120 VAC to 12 VDC water heater conversion anyone?

C

Captain Starbucks

Member
Hello Brats,

I'm reaching out to see if anyone has converted their electric water heater from 120 volts alternation current to 12 volts DC? I see some vanlife people have done this for more self contained camping.

Anyway, I see some 12 volt heating elements that would fit my water heater. I'm not expecting a luxuriant shower experience, but anything higher than lukewarm would be outstanding.

The element part is self explanatory, I was just wondering mostly about the circuitry to control temperature.

After going to the boat show and seeing prices go almost double in the last 4 years, I'm committed to owning this boat forever. Might as well make her a palace!

Rob
 
Hi Rob,

Unfortunately it's not that simple. 12V would require a lot more amps and heavier wiring back to the batteries etc etc. Running any resistance type heater or air conditioner off 12V is a fool’s errand (apologies to Fluid Motion).

In 11 years of couples cruising on our TC255, we find the simplest solution is best…1 pound cheapo propane bottles fuel a $19 2 burner Coleman stove, SS camper percolator coffee maker and Little Buddy cabin warmer (while awake).

Pour the boiling water from the percolator (w/o coffee) into a collapsible wash basin, add cold water to taste, and do a ‘basin bath’ in the privacy and relatively lots more room in the cabin (compared to crouching on the head with a HH shower).

However, don’t treat propane bottles on your boat lightly…fashion a PVC pipe storage unit that you hang OUTSIDE, on the engine bracket, so that any leak could not possibly get into your boat.

Grand Total cost including three Coleman bottles, Little Buddy, SS stove and best SS percolator under $115. Compare that to other options I hope you receive.

https://www.amazon.com/Collapsible-Fold ... 5056&psc=1

https://www.amazon.com/Mr-Heater-F27320 ... RGRG&psc=1

Best of luck and Safe Travels!

John
 
Thanks for the response GC John. I appreciate the words of wisdom and experience.

I will take your advice. I already have those things anyways so that'll be cheap and easy.

I'm considering a small onboard water maker and was thinking with full fuel and an endless supply of freshwater, the only thing missing on longer term trips is hot showers but you've solved that. Now to just decide if the water maker is worth it....

Rob
 
Unless you are going to Mexico, or similar areas, I would not consider a water maker. I have owned several but on boats greater than 45 feet. There are some 12 volt water makers which run well. But they use a moderate amount of power and take up a fair amount of room. Watermakers should not be used in harbor with possible oil or sewage in the water. They really have to be used regularly, or you end up replacing the membranes frequently.

We took out the 6 to 11 Gallon water heaters, and put in 2.5 gallon under the sink area. This gets rid of the "dead" space in the lines, which wastes a lot of water. I have used the shower in Tom Cat and CD 25--but more often use the basin of hot water (heated on stove) and then a quick rinse off with the shower. There is also the "sun shower" route which I have used in the cockpit of boats, or even in a 3' x 3' enclosure.
 
We carried a Honda 2000W Inverter generator on our 255 TomCat. Kept it in the front starboard sponson, under the bed until needed. I put it on the swimstep, exhaust pointed aft to operate. Hot water in 15 minutes. Two could shower, one after the other. We often cruised for up to 3 months at a time with the generator aboard. South East Alaska. Never a problem. Just nice to have 120 AC aboard when desired.

We also used the Sun Shower when in Mexico, Florida or Lake Powell. Where the sun actually would shine.
 
Captain Starbucks":30ycoigg said:
I'm considering a small onboard water maker...
Click to expand...
I'm planning on something like this unit, which takes up very little room and does not need to be permanently mounted.
https://seawaterpro.com/products/micro-water-maker

As Bob stated, you need to start with relatively clean water, not what's found in a typical boat harbor. Pump sea water in from one side of the cockpit, and pump the brine over the other side. According to the mfg. specs, 15Ah should deliver five gal. of fresh water. That's their ideal specs so double that and safely assume 30Ah for at least five gallons. Not a luxurious amount, but it will do my wife and I for two days. You also have to plan on regular useage, flushing, and maintenance like replacing filters, etc. If not used at least once a week, they need to be pickled (filled with something to keep bad things from growing) and then flushed before using again. So maintenance and proper care is no little thing for these devices, but if you are exploring and boondocking in remote areas, they make total sense to me.
 
