Watermaker - Experiences life expectancy of membranes

[Gerrycooper56]

Originally Posted by Dos

Hello everybody,

hope you are all well!

I am faced with the decision to equip a 12V or 230V watermaker in the approx. 60L/h range (+/-) for my Contest 41.

Knowing that the life expectancy of 230V systems obviously seems to be significantly better, these also usually have a power consumption that is more than twice as high. I want to try to do without a generator (have 800Wp solar and a silentwind), so that I inevitably get out of the 12V watermaker first.

Hence the question for you about your practical experience with the service life of the membranes (12V and 230V systems). Can you name a few of your experiences here? Of course, this is very dependent on the sea area (for me mainly the tropical barefoot route Atlantic + Pacific) and the frequency of use, but currently I have not been able to find any empirical values.

Would be very grateful for your hopefully numerous replies :-)

Best regards,
Dosheimer

We have around 810W of solar and have a LWM-145 12v watermaker. It produces around 5 gallons per hour and runs for a couple of hours each day. Parker advise the membrane life is 3 to 5 years. Power draw around 15A.

[Alberdina1]

Originally Posted by Dos

Hello everybody,

hope you are all well!

I am faced with the decision to equip a 12V or 230V watermaker in the approx. 60L/h range (+/-) for my Contest 41.

Knowing that the life expectancy of 230V systems obviously seems to be significantly better, these also usually have a power consumption that is more than twice as high. I want to try to do without a generator (have 800Wp solar and a silentwind), so that I inevitably get out of the 12V watermaker first.

Hence the question for you about your practical experience with the service life of the membranes (12V and 230V systems). Can you name a few of your experiences here? Of course, this is very dependent on the sea area (for me mainly the tropical barefoot route Atlantic + Pacific) and the frequency of use, but currently I have not been able to find any empirical values.

Would be very grateful for your hopefully numerous replies :-)

Best regards,
Dosheimer

Here is my response to your question regarding the purchase of a freshwater maker.
It seems sensible to me to purchase a smaller one with two people permanently on board, you will need more than a 30 liter / hour water maker. 12 volts is no problem and the advantage is that these machines are small in size and therefore easy to build in. We have been sailing with such a machine for years, replacing the membrane once every 5/6 years.
Pre-filters of 5 and 20 micron available very cheaply from our Chinese friends ÄlieExpres ""
We run the water maker in the Med for two hours a day. Solar cells and or a windmill is enough to keep everything running.
\ If I can make a suggestion I would look to Schenker watermaker, they have good service in the Med (Italian product)

[Jon Hacking]

If you already have a generator, then an AC system makes sense, as you probably won't use all the power that you generate.

We started cruising Ocelot in 2001, & at the time made the decision not to have a generator, but to be a 12v battery boat. There are 2 different types of 12v Watermaker: Direct drive, & energy recovering. The direct drive units just connect a motor to a high-pressure CAT pump & call it good. These are cheap to make, but the running cost (liters/Ah of electricity) is higher.

The Energy Recovery types use relatively high-volume but low-pressure pumps (std pressure water pumps on steroids) & run that through a pressure amplifier, that converts this to the high-pressure (but low volume) that the membrane needs to work. This amplifier is completely passive & uses no electricity, but it DOES use the pressure already in the membrane housing to help power the next stroke. So the waste water is at essentially zero pressure. These types are more complex, & more expensive initially, but give better liters/Ah (Spectra advertises 1US-gal/Ah, but reality is somewhat less, we get about 3+L/Ah). Spectra pioneered this type, but now there are several copy cats.

So we bought a small Spectra, & then upgraded it with a second 12v pump. This gives us about 50 liters/hr (drawing 16A) with both pumps running, or 28L/hr with only 1 (& slightly better efficiency, only 8A). The ShurFlo pumps wear out faster when I run both, but the water quality is better, so that's the way we usually run it (from solar, 480W initially, now 1200W).

But to your question, we get about 7 years out of our membranes (we've changed it 2x). Another important consideration: Make sure your unit uses a standard membrane, so you don't have to buy it from the watermaker manufacturer. Our Spectra uses a standard 2540 membrane (so called because it's 2.5" diameter by 40" long).

We talk more about this on our Watermaker page.

[nofacey]

120v system Changed at 5 years.....I believe prematurely. Throughput issue turned out to be worn hp pump seals.

[mstr_cmdr]

To answer the question:
From experience, I am currently at 5years since replacement of the SW-30 25-40. When last used (approximately 6 months ago), the TDM was 78ppm.

Some of the reasons for service life longevity of the membrane are:
a. manufacturer (AMI or Dow FilmTec).
b. filtration - screen filter, then 2x 250mm cartridge filters (10u and 1u).
c. non-usage preventative measures ("pickling" / regular back-flush).

