You know what, I've been driving crazy trying to place a solar hot water system in the roof of my house and haven't thought about solving it with electric solar panels. Thanks for the idea 💪
Simple is always better. My dad had a solar preheater for his house that had a separate system of water circulation but seemed very complex and more likely to break or leak than this simple solution. Bravo!
Jeff great video and straightforward common sense application of solar power to heat the water in the second tank before it goes into the main tank. I understand what you were saying to preheat the water to a good 80 or 90 degrees before it goes into the main tank therefore saving a lot of power usage. You have definitely inspired a lot of people to apply that application and you've also inspired me to do the same thing. I want to put in a 2 element secondary tank and use a wind turbine for the bottom element. That way at night the wind turbine can be Heating with the bottom element. Keep up the inspirational work
Exactly what I have done and it works great. No thermostat, no charge controller, no batteries. Using the original heating elements. Plenty of hot water.
My friend has a similar system but he just uses the 120 V standard heater and runs some panels in at somewhere over 120V DC. The panels are hooked directly to the water heater, no charge controllers or anything in between. The fact that it does not freeze in winter is key here in Canada
Thanks, this is great! I like the water in the cup temperature test. I wish you also showed it for the thermo system - it'd be an interesting comparison, especially in winter.
Thank you. Very smart idea and set up... I have a120 volt, 10 gal tank, with a timer set for 1 hour in the morning. That's the 'only' time I want 'HOT' water. Then it's very warm for the rest of the day. If you put a digital timer on you 'grid-tied' heater, you could save even more.
I like your dual tank setup. You could use passive solar as well in a similar method with a separate loop that contains coolant, allowing it to run year-round and heats your supply line through a heat exchanger.
Smart. using solar in this way completely eliminates the need for a battery. Your battery is your water.... stored power!! ITS JUST MATH!! GREAT TO SEE A MAN USE HIS BRAIN
Thanks for doing all the work that we all will benefit from. Very well done.All questions answered except: What is the wattage of the element you used on the back up 19 gallon tank?
I live in the high desert of southern Arizona and use a batch type heater year around but have a shortage at times in the winter due to losses at night. With a PV system and a 50 to 100 gallon system I could superinsulate the tanks and probably have sufficient hot water year around. I have not had another source of hot water for over 18 years.
That is exactly how I plan to heat my insulated 30x40 shop. Probably wont get that done until next yr but it is gonna happen specially after my electric bill went from 120 bucks to over 350 bucks from October to November when I deployed my electric shop heater. Nice side benefit will be hot water for hand washing out in the shop. Wont do anything for me in summer though. I will deploy small mini split air conditioner for cooling wired up what ever way it will take, I'll do the research. that may work for heating also??
Request to every one who can translate this video into urdu language , that it will be easy to understand for those who don't understand english language . Thanks You very much , MOHAMMED Anwar PAKISTANI .
This is great thanks. Question. This vid is now a few years old. What if any improvements have you made and is there an updated video? Id love to see it thanks again
That circuit breaker doesn't protect you against lightning. Lightning acts too quickly for circuit breakers to react. They're useful, for example, for cutting off current when there's a short circuit. For lightning, you need to make sure your panels and metal frame are grounded to a ground rod driven deep into the soil. Also helpful is using a device specific for lightning protection. Midnite Solar sells a line of AC and DC lightning/surge protection devices that can be added onto an existing system (e.g. mounted on the side of a combiner box). Also, it's not just the amperage rating of a hot water heater thermostat that's important. It's also the voltage rating, and a device like that isn't going to be able to handle nearly as much DC voltage as AC (as it's designed for).
So do I understand it correctly, you do not have a solar charge regulator at all? It is the solar panels, directly to the heater element, right? I like your clear and no BS way of describing things. All makes total sense. Thanks dude!
What you are doing is fine but there is another way. I have 1500 watts of solar panels wired in series to give about 115 vdc. This goes to my water heater which has a standard 115 vac heating element in the bottom of the water heater. The upper element remains connected to 220vac power. It's a 50 gal tank and reaches full temp over the course of a day. The only hitch is I had to create my own temp controller using a thermistor and an Arduino to open up a solid state relay when the temp reached its setpoint. Without the controller, the tank would over pressurize and pop the relief valve.
I live in Germany and have 7,2 KW photovoltaic and 12 m2 solar. The solar did cost me 7000 Euros and I have always more hot water than I need. However, if you do the calculation, all the hot water (it also supports heating) saves me not more than 200 Euro per year. So, it will take me 35 years to get back the costs. If I had the choice again, I would put 10 m2 more of photovoltaic on the roof and heat my water with a heat pump system for 1200 Euros. So the main point is return of investment.
Just curious. How much electricity kWh Cost in Germany? 200e savings sounds like there must be something wrong or you don't really need electricity? Here average house uses 20000kwh per year. That is about 2500euro bill. If you add 7,2kw panels for a house In think it would save alot more than 200e. Maybe a thousand euro?
@@Zanderman2000 I talked about hot water only. Not heating. I have heating with wood pellets (1000e/year), and it makes also hot water in the winter. I have additional 10m2 solar, which was thought to also heat the house, but that doesn't work. That is the cost of 200Euro I save. I have also 7.4KWp PV were I get 200 Euro per month from the gvn (29cent/KWh). 1 KWh costs 30 cent in Germany.
@@JakobFischer60 i think your panels should be able to easily power a heatpump. Ground sourced heatpumps and air (fresh/waste) sourced heatpumps are very common here in new houses and added also to old houses because energy prices hikes up. Pellet is a good choise also but theres a lot more hazzle around when you have to burn something. The most simple heater would also be PTC element with fan. They are usually under 400w and even one panel can run a 100-200w heater. In theory you could power 7000w ptc heater bank with your panels on sunny day. Put the ptc elements in massive stonemasonry that will heat itself during day and release steady heat all Night.
@@JakobFischer60 small 100w ptc element heater with a 120mm computer fan transfers around 40-50celsius air >90cubicmeters per hour. I think it should be enough to heat small room? There are quality computer fans on market that are very quiet if the stock one is noisy.
Please tell me which element did you finally install to make this setup work. This is a brilliant plan. I want to do a similar thing at my home. I also find that in winter time the solar geyser is not as effective. Keeping up the good work man 👍
Nice video showing the implementation. Hot water can be 1/3 of one's energy bill. Any reduction in heating would see benefits. Interesting setup with dual tank configuration. A small tank heats up pretty quick. Limited shower maybe. An off grid application might be happy with 80 degrees water. From my reading, a solar heat panel is better for heating water. No electricity required other than a pump. I fast forwarded a bit looking for details on how much energy this saved from the grid. I didn't see any data analysis.
jose gonzales ... You must realize that the added items to do measuring might not be in the budget for everyone. Best guess from my end is an average 30 gallon electric water heater might use a $1 per day or $30 per month. If preheating could chop off 50% then we're looking at $15 per month savings, which could be $180 per year. OTOH, it might be less in certain areas, but at least you have some numbers to work with for figuring payback. I'd start with 25% savings and be pleasantly shocked if it was better.
love this setup nice and simple, im new to solar and your making it very understandable with this video thanks for that! Im curious if it would be conceivable to have a similar system work on a central heaing unit maybe 3 of these elements with 6 or more panels add a thermostat valve and 12v pump to supply the radiators heat up the tank during the day and use it to run the radiators at night that way the system gets time to heat up.
Gene V... just seeing this video today... so is this definitely saving him a lot more energy than if he simply had those solar panels and a battery hooked up to his whole electric system? with average hot water use I guess we're talking
I'm surprised you don't have a charge controller on to suppress the electrons in your solar panels. Mine runs through black tubing. Pre heat. I like your video I bought elements years ago and I was gonna do the same thing I've never got to it good job.
Steve Kellett don’t knock climate change - I could use a hotter winter up in Alberta by at least 10 degrees to extend the growing season - had to pic my tomatoes in early September because of freezing.
