How do you heat your water with an electric engine?

[Rohan]

Just curious - those who have switched their engines from diesel to electric, is there another option for heating your water?

I suppose if you still have a marine diesel generator, you could heat the water though that, although it wouldn't do the job as well. You could also use your battery power to heat the water too, but that would drain your batteries pretty quick. So I'm wondering, are there other solutions out there?

[dougweibel]

On boats with a fair amount of solar it is not uncommon to change out the 120V water heater element for a 12V element which is typically powered from the 'load output' of a solar controller. This allows the solar to charge your batteries first and then to direct excess energy into your hot water heater. When things are sized properly on most days you have excess solar energy available while your batteries are going through their absorption and float charge stages and that heats your water. A similar arrangement is available for wind power.

[Tomodore]

Guess i’ll depend where you cruise and your individual solar electric set up. On our 34’ boat on the west coast of Mexico we only have small engel fridge and not much excess solar power, if water gets heated it is in solar shower on deck or propane on stove.

[thinwater]

On-demand propane heaters are pretty common. Must be vented outside.


That is how the PDQ works (outboard engines--same problem).

[Dockhead]

How they DO do it, I don't know, as I don't have an electrical boat.

How I WOULD do it, however, I can tell you -- I would have a hydronic furnace and I would have a tank for kerosene/jet fuel/light heating oil/diesel fuel. Get your space heating the same way.

If you're going to burn something, which is about the only way you're going to do space heating on an electric boat, and will be about the only way to heat water, too, unless you're in a very hot and sunny location, then much better to burn some kind of oil, than propane -- it's far safer, far easier to store, far easier to obtain and get onto the boat, cheaper, lighter (because the tanks are lighter and larger).

[GRIT]

Originally Posted by Dockhead

How they DO do it, I don't know, as I don't have an electrical boat.

How I WOULD do it, however, I can tell you -- I would have a hydronic furnace and I would have a tank for kerosene/jet fuel/light heating oil/diesel fuel. Get your space heating the same way.

If you're going to burn something, which is about the only way you're going to do space heating on an electric boat, and will be about the only way to heat water, too, unless you're in a very hot and sunny location, then much better to burn some kind of oil, than propane -- it's far safer, far easier to store, far easier to obtain and get onto the boat, cheaper, lighter (because the tanks are lighter and larger).

We don't have electric propulsion, but seldom use our Diesel engines either. One of our diesels has an alternator, which requires a special key to energize, as we almost never charge the lithium batteries with the alternator; and neither of the engines are connected to the hot water system. (The alternator is for emergency backup use only.)

We are a 100% solar charged, boat; and do as Dockhead said. We heat the water with Hydronic and the living space with air heaters. In hindsight, we'd have used hydronic to heat the living space too; but we already owned the air heaters, which were used heat our infusion table.


Cheers.
Paul.

[Ded reckoner]

We don't have an electric boat. But, we've configured the hot water heater to run only on 120V electricity. There is no hot water circulation from either the engine or the diesel generator. This system runs nicely at the dock or when the diesel generator (used on anchor on cloudy days) is running. Also, we have 880W of solar and a wind generator. Unfortunately, our battery bank is relatively small. But, on nice sunny days at anchor, we can heat the water for a certain amount of time using the inverter. As was mentioned above, the drawdown on the battery bank is significant because the hot water heater is a 1500W system. Often, the batteries will be fully recharged within an hour and the same heating cycle can be applied, if we need the water hotter. This system has worked well for a year, so I don't think we'll change it.

[seandepagnier]

Originally Posted by Dockhead

How they DO do it, I don't know, as I don't have an electrical boat.

How I WOULD do it, however, I can tell you -- I would have a hydronic furnace and I would have a tank for kerosene/jet fuel/light heating oil/diesel fuel. Get your space heating the same way.

What is the point of the electric boat if you burn diesel fuel? This is completely backward way of thinking shows lack of innovation, and essentially misunderstanding of use of energy. Your suggestion to use fuel doesn't pay for the true cost of the fuel, otherwise it would not be affordable compared to alternatives. Suggesting using fuel is essentially suggesting it is ok to not pay the price, which is actually stealing as you deprive others from the world you inherited.



1) evaccuated solar tube. This makes super solar oven as well as can boil water in freezing. With one of these rigged up, it is smaller than a 30 watt solar panel but could give you gallons of hot water in little time most of the time for shower etc. This is like steroids version of solar shower which works even on partial overcast/windy/cold weather.



2) wood stove. This is how you can have space heating and water heat in the winter or overcast/raining. It takes about 10 pinecones to make a hot shower.


3) wind turbine. I have powered a small electric space heater (thru inverter) from a wind turbine in 25knot winds. With backpacking heat pumps available at 250-600 watts and huge battery capacities, this could be even more efficient than ever.


4) electric water heater. This doesn't use too much power if you ensure it is in a vacuum insulated container. A huge waste of hot waters is heating the water hotter than it needs to be and/or not using immediately after. The specific heat capacity of water is 4,200 Joules per kilogram per degree Celsius, so if you need to heat the water 25C and have 2kg (enough for shower) then a 60 watt solar panel can do this in 1 hour. It's not a lot of power.


5) shower loop. This recirculates the water through a filter saving water as well as the energy to heat it. This is really the ultimate option, but I am still investigating using multiple vortex filters to separate oil as well as debris.. so lets hear from others as this option I have not managed to construct yet.





burning fuel is cheating because it's taking advantage of the world's most vulnerable people, the same people who contribute to the problem the least. It's like stealing from a child, or pushing an elderly person out of the way just because you don't want to change and do things a different way. well the choice wont be forever, and the less people who do the right thing now, the worst the consequences in the future for everyone, and in the future governments may just close down cruising (like saudi arabia) if most of the people doing it are part of the problem there will be no choice.

