 2016)

Commercial Content removed per Forum Rules- Jeff_H SailNet Moderator


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## Paul_L (Sep 16, 2004)

Minnewaska said:


> That's not true. We run ours at least once per day. It makes hot water to shower, air conditions the stateroom for getting out of the shower, refreezes the ice maker, runs the coffee maker, toaster and microwave. Of course, we could live without all of these, but it's just not that uncommon to use a generator for some or all.
> ......


Certainly there are boats that are extremely heavy users of AC. And if it makes your cruising enjoyable, that's fine with me. But it is the exception for cruising boats.

We are full time cruisers and set the boat up and live a lifestyle that minimizes genset usage. I've probably run the genset twice in the last 2 months. That's low for us, but there's been lots of solar lately. We have 520watts of cheapo panels.
The time we need our genset is while on passages. Then there is heavier loads, autopilot and chartplotter, and shaded solar. In that case we usually run the genset for an hour in the morning.


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## Minnewaska (Feb 21, 2010)

Paul_L said:


> Certainly there are boats that are extremely heavy users of AC. And if it makes your cruising enjoyable, that's fine with me. But it is the exception for cruising boats.......


I would not call having the AC on for 20 in our stateroom a heavy user. It is glorious, however, to step out of a hot shower and be able to dry off and dress, before sweating through your clothes again. Other than that occasion, our AC never runs while cruising.

The truth is, our generator use is symbiotic with battery charging. When we need the genset for any of the 110v appliances, we're always getting battery charging along with it, which we'll eventually need anyway.


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