DIY water heater?

Francisco Manuel

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Mar 17, 2021
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Es barato 86€ 3500w capacidad


 

LanduytG

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Use your vehicle motor along with a flat plate heat and a surflow water pump and a mixing valve and your done. No need to complicate things.

Greg
 

geoffire

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Use your vehicle motor along with a flat plate heat and a surflow water pump and a mixing valve and your done. No need to complicate things.

Greg
Do you know anything about sizing? Like would a somewhat cheap exchanger like this one work? (5" x 12" 50 Plate). My main 15 gallon tank does have a spot for a heating element so I could heat that up to something like 80F so the normal water won't be cold (at least after it's had the chance to heat up).

edit: I realized I could use the plate to heat the water I feed into the tank as well, so the little element will only have to keep warm.
 
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Luthj

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That 50 plate is way bigger than you need. A 10 plate will work just fine.
 

geoffire

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I found Scintex has some good info on their site. They recommend a 30 plate for showers (smaller plates than the one I linked before). This one on amazon looks equivalent to their almost boiling "washing dishes" one and is $66. Might as well go overkill as it's a rather small weight and coin difference. I only wonder how likely a cheap one is to fail and mix fluids however...
 
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Luthj

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You need flow in both loops to get heat transfer. So the engine running and a fresh pump.
 

LanduytG

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Also be sure to counter flow the loops. You don't need a tank other than supply water. Water out of the plate will go direct to the shower or faucets. Sportsmobile has been using this method of heating water for years. I would also use a double wall flat plate so if one side ruptures it will not get anti freeze on the domestic side.

Greg
 

geoffire

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You need flow in both loops to get heat transfer. So the engine running and a fresh pump.
I was wondering about the flow. This is a large SUV, do you think the run to the rear heater core sufficient? (I understand that might be a hvac controlled valve somewhere but I plan on hacking that anyways).

I would also use a double wall flat plate so if one side ruptures it will not get anti freeze on the domestic side.
Rupture due to freezing or is that something you've seen otherwise? (I'm socal based so freezing isn't much of a concern) An intermediate loop adds a bit of complication, but decoupling would allow going the other direction as well - When in hot places cold charging the main water tank with the AC while we drive and use that much like do with the heating system at night 😎

What do you use in that intermediate loop? Something non-toxic yet growth inhibiting and anti-freezing ideally.
Edit: I see there is Non-Toxic Anti-Freeze for winterizing RV water systems. I'm guessing that would work well.
 
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Luthj

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Most water systems of this type are always pressurize to around 30 PSI. In cases like that the freshwater flows into the coolant not the other way around. As far as poisoning yourself, you definitely won't be able to drink water even if a small amount of antifreeze gets in. It contains a bettering agent which is quite potent.

Coolant flow to the rear heater core loop should be fine in most situations .
 

dmitrimedina

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Feb 16, 2021
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Hi, I'm building an overlanding vehicle for our family of 4 and need the ability to somewhat regularly take hot showers. I'm looking to go fully electric and don't see anything on the market that would work well. There are small electric water heaters and small "instant" electric water heaters, but none of those have the ability to actually shower multiple people from non already quite warm water at reasonable power levels. Plus they are 30a 120v (or even larger 220v) so I'd need to run a very large inverter for no real reason (2000w is enough otherwise).
Here's my thought: ~3600 watts of DC heating elements in a homemade ~2 gallon hot water tank. I'm specing the electrical system (for the whole vehicle) still and currently leaning 12v, so 6 of these would do the job https://www.amazon.com/gp/product/B0182BETBE, or if I go 24v 4 of these https://www.amazon.com/gp/product/B0182BETBE. Likely I'd set it up so one element is used to maintain temp normally, but I can disable the inverter and enable the full power when we take showers (likely all of us one after the other after a hike or whatever).

I have 16 280ah EVE type cells on the way, so can power it (with ~4800 watt bms and less than 1000w peak of non-inverter powered load). Max power is quite a lot (especially for 12v), but it's only every other day or so for a short period of time and the wire runs will be very short.

