DIY Solar - Episode 14 - Hybrid Solar (PV) Hot Water Heating - Update
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- เผยแพร่เมื่อ 11 ม.ค. 2025
- In this episode, I provide an update for the last video I posted about the Hybrid Solar How Water Controller.
So far, everything seems to be working well. I have plenty of hot water despite having disconnected A/C power from the lower heating element and replacing it with the connection to the solar controller.
Nice update sir , can’t wait to see how it does when you disconnect the upper element to see if your solar will do the job , thumbs up sir
You should be fine disconnecting the upper element. Our water heater ran on one element for a while before we realized the other one was bad. However, the time that will get you will be morning and evening showers. You have a large tank so maybe...
Water saving showerheads help a bunch too.
Thanks for the update!
I monitored my HPHW unit with a less than $10 panel power meter from ebay. This has a toroid transformer that you can extend sense wires to and just slip the current wire thru. This records the total hours, WH, etc and doesn't loose those values in a power outage. Would easily mount on your box. I kept mine portable and just plugged mine into a 120V outlet. I didn't care about slight voltage variations and just doubled the W and WH since it was measuring 120V. Although many of these are rated to work 240V, the resistors they use are not rated for that voltage. Half voltage makes them a little safer. I find my portable unit quite handy with only having to slip a single wire thru.
This is an old video but there are some problems with the installation of the electric cable and wire that can still be corrected.
1. The red and white wires on the right side of the box are passing through a metal connector which is designed to squeeze on to a cable (not insulated wires). The cable would have protected the wires from damage by the clamp. This metal clamp can cause a short circuit and fire. It is also a violation of the National Electric Code (NEC). This is easily corrected by using a connector which is plastic and designed for holding insulated wires.
2. The metal clad cable or armored cable which is connected to the box on the bottom and the water heater must be supported within 12 inches of the connectors. This requires the installation of a strap and anchor in the sheet rock and a strap and a short sheet metal or self tapping screw on the water heater's shell. If this is not done, the cable may eventually pull out of the connectors and put stress on the wires' terminals. This is also a violation of the National Electric Code. (I do not know if the wires are correctly connected to the heating element, but those connections must be made securely with a national recognized testing laboratory (NRTL) (like UL) recognized connection method. The reason for this concern is that the cable is connected to an inspection cover and not an manufacturer's supplied connection panel. The use of the inspection panel is also a violation of the NEC because once a product like the water heater is inspected and Marked by a NRTL, modifications void the Marking.)
Remember that the National Electric Code is written by the folks who are writing the various National Fire Protection Association and is designed to save lives and property.
3. The strange looking union between the cold water line at the bottom of the water tank appears to be an electrical isolating (dielectric) union. This was installed to electrically separate the hot water heater from the rest of the building's metal. The reason for this is to help the water heater's anode protect the inside of the tank from corrosion. Unfortunately, the metal cable's jacket and ground wire short-circuit the union's isolation. This will cause a dramatic reduction in the life of the anode and possibly the life of the tank as well. Be sure to remove and inspect the anode annually when you are flushing the muck out of the bottom of the tank. When the anode is corroded away, try to replace it with an electrically powered anode which is designed to last much longer.
nice job thanks for sharing we have one but going to run 2 for off grid
Amber & John Homestead Projects Great! I will be interested in seeing how a dual system works. I imaging you will get plenty of hot water from it. I just subscribed to your channel.
@@jimginnyohio Thank you so much for supporting our channel
That's awesome how it works I'm interested in getting 1.
At least your heading in the right direction. I don’t have a grid tie system, but when I do I plan on building your safety design. Did you see the new generation 2 tie grid inverter?
Matt Martin Thank you! No, I haven’t seen any new gen2 inverters. Do you have a link to those so I can check out?
Hi again, so how did your hybrid water heater work in winter? Is it still working?
What is your wattage of the lower element?
Hi Jim, so your board takes DC (how many volts?) and converts to AC at 240 volts? Or just 120v? Thanks Jim
j jones The off grid side can handle between 60-140 volts in (DC) and outputs 120v AC. The grid tie side can handle 60-90v DC in and converts to 120v out.