How bout an update on the performance of ur 2 tank PV Water Heater. Mods u may want to consider... 1) Exchange heat between tanks by heat exchanger. Fill the PV connected tank with distilled water and don't connect to water main or house water heater. Transfer the heat via tube in tube heat exchanger to house water heater. This will keep heat flow to 2nd tank when hot water is not being drawn in house. 2) Add a DC switcher so PV could also charge a battery bank if electrical grid is down.
Let's talk about AC and DC heating elements. The AC that comes from the grid 240VAC, which is AC RMS which stands for Root Mean Square. RMS is the AC voltage that will heat a resistor to the same temperature as a DC voltage of that value. 120VAC and 120DC will both heat the same resistance the same amount. So there is no difference between an AC element and a DC element, in fact you can use an AC element with DC because water heating elements are simply resistors, they have very low inductive reactance. The AC frequency of 60 Hz has very little inductive reactance effect - if any. XL=2piFL or inductive reactance = 6.28 x frequency x inductance. At 60Hz the inductive reactance is minimal to the point of insignificant. So buying a 12V or whatever DC element is spending money on something you don't need, especially because they are so expensive compared to box store common AC elements. What is important is the wattage of the element and it's resistance. A 1200 watt element will work with 10 amps from your wall outlet - 10 amps x 120 volts = 1200 watts. The same element will work with 12 volts too BUT the current will have to be higher - 12 volts x 100 amps =1200 watts. The formula is P=EI or power = voltage x current. Just as long as the element's power is not exceeded you can use AC or DC - it doesn't matter! If you have a 1200 watt AC element you can heat it just as much with 4 or 5, 24V PV modules or you can take two or three AC elements and put them in parallel. If we took three 1200 watt elements in parallel the resistance would be 1/3 so you could get the same heat with less PV modules for example if they can carry that much load. Why? Because the resistance is lower and the load is greater the PV voltage sees. You're basic idea to preheat the water is good but understanding what I just wrote will save you unnecessary expenses.
sounds to me like what he needed to do was get a 240 volt 30 gallon tank. hook up both elements and remove the thermostats so they would run full out heating the water. Might even get the water to a higher water temperature where the delta 10 could be down to 10 degree or less
then wouldnt connecting the solar dc current directly to the secondary AC element he stated was not connected, along with a few other automation mods. PS installing a timer to turn off ac voltage during off hours could very helpful
DC switching and AC switching are two very different things. Even if you are staying under the amperage rating of the contacts, using DC on an AC rated thermostat could still pose a problem. I burned out one of these thermostats at about 70Vdc and 9A after a couple months when normally the tank would operate at 240Vac and ~18A.
@@johnwyman6126 yeah there’s certainly ways to do that using a separate dc relay. But it was just sort of a temporary way to get hot water while we were building a house in the Bahamas with limited materials available. Since then we have finished a full solar system with an inverter that can support that load using AC so it’s no longer an issue. So far the capacity of the system hasn’t been a problem to drive the hot water heater, but we may eventually add a relay based on the battery SOC.
You have 2 parallel 300W panels that will give you 36V, 17A. So if my calculations are right, you need 600W/ (17Ax17A) = 2 Ohm 600W heating element, sice W=I*I*R. The voltage on it doesn't matter. I don't understand why they don't specify Watt and Ohm in them instead.
I started out wanting to do a solar water heater with water on my roof at home, (which I will still do in the summer) but then decided to do exactly what you're doing here. I want to travel and use the small hot water heater in an RV if possible, realizing it may not be really hot, (Arizona in January).
This can be a lot more efficient with modern mppt solar thermal management electronics. Just coming out on the market, acts like a mppt solar charge controller for batteries except it's for resistive heating elements. Bassically an array of different resistance heating elements are connected by the mppt solar thermal management electronics in specific configurations to pull the right amount of current at the right voltage from your panels. Makes everything a lot more efficient!
@@AlekseiPetrovski Geyserwise is south African made product. PTC 2000 watt element. Charger controller. Plus the thermostat control unit. The whole system runs off three 300 watt solar panels. search for Geyserwise on Google.
So I'm getting into solar. I'm playing with the idea of heating my water and adding supplemental heat to my house. I have yet to come to a destination. I have watched to the end and read a lot of comments. I understand your situation any why you have the two tanks and using PV panels and doing what you can with what you have. If you where to do it again. Couldn't you use solar thermal in a drain back system as a preheat. Then run a dual element tank like others have suggested. Then maybe some magical plumbing and controls with a circulation pump or valve in a way where in winter your using the thermal panels to preheat, without worrying about freezing. Then in the summer it will take most of your heating needs and add capacity to the system. Like I said I am new to this and my comment is more based on what I somewhat know.
I see one slight problem with having two tanks. The hot water from the solar driven tank stays in one tank, and only travels to the second tank once there is water flow. This means that if you are not using the water, the mains electric water tank is still using energy to heat up the water when not being used due to thermal losses of the tank. I think the idea from another commenter to put the 24V element into the same water tank as the tank with elements driven off the mains, and this would both reduce the electricity when no hot water is being used, and while hot water is in use.
Excellent video on your set up. I am in the process of designing my own solar water heater right now, and this information is great. I am on the fence about using PV cells or heat collectors. I am in Austin, TX area and if I use heat collectors, plan to use evacuated tubes of my own design, so when we do get the few days of freezing a year, it won't be a problem. Great video. Keep it up!
Adding a timer to your 120v tank will help with that. I need to add the solar side to mine, but right now just have my tank set up on a timer to run for 1 hour a day at 5am. Enough for showers in the morning and dishes in the evening. Then the solar could take over during the day.
Yes I thought that also. While the water from the first to second tank is always warmer and reducing mains power usage, you have to let it travel to the second tank before use causing losses? If he had just one tank and maybe a bigger pv array he could just use solar and not use mains at all?
I have a 300w 12v element like you showed in the start of your video and was wondering if you know or can direct me where I can find a correct wiring diagram for it? Many thanks
would this work efficiently for instant hot water heater? i think they only have a low and a high flame depending on water temp but im not sure if doing this for an instant hot water heater would be practical
curious your heater ac controller on the water tank still working? it should run ac 24v to the thermostat then to a relay to control dc to the element (safety)
This is okay as long as you’re thermostat never gets to temperature to shut off. DC voltage will weld the contact’s together and never shut down. Keep small scale like this and you won’t have a mess to clean up. I personally had the same idea 15 years ago but made a 200 volt 60hz dc chopper mosfet circuit that works great. Free hot water with no modifications to hot water tank because it’s kind of AC -off -on at 60hz instead of a grid sine wave.
What about using DC SSR switched via ac? The water heater thermostat could turn that on/off right? If dc is needed to switch the DC SSR you could use a small wall style transformer to turn it to dc to control the SSR.
I am thinking of doing the exact thing... which brought me to your video.... one thing concerns me... my home water tank is set at 135 degrees.. mainly to lessen the chance for microbes to grow... bacteria algae etc... so wondering after all this time... have you had any issues with the PV powered tank growing microbes since the water temp being much cooler is ideal for them to grow.
Are you circulating the water from solar tank to grid tie tank constantly? If not, how is the hot water helping? Themostat would keep conventional power on in 2nd tank.
You save a lot of power if you put a 1 hour timer on the house powered heater. You can switch it on bypass if Desired. Saved me maybe a 100 on electric bill.
Even with a relatively low current output the 24 volt nominal panels will eventually burn up the contacts of your AC thermostat. There is a simple way to avoid this though, especially with the low currents you are running: Wire a capacitor across (in parallel with) the thermostat contacts. What this does is provide a secondary path for the current for a brief moment when the contacts open. With tends to massively reduce or even totally eliminate any arcing. A grunty 6 microfarad non-polarised capacitor such as those found in fluorescent light fixtures or motor start caps would be ideal. This only works for DC - it wouldn't work on AC as current would continue to pass.