[JC Reefer]

Aren’t some electric motors water cooled? You could heat the water using a heat exchanger just like we do with a diesel?

[Dockhead]

Originally Posted by seandepagnier

What is the point of the electric boat if you burn diesel fuel? This is completely backward way of thinking shows lack of innovation, and essentially misunderstanding of use of energy. Your suggestion to use fuel doesn't pay for the true cost of the fuel, otherwise it would not be affordable compared to alternatives. Suggesting using fuel is essentially suggesting it is ok to not pay the price, which is actually stealing as you deprive others from the world you inherited.

1) evaccuated solar tube. This makes super solar oven as well as can boil water in freezing. With one of these rigged up, it is smaller than a 30 watt solar panel but could give you gallons of hot water in little time most of the time for shower etc. This is like steroids version of solar shower which works even on partial overcast/windy/cold weather.

2) wood stove. This is how you can have space heating and water heat in the winter or overcast/raining. It takes about 10 pinecones to make a hot shower.

3) wind turbine. I have powered a small electric space heater (thru inverter) from a wind turbine in 25knot winds. With backpacking heat pumps available at 250-600 watts and huge battery capacities, this could be even more efficient than ever.

4) electric water heater. This doesn't use too much power if you ensure it is in a vacuum insulated container. A huge waste of hot waters is heating the water hotter than it needs to be and/or not using immediately after. The specific heat capacity of water is 4,200 Joules per kilogram per degree Celsius, so if you need to heat the water 25C and have 2kg (enough for shower) then a 60 watt solar panel can do this in 1 hour. It's not a lot of power.

5) shower loop. This recirculates the water through a filter saving water as well as the energy to heat it. This is really the ultimate option, but I am still investigating using multiple vortex filters to separate oil as well as debris.. so lets hear from others as this option I have not managed to construct yet.

burning fuel is cheating because it's taking advantage of the world's most vulnerable people, the same people who contribute to the problem the least. It's like stealing from a child, or pushing an elderly person out of the way just because you don't want to change and do things a different way. well the choice wont be forever, and the less people who do the right thing now, the worst the consequences in the future for everyone, and in the future governments may just close down cruising (like saudi arabia) if most of the people doing it are part of the problem there will be no choice.

Well, that's the extreme and purist point of view. But I would suggest that you can do more good for the environment or against climate change with one well-written blog post in favor of nuclear power which contributes even one iota to dispelling ignorance about that, than a lifetime of not heating water on a boat with kerosene. This is a microscopic footprint.

And if you want to maintain 100% purity, just use 100% bio fuel in your hydronic furnace and Bob's your uncle. Here is an example of 100% bio (B100) heating oil: https://sippin.com/heating-oil-propa...-heating-fuel/

The methods you describe will not work well in any combination of (a) high latitude, cold climate; (b) more than one or two people on board; (c) boat which has no space for kilowatts of solar power. None of them would work for me -- I cruise sometimes in sub-freezing temperatures, so space heating can be life and death.

Burning wood is not all that environmentally good and it's a big PITA on a boat in terms of storing and handling the fuel.

So in sum, I would say even for the extremely environmentally conscious, liquid fuel is the way to go.

[sail sfbay]

Originally Posted by Rohan

Just curious - those who have switched their engines from diesel to electric, is there another option for heating your water?.........

My sailboat water is heated with 110 volt electric heater and my powerboat water is heater with a diesel space and water heater or 110 volt electric heater.

[patrickbarbary]

I saw an answer including solar and wind. My understanding is that there is one big difference between to two. When solar power is in excess, you can simply shut the input without damaging the panels. As to the wind power, the excess MUST be used/burned somehow to avoid damaging the turbine. And an heating element in the hot water tank does perfectly serves that purpose.

[moseriw]

Rub your finger tips or take the bucket in the sun. What a pitty - no sun! But I drive all electric with SOLAR.

[Rohan]

Originally Posted by Ded reckoner

We don't have an electric boat. But, we've configured the hot water heater to run only on 120V electricity. There is no hot water circulation from either the engine or the diesel generator.

I am curious, why would you configure your water heater that way? If you use your diesel engine or generator anyway, then the heat from those engines is basically a free by-product, you might as well put it to some use through your water heater.

[Brewgyver]

Originally Posted by Dockhead

Well, that's the extreme and purist point of view. But I would suggest that you can do more good for the environment or against climate change with one well-written blog post in favor of nuclear power which contributes even one iota to dispelling ignorance about that, than a lifetime of not heating water on a boat with kerosene. This is a microscopic footprint.

And if you want to maintain 100% purity, just use 100% bio fuel in your hydronic furnace and Bob's your uncle. Here is an example of 100% bio (B100) heating oil: https://sippin.com/heating-oil-propa...-heating-fuel/

The methods you describe will not work well in any combination of (a) high latitude, cold climate; (b) more than one or two people on board; (c) boat which has no space for kilowatts of solar power. None of them would work for me -- I cruise sometimes in sub-freezing temperatures, so space heating can be life and death.

Burning wood is not all that environmentally good and it's a big PITA on a boat in terms of storing and handling the fuel.

So in sum, I would say even for the extremely environmentally conscious, liquid fuel is the way to go.

+1
Very well put. Let's see, what will I have to leave behind in order to have a dedicated "pine cone locker"...