Watermaker

[SV THIRD DAY]

Originally Posted by Terra Nova

You're already at the bottom of the slippery slope once you rationalize installing and operating an inverter large enough to easily start and safely run an A/C watermaker.

I love slippery slopes, but all ya need is a 2000W inverter...been doing it myself now for going on year 5.

I don't think I would install an inverter just for the water maker, but lets face the truth here. A boat that wants/needs a 20 or 30 GPH water maker, they are going to have at least a 2000W inverter on board anyway. How else would they power the espresso machine....

A 2000w inverter is all you need to power the 1.0Hp motor including start-up. The trick and key that people forget that a water maker is NEVER started (or stopped for that matter) under pressure. So the motor is never started under load. So some massive inverter isn't needed. The 1100W constant load of the 1.0Hp motor is right in the sweet spot of the 2000W unit.

[CAELESTIS]

One day Rich is going to write a book, "How to talk your wife into going cruising and not complaining". When he does, he will be so wealthy he will sell the business and sail off into the Sea of cortez . . . ..Millions of sailors will hold him up as the modern day Lord Admiral Nelson! Huzza, Huzza!

Oh, and I want the first autographed copy.

[SV THIRD DAY]

Originally Posted by SV THIRD DAY

I love slippery slopes, but all ya need is a 2000W inverter...been doing it myself now for going on year 5.

I want to make sure I don't give the wrong impression with that comment, so let me clarify.

I would Not...repeat...Not recommend one of my AC water makers to a cruiser without an AC Generator. To me the inverter powering approach is a secondary or backup way to power the water maker but it just doesnt make sense to look at an inverter as the primary power approach. So if someone calls me with no AC generator and doesnt want one but is hoping they can buy one of our units, I give then the Spectra sales pitch and give them Tellie's contact information!

I also don't think the strength of our units are in replacing the AC motors with DC, unless you REALLY know what you are doing and have specific wants and goals like we did on Pelagic's 24v DC system. At first I tried to talk him out of it with some of the same reasoning Mark has laid out, but then I realized that for his goals and application it would work, and I'm thrilled to hear he is happy with the unit!

Tellie commented that what is a perfect choice for your buddy's boat may be a disaster for your boat and he is dead on. The advantage you have here on CF is that you have some industry guys that will honestly and without too much sales job approach answer your questions so you can pick what works best for YOU. That is hard to find these days.

[Pelagic]

Originally Posted by LeaseOnLife

Pelagic mentioned way back he has a 24V system, his DC pump motor will run at 50A then. Above he mentioned 2080Ah @ 12vdc, I assume 1040Ah @24V. Running 1 hour would deplete his bank by 5% of capacity, not too bad I think.

A DC motor with commutator and brushes can be more efficient than a squirrel cage AC motor. Real world data from CruiseRO would help compare.

Dirk

That is correct Dirk.... I just stepped it down to 12v so guys could sense how large my house bank is....
My main reason for asking Rich to supply DC motor is that in the Philippines.... Not easy to repair invertors/generators.. or anything sophisticated. but rebuilt alternators run off my reliable Perkins main engine are an easy fix while traveling Asia

[Paul L]

Originally Posted by colemj

I don't think I understand this - if you are running a generator while making water, you are running a generator regardless of the watermaker. Efficiency isn't applicable here - output is. So if running the generator, one would want the most water made during that time as possible.

Efficiency only comes into play when not running the generator, and really only relates to DC systems.

Mark

There's some middle ground on the genset. I often start my low-output DC WM when I get up at 6am. Let it run for 2-2.5hrs, then run the genset for an hour. This gets me my 25 gals of water with an hour of genset running and the batteries kicked up enough for solar to finish them off.

[colemj]

Originally Posted by Paul L

There's some middle ground on the genset. I often start my low-output DC WM when I get up at 6am. Let it run for 2-2.5hrs, then run the genset for an hour. This gets me my 25 gals of water with an hour of genset running and the batteries kicked up enough for solar to finish them off.

Yes, this is similar to how we operated our Village Marine (except I started the genset in the morning to take advantage of the high bulk charging during lowest battery SOC and let the solar work the rest of the day).

However, we found ourselves still running the genset to make water and provide charging. And higher water usage needed to be planned well in advance and with hopes for sunny days.

For us, it came down to a choice between installing double the solar or buying an AC watermaker. In our individual case, with an existing diesel genset, HO alternators on two engines, and a large inverter, the AC system made more sense than more solar.

The other consideration is that our water tank is 100gal. Many boats have at least double that, which makes storage and planning easier. Any smaller, and planning water takes more effort.

If we had a Spectra or other energy-recovery unit, we would not have made a change at all.

Michele just told me it is laundry day today and I didn't have to do any prior planning! Even after just using a ton of water washing down the boat!

Mark

[DotDun]

Originally Posted by Terra Nova

You're already at the bottom of the slippery slope once you rationalize installing and operating an inverter large enough to easily start and safely run an A/C watermaker.

It's already been stated, AC WMs aren't for everyone.

Inverters are useful for other appliances, and depending on what you deem essential will determine how large the inverter. Toaster? Coffeemaker? Microwave? IceMaker? Breadmachine? Washer/Dryer? Hairdryer? It's your choice to have any/all/none of such appliances.

Slippery slope is in the eye of the beholder.

[witzgall]

If a 30+ GPH watermaker existed that used 650 watts AC, would that be an option for some? If it was $2k more than a brute force Wm of the same capacity?

[SV THIRD DAY]

Originally Posted by witzgall

If a 30+ GPH watermaker existed that used 650 watts AC, would that be an option for some? If it was $2k more than a brute force Wm of the same capacity?

