is that the right link : Solar Direct Hot Water Controller - $259.95 for whats on there and what it needs to do, it can be made for $15, thats a real good mark up
The panels are not the problem. I have heated water with direct DC from panels to elements before. The problem is twofold. DC arking with destroy the thermostat ( controller eliminates this) and MPPT maximizes the performance of the panels during the morning and afternoon.
Hey Scott, would this MPPT controller work with my 400 watt wind turbine to do the same thing? Is that low of wattage even worth trying to heat a 4500 watt element?
Engineer775 good afternoon quick question I understand the concept of the MPPT controller, what can or type of thermostat should be use to prevent Early death of the thermostat due to the fact we are using DC instead of AC and the Affects of the arcing
How does your MPPT stop dc arcing of the thermostat? As an Elec eng, I would buy an Omron 20A DC solid state relay, ($15) and use the how water service thermostat to trigger the dc solid state relay. Then infinite life of your contacts.
I did the same, but I took the DC direct from the panels to a dc solid state relay. The relay is turned on and off by the thermostat. The solid stare relay is 4-24v dc to trigger so I used a 12v plug pack to provide the trigger current. Works flawlessly. Also 4 panels but 275 watts each.
As a company that designs MPPT's, this is a nice little device and so much better than the expensive Sun Bandit. Because everything is staying at high voltages (~152Vdc), it can be small/efficient/cheap. And it can be MPPT without large components (like 48V systems). They have to constantly pulse/break the DC output at 60-300Hz to mimic AC zero crossings that will not burn up the AC thermostat (you might want to verify that). Off Grid hot water heating is really challenging. Our company has looked at so many different ways for our customers including thermal heaters. Most Off Grid folks have big arrays of panels. It would be nice to be able to dump excess panel energy into the water heater instead of having dedicated panels. But otherwise, this is a nice simple/reliable solution. Thanks for sharing Scott.
Can’t a 2-way switch direct power either to the controller or to a separate charger for the batteries? It would require manual switching but at least power can be redirected.
There Brilliant, I have had one of these for about 12 Months. On a second hand ($100) 315 Liter twin element Unit, I wired it to the top tank element first and then it swaps over to the bottom element via the thermostat wiring, when the top tank is up to temp it then starts on the bottom large section. In this configuration its recovery time is a lot quicker. I have 4 X 250W panels in series and both elements are 4.8KW. It works great and have never run out of hot water in our off grid weekender. Well worth the investment as it only needs light, the Evacuated tube Hot water units are VERY expensive and not good in very cold conditions. The Heat Pump units are good, Very expensive and have climate limitations although you could use this to connect to the backup element in some heat pump units.
I used a secondary hot water tank with about 900w solar panels to supply the main tank with pre-heated water. I rewired the elements in series to eliminate a controller. This way both elements heat at the same time and don't cycle between the upper and lower elements. For the most part, each 12 panel operates around 17 volts. When there is insufficient solar energy, the grid keeps up. I also benefit from some ambient heat to pre-heat the water in the dead of winter when solar is almost non existent.
I use real direct water heating, without a regulator. A bit of simple mathematics (ohm's law) and selection of a suitable cartridge (heating element) designed for PV. There is also a choice of pipe thread or reduction so that you do not have to buy a new boiler. The thermostat must never be connected directly to DC. I bypassed this with a much smaller solar field (a cheaper solution) so that the temperature reached 60C in winter or under clouds and around 80C in summer.
I have had one of these for two years now. It lowered my electric bill almost 40 percent. The upper element does not come on during the summer, and often, the lower element turns off too. Thinking about replacing the lower thermostat with an upper thermostat and divert excess dc to a small preheat tank. I am using 960 watts of panels.
It seems to me that one could simply run wild solar power into the element and then use a DC relay with an ac actuation coil to shut off the solar wattage when the thermostat says stop. I know you want to sell the controller, but any comments? Thanks
That exactly the way I set mine up. 6-175w 35v x 5a panels, using a 36v 1200watt DC element (Amazon 25 bucks) Tank is a dual element, 28gal I use in a shop bathroom. Solar keeps the tank plenty hot enough for hand washing/paint brush rinse/etc, and if I need more hot water for an extended use, I flip the upper element on to use 120vAC power. Panels to combiner box to breaker (SqD QO 40a SP) to 36v 1200w heating element mounted in the lower hole. Used the original thermostat that came with the water heater, ran 12vDC from an old 'wall wart' (hasn't everybody got a bag of them laying around ?) thru the thermostat to a 12v 120a amp relay (Amazon, 15 bucks) with the solar positive connected to the relay in/out. My understanding is AC thermostats that come on standard water heater will NOT take the full DC current (for very long), so you can't wire them direct.....but using the wall wart (just a few milliamps) to control a relay, it works just fine. Water heats to temperature set on tank thermostat (I use 140), relay drops out and no more power from panels to heating element. Dead simple....no circuit board controller to go buy or go bad. I also added a small 12v LED read out thermostat with a K type probe that has 1/2" male pipe thread on probe end, screwed into a female adapter in a T on the tank outlet line so I can easily read the tank outlet temperature (25 bucks/Amazon). The 12v power for this comes from the same 12v wall wart that runs the relay above. Works like a charm.
@@RRaucina Working out great for me so far. I bought a spare relay to have on hand in case the 1st one dies, but with 120amp rated contacts, I'm thinking it should last a long time. Based on how well this one has worked out, next project is a setup using a larger 200 liter tank as a pre-heater for my house propane water heater. Hope to cut my propane use considerably.
It is shocking the number of people that never think about what can be run/converted to DC to not touch an inverter. From a PC all the way to TV's you can find models that take 12vdc directly for direct drive from PV or from batteries. Did you use thermal paste between the controllers plate and the metal box? Now to find a NG/LP water heater that can take a DC element to have all bases covered.
A lot of MPPT controllers have a load +/- output as well as for charging the batteries, so its a good use of extra power when not charging up the batteries to root it instead to a water heater.