That is smart. You went over my head a bit and I will have to study a bit to figure out what "A grunty 6 microfarad non-polarised capacitor" is but I think i get what you are saying and I will keep working on this. Thank you for your feedback, i take it seriously.
If you get your hands on an old fluorescent light fixture open it up and inside you'll see a white or grey plastic cylinder (occasionally they are a shiny metal cylinder) with a couple of connexions on the end. That's the cap you want. Rip it out and connect one terminal to the wire feeding your thermostat and the other to the wire which goes from the thermostat to the element. Easy as that. Doesn't matter which way round you connect the cap as it's non-polarised. But keep the wiring as short & as close to the thermostat terminals as possible. This increases the effectiveness.
xanataph Arc Suppression When a switch/relay is opened an arc can develop across the contacts which over time can erode away the contacts over time. To prevent the contacts from being eroded a RC network is placed across the contacts. When the contacts open the applied voltage is placed across the capacitor and not the contacts. The capacitor is to charge up at a rate faster than the contacts open thus preventing an arc from forming across the contacts. When the contacts close the inrush current from the charged capacitor and source can be substantially higher than the contacts can safely conduct causing the contacts to deteriorate. This is why it is important to have a resistor in series with the capacitor. The resistor acts as a current limiter which reduces the inrush current by a significant amount that the arc caused at contact closure is greatly reduced extending the life of the contacts. C=I^2/10 R= V / ( 10 I ( 1+(50/V) ) ) Example: 120vdc @ 10amps. C=10uF R=141Ω (150Ω) 240vDC @ 10 amps C=10uF R=300Ω
Interesting formula. I have considered the situation of the charged capacitor being shorted out when the contacts close, but I determined that to be less of an issue as the relay I am using in my case is rather substantial and the voltage is only 24 volts nominal. I suppose there could be some arcing though when it closes as contacts always have a tendency to "bounce". How is that constant of 10 in the formula determined?
You are best to keep the voltage higher I use a 230 volt element with a series solar array to match that voltage of the element the problem is it drawers a substantial arc when the switch is opened this can be overcome with a capacitor across the switch a good quality cap must be used I use a motor run capacitor 4uf 450 volt something a bit smaller is ok
@Mr Sunshines actually you can 100% run an ac element from a DC system, it's just a resistive load. The only difference is that with DC your disconnect ARC (the spark that happens when you disconnect a DC load) will be MUCH greater than an AC system, hence why you would use a 'snubbing capactior'
I've done similar. We have 3 water heaters on our place. #1 in my shop 1/2 bath is a 28gal under counter 120v single element that used to be in location #2. Right now, I run four 175w/35v/7amp panels in parallel to a 1200w 36v DC element (Dernord brand, Amazon). It will heat water to the 110-20 degree range. #2 is a 28gallon 240v 2 element tank. I replaced the bottom element with another 36vDC element like above, but and replaced the top element with a 1500w 120vAC element (because I only had 120v to work with) that I wired thru a switch. The solar feed is five of those same 175w panels as above instead of four. That heater is used in a work room we have that sometimes we need a lot of hot water (hence the 120vAC element), but often only need some standby hot water (the purpose of the DC element). That tank will heat to 150+ degrees, and I ended up using the AC thermostat that came with the tank to control it. I wired 120vAC thru the thermostat and a relay to send the DC power to the element. The contacts in that thermostat are not rated for DC power is why I did this. #3 is our main house water heater.....a 40 gallon propane. I had a 120 gallon tank left from something else, and plumbed it inline ahead of the propane tank to pre-heat water the way you did. It has one 36v 1200w element in it, and five 245w panels in parallel. So far (just been connected a month starting 1 December), best it will do is heat the tank to around 80 degrees. Low sun angle right now on the panels, I expect that to improve on into spring. Even so, the propane savings from heating water to 80 degrees over the incoming 50 degree temperature will save propane. The one big advantage of using PV (these were all used panels that were cheap) over a batch type or vacuum tube type heating is, as you said, not having to deal with freezing water, running glycol in a closed loop, pumps, controllers, etc. A PV setup like this is dead simple.
while that is a lot of water heating adventure i commend the effort to break up appliances and individually power them rather than going for a large system that fails as a singular unit or requires grid connect or expensive battery install. Question though on tank #3 with the 40 gallon propane primary and solar pre-tank... You said that pretank is 120gallons but only mention a single element supporting it.. i think you should shop around for some 300plus panels and large DC element to install in the bottom and move the 36v-1200 to the top. Propane unlike NG is going up faster than Elon Musks EGO. I agree about the vacuum tubes unless your setting up some sort of heat pump booster the systems get to complex and require to much maintenance.
I appreciate the video. Love the experimentation. Unfortunately, you negated ALL of the possible savings you might have had from the supplemental Solar heater by using a 120v heater in the second heater. If you simply ran a 240v Element in that heater you would have halved your energy usage, which is why high amp draw items in the home run on 240v.
That is not true! Hydro doesn't charge you per Ampere Hour, they charge you per Watts Hour. You will half the Amps, but double the Volts, which equals the same, only wires will be thinner.
I just started to post a similar comment, that the first tank would be a potential breeding ground for bacteria. While in theory the second tank will probably heat it enough to kill it off, that's assuming water will always stay in the tank long enough to kill it. In the real world - especially if you're running a lot of hot water at one time - there is a likelihood of water being pulled into the second tank just long enough to be pumped back out again. If you end up with a runaway bacteria problem in that first tank, it could pose a serious health risk.
It also grows only in places where there is no water flow. It could be a problem in big commercial water tanks and not in a small home tank where water is replaced daily if that makes sense.
@@gregfromthevaley makes sense but do you know how fast it grows in a tank? Would a day or two be enough? I’m wondering if taking a weekend vacation would be enough time for the water to stagnate and allow listeria to grow.
Would it be worth insulating the tanks so they retain the heat better. They used to make strange jackets for hot water tanks to keep them warm! Red ones!
I bought the 600 watts and did the calculations (600/12 = 50) so that’s 50amps per hour on my 300AH lithium batteries that’s a lot isn’t? If I use the original element (1400 watts / AC 110volts it’s only using 12.7amps per hour. That’s a big of a difference. Any input on this?
Good idea, how it works on winter? I have similar idea, i want to find a way how to redirect power from mppt to my boiler when battery is full, so i can use that wasted energy on water.
Dino Pasic ... that's an easy answer but will require some math to see how long the pay back might be. All you need to do is rig up another water storage tank (water heater should work) and connect everything via a relay so when one system is done it will switch to the other, (the tank) which you plumb in the return side of the boiler to catch the cooler water after the radiator loop but before the boiler itself. You'd have to fool with the aquastat settings so your preheat tank will be at a higher temp than the lowest boiler settings. Typical boiler will be set at say 160 degrees for the low and 190 for the high. Going below 160 may not give you enough domestic hot water if it's a tankless coil and you may have trouble getting a normal electric water heater up above that... but there are modifications that can be made if you re good at that stuff. Personally I would not expect much in the way of savings because you'd need to generate many hundreds of gallons of water daily to make much difference... and a boiler can do that in an hour for the cost of 1-2 gallons of fuel oil. See where this is going?
Why use second tank? why not add your dc element next to the ac element ? How much savings have you realized? Also would be interested in determining size of pv panel in the application. thanks , seems the way to go
Dear Sir, i want to use 02 Charge Controllers 30amp and 06 PV Panels@ 3 Panel with each Charge Controllers and 02 Batteries 200ah in 12 volt Dc. I want to use only DC power in my all rooms with 6guage Wire, DC Fans and Dc lights. My question is how i handle 02 Charge Controller 12 volt dc. 1. Can i joint both Charge controllers with same batteries 2x200ah bank? Boht charge controller will charge the batteries at the same time? 2. Can i use Dc power for use of my appliances from both charge Controllers on same time as parallel or use Dc power from Batteries for house uses. My appliances Load will be not more than 34Amp 408watt. Please guide me if possible.
