Re-purpose Generator Space for Watermaker

[flightlead404]

I have an H38 with the FP4200 generator, which I don't use. Currently 600AHr LiFePO4 house batteries 660W of solar, and stock Hitachi 80A internally regulated alternator.

If I end up going the Bahamas this winter I'm seriously considering repurposing the generator space for a 12v watermaker. Soliciting input, especially from anyone who has already done this.

I like the idea as I already have a through hull under the boat to pick up raw water, and have the generator exhaust to dump waste water. I have large cables from that space to the panel (I think 0AWG).

What else do I need to think about?

For the water maker itself, I'd need to fabricate some sort of mounting board for the various components, plumb the intake and exhaust, and somehow get the product water into the tank. How should that be routed? To the top of the tank? Or could I run the product water to the fresh water manifold and let pressure push it into the tank via the current feed from the tank to the manifold (close by under the galley sink).

In the electrical side, I could repurpose the cabling and move it to a dedicated 12v house-side breaker. Then simply remove the generator control panel and its wiring. Anything I need to do with the A/C side inputs from the generator?

I'm probably going to add another 2-400 W solar, additional controller, and am considering either going with an external regulator on the current alternator (will this buy me much?) or even a larger Balmar or similar (still a small frame alternator though) and charging house directly and back to start via dc-dc. Currently I'm charging start, then house via dc-dc.

[hlev00]

How much water capacity do you have? A permanent water maker could be convenient but you might not need it. As a couple, we got by with our 75 gallon tank for three months in the Bahamas including 7 days in the Raggeds without begging for water. We are stingy with water but not overly so. There are places to get free water and you can top off once or twice by buying it otherwise. If the generator space is not needed for something else of a higher priority then go for it. Or a portable unit stored in that space with other stuff.

[flightlead404]

Originally Posted by hlev00

How much water capacity do you have? A permanent water maker could be convenient but you might not need it. As a couple, we got by with our 75 gallon tank for three months in the Bahamas including 7 days in the Raggeds without begging for water. We are stingy with water but not overly so. There are places to get free water and you can top off once or twice by buying it otherwise. If the generator space is not needed for something else of a higher priority then go for it. Or a portable unit stored in that space with other stuff.

70 gals, and I'll likely be single-handing.

[hlev00]

If you don't get more input, you might try reposting with the subject "Looking for tips on installing a water maker". Some of your questions, like running the output line, probably depend on the unit and how sophisticated it is.

[coopec43]

"I like the idea as I already have a through hull under the boat to pick up raw water, and have the generator exhaust to dump waste water"


I hope they are not so close that you suck in waste water?

[mako]

The stock alternator is slightly better than useless for charging your lithium bank. Install a large frame HO or big Balmer alternator to take up the slack for bad solar days.

[Flatswing]

Another option is keep the generator & use a portable desalinator like Rainman. They come up used for sale frequently. Depending on the membrane size, up to 35gals/hr. No plumbing required. A bit noisy but very easy to use.

[dougweibel]

Water makers don't like to push product water against pressure. The manuals for the two I have owned both said excessive pressure on the product water output would damage the water maker. Generally you want the water maker output routed to the top of the tank. If you mean a manifold before the house water pump that may be OK depending on the height of the manifold relative to the height of the top of the tank. If the manifold is much below the top of the tank that could be a problem. The water pressure at the manifold will be about 0.5 psi per foot below the top of the tank. IDK how much pressure is too much - you could ask the manufacturer

Having the intake and brine discharge near each other could be an issue but I would think just a few feet of separation would be enough. Many water maker manufacturers want a forward facing scoop type thru hull for the intake but you may get by without depending on the water flow under your boat when underway. As far as mounting just plan out where you will mount items and make sure there is enough room. Check the specs on the water maker you are looking at to be sure you can get the pump(s) mounted low enough relative to the intake to meet the spec. There may be allowed/disallowed orientations to check for different components. Think about access to the filter housings for changing the filters. Everything must be mounted securely. I have seen several nice and clean installations where everything was mounted on a piece of Starboard and then that piece of starboard was bolted in.

[flightlead404]

Originally Posted by coopec43

"I like the idea as I already have a through hull under the boat to pick up raw water, and have the generator exhaust to dump waste water"


I hope they are not so close that you suck in waste water?

pickup by the keel, exhaust out the side above the water line

[flightlead404]

Originally Posted by mako

The stock alternator is slightly better than useless for charging your lithium bank. Install a large frame HO or big Balmer alternator to take up the slack for bad solar days.

it puts in 20 amps. It won't charge me from 0 very quickly, but its a decent enough help if I have a couple low solar days.

[Sailorlady2022]

We have been running a Schenker Zen water maker for just over a year now. It was wonderful to have the 'luxury' of being able to make our own water. We were just over a yr into use when the high pressure sensor failed. Schenker was super helpful in trouble shooting the problem, responded promptly, identified the issue, shipped us the new part with instructions on how to install all within 24 hrs.

We run our water maker almost every day. We watched sailors in the Bahamas spend a lot of money on water and then (in places) have to transport it by jerry can back to the boat. I would highly recommend Schenker.

Our model is the Zen which is 12v and runs off the batteries.

[mako]

Originally Posted by flightlead404

it puts in 20 amps. It won't charge me from 0 very quickly, but its a decent enough help if I have a couple low solar days.

You have a 600 amp bank. During bad solar days you'll get (say) 40 amps. If your bank has drawn 80% down, then you'll need to put nearly 500 amps back in.

I think it's great that you're considering removing the genset and relying on your large solar array, but at the least, remove the stock alternator and replace it with a 150-200 amp large frame, something that knocks out 100-125 amps easily.

[Statistical]

Originally Posted by flightlead404

it puts in 20 amps. It won't charge me from 0 very quickly, but its a decent enough help if I have a couple low solar days.

20A really is nothing. If you are ditching the genset you will want a more powerful alternator unless you are staying connected to shorepower.