Vert nice setup. Could a system like this be modified to work with a propane water heater? I would be interested in a followup in a week or so running this system off grid. How long does it take in the morning until this comes up to temp?
a gas heater won't have electric heating element's in it. I suppose you could install a second heater feeding into the gas heater to pre-heat water going in. If your going that route it's probably cheaper and more efficient to heat water with sunlight directly rather then changing to to electricity first
Okay thanks. I wonder if anyone makes a gas heater with an electric element or if there is a way to tap into an existing port. It would be a small market but I could sure use one. We are off grid but will have access to propane. We are planning on a 6-10k solar array and possible wind generator in the future. I have to heat water and radiant floor so I assume I need propane or a larger array. Ive read it is a good idea to dump excess energy into the water heater. Just trying to figure out how I could do this.
if you can't store the excess power then sure dumping it into water heating would be a good use. There's solar heating setup's that don't use electricity at all. If your looking to use solar to heat as part of your plan you can do something like sticking 500' of black poly on the roof and run water through it, that will pickup a ton of heat from the sun into the water. This is just a basic ghetto idea, but turning solar energy directly into heat to use is far more efficient then turning solar into electricity, then back into heat. There's some company that takes soda can's, paints em black and set them up in big strings. By blowing air through it they pickup a ton of heat from the sun, they won't work if your doing radiant floor heat though, you need something that heats the water with the sun
I could use the black poly but because of the climate I'd have to use antifreeze and a heat exchanger to heat the water heater/radiant. I have watched some vids on the evacuated tubes I think they're called. They seem to have the best performance but I hear mixed results. I'd like to heat everything with PV if possible since that would be the most self sufficient system.
There are electric/propane hybrids made for RV's that you could probably use. There is also a kit that will let you put an electric heating element into the drain plug of a propane tank, though the one I use is only 400 watts.
Great Idea, I'm going to do this and add a time clock to the AC powered top element. I want my hot shower in the morning so AC available during the night to keep it hot, but turn off so AC does not reheat the tank right after a hot shower, let the solar have all day to do that.
i understand that you removed a load from one side of the 220/240vac lines, which unbalances the load unless you can move other loads over to that side. Also I was told that in old style meters, the highest load side is what the meter shows to the meter reader, not the total load. So you get charged more for electricity than you should. I may be wrong on all this.
Complete noob here, what happens if the panels produce more power then needed or the thermostat shuts off due to the temp being reached? I understand that's the charge controllers job but where does the surplus power go without a battery bank or grid tie? THANK'S!
You have a great question with no answers. I am no expert but if a PV has no load it might heat up as in overheat? I wish someone would address this question.
My dad doesn't want me to fool with the heating elements on our water heater but doesn't mind me hooking up a loop between the drain and the pressure relief valve. So I'm going to tee into each of these points and install a DC element/thermostat with a small DC circulating pump.
Did you leave the stock heating element in the tank ? You mentioned having 130 volts dc going to the heater so i assume its a 120 volt ac element. How many dc volts do i need to power a 240 volt ac element?
How safe this type system is in the event of a fault or element failure in regards to overload protection, risk of electric shock, or separation from AC. What are the options?
It would be interesting to compare the total cost to a solar thermal water heating system. The solar thermal will be considerably more efficient, but if you have the space for the solar electric panels, the efficiency does not matter.
A piece of black electrical tape works wonders for your temp measurement ;0) .... In the UK we have many similar hot water tanks, the electrical heaters being fed from the mains (Economy 7 ... low night rate electricity) to the bottom element and a timed manual boost to the top! You could run your unit similarly with the bottom being PV and meter the top to see how much (if any) top up is required? Just as a point of interest ... how does the loss of running DC from the panels to the controller relate to the losses in an inverter?
Hi E775. When you talk about the electrical box with the disconnect that you use with the mppt controller, I didn't understand the term you used. What is that box called? It sounds like the exact disconnect needed for the project. Thanks for all your great videos!!!
Hi just stop by the website to check out the product but had some questions to ask and was not sure where to ask them so here i go 1.do you ship to Australia 2. what is the voltage coming out as i need 240 volt 3.what is the max solar input thank you for your reply
that's excellent I would like to do that here in Tavares Florida where I live at just on my hot water heater but I have a question if I get the controller in the parts that are needed to do the job it looks like it's pretty self-explanatory but question is can you just hook it up only solar power to that hot water heater and nothing else
That's what I do. I connect to the top part where you would normally connect AC and it will start heating with the upper element and then switch to the lower element as it was designed to do with grid. I also have a plug on that so I could plug into grid if I really had to, but who wants to give them money? Generally for 2 people, 750W is good but panels are cheap now and there are cloudy days where you could get better power with around 1000W so it depends on what you want to do and what deals you can get on panels and mounts. Cloudy days are not wash days. It all depends on your use.
I've deployed this TechLuck and an EU unit, both works well, . As a solar contractor we should be able to use the enphase IQ8 micro in microgrid mode for this when in ships in a few months for a code compliant solution. Grid free Reliable hot water is necessary for life.
What is your average daily energy input to the tank in kWhrs? You have a 50 Gal tank so 1kWhr of energy in will raise the water temp by 8 degrees F. You mentioned 58 degrees starting temperature and 150 degrees thermostat switch off so that's 11.5kWhrs to heat the whole tank to 150. What's your cumulative energy output of your four panels?
The controller takes solar energy and heats water electrically through existing element in an electric water heater. The nice thing about the controller is that it maximizes the solar output of the panels during lower light ( morning and afternoon hours) via maximum power point tracking. The second things if does is to convert the DC power into a pulsed DC so that the contacts in an OEM thermostat do not fry.
150 F and no tempering valve? For shame. So the MPPT controller chops the DC up enough so the regular water heater thermostat will work? That is a neat trick as it saves you from needing a solid state relay.
I'd sure like to hear how it's going to work with the upper element running off the grid, if my solar panels are covered in snow do I only heat the top of the tank to a lower temperature than the bottom element uses?
As a deterrent to using grid power you could connect a old pay phone to the circuit and every time you need to use grid you have to put in a quarter. Then you learn real quick to watch the weather and not do the wash on bad days. I find that the plug method works well, connect the heater as normal but to a plug, then you have to unplug it from solar and plug it into grid. This notifies your brain that you have to pay for that power and after a while you don't want to plug into grid ever. It also makes you want to go out and sweep the snow off your panels like you should. The other option is what you said, turn the top grid element down to bare minimum so it hardly comes on and also add in a timer so it doesn't come on during the day. Your choice, the plug method works really well and the top element comes on first.
