Instructables

How to Make Any Home Appliance Into a Solar Electric Hybrid

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Picture of How to Make Any Home Appliance Into a Solar Electric Hybrid

This project is a simple and cheap way to integrate renewable energy into your home by turning your appliances into solar electric hybrids. Here is how it works. A solar panel (or any other renewable power source) charges a storage battery. A control circuit continuously monitors the battery's voltage. When the battery is fully charged, the circuit automatically turns on a power inverter and switches the appliance from running on grid power to running on the energy stored in the battery. Then when the battery's voltage drops too low, the circuit automatically switches the appliance back to grid power until the battery is recharged.

This design doesn't require any modification to the appliance or your home's electrical system. It can work with any power source that is capable of charging a 12V battery (examples: wind turbines, bike generators, etc.). But most importantly the system is scalable. This design is set up for outputs of up to 75 watts, but by swapping out parts for ones with higher power ratings you can power larger appliances or multiple smaller appliances at the same time. This lets you build a system that fits your energy needs and your budget.

I am still trying to make improvements to the design. So if you have any questions, problems or suggestions please leave a comment. I would really appreciate the feedback.
 
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Step 1: System Overview

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Here are the five basic parts of this system:

1. 12V Solar Panel (or other renewable power source)
2. 12V Rechargeable Battery
3. Control Circuit
4. 12V Power Inverter
5. Automatic Switching Circuit

When assembled, the solar panel, battery, and inverter plug into the control circuit. The automatic switching circuit plugs into the inverter and the wall outlet. Then the appliance plugs into the automatic switching circuit.

The solar panel, battery, and inverter may be purchased off-the-shelf from a variety of locations. The last two parts of the system (the control circuit and the automatic switching circuit) will need to be constructed. This is detailed in later steps.
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hey ive done this project but i do not get stable output from the inverter. The relay in the switching circuit just goes on and off all the time. The battery gives constant 12V but the inverter dosent. What should I do?

When the inverter turns on and starts power from the batter, the battery's voltage will drop. And then the inverter is disconnected, the voltage will go up a little. So if your two voltage points that are set by the resistors are too close together, it may go back and forth very rapidly. So first, try making a bigger difference between the two settings. The high voltage should be somewhere around 14 volts. The low point should be about 11.5. This effect also is more dramatic the smaller your battery is. So a larger battery may help.

nukepredator2 months ago

how can we test if this circuit is working or not on the bread board?

The easiest way to do it is to make different battery packs with different voltages. 8 AAs make 12 volts. 10 AAs make 15 volts. This lets you try out different voltages to test when the system switches on and off.
nukepredator2 months ago

Thank you for the help but again i am having some trouble. Now i am trying to set the potentiometer but if i set the value to 8600 ohms between wiper and positive terminal, i get 440 ohms automatically between negative and wiper. How do i get 1400 ohms on the negative side?

The exact values are not really important. What really matters is the ratios. If you adjust it so that they ratios are the same as the ones listed it should work. Or you could simplify things and just used fixed value resistors with the appropriate ratios. You won't find exact values so just get close.
nukepredator2 months ago

Sorry to ask such a silly question but what is "8600â" and the other values in that potentiometer section u described. I mean is that ohms or something?

And how do we set two values in one potentiometer, like between positive rail and wiper and negative rail and wiper?

Plz do answer. I am having a hard time getting this :P

Yes. That was supposed to be ohms. The text editor messed up the symbol. Use a multimeter to measure the resistance between the pins and adjust them until they match up with these values.
yolande132 months ago

I would like to know what type of house hold appliances can i use in the house? We will be moving to a house that solely working with solar panels? Will i be able to do washing with a top loader,or even do ironing? Please help this is all new things to me. I was use to electricity.

DIY Hacks and How Tos (author)  yolande132 months ago
The system that I describe in this project isn't really suitable for powering a whole house. But with any solar system, you need to balance the power ratings of the appliances to the power rating of the inverter, the battery and the solar panel.

This is awesome. I an going to try this form my laptop!

I think this is a brilliant idea, I woud just like to know if its possible to "over charge" a battery? I'm just trying to think of what could go wrong. Because if this goes as well as I'm hoping it will, I plan to make this into a small house system where all of my electronics run solely on solar power.

If you set the charge controller circuit properly, then it shouldn't over charge the battery. The main advantage of this system is that it can work on a small scale, if you intent to power your whole house, then it would be more efficient to use a professional system that is designed to power a whole house.
Conquest1027 months ago

This is going to be my first follow thru instruct able. NO experience doing circuit boards but this project is PERFECT for my needs. I am have a problem with the control circuit list.The optional items what are they needed for and what happens if not used? How about a picture of the backside of the board? So I can see the traces please.

The optional parts are for a charge controller circuit that prevents the battery from being over charged. But this isn't necessary if you regularly turn on the appliance. Sorry, I don't have the original board anymore. I gave it to a friend. So I can't get any new pictures of it. You will just have to follow the circuit diagram.
boardsmm7 months ago

This is BRILLIANT! Any guidence on the improvements you suggest?

THANK YOU!

tygger2812 years ago
VERY NICELY done! I do have a comment / question: We decided to use the complete kit because it came with "compatible" lights that just plugged into one of the adapters on the inverter that came in the kit.

We put one on the back porch and the front porch, and bought a cute, very small Kitchen cabinet. We painted the cabinets to match the house and BOOM, we are off and running!

The cabinet was PERFECT because it had two shelves - one for the inverter, and one for the battery. We were using the existing lights - two came with each kit. We hung one set on the back porch, and one on the front porch. So, the battery started charging, and within hours, had lights on the front and back porch!