Question? You mentioned these double dc water heating elements aren't specific on how you wire them. I don't understand why there are 4 terminals, how could it not matter? I just received a dc element like this and have tried it a couple ways and it sparks when I connect to my battery. Is that normal? I am using 12awg wire but it started smoking. The element is 300 watt 12 volt. Does that mean the wire is too small? Thank you in advance.
You got a nice set-up there. And you planned this out pretty smart too. I'm trying to alter my solar system to run from just a few or a couple panels to heat my water away from my household solar system. My water heater is 30 gallons and uses too much of my solar power, so I want to convert the heating element from a 220 volt 4000 watt system to just using the necessary amount of solar panels wired directly to a specific heating element. Hope this makes sense? Anyways the real question here is how do you determine how many panels you need and to what type of heating element to use. There has to be some compatibility of the panels to the heating element, correct?
Wattage and BTU calculations is the cut and dry answer.. the long answer is everyone's situation will be different and dependent on season ( may have to add or take off a panel or 2 in seasons), hot water consumptions, storage tank size, incoming water temp (is a big factor), panel type, output, design/wiring configuration, control systems, and list goes on. For a roundabout answer you would need 3-5 panels of 300-375watt to charge a 50 gallon tank under very low daily consumption rate. This could be done with a dual element tall tank using the bottom element only and could be as simple or as complex as the DYI'r wishes. Using the bottom element accounts for thermal stratification which would reduce the cyclic rate of the upper element provided all is working well. As others mentioned there are limitations to using mechanical thermostat controls for DC power keep that in mind. The TPS will be as it was before a safety and will require to be plumbed properly as many are not ever.. The particular point of this specific video is to have pre-tank storage and secondary electric to take the most advantage of both sources of energy. It is possible to fully solar, single tank dual energy, or to split tank as shown. Split tank would seem to be the most efficient but ONLY if using the low boy style tanks and using good insulation practices. If your not doing those 2 things the surface area and low efficiency of standard tall tanks come into play. If your capable there are people out there modding arduino controls i personally prefer mechanical controls on everything if i can have it. There are both dual and single element versions of low boy (short tanks) in both 120/240 options but always consider the smaller the tank the more efficient for a few reasons. These include but are not limited to less surface area for thermal transfer, much faster recovery rates if properly powered, and less storage mass to prepare and maintain at temperature for use. A low boy 20 gallon dual element tank can recover over 12 gallons of water during a depletion event this means it has an actual capacity output of 30gallons at a set flow rate. The larger the tanks are the less gallons are recovered during a depletion event and the more is lost to surface area. This is something the content creator didn't touch on that is beneficial to him but he may or may not know and may or may not be under powering the units as well as he obviously has to much faith in the insulation of these units. Using a Pre-tank even if it isnt powered directly but picks up heat from a conditioned space alone adds efficeincy due to not heating the water from incoming temps 35-50F but rather have a tighter temperature differential. Say the home is heated with wood heat usually there is an abundance of such a heat a pretank could be installed near that wood burning device and look more like a radiator than a pre-tank. Also that incoming water temp is said to be common reason of heating element damage along side of scale build up because the element sees to drastic a change to quickly. Him and many others add risk by not heating the water high enough which is a concern for specific kinds of bacteria (not my field so no comment). The solar pre-tank should be set to 130F and the primary at 140F and if the fleshlings are to stupid to modulate water at the faucet then a mixing system should be installed to control temps. These higher settings allow for smaller systems to act as bigger ones in the common situation a depletion event happens like your teenage make-up monster swapped your 30 gallon maytag washer to hot water wash cycle just before your credit card holder wants to do the dishes. The tanks/lines should be stored in insulated closets/cabinets/enclosures, even if he had had them in conditioned space because if we are penny pinching to keep the electric monkey off our backs why the hell would we throw bananas on the floor. Going to stop here as adding anything more is a waste as not many people would ever see it nor bother to use the info because it wasnt off of tiktok.
@@masterdebater8757 interesting points and ideas added......but boy I feel sorry for your credit card holder...... Your arrogance is repulsive and negativity unbearable. (The true reason your intellect goes unappreciated or why "no one will ever read it")
@@mikeb4824 Few questions for you. What is it you found to be arrogant in my reply? Why do you assume i use credit cards? How is it you reply if "no one read it" or did you mean your "no one"? If this is some attempt to troll it landed on deaf ears since it has no bearing on the topic of conversation we adults are having here. If you think my lengthy reply in some way makes my statement arrogant, you should consider that some of us have the ability and capacity to exchange large amounts of worth while information in a matter of seconds. That said will you be joining the conversation, I.E. if you have the intellect to do so.
I was curious about the std. ac heater elements. A guy on eBay was selling what he called a DC element. When I ask why wouldn’t a regular AC element work with DC input. He never answered, so I experimented with a std. AC element connected to 1 solar panel in a bucket and it heated instantly. Apparently dc input to an element either dc or ac still works.
My only concern is what happens when the temperature exceeds the temperature setting, I assume the safety is the pressure valve that will automatically open and avoid creating a bomb. I am going to retry my original idea of using a old hot water tank remove the thin metal case of the exterior, paint it black and add one conventional AC element and connect to a solar panel. My application will installed on my roof. Again, my only concern is over heating the water. However I hope that the pressure valve will be sufficient.
Jeff please do it little more on the connection on your next video. This wonderful. I need the 24 volt element. I have lots of panels it need hot water
You know what, I've been driving crazy trying to place a solar hot water system in the roof of my house and haven't thought about solving it with electric solar panels. Thanks for the idea 💪
I love your set-up: no solar controller, no batteries, no pump, excellent :)
Simple is always better. My dad had a solar preheater for his house that had a separate system of water circulation but seemed very complex and more likely to break or leak than this simple solution. Bravo!
Jeff great video and straightforward common sense application of solar power to heat the water in the second tank before it goes into the main tank. I understand what you were saying to preheat the water to a good 80 or 90 degrees before it goes into the main tank therefore saving a lot of power usage. You have definitely inspired a lot of people to apply that application and you've also inspired me to do the same thing. I want to put in a 2 element secondary tank and use a wind turbine for the bottom element. That way at night the wind turbine can be Heating with the bottom element. Keep up the inspirational work
Exactly what I have done and it works great. No thermostat, no charge controller, no batteries. Using the original heating elements. Plenty of hot water.
My friend has a similar system but he just uses the 120 V standard heater and runs some panels in at somewhere over 120V DC. The panels are hooked directly to the water heater, no charge controllers or anything in between. The fact that it does not freeze in winter is key here in Canada
That is what I use. For 2 years now. Works great.
We wait a video
120 V standard heater? What is that? Just interested
@@vaq137 they make small ones for installing under a sink so you don't haft to wait for the hot water to reach the faucet. Brilliant idea actually.
Yup
Very well explained! I am learning about solar power, and this cleared alot of confusion! Thanks!
Thanks, this is great! I like the water in the cup temperature test. I wish you also showed it for the thermo system - it'd be an interesting comparison, especially in winter.
Thank you. Very smart idea and set up...
I have a120 volt, 10 gal tank, with a timer set for 1 hour in the morning. That's the 'only' time I want 'HOT' water. Then it's very warm for the rest of the day.
If you put a digital timer on you 'grid-tied' heater, you could save even more.
I like your dual tank setup. You could use passive solar as well in a similar method with a separate loop that contains coolant, allowing it to run year-round and heats your supply line through a heat exchanger.
Smart. using solar in this way completely eliminates the need for a battery. Your battery is your water.... stored power!! ITS JUST MATH!! GREAT TO SEE A MAN USE HIS BRAIN
Love it. Love the small water heater's. Description on the small water heater.
Excellent video. I didn't know you could do that. Thank you so much.