7 amp 130 volt ~900 watts I’m never too sure if my math is correct. If you have 4 panels connected, are those 24V panels (39 voc) producing around 32 volts each for water heating? The heating element is 2000 watt, 120V ? Does the MPPT controller regulate voltage output?
You could use this same controller to run those electric space heaters right? Do you have the specs on the controller? Like how many volts/amps it will handle?
Put two blankets on it and insulation on top of any ELECTRIC heater, and do it now, it's cheap, even if you are not going solar. Typical insulation is like 1/2". Water always tries to go back to room temp. With this idea you turn the thermostat all the way up to store extra heat like a battery. If you have a person with scalding risk in the house then you install a special mixing valve.
Yes yes, no batteries. And you can do two things with eqip if had to. Like ol times, summer kitchens ect. Need to develop a outdoor portable-ish building. >Power(with add lugs) include shower floor drain, washer, composter, stove. Poly-sheet facing south for cooler days then when air dries can hook up power back to house water storage. This will keep moister out of house(and you, lol) and possibly a smaller house(parts of).
Hey Scott. Great video and timely too! Even though it's 5 years old, I have just started to think of how I can use solar. I live in upstate NY and would like to create a warm basement to my 1 story home. I have a newer gas hot air furnace but the ducts run in a colder basement. So I am thinking a standard electric water heater powered by solar to be the source of heat for something similar to hot water baseboard heat, maybe with a fan to circulate the warm air. Maybe I am looking in the wrong places, but this seems like something someone would have commercialized by now! Some simple controls, a circulator pump and expansion tank and sun. Let me know if it's possible and / or if there are commercial packages I can have put in. Thanks
I don't like batteries either. I like what batteries can do, but not their limitations. I've always thought a off grid system required batteries so thank you for clarifying.
That is very cool, but the controller is out of stock. Do you manufacture them? This seems to be the most practical use of PV I have seen. No batteries, no grid-tied issues, and if your upper heating element can be programmed to heat at a lower temperature, you can still leave it connected, right?
What size solar panels are good to use for this, volts and watts? and how do you hook the solar panels up to the disconnect box outside? and are the panels connected in series, or parallel ? thank you for you video on this i've had the controller laying around to do the project but i'm new to solar project world but really like it.
You can put up to 1,200 and 80 watts of solar so any combination of panels and sizes in series up to that amount will work. For example 4- 300 watt panels works really well.
Yes. I think you mean 4500W 240V element which is standard for most USA heaters. It also works at lower power levels with a 1500W 120V element which is on some smaller heaters, also a 2000W 120V one but only up to 500W which is good for a small cabin situation or SHTF with something like a 30 gallon heater. MPPT makes it all possible with just a few panels.
nrodge1, I do mean 220v 4000w element. FYI I moved to Greece about ten years ago and the water heater I have here at my home is situated on the utility terrace on top of the house. It's primary heating is via solar collectors with approx. 3 square meters surface area through a closed loop into the heater, secondary circuit is via a 4Kw 220v mains connection followed by a third closed loop which connects to a boiler in the basement. There are times in the winter when we have very little sun but plenty of wind power 24 hours a day. I am really wondering if this might work connected to a 1 Kw wind turbine and if need be to a battery bank so as to provide a constant load to the turbine through its regulator. Any information to its feasibility would be appreciated.
For **solar** that element would perform the same as the USA standard. But this MPPT controller should not be used with a battery or directly to a turbine. You need to study wind systems and figure out how best to do what you want. Your water "loops" are going to be a lot of loss so you need to think about that. A well insulated tank just sitting there is much more efficient. For custom solutions, or if you want to switch between systems you might want to contact the manufacturer of the controller. I have personally run that controller off of a 84V 7A AC power supply to run it off of my main Li-Ion + inverter system at night, so there are other possibilities. The power supply needs to be able to handle being maxed out, some don't like that and shut down until reset.
Thanks for this usefull video... If I have enough solar pannel, can I use the existing AC 120v 2000w heater of my boiler, connected to a DC thermostat to the solar pannels ? Is there a difference betwenne AC and DC resistance ?
n00b question: why PV direct versus "indirect" PV via house inverter? If PV direct means the solar panels are directly wired to the water heater anode (except this power point tracker/controller), then connecting the water heater this way is more efficient?? better than the water heater being wired up to standard AC that's powered by the house's inverter & same solar array? You say you've got panels on your roof already for air conditioning, and that must mean you have an inverter ... I'm going to be very interested in replies if folks say "yes, direct PV is more efficient" because folks have beaten down the old DC House concept (everything powered direct from solar panels to appliances/house on 24 or 48V circuits) for awhile and I've been told AC/DC whole house inverters are soooo efficient now that there's no need to do direct anymore.
I don't see an inductor (transformer) on that board. The best it could be is a PWM controller. To be true MPPT it tracks Max Power Point and does dc to dc conversion (buck) for stable output voltage to the load. No inductor means no buck converter which means it is not MPPT. PWM can approximate but not match the efficiency of MPPT. PWM is well under $100. What does this one cost?
I know there are variables such as location and energy costs but I'm curious, how long do you think it would take to save enough electricity that material costs would be covered? I saw in another comment that you sell controller. Do you sell panels also?
David Jolley yes I can get you a complete kit, panels, wire, controller. For around 1500 for a 4 panels upto 1200 watt system. Send me an email it you are interested. info@practicalpreppers.com
A guy that calls himself hot water on the website thebackshed. Com has been talkin about a controller like this for a long time very simple to make the plans on the website
MPPT without a "conductor"! 240VAC system, the minimum VDC will be 240*sqrt(2) = 340 VDC; which is more in-line with the "CyboInverter! Hot Water, you now promote.
This is better because no compressor is running and also the geyser takes up space that a lot of folks do not have in their closets or mechanical rooms. Don't get me wrong , the dehumidification byproduct of the Geyser is great in some applications. Again, We have a lot of solutions and we make sure the right one is implemented.