Seem reasonable?
Thanks,
Jeff
I have this and it’s better because you won’t need a water tank and you would have hot water every time you shower or you Can just disconnected when you don’t want hot water BFB06E3C-32D1-4FF1-9123-D6B49CFE4BF5.jpeg
 

alfaeric

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Hi, I'm building an overlanding vehicle for our family of 4 and need the ability to somewhat regularly take hot showers. I'm looking to go fully electric and don't see anything on the market that would work well. There are small electric water heaters and small "instant" electric water heaters, but none of those have the ability to actually shower multiple people from non already quite warm water at reasonable power levels. Plus they are 30a 120v (or even larger 220v) so I'd need to run a very large inverter for no real reason (2000w is enough otherwise).

I have this and it’s better because you won’t need a water tank and you would have hot water every time you shower or you Can just disconnected when you don’t want hot water View attachment 41593
We really considered getting one of those. Especially since we go to Puerto Rico pretty often (and, ironically, the Home Depot in Ponce). The house we got to uses one, and it works. The issue we had was packaging it into our tiny shower... Maybe next time.

Although, the power requirements also made us pause- IIRC, it would need a 25A circuit. Not impossible, but everything would be turned off when taking a shower for a 30A shore plug in.
 

Peterbylt

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Oct 20, 2020
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I have found this topic interesting, I have been contemplating something similar as I build the Solar System in my Bus conversion.

One of the central components to my solar build is the SBMS0 by Electrodacus https://electrodacus.com/

One of the things he has added to this BMS and solar charger is the concept of Diversion.

When you are charging your batteries, hopefully at some point the batteries become fully charged and the charge controller stops charging the batteries from the solar panels, the panels are still producing electricity that basically gets wasted.

What diversion does is channels that unused electricity to some other task.

In my case I would like to channel it to a hot water heater and basically get hot water for free.

I am thinking a well-insulated 20 gallon tank with one (or more) of the 24 volt heating elements.

https://www.amazon.com/gp/product/B0182BETBE

My system will be 24 volt with 280ah of Lifepo4 batteries, to start I will have 6 250 watt panels for a total of 1500 watts peak power.

The panels will be wired with 3 sets of 2 panels in parallel using 3 of the Electrodacus DSSR20 with diversion.

If the Tank is well enough insulated it should keep us in hot water for most of the day, I currently have an 8 gallon Bosch hot water heater that works quite well for our purposes when we are plugged in.

http://amzn.com/B0148O658Y

With the amount of people you have wanting showers in a short amount of time, this might not be feasible for you.

I have not yet devised a plumbing plan that could take advantage of both the Bosch and the diversion hot water, I am open to suggestions.

Peter
 

Hendo7

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Arizona
just a thought,
i use a 20 electric water heater as a pre heat my house main electric water heater,in the 20 gallon i use a Dernord 24v,/300 watt element set temp about 160 degrees my main water is set around 100 .
the preheat water heater takes most the morning to heat up but the hot water heating is somewhat free.
on you Rv you go with a 20 set like and solve you water storage at the same time , providing you have the room.
good luck on your projects
 

Hendo7

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missouri wind and solar seemed to have it figured watch their video on there web site (sorry no linky) i personally wouldn't fo what hes doing for safety reasons, talk about hillbilly rigging
 

curiouscarbon

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Jun 29, 2020
Messages
1,805
Hi, I'm building an overlanding vehicle for our family of 4 and need the ability to somewhat regularly take hot showers. I'm looking to go fully electric and don't see anything on the market that would work well. There are small electric water heaters and small "instant" electric water heaters, but none of those have the ability to actually shower multiple people from non already quite warm water at reasonable power levels. Plus they are 30a 120v (or even larger 220v) so I'd need to run a very large inverter for no real reason (2000w is enough otherwise).

Here's my thought: ~3600 watts of DC heating elements in a homemade ~2 gallon hot water tank. I'm specing the electrical system (for the whole vehicle) still and currently leaning 12v, so 6 of these would do the job https://www.amazon.com/gp/product/B0182BETBE, or if I go 24v 4 of these https://www.amazon.com/gp/product/B0182BETBE. Likely I'd set it up so one element is used to maintain temp normally, but I can disable the inverter and enable the full power when we take showers (likely all of us one after the other after a hike or whatever).

I have 16 280ah EVE type cells on the way, so can power it (with ~4800 watt bms and less than 1000w peak of non-inverter powered load). Max power is quite a lot (especially for 12v), but it's only every other day or so for a short period of time and the wire runs will be very short.