3.11 Your smile make my Day. keep smiling.
Good vid - should maybe install a temp gauge on that first tank - looks good though - cheers
Very good idea i appricate it you can get warm water without break and can utelise solar energy in a better way
Well done
Ye kess chiz sa banya ha zara hama be samjawo
Thanks for doing all the work that we all will benefit from. Very well done.All questions answered except: What is the wattage of the element you used on the back up 19 gallon tank?
I live in the high desert of southern Arizona and use a batch type heater year around but have a shortage at times in the winter due to losses at night. With a PV system and a 50 to 100 gallon system I could superinsulate the tanks and probably have sufficient hot water year around. I have not had another source of hot water for over 18 years.
That is exactly how I plan to heat my insulated 30x40 shop. Probably wont get that done until next yr but it is gonna happen specially after my electric bill went from 120 bucks to over 350 bucks from October to November when I deployed my electric shop heater. Nice side benefit will be hot water for hand washing out in the shop. Wont do anything for me in summer though. I will deploy small mini split air conditioner for cooling wired up what ever way it will take, I'll do the research. that may work for heating also??
Request to every one who can translate this video into urdu language , that it will be easy to understand for those who don't understand english language . Thanks You very much , MOHAMMED Anwar PAKISTANI .
This is great thanks. Question. This vid is now a few years old. What if any improvements have you made and is there an updated video? Id love to see it thanks again
Jest wanted too say that clear plastic over the windows is a really great idea ,not sure why I didn't think of that.
That circuit breaker doesn't protect you against lightning. Lightning acts too quickly for circuit breakers to react. They're useful, for example, for cutting off current when there's a short circuit. For lightning, you need to make sure your panels and metal frame are grounded to a ground rod driven deep into the soil. Also helpful is using a device specific for lightning protection. Midnite Solar sells a line of AC and DC lightning/surge protection devices that can be added onto an existing system (e.g. mounted on the side of a combiner box).
Also, it's not just the amperage rating of a hot water heater thermostat that's important. It's also the voltage rating, and a device like that isn't going to be able to handle nearly as much DC voltage as AC (as it's designed for).
Brilliant idea i may try it!
So do I understand it correctly, you do not have a solar charge regulator at all? It is the solar panels, directly to the heater element, right? I like your clear and no BS way of describing things. All makes total sense. Thanks dude!
What you are doing is fine but there is another way.
I have 1500 watts of solar panels wired in series to give about 115 vdc.
This goes to my water heater which has a standard 115 vac heating element in the bottom of the water heater. The upper element remains connected to 220vac power.
It's a 50 gal tank and reaches full temp over the course of a day.
The only hitch is I had to create my own temp controller using a thermistor and an Arduino to open up a solid state relay when the temp reached its setpoint.
Without the controller, the tank would over pressurize and pop the relief valve.
I live in Germany and have 7,2 KW photovoltaic and 12 m2 solar. The solar did cost me 7000 Euros and I have always more hot water than I need. However, if you do the calculation, all the hot water (it also supports heating) saves me not more than 200 Euro per year. So, it will take me 35 years to get back the costs.
If I had the choice again, I would put 10 m2 more of photovoltaic on the roof and heat my water with a heat pump system for 1200 Euros.
So the main point is return of investment.
Just curious. How much electricity kWh Cost in Germany? 200e savings sounds like there must be something wrong or you don't really need electricity? Here average house uses 20000kwh per year. That is about 2500euro bill. If you add 7,2kw panels for a house In think it would save alot more than 200e. Maybe a thousand euro?
@@Zanderman2000 I talked about hot water only. Not heating. I have heating with wood pellets (1000e/year), and it makes also hot water in the winter. I have additional 10m2 solar, which was thought to also heat the house, but that doesn't work. That is the cost of 200Euro I save. I have also 7.4KWp PV were I get 200 Euro per month from the gvn (29cent/KWh). 1 KWh costs 30 cent in Germany.
@@JakobFischer60 i think your panels should be able to easily power a heatpump. Ground sourced heatpumps and air (fresh/waste) sourced heatpumps are very common here in new houses and added also to old houses because energy prices hikes up. Pellet is a good choise also but theres a lot more hazzle around when you have to burn something. The most simple heater would also be PTC element with fan. They are usually under 400w and even one panel can run a 100-200w heater. In theory you could power 7000w ptc heater bank with your panels on sunny day. Put the ptc elements in massive stonemasonry that will heat itself during day and release steady heat all Night.
@@JakobFischer60 small 100w ptc element heater with a 120mm computer fan transfers around 40-50celsius air >90cubicmeters per hour. I think it should be enough to heat small room? There are quality computer fans on market that are very quiet if the stock one is noisy.
thank you for sharing good information, makes sense.
Great information Thank you
Would be nice if you could turn this into water radiator heat for the home. Thanks for the video.
Please tell me which element did you finally install to make this setup work. This is a brilliant plan. I want to do a similar thing at my home. I also find that in winter time the solar geyser is not as effective. Keeping up the good work man 👍
Nice video showing the implementation.
Hot water can be 1/3 of one's energy bill.
Any reduction in heating would see benefits.
Interesting setup with dual tank configuration.
A small tank heats up pretty quick.
Limited shower maybe.
An off grid application might be happy with 80 degrees water.
From my reading, a solar heat panel is better for heating water.
No electricity required other than a pump.
I fast forwarded a bit looking for details on how much energy this saved from the grid.
I didn't see any data analysis.
jose gonzales
... You must realize that the added items to do measuring might not be in the budget for everyone. Best guess from my end is an average 30 gallon electric water heater might use a $1 per day or $30 per month. If preheating could chop off 50% then we're looking at $15 per month savings, which could be $180 per year. OTOH, it might be less in certain areas, but at least you have some numbers to work with for figuring payback. I'd start with 25% savings and be pleasantly shocked if it was better.
LOVED YOU IN THE GROUP METALICA
love this setup nice and simple, im new to solar and your making it very understandable with this video thanks for that! Im curious if it would be conceivable to have a similar system work on a central heaing unit maybe 3 of these elements with 6 or more panels add a thermostat valve and 12v pump to supply the radiators heat up the tank during the day and use it to run the radiators at night that way the system gets time to heat up.
Excellent job.
Smart! Direct storage of an extremely costly daily usage commodity. Smart! ANy way to get around batteries is a smart thing.
Bob
Gene V... just seeing this video today... so is this definitely saving him a lot more energy than if he simply had those solar panels and a battery hooked up to his whole electric system? with average hot water use I guess we're talking
I'm surprised you don't have a charge controller on to suppress the electrons in your solar panels. Mine runs through black tubing. Pre heat. I like your video I bought elements years ago and I was gonna do the same thing I've never got to it good job.
Anti freeze can be added to solar hot water. But the big issue has always been energy loss between panel and tank hence go electric
What a great idea. this is the way to combat climate change, by a simple common sense application. A really great video!!
Steve Kellett don’t knock climate change - I could use a hotter winter up in Alberta by at least 10 degrees to extend the growing season - had to pic my tomatoes in early September because of freezing.
How bout an update on the performance of ur 2 tank PV Water Heater.
Mods u may want to consider...
1) Exchange heat between tanks by heat exchanger. Fill the PV connected tank with distilled water and don't connect to water main or house water heater. Transfer the heat via tube in tube heat exchanger to house water heater. This will keep heat flow to 2nd tank when hot water is not being drawn in house.
2) Add a DC switcher so PV could also charge a battery bank if electrical grid is down.
A glycol system can work in the winter, especially with a liquid-liquid heat pump
Let's talk about AC and DC heating elements.
The AC that comes from the grid 240VAC, which is AC RMS which stands for Root Mean Square. RMS is the AC voltage that will heat a resistor to the same temperature as a DC voltage of that value. 120VAC and 120DC will both heat the same resistance the same amount. So there is no difference between an AC element and a DC element, in fact you can use an AC element with DC because water heating elements are simply resistors, they have very low inductive reactance. The AC frequency of 60 Hz has very little inductive reactance effect - if any. XL=2piFL or inductive reactance = 6.28 x frequency x inductance. At 60Hz the inductive reactance is minimal to the point of insignificant.