Excellent questions and beleive it would depend on the mode you are in. If in heatpump mode only will the lower thermostat work? What brand? I need to work figure this out. Thanks for another project. :)
I’ll be purchasing the AO smith signature series 59 gallon hybrid at Lowe’s. $1299. It has dual 4500 elements just like a regular electric water heater. Side note, I emailed Gaines to see if they came to me. I’m in northWEST NC About an hour north of Charlotte. No reply yet. May look at a 9.5kw grid tie system. Thanks.
Chris Heath would be glad to help you with the solar. Do you need a site visit? I'm in wnc alot. Send me an email. info@practicalpreppers.com I'm still thinking about how to handle the water heater.
I may get you to come up. It will be later in the year for sure. I’ll send you an email. Watched all of your install videos. Very nice. Thanks for the reply!
Hey Scott like your approach and the redundancy you have in the system. Question I have is: how does your hot water input from wood stove work into the equation in winter when you have sun and heat with furnace? I would think the hot water input would keep the thermostat off ....would this not cause overheating of the controller from the panels? Thanks for all your useful info...John
Forgotten Heritage Homestead is a good question. I've been turning off the thermo siphoning Loop because like you said the thermostat just stays off with my wood 24/7. Right now I'm charging the tank on wood and then I go several days on the controller. Since we've had a lot of rain I turn the thermosiphon loop back on when we're out of hot water because I leave the grid supplied element disconnected.
I'm seeing cheaper controllers than this one but I really like this controller better atm. Small foot print, easy to install and I have proof that it works via you! Can we get an update on this project before I buy one? Look forward to hearing from you. I would like to install this on the bottom element and leave the grid power hooked to the top element. The top element, i'd like to install a timer so that it only comes on at 4:30 am and turns off at 7am. The rest of the time only running on solar. Does this sound like a good option? Most morning we have 4 folks in the house taking a shower.
By the way thanks for this. I have been looking for this for a long time. Did an experiment last year with a 15 gal WH and a couple of panels and it worked!
To prove this is really MPPT you need to show the voltage and current of the panels feeding this controller at the same time while under a load with this water heater. Otherwise this is just an expensive device to save the on-board water heater thermostat from arcing and if that is all it is doing there are much cheaper options.
It's MPPT, read the comments here, E775 has been measuring it all this time. There's also a video showing meter readings for this unit that was posted 5 years ago on my channel. It's been working great!
I have the Techluck controller on my system and I am doing these tests now and will share the data later on. So far all I can say is that water is being heated - albeit at a low level and on average about 30-50% less than my panel setup's rated capacity. I think one of the important things is to match the tank's element resistance with the rated output of your panels. However as Techluck seller points out the heat sink consideration is also important. Which brings me to the question of how long the MPPT controller is going to last if it operates at a system's design capacity?
If the thermostat is turning on and off after the water is heated up, then energy usage is not maximized. Guessing if you had two tanks setup thus and switched back and forth between (Arduino-controlled based on thermostat on/off?), then you can have a lot more hot water in reserve, no? Unless your upcoming metrics show this setup only supplements what the grid-side does in just one tank.
The thermostat in most cases will not be turning ff and on. With the thermostat turned up to 150 and entry water coming in at around 60 degree there is a lot of room for the controller to work all day to heat a 50 gallon tank to 150. The average american home is going to need about 7kwh of solar a day.
True, usage has a lot to do with it. I was contemplating folks being typically gone for much of the day or at least not using much hot water. I forget there are kiddos and dirty laundry to wash. :) Thanks for all you do, Scott.
To purchase the controller go to .... goo.gl/dHiKnW
is that the right link : Solar Direct Hot Water Controller - $259.95
for whats on there and what it needs to do, it can be made for $15, thats a real good mark up
+Steven Ruscoe I install $700 MPPT charge controllers. Do you really think you could design and manufacturer that board? For less than $100?
The panels are not the problem. I have heated water with direct DC from panels to elements before. The problem is twofold. DC arking with destroy the thermostat ( controller eliminates this) and MPPT maximizes the performance of the panels during the morning and afternoon.
Hey Scott, would this MPPT controller work with my 400 watt wind turbine to do the same thing? Is that low of wattage even worth trying to heat a 4500 watt element?
Engineer775 good afternoon quick question I understand the concept of the MPPT controller, what can or type of thermostat should be use to prevent
Early death of the thermostat due to the fact we are using DC instead of AC and the Affects of the arcing
How does your MPPT stop dc arcing of the thermostat? As an Elec eng, I would buy an Omron 20A DC solid state relay, ($15) and use the how water service thermostat to trigger the dc solid state relay. Then infinite life of your contacts.
How do you calculate what temp control and ssr to buy?
@@bencordell1965 You use the existing thermostat contacts to switch the SSR on and off using a 12V plug pack DC
Brilliant.
I did the same, but I took the DC direct from the panels to a dc solid state relay. The relay is turned on and off by the thermostat. The solid stare relay is 4-24v dc to trigger so I used a 12v plug pack to provide the trigger current. Works flawlessly. Also 4 panels but 275 watts each.
As a company that designs MPPT's, this is a nice little device and so much better than the expensive Sun Bandit. Because everything is staying at high voltages (~152Vdc), it can be small/efficient/cheap. And it can be MPPT without large components (like 48V systems). They have to constantly pulse/break the DC output at 60-300Hz to mimic AC zero crossings that will not burn up the AC thermostat (you might want to verify that). Off Grid hot water heating is really challenging. Our company has looked at so many different ways for our customers including thermal heaters. Most Off Grid folks have big arrays of panels. It would be nice to be able to dump excess panel energy into the water heater instead of having dedicated panels. But otherwise, this is a nice simple/reliable solution. Thanks for sharing Scott.
Can’t a 2-way switch direct power either to the controller or to a separate charger for the batteries? It would require manual switching but at least power can be redirected.
There Brilliant, I have had one of these for about 12 Months. On a second hand ($100) 315 Liter twin element Unit, I wired it to the top tank element first and then it swaps over to the bottom element via the thermostat wiring, when the top tank is up to temp it then starts on the bottom large section. In this configuration its recovery time is a lot quicker. I have 4 X 250W panels in series and both elements are 4.8KW. It works great and have never run out of hot water in our off grid weekender. Well worth the investment as it only needs light, the Evacuated tube Hot water units are VERY expensive and not good in very cold conditions. The Heat Pump units are good, Very expensive and have climate limitations although you could use this to connect to the backup element in some heat pump units.