My system is 240vac powered (7.0kVA genset), and draws about 9.2A for both LP flow and HP pumps.
It produces about 66~72 lt/hr.

The company that I use for servicing the water maker is emphatic about using dual pre-filters of 10 and 1 microns (250mm loa), especially in tropical and/or reef areas, as any particle above 1u can reduce the service life of the membrane.

As for other posters' comments about wind/solar vs ICE generators, I will leave the choice of power installation to you. As an aside, I have both wind and solar (300w wind and 1400w solar) AND an ICE generator (7.0kVA diesel powered), along with a 3000w inverter. House batteries are 4x Trojan T105 6v batteries in series/parallel giving about 480AH capacity.

Genset gets used about 2 hours each other day for water maker (~140 ltr water produced).

[charldp]

Would you believe 17 years? To be fair, the watermaker was producing water at around the 600ppm mark tho.

The unit was a 12v schenker 60l/hr and of course it produced somewhat less than the rated output. We ran it almost daily, backflushed briefly after each use and picked properly each winter.

We sold the boat in 2018 and the new owner was stil using the original membranes... in 2018 anyway!

[johnmort]

Had a Spectra Cape Horn since 2012 only changed the membrane once after 8 years was still going ok even then.
Frequently used every year when cruising

[CaptainRivet]

The membranes of the watermaker generally last very long, doesn't matter if 12V or 110/220v.
You cannot keep a spare membran stocked very long, max 1 year and the membran need to be kept wet. One little hole in the packing and its toast.
Membranes are not an issue and spare part you need but the pumps and on the regen systems like spectra or schenker the pistons and seal are failing much more often.

[chrisr]

we have an 80lph echotec running off a 240v ac gennie

membrane would now be about 15yo but only say 1500hrs use in that time (that's the hours on the gennie)

does not get much care...never backwashed or pickled, and still producing fw better than spex

personally i cannot see what diff 12v or 240v will make to the membrane. you need the same pressure...12v will run at slower flow rate, but for a longer time.

cheers,

[Nicholson58]

Originally Posted by Dos

Hello everybody,

hope you are all well!

I am faced with the decision to equip a 12V or 230V watermaker in the approx. 60L/h range (+/-) for my Contest 41.

Knowing that the life expectancy of 230V systems obviously seems to be significantly better, these also usually have a power consumption that is more than twice as high. I want to try to do without a generator (have 800Wp solar and a silentwind), so that I inevitably get out of the 12V watermaker first.

Hence the question for you about your practical experience with the service life of the membranes (12V and 230V systems). Can you name a few of your experiences here? Of course, this is very dependent on the sea area (for me mainly the tropical barefoot route Atlantic + Pacific) and the frequency of use, but currently I have not been able to find any empirical values.

Would be very grateful for your hopefully numerous replies :-)

Best regards,
Dosheimer

We have a Spectra 200 24 volt DC. It has been high cost of operation, new membrane needed at 3 years. I have had to rebuild the Clark Pump four times since November this year. 660 watts solar MPPT. We often run the generator due to clouds etc. I suggest a watermaker big enough to do the job on the generator in about an hour or two. Don’t get anything but a simple brute force unit, easy to service.

[Jon Hacking]

Originally Posted by CaptainRivet

The membranes of the watermaker generally last very long, doesn't matter if 12V or 110/220v. You cannot keep a spare membrane stocked very long, max 1 year and the membrane need to be kept wet. One little hole in the packing and its toast...

Rivet, this certainly used to be true, but technology has advanced & this is no longer the case. You can now buy dry membranes that can be stored indefinitely. This is a boon for those who like to carry spares, just in case.

[Jon Hacking]

Originally Posted by Nicholson58

We have a Spectra 200 24 volt DC. It has been high cost of operation, new membrane needed at 3 years. I have had to rebuild the Clark Pump four times since November this year. 660 watts solar MPPT. We often run the generator due to clouds etc. I suggest a watermaker big enough to do the job on the generator in about an hour or two. Don’t get anything but a simple brute force unit, easy to service.

Nich, I'm sorry to hear this. In 20 years of running ours every other day, we've sent our Clark Pump in to be serviced exactly twice, & one of those times was because we pickled it for too long (2.5 years) & something softened up.

But you say "I have had to rebuild the Clark Pump..." If you're doing the work yourself & it's not lasting, I submit that you're doing something incorrectly. The Clark Pump is a complicated beast. I've opened ours a couple of times, but Spectra will give you a completely rebuilt one for only $450 when you send your old one in. Sounds like a pretty good deal to me. Or, if you're in a hurry, they'll send you a complete unit right away, & charge you for it, but then refund you the difference when you can send them your old one. Spectra is considered a very good brand, certainly the best for 12/24v, with MANY folks using theirs for years with very few problems. Either you got a lemon or you're not doing your repairs correctly. Swap it out!