So buying a 12V or whatever DC element is spending money on something you don't need, especially because they are so expensive compared to box store common AC elements.
What is important is the wattage of the element and it's resistance. A 1200 watt element will work with 10 amps from your wall outlet - 10 amps x 120 volts = 1200 watts. The same element will work with 12 volts too BUT the current will have to be higher - 12 volts x 100 amps =1200 watts. The formula is P=EI or power = voltage x current. Just as long as the element's power is not exceeded you can use AC or DC - it doesn't matter!
If you have a 1200 watt AC element you can heat it just as much with 4 or 5, 24V PV modules or you can take two or three AC elements and put them in parallel. If we took three 1200 watt elements in parallel the resistance would be 1/3 so you could get the same heat with less PV modules for example if they can carry that much load. Why? Because the resistance is lower and the load is greater the PV voltage sees.
You're basic idea to preheat the water is good but understanding what I just wrote will save you unnecessary expenses.
That's wots I need to know cheeks
My brain hertz.
The problem you have though is switching the dc with the ac thermostat. The dc draws an arc an the thermostat and eventually welds closed.
sounds to me like what he needed to do was get a 240 volt 30 gallon tank. hook up both elements and remove the thermostats so they would run full out heating the water. Might even get the water to a higher water temperature where the delta 10 could be down to 10 degree or less
then wouldnt connecting the solar dc current directly to the secondary AC element he stated was not connected, along with a few other automation mods. PS installing a timer to turn off ac voltage during off hours could very helpful
are we able to boil the water with hand powered microwave frequency magnetrons or oven by hydraulic pressure setup
DC switching and AC switching are two very different things. Even if you are staying under the amperage rating of the contacts, using DC on an AC rated thermostat could still pose a problem. I burned out one of these thermostats at about 70Vdc and 9A after a couple months when normally the tank would operate at 240Vac and ~18A.
You might be able to use a snubber circuit to protect the contacts on your thermostat.
Have you tried using 12 V DC through the thermostat to control a relay to connect the 70 volts DC?
@@johnwyman6126 yeah there’s certainly ways to do that using a separate dc relay. But it was just sort of a temporary way to get hot water while we were building a house in the Bahamas with limited materials available. Since then we have finished a full solar system with an inverter that can support that load using AC so it’s no longer an issue. So far the capacity of the system hasn’t been a problem to drive the hot water heater, but we may eventually add a relay based on the battery SOC.
thank you i never thought to heat water like that
You have 2 parallel 300W panels that will give you 36V, 17A. So if my calculations are right, you need 600W/ (17Ax17A) = 2 Ohm 600W heating element, sice W=I*I*R. The voltage on it doesn't matter. I don't understand why they don't specify Watt and Ohm in them instead.
I started out wanting to do a solar water heater with water on my roof at home, (which I will still do in the summer) but then decided to do exactly what you're doing here. I want to travel and use the small hot water heater in an RV if possible, realizing it may not be really hot, (Arizona in January).
This can be a lot more efficient with modern mppt solar thermal management electronics. Just coming out on the market, acts like a mppt solar charge controller for batteries except it's for resistive heating elements. Bassically an array of different resistance heating elements are connected by the mppt solar thermal management electronics in specific configurations to pull the right amount of current at the right voltage from your panels. Makes everything a lot more efficient!
any companies selling this?
could you send mppt controller name?
@@AlekseiPetrovski Geyserwise is south African made product. PTC 2000 watt element. Charger controller. Plus the thermostat control unit. The whole system runs off three 300 watt solar panels. search for Geyserwise on Google.
So I'm getting into solar. I'm playing with the idea of heating my water and adding supplemental heat to my house. I have yet to come to a destination. I have watched to the end and read a lot of comments. I understand your situation any why you have the two tanks and using PV panels and doing what you can with what you have. If you where to do it again. Couldn't you use solar thermal in a drain back system as a preheat. Then run a dual element tank like others have suggested. Then maybe some magical plumbing and controls with a circulation pump or valve in a way where in winter your using the thermal panels to preheat, without worrying about freezing. Then in the summer it will take most of your heating needs and add capacity to the system. Like I said I am new to this and my comment is more based on what I somewhat know.
No pump needed thermal Sifoning. SCOTT FROM N.S.
I see one slight problem with having two tanks. The hot water from the solar driven tank stays in one tank, and only travels to the second tank once there is water flow. This means that if you are not using the water, the mains electric water tank is still using energy to heat up the water when not being used due to thermal losses of the tank. I think the idea from another commenter to put the 24V element into the same water tank as the tank with elements driven off the mains, and this would both reduce the electricity when no hot water is being used, and while hot water is in use.
dammm, you are right! My electric bill did drop consistently though. The next time I build something like this I will look into doing it that way.
Excellent video on your set up. I am in the process of designing my own solar water heater right now, and this information is great. I am on the fence about using PV cells or heat collectors. I am in Austin, TX area and if I use heat collectors, plan to use evacuated tubes of my own design, so when we do get the few days of freezing a year, it won't be a problem. Great video. Keep it up!
Adding a timer to your 120v tank will help with that. I need to add the solar side to mine, but right now just have my tank set up on a timer to run for 1 hour a day at 5am. Enough for showers in the morning and dishes in the evening. Then the solar could take over during the day.
Yes I thought that also. While the water from the first to second tank is always warmer and reducing mains power usage, you have to let it travel to the second tank before use causing losses? If he had just one tank and maybe a bigger pv array he could just use solar and not use mains at all?
Simple convection will transfer heat.
Can you list out the parts and pricing required for this setup?
I have a 300w 12v element like you showed in the start of your video and was wondering if you know or can direct me where I can find a correct wiring diagram for it?
Many thanks
would this work efficiently for instant hot water heater? i think they only have a low and a high flame depending on water temp but im not sure if doing this for an instant hot water heater would be practical
I am setting up to do the same thing here for summer time heating.
cool. Check out Curtis Albrecht down below. He has a good working system and a detailed video.
If you have surplus of hot water, you could run that thru pipes in floor and help with in floor house heating perhaps.
Seems like combining the two tanks makes one tank. What keeps the AC tank from radiating heat back into the cooler DC tank?
Interesting video. Great idea. Wondering what happens in the summer if you are not using hot water. Will the system overheat?
do you keep your lovely heating element even while sleeping?
curious your heater ac controller on the water tank still working? it should run ac 24v to the thermostat then to a relay to control dc to the element (safety)
You can use the water heater roof type panels in winter antifreeze goes in the circulating system
This is okay as long as you’re thermostat never gets to temperature to shut off. DC voltage will weld the contact’s together and never shut down. Keep small scale like this and you won’t have a mess to clean up. I personally had the same idea 15 years ago but made a 200 volt 60hz dc chopper mosfet circuit that works great. Free hot water with no modifications to hot water tank because it’s kind of AC -off -on at 60hz instead of a grid sine wave.
Hello, I tend to do the same setup, but what happens if the mos fet burns and remains in on state?
What about using DC SSR switched via ac? The water heater thermostat could turn that on/off right? If dc is needed to switch the DC SSR you could use a small wall style transformer to turn it to dc to control the SSR.
I am thinking of doing the exact thing... which brought me to your video.... one thing concerns me... my home water tank is set at 135 degrees.. mainly to lessen the chance for microbes to grow... bacteria algae etc... so wondering after all this time... have you had any issues with the PV powered tank growing microbes since the water temp being much cooler is ideal for them to grow.
Are you circulating the water from solar tank to grid tie tank constantly? If not, how is the hot water helping? Themostat would keep conventional power on in 2nd tank.
You save a lot of power if you put a 1 hour timer on the house powered heater. You can switch it on bypass if Desired. Saved me maybe a 100 on electric bill.
I really want to do this. Do you happen to have a material list?