I used a secondary hot water tank with about 900w solar panels to supply the main tank with pre-heated water. I rewired the elements in series to eliminate a controller. This way both elements heat at the same time and don't cycle between the upper and lower elements. For the most part, each 12 panel operates around 17 volts. When there is insufficient solar energy, the grid keeps up. I also benefit from some ambient heat to pre-heat the water in the dead of winter when solar is almost non existent.
i like this idea because if you have extra solar power, it gets stored in a hot water battery.👍
I use real direct water heating, without a regulator. A bit of simple mathematics (ohm's law) and selection of a suitable cartridge (heating element) designed for PV. There is also a choice of pipe thread or reduction so that you do not have to buy a new boiler. The thermostat must never be connected directly to DC. I bypassed this with a much smaller solar field (a cheaper solution) so that the temperature reached 60C in winter or under clouds and around 80C in summer.
I have had one of these for two years now. It lowered my electric bill almost 40 percent. The upper element does not come on during the summer, and often, the lower element turns off too. Thinking about replacing the lower thermostat with an upper thermostat and divert excess dc to a small preheat tank. I am using 960 watts of panels.
That is great feedback. Thank you! What size tank are you using? How many people?
clergyurge h
I get "page not found" when I try to get to the controller. is it no longer available?
Are you still using this hybrid pv system
It seems to me that one could simply run wild solar power into the element and then use a DC relay with an ac actuation coil to shut off the solar wattage when the thermostat says stop. I know you want to sell the controller, but any comments? Thanks
That exactly the way I set mine up. 6-175w 35v x 5a panels, using a 36v 1200watt DC element (Amazon 25 bucks) Tank is a dual element, 28gal I use in a shop bathroom. Solar keeps the tank plenty hot enough for hand washing/paint brush rinse/etc, and if I need more hot water for an extended use, I flip the upper element on to use 120vAC power.
Panels to combiner box to breaker (SqD QO 40a SP) to 36v 1200w heating element mounted in the lower hole.
Used the original thermostat that came with the water heater, ran 12vDC from an old 'wall wart' (hasn't everybody got a bag of them laying around ?) thru the thermostat to a 12v 120a amp relay (Amazon, 15 bucks) with the solar positive connected to the relay in/out.
My understanding is AC thermostats that come on standard water heater will NOT take the full DC current (for very long), so you can't wire them direct.....but using the wall wart (just a few milliamps) to control a relay, it works just fine.
Water heats to temperature set on tank thermostat (I use 140), relay drops out and no more power from panels to heating element. Dead simple....no circuit board controller to go buy or go bad.
I also added a small 12v LED read out thermostat with a K type probe that has 1/2" male pipe thread on probe end, screwed into a female adapter in a T on the tank outlet line so I can easily read the tank outlet temperature (25 bucks/Amazon). The 12v power for this comes from the same 12v wall wart that runs the relay above.
Works like a charm.
@@edsmith4414 Sounds like a good and reliable set up.
@@RRaucina Working out great for me so far. I bought a spare relay to have on hand in case the 1st one dies, but with 120amp rated contacts, I'm thinking it should last a long time.
Based on how well this one has worked out, next project is a setup using a larger 200 liter tank as a pre-heater for my house propane water heater. Hope to cut my propane use considerably.
@@edsmith4414 I'd like to do this, but what's a wall wart?
It is shocking the number of people that never think about what can be run/converted to DC to not touch an inverter. From a PC all the way to TV's you can find models that take 12vdc directly for direct drive from PV or from batteries.
Did you use thermal paste between the controllers plate and the metal box?
Now to find a NG/LP water heater that can take a DC element to have all bases covered.
Just make one. You can buy the element mount that bolts right on to the tank.
A lot of MPPT controllers have a load +/- output as well as for charging the batteries, so its a good use of extra power when not charging up the batteries to root it instead to a water heater.
Do you have a up to date link for the mppt controller?
Hey Scott, how is the pv direct water heating going . is it up to the task? thanks
Vert nice setup. Could a system like this be modified to work with a propane water heater? I would be interested in a followup in a week or so running this system off grid. How long does it take in the morning until this comes up to temp?
a gas heater won't have electric heating element's in it. I suppose you could install a second heater feeding into the gas heater to pre-heat water going in. If your going that route it's probably cheaper and more efficient to heat water with sunlight directly rather then changing to to electricity first
Okay thanks. I wonder if anyone makes a gas heater with an electric element or if there is a way to tap into an existing port. It would be a small market but I could sure use one. We are off grid but will have access to propane. We are planning on a 6-10k solar array and possible wind generator in the future. I have to heat water and radiant floor so I assume I need propane or a larger array. Ive read it is a good idea to dump excess energy into the water heater. Just trying to figure out how I could do this.
if you can't store the excess power then sure dumping it into water heating would be a good use. There's solar heating setup's that don't use electricity at all. If your looking to use solar to heat as part of your plan you can do something like sticking 500' of black poly on the roof and run water through it, that will pickup a ton of heat from the sun into the water. This is just a basic ghetto idea, but turning solar energy directly into heat to use is far more efficient then turning solar into electricity, then back into heat. There's some company that takes soda can's, paints em black and set them up in big strings. By blowing air through it they pickup a ton of heat from the sun, they won't work if your doing radiant floor heat though, you need something that heats the water with the sun
I could use the black poly but because of the climate I'd have to use antifreeze and a heat exchanger to heat the water heater/radiant. I have watched some vids on the evacuated tubes I think they're called. They seem to have the best performance but I hear mixed results. I'd like to heat everything with PV if possible since that would be the most self sufficient system.
There are electric/propane hybrids made for RV's that you could probably use. There is also a kit that will let you put an electric heating element into the drain plug of a propane tank, though the one I use is only 400 watts.
@ 3:20 Hot water heater ? Do you toast your bread, before putting it in the Toaster ?
That's a pet peeve of mine also. Water heater. Hot water appliance. Not- hot water heater.
