DC Generator / Watermaker combo ?

[Tspringer]

I am trying to figure out the best plan for refitting our new boat, an '81 Stevens 47. Currently, she charges batteries via the alternator and charges the fridge/freezer with an engine driven compressor. Neither works great. ( but she sails fantastic!)

We will be full time live aboard cruising, a family of 4. We want to have plenty of power and water. I plan to install frigoboat keel cooler CD fridge and freezer and we want a watermaker. Also, I plan to charge through means other than the main engine (Yanmar 75hp turbo).

I prefer a DC based boat with a large enough inverter to power any AC needs. We will have a large enough battery bank and I am in the early stages of designing the electrical system to meet our needs.

I am interested in a DC generator or charger system and watermaker combo. The Watermaker store used to sell these, but no longer does. Also, it seems that Balmar also used to make these but no longer does.

Anyone have any ideas or info or opinions?

Thanks!

Terry

[AnchorageGuy]

Some of our Aussie friends have been building these themselves so perhaps they can enlighten you.

[Whimsical]

Her's a comercial unit
Aquamarine, Inc - Home.
If you want to self build the watermaker side here is a start. The generator is just a normal alternator.
Watermaker

My barge is getting 2 20hp propulsion motors so one will do double duty to save wieght.

Mike

[AnchorageGuy]

I worry about web sites like Aquamarine that don't publish the price of their product anywhere on the site.

[Evan]

Aquamarine has a good reputation in the Pacific Northwest. I've had friends with their system and they are simple to use. Just send 'em an email and they'll send you their current price list. They do have boat show specials at times.

[Tspringer]

The Aquamarine unit looks perfect and the idea of a 150GPM bilge pump is very appealing. The modular capability should also make fitting it to our space restrictions easier. Sucks that they do not advertise any prices (and makes me think its a "if you have to ask you cannot afford it" king of product) but I will email them and post back what I learn.

A 150 amp alternator for charging AND a 62 GPH watermaker, coupled with plans for solar panels, wind generator and smart controllers plus a sized battery bank... we should only have to run it for an hour or so every few days to be good to go. Thats my goal, to not have to run the main diesel and to have plenty of power and water through as efficient a system as I can devise.


Terry

[Charlie]

Hi Terry:

I looked into the systems by the watermaker store and was thinking of going that way except that I already had a water maker and then the cost of cabling from the DC generator to the battery bank was quite expensive given that the acable had to be around 2/0 or so. I ended up buying a next gen genset that runs off of a small kubota engine and produces both 110 and 220. I will operate the watermaker off of an electric motor and then charge the batteries off of the 110. With this system I hope to not have to run the main engine much at all.

I know that this is not the question that you asked but I thought I'd just throw out some other ideas for you.

[Tspringer]

Thanks Charlie,

I did see the watermaker stores combo units on the web, but when I called them I learned that the company had recently been sold and the new owners were no longer making/offering the DC chargers / watermaker combo units.

Its likely to boil down to costs. If the Aquagen unit is $10K or something then no way do I go that route. After all... a modular built watermaker run off inverter powered by a portable honda is one possible cheap solution.


Terry

[btrayfors]

Terry,

Many of us have gone thru the same calculus. I had a 12V DC Kubota-powered diesel genset on my boat for over 10 years, and it worked fine most of the time.

However, there came a time when I needed (wanted?) to add air-conditioning to my boat. While it's conceivably possible to power A/C units from large inverters, it's not a great idea IMO. After much calculating and measuring and ruminating, I decided to go with a 115VAC generator, also Kubota powered. I chose the NextGen 3.5KW unit because it was the largest one that would fit in the space I have available.

It's been 3 years (and 3 summers and winters) now, and the generator has been great. It will power either of my two A/C units (one is 16,500BTU, the other is 12,000BTU) with ease, while having some leftover power for battery charging and other needs. In a pinch, it will power BOTH of the A/C units, but for a short time. I'd love to have a 5KW model, but don't have the room.

The generator also provides AC power for battery charger(s), hot water heater, and other appliances when needed.

I do have a big inverter/charger also (a Victron MultiPlus 2,500Watt model), and between the AC generator and the Victron inverter/charger I have a flexible and redundant setup which serves my needs very well.

OTOH, had I chosen to go with another DC generator, I would be totally dependent on the inverter for AC needs when away from the dock. No backup. No redundancy. That makes me nervous :-)

Bill

[Tspringer]

Bill,

Yup.... this is a tough choice. We also want to have A/C and I had planned to purchase a large inverter for this option. The boat already has a 1000 watt inverter and I thought to run another 2500 or 3000 watt as well. That way if one inverter failed there would be a backup (though not enough to run A/C if the biggie kicked the bucket).

I figure that while we want the boat to have A/C we would probably be most likely to run it either at a dock or only rarely when out in very hot weather. In any event, the hope is to not run A/C that much so it is a secondary consideration.

Water is a bigger issue. I know we will use a good bit. Power as well. So a big battery bank and multiple charging systems and a great watermaker are higher on the priority list than A/C. This is why I lean toward the DC genset / watermaker combo. But.... clearly I am VERY early in the evaluation process as I have not priced out this solution as yet.

Right now, the boat has about 250 gallons of water tanks. I still have to measure, but I am thinking of removing the 100 gallon tank under the port settee in order to create room for the genset, and watermaker and if I get lucky some battery space.



Terry

[Charlie]

Terry:

One of the things that I found useful was advice from people on this forum to just "use the boat for awhile." We've had our boat for 18 months now and some of the can't live w/o items are being taken off the boat and sold on Ebay. Other things that we didn't think we would need are being moved up the priority list. It was very hard not to put these things on the boat that I knew we couldn't live w/o but after using the boat for awhile I realized that I hadn't used them. Examples-- inflatable sea kayaks -- washer (was already on the boat) haven't used it. SSB (but we haven't gone off shore any distance yet)An extra Freezer. Haven't used the water maker yet either. In fact we've never used more then the 30 gal tank. Haven't touched the two 75 gallon tanks. Anyway just a thought that I wish I had listened to better. After sailing for awhile you'll find some things that you really need and you don't want to blow your budget right at the start.

[Tspringer]

I hear you.... and agree. But after 8 days aboard, we already know we do NOT want to have to run the main engine to charge batteries and the fridge! I hate listening to that thing.

Terry

[btrayfors]

Charlie,

Right on! Excellent advice. Ignore at your peril :-)


Terry,

Let me get this straight....you're thinking about removing a 100 gal water tank so you can install a watermaker?

OK, so there's a generator attached to it. But isn't this just a little ironic?

Bill

[Charlie]

You'll figure it out I'm sure. I understand the not wanting to use the engine. My rational was that a repower is a $15k and up affair where as a genset is as little as $2k for a honda generator to $4.5k for a genset like Bill and I have. I figured that the genset was more practical then the Honda but it would have saved me alot of money. The AC was a consideration as well as keeping the amount of gas onboard to a minimum. I think the calculus is boat specific so there is no really good way to say what is best. Oh BTW if you get a genset think about getting the quiet case they come with b/c mine is in the engine room and more noisy than the big engine.