Did you ever do a full sun test on the water temp? Thanks
Even with a relatively low current output the 24 volt nominal panels will eventually burn up the contacts of your AC thermostat. There is a simple way to avoid this though, especially with the low currents you are running: Wire a capacitor across (in parallel with) the thermostat contacts.
What this does is provide a secondary path for the current for a brief moment when the contacts open. With tends to massively reduce or even totally eliminate any arcing.
A grunty 6 microfarad non-polarised capacitor such as those found in fluorescent light fixtures or motor start caps would be ideal. This only works for DC - it wouldn't work on AC as current would continue to pass.
That is smart. You went over my head a bit and I will have to study a bit to figure out what "A grunty 6 microfarad non-polarised capacitor" is but I think i get what you are saying and I will keep working on this. Thank you for your feedback, i take it seriously.
If you get your hands on an old fluorescent light fixture open it up and inside you'll see a white or grey plastic cylinder (occasionally they are a shiny metal cylinder) with a couple of connexions on the end. That's the cap you want.
Rip it out and connect one terminal to the wire feeding your thermostat and the other to the wire which goes from the thermostat to the element. Easy as that. Doesn't matter which way round you connect the cap as it's non-polarised. But keep the wiring as short & as close to the thermostat terminals as possible. This increases the effectiveness.
xanataph Thanks for the tip.... I'd COMPLETELY forgotten about using a cap as an arc snubber! Brings back my old points and condenser car days.
xanataph Arc Suppression
When a switch/relay is opened an arc can develop across the contacts which over time can erode away the contacts over time. To prevent the contacts from being eroded a RC network is placed across the contacts. When the contacts open the applied voltage is placed across the capacitor and not the contacts. The capacitor is to charge up at a rate faster than the contacts open thus preventing an arc from forming across the contacts. When the contacts close the inrush current from the charged capacitor and source can be substantially higher than the contacts can safely conduct causing the contacts to deteriorate. This is why it is important to have a resistor in series with the capacitor. The resistor acts as a current limiter which reduces the inrush current by a significant amount that the arc caused at contact closure is greatly reduced extending the life of the contacts.
C=I^2/10
R= V / ( 10 I ( 1+(50/V) ) )
Example: 120vdc @ 10amps.
C=10uF
R=141Ω (150Ω)
240vDC @ 10 amps
C=10uF
R=300Ω
Interesting formula. I have considered the situation of the charged capacitor being shorted out when the contacts close, but I determined that to be less of an issue as the relay I am using in my case is rather substantial and the voltage is only 24 volts nominal. I suppose there could be some arcing though when it closes as contacts always have a tendency to "bounce". How is that constant of 10 in the formula determined?
How about legionella bacteria's in the DC-tank? How do you prevent that? By using the water in it every day and not have it longer then 24 h in there?
You are best to keep the voltage higher I use a 230 volt element with a series solar array to match that voltage of the element the problem is it drawers a substantial arc when the switch is opened this can be overcome with a capacitor across the switch a good quality cap must be used I use a motor run capacitor 4uf 450 volt something a bit smaller is ok
@Mr Sunshines actually you can 100% run an ac element from a DC system, it's just a resistive load. The only difference is that with DC your disconnect ARC (the spark that happens when you disconnect a DC load) will be MUCH greater than an AC system, hence why you would use a 'snubbing capactior'
Been thinking of doing the same thing with a dump load heater
I've done similar. We have 3 water heaters on our place.
#1 in my shop 1/2 bath is a 28gal under counter 120v single element that used to be in location #2. Right now, I run four 175w/35v/7amp panels in parallel to a 1200w 36v DC element (Dernord brand, Amazon). It will heat water to the 110-20 degree range.
#2 is a 28gallon 240v 2 element tank. I replaced the bottom element with another 36vDC element like above, but and replaced the top element with a 1500w 120vAC element (because I only had 120v to work with) that I wired thru a switch. The solar feed is five of those same 175w panels as above instead of four. That heater is used in a work room we have that sometimes we need a lot of hot water (hence the 120vAC element), but often only need some standby hot water (the purpose of the DC element). That tank will heat to 150+ degrees, and I ended up using the AC thermostat that came with the tank to control it. I wired 120vAC thru the thermostat and a relay to send the DC power to the element. The contacts in that thermostat are not rated for DC power is why I did this.
#3 is our main house water heater.....a 40 gallon propane. I had a 120 gallon tank left from something else, and plumbed it inline ahead of the propane tank to pre-heat water the way you did. It has one 36v 1200w element in it, and five 245w panels in parallel. So far (just been connected a month starting 1 December), best it will do is heat the tank to around 80 degrees. Low sun angle right now on the panels, I expect that to improve on into spring. Even so, the propane savings from heating water to 80 degrees over the incoming 50 degree temperature will save propane.
The one big advantage of using PV (these were all used panels that were cheap) over a batch type or vacuum tube type heating is, as you said, not having to deal with freezing water, running glycol in a closed loop, pumps, controllers, etc. A PV setup like this is dead simple.
while that is a lot of water heating adventure i commend the effort to break up appliances and individually power them rather than going for a large system that fails as a singular unit or requires grid connect or expensive battery install. Question though on tank #3 with the 40 gallon propane primary and solar pre-tank... You said that pretank is 120gallons but only mention a single element supporting it.. i think you should shop around for some 300plus panels and large DC element to install in the bottom and move the 36v-1200 to the top. Propane unlike NG is going up faster than Elon Musks EGO. I agree about the vacuum tubes unless your setting up some sort of heat pump booster the systems get to complex and require to much maintenance.
Thanks!
Thanks for sharing
Sweet!! That's what I'm talking about. Its got to save money. I have two free 150 watt panels I want to do this with. simple not too much fuss.
I appreciate the video. Love the experimentation. Unfortunately, you negated ALL of the possible savings you might have had from the supplemental Solar heater by using a 120v heater in the second heater. If you simply ran a 240v Element in that heater you would have halved your energy usage, which is why high amp draw items in the home run on 240v.
That is not true! Hydro doesn't charge you per Ampere Hour, they charge you per Watts Hour. You will half the Amps, but double the Volts, which equals the same, only wires will be thinner.
Need a connector for the cable going into the water heater on the right.
Great system.
may be som solar lighting so we can see what you are pointing at thanks
Listeria might become a problem in the low temp solar tank. It grows in tanks with water below 120f.
I just started to post a similar comment, that the first tank would be a potential breeding ground for bacteria. While in theory the second tank will probably heat it enough to kill it off, that's assuming water will always stay in the tank long enough to kill it. In the real world - especially if you're running a lot of hot water at one time - there is a likelihood of water being pulled into the second tank just long enough to be pumped back out again. If you end up with a runaway bacteria problem in that first tank, it could pose a serious health risk.
It also grows only in places where there is no water flow. It could be a problem in big commercial water tanks and not in a small home tank where water is replaced daily if that makes sense.
@@gregfromthevaley makes sense but do you know how fast it grows in a tank? Would a day or two be enough? I’m wondering if taking a weekend vacation would be enough time for the water to stagnate and allow listeria to grow.
That's an interesting point. If the chlorine PPM was at 1 or above, I thought it would have killed any spores along with the bacteria and pathogens.
Would it be worth insulating the tanks so they retain the heat better. They used to make strange jackets for hot water tanks to keep them warm! Red ones!
I bought the 600 watts and did the calculations (600/12 = 50) so that’s 50amps per hour on my 300AH lithium batteries that’s a lot isn’t? If I use the original element (1400 watts / AC 110volts it’s only using 12.7amps per hour. That’s a big of a difference. Any input on this?
You could try an AC mppt controller from Microcare a South African company who builds them. Uses 4 pv panels and no more ac needed
Where did you get the elements from?
Did you look at the tech luck mppt ? If not might help heating more water faster.... works outstanding...
Good idea, how it works on winter? I have similar idea, i want to find a way how to redirect power from mppt to my boiler when battery is full, so i can use that wasted energy on water.