Rob/Capt Starbucks,

Discovery crew Brent & Dixie make an excellent point re using a Honda suitcase generator for 110v power. Waypoint crew finds the new Honda 2200 will even power a 15k BTU Coleman rooftop AC like ours (though our ancient Honda 2000 won’t, 10k BTU is about the limit).

Although we choose not to use any portable generator on the boat, many Brats do and have, including Dr Bob.

We have learned from and copied MANY of Discovery’s cruising techniques over the years. Credit to them for this alternative (although it’s fair to say that even the old Honda 2000 retails for considerably more than $115 all in).

Bahamas cruisers seem to agree that these days marina water is safe and cheaper overall than watermaker expenses, unlike in prior times. I suspect that in Mexico some silver bars can get you clean water if you need it. Or even a stack of $20 US cash bills.

Cheers Discovery crew!
Hope to meet them someday.
Safe Travels everyone!

John
 
You guys are great. Thank you for all the great tips. I think I'll take a mix of the ideas provided.

We have a house that is 120 years old and is heated by a boiler. We don't often lose power where I live in the PNW, but I can't have those pipes freezing. I've been toying with the idea of getting a Honda EU2200i for a bit. We also dry camp a lot with our travel trailer that does not have a generator. We've always been fine without it, but would be a nice-to-have feature.

So, all signs point to a generator.

Dr. Bob, did you have the Bosch 2.5 gallon instant hot water heater? I run my boat very heavy in some pretty terrible ocean conditions here with full camping gear, big game fishing gear, and fuel for 100+ mile days in the ocean. I'm always trying to make it lighter so considering now getting rid of the 6 gallon tank, replacing with the Bosch 2.5 and getting the 47 lb Honda generator. Should be close to a wash weight wise.

Thanks again,

Rob in Tacoma
 
thataway":336d6qge said:
Dr. Bob, did you have the Bosch 2.5 gallon instant hot water heater?
Click to expand...

Yes, We did the change. The cats really do better when light. Plus you open up a good storage area.
Click to expand...

Thanks for that.

I was considering putting it outboard of the Wallace stove, drilling holes through the outside of the boat and mounting it internally obviously, but holes penetrating the house wall. I'm concerned the material there isn't structurally sufficient to support about 25 lbs bouncing around. Only considering that to keep the previous water heater area 100% open.
 
thataway":3jf9rrpe said:
Dr. Bob, did you have the Bosch 2.5 gallon instant hot water heater?
Click to expand...

Yes, We did the change. The cats really do better when light. Plus you open up a good storage area.
Click to expand...

Bob,

Did you put the Bosch in the same place as the old water heater? I found some space just forward of the Starboard fuel tank next to the shower sump that might work. It's going to be a challenge getting it in there, but out of the way.

Rob
 
Bosch water heater outboard of the faucets of the galley sink. We made a shelf, supported on the aft bottom, with a leg to the already mounted main shelf. Forward a cleat on the bulkhead aft of the "helm seat", shelf glued on that cleat. Straps (white, so hard to see) from a block glued on the hull, to the bulkhead aft of the helm seat.

DSC00441.sized.jpg
 
Howdy,
i use disposable LP cylinder refill adapters with great success. If I could figure out how to add a link, I would....

DNFH
 
Update on my decision. I actually ordered the Bosch 2.5 gallon heater and received it. I decided it wasn't worth installing for my use case for the few pounds it would save. What I did do though was change up some of the plumbing on the original water heater I reinstalled. I added an intake valve and a much higher quality and easier access drain valve. That way, I can simply shut off the intake water side when I leave the dock and still leave the water pump on, and at the same time, open the drain valve and pump most of the 6 gallons and 48 lbs overboard.

The 6 gallon tank itself doesn't really weigh that much empty. And this way, I can choose to run it empty, or heat it up at the dock and take 6 gallons of hot water with me. The risk though is forgetting it's empty and turn on a heater on an empty tank, but I generally put my landing gear down before I land so I'm okay with that risk.
 
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