Seem reasonable?
Thanks,
Jeff
Hi Jeff,

I admire your intent to provide hot showers in a renewable fashion. Very fashionable.

Lots of people have great advice about how to follow up with high power heating elements, and I do think that's the quickest way to meeting the immediate needs of four people, so keep with it!

I too want to efficiently provide access to heated water, and have been searching hard for a solution with few pain points. It's challenging.

I want to mention another source of heat that might or might not be viable for your situation: pumping heat from the photovoltaic panel backing. Have not seen any commercial offerings of this yet, so I'm just kinda hacking around at small scale to learn for now. The photovoltaic solar panels will only provide a low grade heat, which is why I consider peltier or compressor/refrigerant heat pump to be mandatory for this type of application to work. Fun fact: peltier is always more efficient at heating water than a normal resistive element because it's using Joule Heating and Peltier Effect instead of only Joule Heating. Also, another fun fact, some peltier elements are able to achieve CoP of 2-4 when operated at low voltage, dependent on temperature ranges, and can be stacked to sum their heat pumping abilities.

Anyways, to overcome the issue that the backside of the solar panels isn't directly hot enough for a shower, I propose having one coolant loop that runs to the backside of the solar panels, and goes into an aluminum or copper water block that interfaces with a stack of peltier elements. On the other side of this stack of 4-10 peltier elements is another aluminum or copper water block that interfaces with your hot water shower tank. Basically an arduino would pump heat out of the water loop touching the back of the panels and into the water block and pumped into tank. Again, not aware of a commercial offering that does what I'm describing, and I would certainly be buying that instead of engineering it myself if I could avoid it 😅

1628587273528.png
 

Solarfun4jim

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Sunny Scotland
I adopted a different strategy for showering...so this is no help whatsoever to your project, simply a different way of thinking about issue.
I like to take long showers after a hike, but wish to keep power consumption and water use to an absolute minimum. I therefore use a recirculating pump in the bottom of the shower tray. I heat water in my microwave and blend with cold to get the desired temperature(2litres). Since i am simply trying to remove sweat, there is no real need to use harsh chemicals or soaps...a simple sponge suffices. It does mean however the hot circulating water soothes the aching muscles etc and basically you can remain in the circulating shower water till it cools down. You can always take in water at a higher temp and add it to the circulating mix if you wish to remain in the shower longer. Some people scoff at showering in their own recirculating water, but don't bat an eyelid taking a bath....go figure!!!

If you really must use soap/shampoo etc, then you can use a two step method whereby you have two containers of water...the first is used to wash, then empty the shower, then the second is used to rinse. Lets face it, in modern life we tend to get sweaty rather than really dirty, so a good long shower with a sponge is a treat after a long hike, rather than a two minute whizz.
In between each person showering, a solution of milton is cycled through, to keep things germ free. The less soap that is used, the cleaner running the system.

I am all electric with no gas heating of any sorts...so need to make max use of my 740W solar PV... i'm forced to stay frugal. :)

Just an alternative thought.
 

EddieM

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Joined
Sep 19, 2020
Messages
36
I have been looking at making my own water heater using 12 volt power to run it.
I want to get a 6 gal house water tank and then change the elament to a 12volt elament this way it all has all the hook ups and everything.
The Down side is a 6 gal house water heater tank cost a lot now days over $300 i have been pricing them.
I have been trying to find a used one to get.
Or i can use somethign else to make one.
I will be running 1200 watts of solar and 412AH of lithem.
Looking to use a 700 watt 12v heating elament.

We would just turn it on 40 min or so in advance when needed for a shower in our Truck.

I also want to come up with some way to use the trucks solar power every day at home when we are not using the truck to travel. I will put a ELC plug on the truck to plug into to bring power into the house or for any outside use.

Thinking about making a much larger version for our home for a second system i am working on to run a small freezer and small fridge for power out protection. But when we have no power out i could be running a heater elament with all the solar every day to heat up the water heater for use to shower every day.
With how we work we shower around 4pm every day so it would have most of the day to heat up the water slow over time. Sort of a solor over flow to use to power the water tank.

I found this place that sells the real 12 volt elaments and all the parts needed to build one from scratch even a elament thurmastate set to a temp you want. Or a elament with the thurmastate built in it.
https://windandsolar.com/dc-water-heating-elements/
 
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