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

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.

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??

Could a DC ground fault cause galvanic corrosion?

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.

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.

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.

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.

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

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.

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

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.

Ye kess chiz sa banya ha zara hama be samjawo

ikr

There is no difference.

The thermostat switch has to be stronger because the DC arcs more than AC when the thermo switch opens.

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?

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.

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.

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.

Have you how much energy does your resistor draw from the PV panels?

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.

No pump needed thermal Sifoning. SCOTT FROM N.S.

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!

nah... he's letting a passive low voltage thing do most of the heavy lifting now.. .that has to be saving more energy

Or, have an on-demand unit as your secondary.

Why dont you just have 1 tank with 2 heating elements. 1 solar and 1 mains. Adding 19 gallons of water into the system is necessary and inefficient .

@@thomasgallagher5224 ... you could do exactly that but the two element tanks will create their own problems with temp stacking. IOW, the bottom element can heat the whole tank (if you have the time, heat rises) but the top element will only heat the top of the tank (heat never falls) so a 30 gallon tank might have maybe 10 gallons of useable warm water if the bottom was heated by solar and it was a cloudy day and you had to fall back on just the top element.

@@thomasgallagher5224 because solar is slow and not always active when the water is consumed. If you drian a dual element tank that has solar and mains electric both will kick on till the water is heated.. With a solar pre-tank less chance of depleting because 2x the size and gives more time for solar pretank to recover from incoming temps rather than using mains electric.

@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'

You can use the existing 120v element and 4 or 5 solar panels. Better. Need a dc thermostat

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.

should be standard 110 volt 1000watt element . allready have a 40 gallon tank going to change lower element to 110 volt 1000 watt element for pv solar. going to plum in second tank and use a inkbird itc608t to control first tank with a small pump to second preheat tank for over heat in summer. maybe 3 more panels and element just for extra water heating in winter if needed hope it works

Yep your right it would be better to have the DC element in a duel element tank with the thermostat on the DC set higher and the AC thermostat set lower so the AC shuts off when the solar has the water hot enough.