Regarding the water heater and sense meter not recognizing it. How electric waters work the Top heating element always has priority over the bottom heating element. and Only one heating element can come on at a time. Both heating elements cannot come on at the same time else it would put to much of a load on the breaker and it would blow. Of course now you have it wired so the bottom element can come on when ever it wants. but the sens meter can still tell when the top element comes on. If it is not sensing it coming on then it is because the solar panel is doing all the work. Just saying the sense meter would of never seen both elements come on at the same time even before your modification.
Jim. How much would you charge to make a controller box like you have I’d be interested. Thanks
barneyessing I would be happy to provide a parts list and sources for everything, but I’m really not interested in building and selling those at this time. Too many other projects going on right now and need to finish a few of them before starting more. :-) I hope you will understand.
@@jimginnyohio i would be interested in the parts list please thanks for sharing your projects
Is there a diversion algorithm in this device to maximize self consumption from your solar array while minimizing grid consumption?
On a different note, if you have a PRV, make sure you place an expansion tank near the street cold water line and after the PRV.
So, have you cut you energy bill by more than 50%?
From all the solar
No, still have quite a way to go for that. We seem to be power hogs...which is why I wanted to move some items to solar. Maybe someday!
I understand. Let me ask you. My wife died 3 yrs ago so it’s just me. Would the expense be worth it I think out per kw is $.08 maybe 10 cents. How long would it take to recover your outlay. Thx. Barney
barneyessing I use the following to calculate water heat energy.
WATERKWH = ( ( TIN - TOUT ) x GAL x 8.33 ÷ 3412.141633127942 ) ÷ %EFFICI
TIN - temperature of water going into the boiler (usually street line water temperature)
TOUT - temperature leaving the boiler (recommended minimum of at least 140°F to kill legionella bacteria in a few minutes).
GAL - capacity of stored water in the boiler or demand of hot water in the house usually between 10- to 30-gallons per person. This number changes depending on your appliances. For instance, if you have a European style washer, then your demand for hot water is less than with an American style washer. If you take a weekly bathtub instead of daily showers, then your demand for hot water increases, and so on....
%EFFI - efficiency of converting (in this case) electricity to heat
In your case, I estimated about 10.3 kWh per day for 40-gallons of water, 55°F incoming temperature, 155°F outgoing temperature, and 95% efficient boiler.
This is about $1.03 per day or $375 per year. If you spend between $1,000 to $2,000, in a similar system, then divide the cost of the equipment by $375.
look likes the board works like an inverter, isn’t it? Jim
Yes, it converts the dc power from the panels into usable ac power for the water heater.
@@jimginnyohio Thank you, Jim
Buy, where did you get those used solar panels? Can you share that info? 🇺🇸👍
@@adassociates8235 There is a seller on eBay named Fred480v that runs a company in Michigan City, Indiana. The company manufactures US made solar panels. They also recycle and sell panels that are removed from solar farms around the area. The used ones I purchased from him were Canadian Solar 315w panels that were only used for 3 years. I also purchased 18 brand new 255w panels they produced in his factory.
@@jimginnyohio Thank you, Jim
I don't understand why you didn't just replace the lower element with a 12 volt element?
does that device just invert to ac?
whipple whittle Lots of reasons! Go read the FAQs on the manufacturers web page since that would be much easier than me trying to enter all of those reasons here.
@@jimginnyohio i read all the manufacturers FAQs and i realized its just a inverter?300 bucks i can just change the lower element for 30 bucks to a dc element
whipple whittle I don’t think you understood everything you read then. Many others have tried that without success. I’ve heard many reports of people burning out those cheaper 12v elements. Also, it’s pretty difficult finding larger panels that output 12v. You ma6 have to go with a 24v element if you do it that way. Good luck though!
Your thermostat setting are too low to protect you against legionella bacteria. You may want to increase the settings up by at least another 20°F: Lower setting to 160°F and upper setting to 145°F.
www.hse.gov.uk/healthservices/legionella.htm
140°F might sound right, but depending on your heat loss factor due to pipe material, pipe thickness, pipe run, pipe insulation, and hot water usage, the bacteria may grow on the pipes rather than in the tank. So keep a safety fudge factor. In addition, if anti-scalding valves or mixing valves are used, then revise accordingly.
Keep in mind that cold water should be delivered below 68°F.
Eric Kosak Yes, I increased the temperature but haven’t had time to post an update video lately. Thanks for your comment.
Are you going to do an update on mppt controller and water heater performance?