Great Idea, I'm going to do this and add a time clock to the AC powered top element. I want my hot shower in the morning so AC available during the night to keep it hot, but turn off so AC does not reheat the tank right after a hot shower, let the solar have all day to do that.
hey was wondering did you ever try your idea?
Hi do you still have the controller’s for sale ????
is this product still available? The link no longer works. Or is anything else similar available now?
i understand that you removed a load from one side of the 220/240vac lines, which unbalances the load unless you can move other loads over to that side. Also I was told that in old style meters,
the highest load side is what the meter shows to the meter reader, not the total load. So you get charged more for electricity than you should. I may be wrong on all this.
Are you putting 120VAC into a 240VAC element? Would it be more efficient to use a 120VAC element?
Complete noob here, what happens if the panels produce more power then needed or the thermostat shuts off due to the temp being reached? I understand that's the charge controllers job but where does the surplus power go without a battery bank or grid tie? THANK'S!
You have a great question with no answers. I am no expert but if a PV has no load it might heat up as in overheat? I wish someone would address this question.
Nice price too seems to be the easiest way no plumbing just some wires. What is the voltage out of the controller?
David Poz give you nice answers he got formula worked out on the Ohms
My dad doesn't want me to fool with the heating elements on our water heater but doesn't mind me hooking up a loop between the drain and the pressure relief valve. So I'm going to tee into each of these points and install a DC element/thermostat with a small DC circulating pump.
An air gap behind box air can curculat 1/2 inch or so. Run cooler
Could you please provide an update on how the system is operating? I am going to build a similar system so any input would be much appreciated.
Did you leave the stock heating element in the tank ? You mentioned having 130 volts dc going to the heater so i assume its a 120 volt ac element. How many dc volts do i need to power a 240 volt ac element?
How safe this type system is in the event of a fault or element failure in regards to overload protection, risk of electric shock, or separation from AC.
What are the options?
how is it possible to use DC from the solar panels to energize the heating element without an inverter?
water heaters elements are simply resistance loads (like an old school tungsten filament light bulb) and will operate with either AC or DC
It would be interesting to compare the total cost to a solar thermal water heating system. The solar thermal will be considerably more efficient, but if you have the space for the solar electric panels, the efficiency does not matter.
A piece of black electrical tape works wonders for your temp measurement ;0)
.... In the UK we have many similar hot water tanks, the electrical heaters being fed from the mains (Economy 7 ... low night rate electricity) to the bottom element and a timed manual boost to the top! You could run your unit similarly with the bottom being PV and meter the top to see how much (if any) top up is required?
Just as a point of interest ... how does the loss of running DC from the panels to the controller relate to the losses in an inverter?
Hi E775. When you talk about the electrical box with the disconnect that you use with the mppt controller, I didn't understand the term you used. What is that box called? It sounds like the exact disconnect needed for the project. Thanks for all your great videos!!!
Is this hot water tank grid tied? Or just all solar powered?
Well done, but do you use the original heating element of the boiler?
Yes.... Works perfect
How is the Multiaqua System? is it readily available for residential use yet?
More questions. How do the ICs get their dc voltage? You have almost 1000 watts going through it, what is the wire gauge used.
Could you describe for a 6th grade science student the difference in connecting panels directly to element vs panels to controller to element
Hi just stop by the website to check out the product but had some questions to ask and was not sure where to ask them so here i go 1.do you ship to Australia 2. what is the voltage coming out as i need 240 volt 3.what is the max solar input thank you for your reply
Hi but you promised to show the actual device wiring diagram, and include it. What happened?
that's excellent I would like to do that here in Tavares Florida where I live at just on my hot water heater but I have a question if I get the controller in the parts that are needed to do the job it looks like it's pretty self-explanatory but question is can you just hook it up only solar power to that hot water heater and nothing else
That's what I do. I connect to the top part where you would normally connect AC and it will start heating with the upper element and then switch to the lower element as it was designed to do with grid. I also have a plug on that so I could plug into grid if I really had to, but who wants to give them money? Generally for 2 people, 750W is good but panels are cheap now and there are cloudy days where you could get better power with around 1000W so it depends on what you want to do and what deals you can get on panels and mounts. Cloudy days are not wash days. It all depends on your use.
First time seeing this, have you made ANY changes to this setup, are you still satisfied with it?
Maybe I missed it. What voltage is coming off the solar panels? Is it 12, 24, or a 110 volts? Thanks.
He said 90
I've deployed this TechLuck and an EU unit, both works well, . As a solar contractor we should be able to use the enphase IQ8 micro in microgrid mode for this when in ships in a few months for a code compliant solution. Grid free Reliable hot water is necessary for life.
Yes, Looking forward to the IQ8!
How much more efficient do you think it would be with a 50 gallon tank? I see they are out of stock. When will you get more?
Can I conect my solar panel direct to the original 240 volt element . Or in your case 120 volt element What's worse senerio . ???
What is your average daily energy input to the tank in kWhrs? You have a 50 Gal tank so 1kWhr of energy in will raise the water temp by 8 degrees F. You mentioned 58 degrees starting temperature and 150 degrees thermostat switch off so that's 11.5kWhrs to heat the whole tank to 150. What's your cumulative energy output of your four panels?
Hey Scott, what is the piping on the side of the water heater? Great videos, keep them coming.
Please explain what exactly the controller is doing
The controller takes solar energy and heats water electrically through existing element in an electric water heater. The nice thing about the controller is that it maximizes the solar output of the panels during lower light ( morning and afternoon hours) via maximum power point tracking. The second things if does is to convert the DC power into a pulsed DC so that the contacts in an OEM thermostat do not fry.
Do all mppt controllers output a pulsed dc voltage?
150 F and no tempering valve? For shame. So the MPPT controller chops the DC up enough so the regular water heater thermostat will work? That is a neat trick as it saves you from needing a solid state relay.
Charlie Devine the mixing valve is there.
I'd sure like to hear how it's going to work with the upper element running off the grid, if my solar panels are covered in snow do I only heat the top of the tank to a lower temperature than the bottom element uses?
