Smaller capacity watermakers?

[SY Harmony]

Everything I’m seeing is 30-40gpd and larger. Are there 5-10gpd small, lower power (12v) units out there?

[Lrak]

Katadyn PowerSurvivor units are small scale. The smallest model (40e) makes 1.5gph @ 12v/4a. They are physically smaller and have smaller power requirements, but aren't any less expensive or more efficient per gallon than higher capacity ones. But a small unit and 50w panel to power it makes sense on a small boat where a large unit and a large panel doesn't fit.

[SY Harmony]

Originally Posted by Lrak

Katadyn PowerSurvivor units are small scale. The smallest model (40e) makes 1.5gph @ 12v/4a. They are physically smaller and have smaller power requirements, but aren't any less expensive or more efficient per gallon than higher capacity ones. But a small unit and 50w panel to power it makes sense on a small boat where a large unit and a large panel doesn't fit.

They’ve done a great job minimizing those, but it’s about double the capacity i really need. Sure, it just means it’ll run half the time.....

[Lrak]

I think the common usage of these small 12v ones is to run it whenever you have excess power. When its windy/sunny/sailing fast and the battery hits the absorption charging phase (~80% ish charged on lead acid), then its time to make water with the extra wind/solar/hydro power. Most people don't run them 24 hours a day.

[Tellie]

Energy efficient in todays standards the Katadyn is not. More than any plunger pump system per gallon made.

[carstenb]

Both Schenker and Spectre (now katadyn) make 8gph 12VDC systems. Schenker is significantly cheaper

We have a Spectre and have run it almost every other day for 7 years- something close to 200,000 liter (say 50,000 gallons).

Can't beat having a watermaker

[OldManMirage]

Originally Posted by SY Harmony

They’ve done a great job minimizing those, but it’s about double the capacity i really need. Sure, it just means it’ll run half the time.....

So you are saying 1.5 gallons per hour is too much ? Or am I mis-understanding you ?

Because I'm thinking if that is too much you don't need one. I must be mis-understanding.

There is a great thread started by Pizzazzz about the watermaker he came up with that makes about 3-4 GPH drawing about 15amps at 12VDC. I plan on making one myself when the time comes. Kick on the diesel at some point after it's making water and then have a hot shower after washing down the boat and clothes and anything else that needs it. Or if I don't want hot water run the little Honda and let the battery charger keep up. And maybe my solar will be enough. I like to have plenty of options.

[rslifkin]

Originally Posted by SY Harmony

Everything I’m seeing is 30-40gpd and larger. Are there 5-10gpd small, lower power (12v) units out there?

Why would you want a watermaker that only makes 5 - 10 gallons / day? That seems useless to me, as you'd have to run it 24/7 and still would only keep up with a small amount of water use.

[Mike OReilly]

Originally Posted by rslifkin

Why would you want a watermaker that only makes 5 - 10 gallons / day? That seems useless to me, as you'd have to run it 24/7 and still would only keep up with a small amount of water use.

Five to 10 gallons per day is plenty in my books. We currently use two to 3.5 gallons per day. We don't do anything special to conserve water. We use what we want. We're just conscious of its use.

Two things we have going for us though. We're higher latitudes so don't sweat so much. And the composting head uses no water. Otherwise we cook and clean as per normal.

[rslifkin]

Originally Posted by Mike OReilly

Five to 10 gallons per day is plenty in my books. We currently use two to 3.5 gallons per day. We don't do anything special to conserve water. We use what we want. We're just conscious of its use.

Two things we have going for us though. We're higher latitudes so don't sweat so much. And the composting head uses no water. Otherwise we cook and clean as per normal.

Using 5 - 10 gallons per day isn't too hard. But wanting a water maker so small that you'd have to run it 24/7 (or even 12+ hours per day at your lower usage) still seems a bit crazy to me. I'd rather have a bigger unit that I can run for an hour or 2 every day or every other day and be done with it.

[Rod Headlee]

Village Marine Little Wonder Sold by Parker/Racor.
6GPH, 12 amps 12v in reality it makes about 5GPH. We are able to run our off of wind and solar for about 3 hours. It has many hours on it.

[Mike OReilly]

Originally Posted by rslifkin

Using 5 - 10 gallons per day isn't too hard. But wanting a water maker so small that you'd have to run it 24/7 (or even 12+ hours per day at your lower usage) still seems a bit crazy to me. I'd rather have a bigger unit that I can run for an hour or 2 every day or every other day and be done with it.

The one mentioned (Katadyn PowerSurvivor) claims to make 1.5 gallons per hour. So I'd only have to run it for two to three hours, to keep me more than topped up.

Whether it is crazy to run these things 24/7 is an interesting question that perhaps Tellie can respond to. We run fridges/freezers 24/7. I realize they are quite different appliances, but is there a reason that quality watermakers can't be run constantly? (Not that I would want to...).

[SY Harmony]

The reality is I don’t need one with my 60g tank. I only use about 10g a week. I want one to keep the tank between 3/4 and full. Because as the weight comes out of the tank the bow starts to rise and she shifts cg rearward.
It looks like the Pur40 is the smallest, powered option out there.

[Pizzazz]

It is always a trade-off between cost, efficiency, durability, noise in this case. The energy recovery water makers are efficient and optimal but so expensive that they only make sense for heavy users. Consider for example, the Spectra Ventura 200, upfront it costs $8,600 and makes water at 15 watts/gallon. The 3-gph watermaker will cost at most $1,100 and makes water for 45 watts/gallon (i.e. needs three times more power).

In the past, designers were optimizing for power. Now, with solar, we have excess power during certain hours which would be perfect to make water. So, while high efficiency is fantastic, it is just no as relevant as it was 5-10 years ago. It is a similar situation with membranes. Many of the commercial units are optimizing for membrane life until you realize that a new membrane is $200 and a cleaning kit is $120 and a hassle. Just to replace pre-filters is half the cost of the membrane. So, you might as well replace the membrane once a year or two and be done with it.

Now, you are bring up another question, can we have a mini-watermaker that runs constantly. Most people will object to the noise level. Producing 800 psi is noisy. Two immediate suggestions would be to find an old Survivor-06 hand operated unit ($130 on eBay) and find a way to use a small motor (you will need a high torque 30-40 watt max gear motor) to move the handle. May be a wiper motor could be ideal. The membranes though would be hard to find. If you can build this, it would operate very quietly and you can run it as a fridge (i.e. connect to a tank level sensor for on-off).

The second idea is to take the 3-gph design and put the pre-filter and pump/motor in an enclosure (i.e. Sch. 80 tube or something similar), seal it and dump it overboard when at anchor. it should quiet it down.

Still, soon or later you start using more and more water and you graduate to more interesting, mainstream designs. You run it for an hour or two and fill up the tank.