They have them already...
They do it by using an energy recovery pump and add a bit more than +$2K
But WHY....is there really a market for that? Follow me here....
Of course this is just one Cruising Bozo's Opinion, don't let it discourage you if you have the Next Big idea sitting in your back pocket....Go For It!

Once you go AC what does it matter if you are using 1100W or 650W? It doesn't really because you are already running the generator that in most instances has more power than it needs, so getting the extra $2K will be a very hard sell. Lets put it this way, I've tested a unit like that on the bench but decided for the extra cost, there wasn't a real market for it.

Lets say on table A, I'm selling the 30GPH system for $5250 that uses 1100W AC, 9.3A at 115v, 4.5A at 220v

Then on table B, I have the 30GPH Low power draw unit for $7250 and it uses 650W AC, 4.7A at 115v, 2.3A at 220v.

On table A is a known off the shelf entity, on table B is some proprietary part, energy recovery pump or "something" that isn't an off the shelf component. So, now will people buy from Table A or Table B? There's the reality, I think it will be lonely on table B because now the price range is in an entirely different market and there are already plenty of players in that market (HRO, Sea Safari, a long list). Oh and that market wants all the electronic controls, Iphone interface, etc. So add a few more thousand to the costs.....uggg.

Water maker technology is well defined and understood at this point, but the next "big thing" will come with the advent of a membrane of other material that can separate fresh water from sea water at a low energy input. People forward me links to graphene, and all the other "change the world" new materials that promise fresh drinking water for all the poor folks living around the oceans without access to save drinking water, but when you read the articles, they are money hunting press releases and years (if ever) away from commercial reality.

But that's the key.
Lower the pressure needed to drive fresh water through the membrane AND then do it so that the membrane lasts and doesn't scale and foul and you my friend will be a wealthy man. Forget about marine water makers...we are such a small insignificant portion of the Desalination market that no one really cares about us from a Big Company R&D budget standpoint. The big boys like DOW make their money from the Utility (Think thousands of GPM production) not us cruisers. That was the world I lived in where a small desal system was 10,000GPM.

[Paul L]

Originally Posted by witzgall

If a 30+ GPH watermaker existed that used 650 watts AC, would that be an option for some? If it was $2k more than a brute force Wm of the same capacity?

That seems like it might hit a pretty sweet spot in the market.

[scuba0_1]

Awesome we looked at water makers at the St Pete boat show. This thread has been helpful in understanding the differences.

Sent from my SM-N910V using Cruisers Sailing Forum mobile app

[a64pilot]

Originally Posted by Terra Nova

You're already at the bottom of the slippery slope once you rationalize installing and operating an inverter large enough to easily start and safely run an A/C watermaker.

I'd say I slid all the way down that slope when I bought the Diesel Genset, just being truthful

On edit, I think a strong argument could be made that for most a watermaker purchase has you going down that slope whatever powers it, I see a watermaker as a luxury item, but it's one that I want.

[leftbrainstuff]

Originally Posted by a64pilot

I have run the numbers, for me to be able to get by with a Spectra, and go with Solar only, I'd have to give up on a big 14 cu ft spill over freezer / fridge, and or become the electricity Nazi, and water Nazi. I don't want to chase my wife around telling her to stop wasting water and or electricity, and I'm sure she doesn't want me to either.
Realize I wanted to go with all Solar, but I just can't get the numbers to work, so I have a Nexgen 3.5 sitting in the garage that I need to install. I didn't want to go with a gen set, I would have preferred Solar, but I'm hoping we can get away with running the thing once or maybe twice a week, making water, washing clothes, maybe running the Hooka to clean the bottom.

My thought is if your going with an AC unit, go high volume so you don't run the generator very long, or if DC go with a Spectra so you don't have to run a generator at all.


Sent from my iPad using Cruisers Sailing Forum

Solar can work but it takes a holistic view and significant change 24/7.

We reduced our power consumption by 75% primarily by ditching inefficient AC to DC conversion. We run a startup as well as living aboard. We also reduced our water consumption from 50 gal / day to 10 gal / day.

We still live a normal life. Becoming water wise and energy wise takes some discipline. Keeping good records of consumption and communicating that information helps to change entrenched habits.

The silence of solar power is music to my ears.

Sent from my SM-N900T using Cruisers Sailing Forum mobile app

[Dennis.G]

Originally Posted by Paul L

There's some middle ground on the genset. I often start my low-output DC WM when I get up at 6am. Let it run for 2-2.5hrs, then run the genset for an hour. This gets me my 25 gals of water with an hour of genset running and the batteries kicked up enough for solar to finish them off.

This is pretty much our routine, with a PUR Powersurvivor 80II. Well, maybe not the 6:00 AM part. Oh, and not getting 25 gallons in so little time

As I have a generator, if I was replacing WM I would be seriously looking a HO AC system. But can make do for now.

[Paul L]

Originally Posted by Dennis.G

This is pretty much our routine, with a PUR Powersurvivor 80II. Well, maybe not the 6:00 AM part. Oh, and not getting 25 gallons in so little time

As I have a generator, if I was replacing WM I would be seriously looking a HO AC system. But can make do for now.

We are more or less 7.5 gals/hour. 2.5 hrs before the genset goes on, 1 to 1.5 hrs of genset. That works out to about 26-30 gals, then you take out the flush water. Staring early in the morning means teh solar will have time to fill the batts after I turn the genset off.
Other days we run WM in the afternoon if we have excess solar days. But most of the time, I'd rather do a longer run and get what we need. Generally we only run the genset every 3 days or so.