As a deterrent to using grid power you could connect a old pay phone to the circuit and every time you need to use grid you have to put in a quarter. Then you learn real quick to watch the weather and not do the wash on bad days. I find that the plug method works well, connect the heater as normal but to a plug, then you have to unplug it from solar and plug it into grid. This notifies your brain that you have to pay for that power and after a while you don't want to plug into grid ever. It also makes you want to go out and sweep the snow off your panels like you should. The other option is what you said, turn the top grid element down to bare minimum so it hardly comes on and also add in a timer so it doesn't come on during the day. Your choice, the plug method works really well and the top element comes on first.
7 amp
130 volt
~900 watts
I’m never too sure if my math is correct. If you have 4 panels connected, are those 24V panels (39 voc) producing around 32 volts each for water heating?
The heating element is 2000 watt, 120V ? Does the MPPT controller regulate voltage output?
How did you wire your solar panels? Series are parallel or a combination?
Series only
How is the system working
You could use this same controller to run those electric space heaters right? Do you have the specs on the controller? Like how many volts/amps it will handle?
If you set it up to be non-hybrid and DC only, will the insulation of a typical water heater be enough to keep it warm during the night?
Put two blankets on it and insulation on top of any ELECTRIC heater, and do it now, it's cheap, even if you are not going solar. Typical insulation is like 1/2". Water always tries to go back to room temp. With this idea you turn the thermostat all the way up to store extra heat like a battery. If you have a person with scalding risk in the house then you install a special mixing valve.
This still available or totally obsolete?
Yes yes, no batteries. And you can do two things with eqip if had to. Like ol times, summer kitchens ect. Need to develop a outdoor portable-ish building. >Power(with add lugs) include shower floor drain, washer, composter, stove. Poly-sheet facing south for cooler days then when air dries can hook up power back to house water storage. This will keep moister out of house(and you, lol) and possibly a smaller house(parts of).
Hey Scott. Great video and timely too! Even though it's 5 years old, I have just started to think of how I can use solar. I live in upstate NY and would like to create a warm basement to my 1 story home. I have a newer gas hot air furnace but the ducts run in a colder basement. So I am thinking a standard electric water heater powered by solar to be the source of heat for something similar to hot water baseboard heat, maybe with a fan to circulate the warm air. Maybe I am looking in the wrong places, but this seems like something someone would have commercialized by now! Some simple controls, a circulator pump and expansion tank and sun. Let me know if it's possible and / or if there are commercial packages I can have put in. Thanks
Sorry I am confused. MPPT controllers output DC ??
I don't like batteries either. I like what batteries can do, but not their limitations. I've always thought a off grid system required batteries so thank you for clarifying.
That is very cool, but the controller is out of stock. Do you manufacture them? This seems to be the most practical use of PV I have seen. No batteries, no grid-tied issues, and if your upper heating element can be programmed to heat at a lower temperature, you can still leave it connected, right?
Hi what voltage were you running the Emersion heater at I want to do the same using 24v
What size solar panels are good to use for this, volts and watts? and how do you hook the solar panels up to the disconnect box outside? and are the panels connected in series, or parallel ? thank you for you video on this i've had the controller laying around to do the project but i'm new to solar project world but really like it.
You can put up to 1,200 and 80 watts of solar so any combination of panels and sizes in series up to that amount will work. For example 4- 300 watt panels works really well.
Well it's been a year so how did this hybrid solar controller work was it able to keep up
How many DC volts does mppt controller send to the water heater if you have 1 kW in panels?
About 100v
Is it possible to heat up 30L of water to 60 Celsius with a 12v system in less than an hour?
Many thanks
is he still making them ? ours got hit by ball lighting they work grate
Thanks Scott. I like the idea of not using batteries.
I’d like some more info on your system. Thank you
Will this work with a 4kw 220 volt element? More of a commercial sized element in our water heater.
Yes. I think you mean 4500W 240V element which is standard for most USA heaters. It also works at lower power levels with a 1500W 120V element which is on some smaller heaters, also a 2000W 120V one but only up to 500W which is good for a small cabin situation or SHTF with something like a 30 gallon heater. MPPT makes it all possible with just a few panels.
nrodge1, I do mean 220v 4000w element. FYI I moved to Greece about ten years ago and the water heater I have here at my home is situated on the utility terrace on top of the house. It's primary heating is via solar collectors with approx. 3 square meters surface area through a closed loop into the heater, secondary circuit is via a 4Kw 220v mains connection followed by a third closed loop which connects to a boiler in the basement. There are times in the winter when we have very little sun but plenty of wind power 24 hours a day. I am really wondering if this might work connected to a 1 Kw wind turbine and if need be to a battery bank so as to provide a constant load to the turbine through its regulator. Any information to its feasibility would be appreciated.
For **solar** that element would perform the same as the USA standard. But this MPPT controller should not be used with a battery or directly to a turbine. You need to study wind systems and figure out how best to do what you want. Your water "loops" are going to be a lot of loss so you need to think about that. A well insulated tank just sitting there is much more efficient. For custom solutions, or if you want to switch between systems you might want to contact the manufacturer of the controller. I have personally run that controller off of a 84V 7A AC power supply to run it off of my main Li-Ion + inverter system at night, so there are other possibilities. The power supply needs to be able to handle being maxed out, some don't like that and shut down until reset.
What is the thermal siphon you mentioned?
I live in Phoenix Arizona and have a 40 gal water heater. How many panels/ watts would I need?
750W
are you hooking up both top and bottom heater elements?
Martin Crilly just the bottom on my setup.
Can I use this with a Ruud hybrid water heater?
Is there a link for buying the solar panels?
this controller not available anymore?
@@kuhbri5265 unfortunately not
What kind of terminal disconnect is that?
Hello, does any one can share its experience with such a direct water heating controller? what are the issues that needs to be double check?
if it's just me how much do you think i would need. i got a 60 gal tank
William Evans I would use 3 panels. What State?
Engineer775 SC
Thanks for this usefull video... If I have enough solar pannel, can I
use the existing AC 120v 2000w heater of my boiler, connected to a DC thermostat to the solar
pannels ? Is there a difference betwenne AC and DC resistance ?
Are your panels in series or parallel
Would any MPPT controller do the job?
n00b question: why PV direct versus "indirect" PV via house inverter?