Dino Pasic
... that's an easy answer but will require some math to see how long the pay back might be. All you need to do is rig up another water storage tank (water heater should work) and connect everything via a relay so when one system is done it will switch to the other, (the tank) which you plumb in the return side of the boiler to catch the cooler water after the radiator loop but before the boiler itself. You'd have to fool with the aquastat settings so your preheat tank will be at a higher temp than the lowest boiler settings. Typical boiler will be set at say 160 degrees for the low and 190 for the high. Going below 160 may not give you enough domestic hot water if it's a tankless coil and you may have trouble getting a normal electric water heater up above that... but there are modifications that can be made if you re good at that stuff. Personally I would not expect much in the way of savings because you'd need to generate many hundreds of gallons of water daily to make much difference... and a boiler can do that in an hour for the cost of 1-2 gallons of fuel oil. See where this is going?
That is a True Hot water heater
its an amazing idea...
Why use second tank? why not add your dc element next to the ac element ? How much savings have you realized? Also would be interested in determining size of pv panel in the application. thanks , seems the way to go
It's dowable, but a pain... There are only two ports for element or you can do it externally. I have a rocket stove externally.
You do have a point!
Dear Sir, i want to use 02 Charge Controllers 30amp and 06 PV Panels@ 3 Panel with each Charge Controllers and 02 Batteries 200ah in 12 volt Dc. I want to use only DC power in my all rooms with 6guage Wire, DC Fans and Dc lights. My question is how i handle 02 Charge Controller 12 volt dc.
1. Can i joint both Charge controllers with same batteries 2x200ah bank? Boht charge controller will charge the batteries at the same time?
2. Can i use Dc power for use of my appliances from both charge Controllers on same time as parallel or use Dc power from Batteries for house uses.
My appliances Load will be not more than 34Amp 408watt.
Please guide me if possible.
Question? You mentioned these double dc water heating elements aren't specific on how you wire them. I don't understand why there are 4 terminals, how could it not matter? I just received a dc element like this and have tried it a couple ways and it sparks when I connect to my battery. Is that normal? I am using 12awg wire but it started smoking. The element is 300 watt 12 volt. Does that mean the wire is too small? Thank you in advance.
what if i have a 230/400v electric water. heater? wich pv should i use?
I try an 220 volts hot water unit with the original resistor and connect two 385 watts panels in parallel and works good.
Have you how much energy does your resistor draw from the PV panels?
You got a nice set-up there. And you planned this out pretty smart too. I'm trying to alter my solar system to run from just a few or a couple panels to heat my water away from my household solar system. My water heater is 30 gallons and uses too much of my solar power, so I want to convert the heating element from a 220 volt 4000 watt system to just using the necessary amount of solar panels wired directly to a specific heating element. Hope this makes sense? Anyways the real question here is how do you determine how many panels you need and to what type of heating element to use. There has to be some compatibility of the panels to the heating element, correct?
Wattage and BTU calculations is the cut and dry answer.. the long answer is everyone's situation will be different and dependent on season ( may have to add or take off a panel or 2 in seasons), hot water consumptions, storage tank size, incoming water temp (is a big factor), panel type, output, design/wiring configuration, control systems, and list goes on. For a roundabout answer you would need 3-5 panels of 300-375watt to charge a 50 gallon tank under very low daily consumption rate. This could be done with a dual element tall tank using the bottom element only and could be as simple or as complex as the DYI'r wishes. Using the bottom element accounts for thermal stratification which would reduce the cyclic rate of the upper element provided all is working well. As others mentioned there are limitations to using mechanical thermostat controls for DC power keep that in mind. The TPS will be as it was before a safety and will require to be plumbed properly as many are not ever.. The particular point of this specific video is to have pre-tank storage and secondary electric to take the most advantage of both sources of energy. It is possible to fully solar, single tank dual energy, or to split tank as shown. Split tank would seem to be the most efficient but ONLY if using the low boy style tanks and using good insulation practices. If your not doing those 2 things the surface area and low efficiency of standard tall tanks come into play. If your capable there are people out there modding arduino controls i personally prefer mechanical controls on everything if i can have it. There are both dual and single element versions of low boy (short tanks) in both 120/240 options but always consider the smaller the tank the more efficient for a few reasons. These include but are not limited to less surface area for thermal transfer, much faster recovery rates if properly powered, and less storage mass to prepare and maintain at temperature for use. A low boy 20 gallon dual element tank can recover over 12 gallons of water during a depletion event this means it has an actual capacity output of 30gallons at a set flow rate. The larger the tanks are the less gallons are recovered during a depletion event and the more is lost to surface area. This is something the content creator didn't touch on that is beneficial to him but he may or may not know and may or may not be under powering the units as well as he obviously has to much faith in the insulation of these units. Using a Pre-tank even if it isnt powered directly but picks up heat from a conditioned space alone adds efficeincy due to not heating the water from incoming temps 35-50F but rather have a tighter temperature differential. Say the home is heated with wood heat usually there is an abundance of such a heat a pretank could be installed near that wood burning device and look more like a radiator than a pre-tank. Also that incoming water temp is said to be common reason of heating element damage along side of scale build up because the element sees to drastic a change to quickly. Him and many others add risk by not heating the water high enough which is a concern for specific kinds of bacteria (not my field so no comment). The solar pre-tank should be set to 130F and the primary at 140F and if the fleshlings are to stupid to modulate water at the faucet then a mixing system should be installed to control temps. These higher settings allow for smaller systems to act as bigger ones in the common situation a depletion event happens like your teenage make-up monster swapped your 30 gallon maytag washer to hot water wash cycle just before your credit card holder wants to do the dishes. The tanks/lines should be stored in insulated closets/cabinets/enclosures, even if he had had them in conditioned space because if we are penny pinching to keep the electric monkey off our backs why the hell would we throw bananas on the floor. Going to stop here as adding anything more is a waste as not many people would ever see it nor bother to use the info because it wasnt off of tiktok.
@@masterdebater8757 interesting points and ideas added......but boy I feel sorry for your credit card holder......
Your arrogance is repulsive and negativity unbearable. (The true reason your intellect goes unappreciated or why "no one will ever read it")
@@mikeb4824 Few questions for you. What is it you found to be arrogant in my reply? Why do you assume i use credit cards? How is it you reply if "no one read it" or did you mean your "no one"? If this is some attempt to troll it landed on deaf ears since it has no bearing on the topic of conversation we adults are having here. If you think my lengthy reply in some way makes my statement arrogant, you should consider that some of us have the ability and capacity to exchange large amounts of worth while information in a matter of seconds. That said will you be joining the conversation, I.E. if you have the intellect to do so.
Insulating those lines and even the heaters can help too
is more voltage is heating the water or more current???
Would this work to heat up a boilers water for heating a house
What is the difference between a DC and an AC element? Resistance is resistance.
ikr
There is no difference.
The thermostat switch has to be stronger because the DC arcs more than AC when the thermo switch opens.
I was curious about the std. ac heater elements. A guy on eBay was selling what he called a DC element. When I ask why wouldn’t a regular AC element work with DC input. He never answered, so I experimented with a std. AC element connected to 1 solar panel in a bucket and it heated instantly. Apparently dc input to an element either dc or ac still works.
My only concern is what happens when the temperature exceeds the temperature setting, I assume the safety is the pressure valve that will automatically open and avoid creating a bomb. I am going to retry my original idea of using a old hot water tank remove the thin metal case of the exterior, paint it black and add one conventional AC element and connect to a solar panel. My application will installed on my roof. Again, my only concern is over heating the water. However I hope that the pressure valve will be sufficient.
Jeff please do it little more on the connection on your next video. This wonderful. I need the 24 volt element. I have lots of panels it need hot water
You can use the existing 120v element and 4 or 5 solar panels. Better. Need a dc thermostat
Can you compare why a DC solution is better as compared to an AC solution?
So you don't have a battery ? The solar panel is wired direct to heating element?