If PV direct means the solar panels are directly wired to the water heater anode (except this power point tracker/controller), then connecting the water heater this way is more efficient?? better than the water heater being wired up to standard AC that's powered by the house's inverter & same solar array? You say you've got panels on your roof already for air conditioning, and that must mean you have an inverter ...
I'm going to be very interested in replies if folks say "yes, direct PV is more efficient" because folks have beaten down the old DC House concept (everything powered direct from solar panels to appliances/house on 24 or 48V circuits) for awhile and I've been told AC/DC whole house inverters are soooo efficient now that there's no need to do direct anymore.
Your not having to buy an inverter in this setup.... And the complicated wiring..
I don't see an inductor (transformer) on that board. The best it could be is a PWM controller. To be true MPPT it tracks Max Power Point and does dc to dc conversion (buck) for stable output voltage to the load. No inductor means no buck converter which means it is not MPPT. PWM can approximate but not match the efficiency of MPPT. PWM is well under $100. What does this one cost?
I know there are variables such as location and energy costs but I'm curious, how long do you think it would take to save enough electricity that material costs would be covered? I saw in another comment that you sell controller. Do you sell panels also?
David Jolley yes I can get you a complete kit, panels, wire, controller. For around 1500 for a 4 panels upto 1200 watt system. Send me an email it you are interested. info@practicalpreppers.com
A guy that calls himself hot water on the website thebackshed. Com has been talkin about a controller like this for a long time very simple to make the plans on the website
MPPT without a "conductor"!
240VAC system, the minimum VDC will be 240*sqrt(2) = 340 VDC; which is more in-line with the "CyboInverter! Hot Water, you now promote.
How would you compare this to a Geyser on PV?
This is better because no compressor is running and also the geyser takes up space that a lot of folks do not have in their closets or mechanical rooms. Don't get me wrong , the dehumidification byproduct of the Geyser is great in some applications. Again, We have a lot of solutions and we make sure the right one is implemented.
Thanks Scott. I can definitely see the KISS principle of this solution.
does any mppt can work without batteries ??
Have you looked into heat pump water heaters?
+Christopher Dizon yes I've installed about it doesn't of them they're great for situations where there's a lot of waste heat to turn into hot water.
+Engineer775 I'm installing a new heat pump water heater this week. Would this application work with it as well?
Excellent questions and beleive it would depend on the mode you are in. If in heatpump mode only will the lower thermostat work? What brand? I need to work figure this out. Thanks for another project. :)
I’ll be purchasing the AO smith signature series 59 gallon hybrid at Lowe’s. $1299. It has dual 4500 elements just like a regular electric water heater. Side note, I emailed Gaines to see if they came to me. I’m in northWEST NC About an hour north of Charlotte. No reply yet. May look at a 9.5kw grid tie system. Thanks.
Sorry, 50 gal not 59
Chris Heath would be glad to help you with the solar. Do you need a site visit? I'm in wnc alot. Send me an email. info@practicalpreppers.com
I'm still thinking about how to handle the water heater.
I may get you to come up. It will be later in the year for sure. I’ll send you an email. Watched all of your install videos. Very nice. Thanks for the reply!
Hey Scott like your approach and the redundancy you have in the system. Question I have is: how does your hot water input from wood stove work into the equation in winter when you have sun and heat with furnace? I would think the hot water input would keep the thermostat off ....would this not cause overheating of the controller from the panels?
Thanks for all your useful info...John
Forgotten Heritage Homestead is a good question. I've been turning off the thermo siphoning Loop because like you said the thermostat just stays off with my wood 24/7. Right now I'm charging the tank on wood and then I go several days on the controller. Since we've had a lot of rain I turn the thermosiphon loop back on when we're out of hot water because I leave the grid supplied element disconnected.
I'm seeing cheaper controllers than this one but I really like this controller better atm. Small foot print, easy to install and I have proof that it works via you! Can we get an update on this project before I buy one? Look forward to hearing from you. I would like to install this on the bottom element and leave the grid power hooked to the top element. The top element, i'd like to install a timer so that it only comes on at 4:30 am and turns off at 7am. The rest of the time only running on solar. Does this sound like a good option? Most morning we have 4 folks in the house taking a shower.
By the way thanks for this. I have been looking for this for a long time. Did an experiment last year with a 15 gal WH and a couple of panels and it worked!
hi
i have 2000w 220v heating element. it doesnt perform well on solar 100dc 500wats total.
what if i replace heating element to 1000 wats?
Go to David Poz channel he got a great formula for the right element Ohms must be right and pannel watts. :-)
To prove this is really MPPT you need to show the voltage and current of the panels feeding this controller at the same time while under a load with this water heater. Otherwise this is just an expensive device to save the on-board water heater thermostat from arcing and if that is all it is doing there are much cheaper options.
It's MPPT, read the comments here, E775 has been measuring it all this time. There's also a video showing meter readings for this unit that was posted 5 years ago on my channel. It's been working great!
I have the Techluck controller on my system and I am doing these tests now and will share the data later on. So far all I can say is that water is being heated - albeit at a low level and on average about 30-50% less than my panel setup's rated capacity. I think one of the important things is to match the tank's element resistance with the rated output of your panels. However as Techluck seller points out the heat sink consideration is also important. Which brings me to the question of how long the MPPT controller is going to last if it operates at a system's design capacity?
Can you provide links to cheaper options. That'd be super helpful! thanks
yup, wht he said...
Cool. Can new flex solar panles be used with system? I have long roof. I have a small water.
Yes.
Celtic Bear yes
What wattage are the heating elements?
Peter Holman 4500
If the thermostat is turning on and off after the water is heated up, then energy usage is not maximized. Guessing if you had two tanks setup thus and switched back and forth between (Arduino-controlled based on thermostat on/off?), then you can have a lot more hot water in reserve, no? Unless your upcoming metrics show this setup only supplements what the grid-side does in just one tank.
The thermostat in most cases will not be turning ff and on. With the thermostat turned up to 150 and entry water coming in at around 60 degree there is a lot of room for the controller to work all day to heat a 50 gallon tank to 150.
The average american home is going to need about 7kwh of solar a day.
True, usage has a lot to do with it. I was contemplating folks being typically gone for much of the day or at least not using much hot water. I forget there are kiddos and dirty laundry to wash. :) Thanks for all you do, Scott.