Our first set of lights blew out most likely about two months later. We went BACK through the instructions, and could find nothing. We tested the solar panel by charging another small battery. It was charging fine. We found something to plug in one of the other ports on the inverter, no issue. So, I went to the store to find bulbs to fit in there; there is nothing else to fit in there that is the correct voltage. ANYWHERE.

So, called HF - and they said, yes, we can send you new replacement bulbs at no charge AND it would take six weeks to get them. What was I going to say but ok. So, new bulbs come, we plug them in - they last two weeks and *poof* they die again. I called again; they said it would take four months this time. They had stopped using those bulbs and that inverter in the kit.

At one point shortly after this, the inverter did die. So we called for a new inverter. Got one after 3.5 months (of course, still waiting on the light bulbs). We hooked up the new inverter. Tested the other parts of it, it seemed to be fine. New bulbs finally came - they worked for less than a day. We gave up on getting more bulbs.

The front porch bulbs lasted nearly a year. Then they died. We never tried to get them replaced. In the meantime, we moved the back panel to our chicken coop, and use a small water pump for emptying out the excess water barrel, if needed, or reuse the water in the yard.

We still use the front porch panel as a trickle charge battery charger for the horse trailer and scooter batteries. But we are not using the inverter.

Is this why you are not buying the kits? Have you ever had similar problems with your inverters? Thanks!!!

u know that harbor freight buys from a Chinese company all u have to do is look up alibaba.com to find yr type of light bulb. while yr there u might find other things as well
My experience says that an inverter needs space for cooling (air), never inside a cabinet, unless there are 2 fans (in an out blow, computer type). Above this, if the label says a wattage, never connect more than the 80% of this number of watts.
Following this rules my 80W inverter works for 4 years... and counting.
luvasu luvasu2 years ago
I've different solar panels (7) up to 105W, feeding several 7Ah and 12Ah batteries, up to 186Ah, using a 10 Amp control charger (near to the limit 9.7 Amps)
On use (nightime) 4 inverters (120+120+80+80 W), sometimes at the same time, but not often.
Only mi first 7Ah battery has been replaced after 8 years duty, because not recharging above 4 VDC. (Similar to the one showed in a picture above).
My battery replacement is mandatory after 10 years duty (that one was a surprise).
None of my components were part of a commercial kits. I just assembled it from off the shelf parts. I haven't been running my system very long but I haven't had much problems with my lamp setup.
Oh, you are showing the kit in the final photo. Please let me know if you had similar issues.
Any idea if this would work by converting a propane water heater to solar electric hybrid?
It isn't really a good idea to use a solar panel for heating. It would be far more efficient to use a solar collector like these: http://www.instructables.com/tag/type-id/?sort=none&q=solar+hot+water
if any possible to connect the solar system into normal home inverter. if it is possible means how it is?
youcantoo1 year ago
What is the switch time for the relay?
The switching time just depends on the relay that you use. I couldn't tell you the exact timing for the relays that I used but in many cases it can cause a noticeable fluctuation in the output. So this kind of design is not suitable for for sensitive electronics. I just used it to power a lamp.
youcantoo1 year ago
Don't use car batteries for your project. They were never designed to handle the requirements of a solar or wind powered system. Yes they maybe cheaper to buy. The car battery was designed to handle the initial load of starting your car and then be charged back up. A solar/wind system does not do this. You will find a car battery will last a short period of time under these circumstances. What was cheap to buy the first time then becomes a expensive replacement cost. Consider paying more up front for a deep cycle battery. You can even buy good used deep cycle batteries like forklift or golf cart batteries. They will well out last a car battery and yu will be money ahead.
useful12 years ago
This seems like a setup I can use. Thank you for posting it with clear instructions.

If I understand it correctly, it seems like an always "on" setup, meaning that when the batteries are topped off, you'll use battery power. Once the battery reaches "low", it switches to the power on the mains from the electrical company.

The relay switches is what controls the path the electricity takes.

Couldn't the problem that "involves regularly cutting power and switching to a second power source that may be out of phase", be solved by adding a UPS backup after the automatic switching circuit and before the light bulb? (as shown in your diagram)

- U
Really if you are using a UPS there would be no need to have the switching circuit as the ups has it already has that sort of circuit built into it.
DIY Hacks and How Tos (author)  useful12 years ago
Actually a UPS was my original concept for this project. In my original design, I took a UPS, and disabled the internal charging function by adding a diode after the battery. I set up the battery to be charged by a solar panel. Then when the battery was charged the control circuit would just cut off the grid power from the UPS and it would smoothly switch to the battery power. I decided to go with my current design because I was able to make it a little cheaper.
useful11 year ago
Just wanted to say, I built this system 2 months later and seems to be working great. The only part that I found frustrating was setting the value of the variable resistor on pin 2, to adjust when the control circuit switches off the relay going to the inverter.

Every time, I kept trying to test the value of pin 2 while the inverter was on, the relay would click and I could not get an accurate reading of the voltage while the system was under load. It was pretty frustrating. The only way to set the low end, was to use up the battery power until it reaches somewhere near 11V and turn the dial down until it clicked off.

But even then, I still don't know what the voltage reading is coming into pin 2.

DIY Hacks and How Tos (author)  useful11 year ago
Thanks. I'm glad to hear that someone else was able to get it to work.
orenyny1 year ago
Great project thank you! My question is if it is possible to do a hybrid that will keep the battery charged (from those 12V sources you mentioned), but if they run out (no wind and no sun) it will top of the battery from the grid.
In addition, it will be tied to the grid so if the battery is full and the solar pannel is generating electricity, it will feed into the grid, and finally, when the grid is down, use the battery (emergency).

Thanks!
DIY Hacks and How Tos (author)  orenyny1 year ago
There are a couple of devices that are similar to your description. I grid-tie inverter would let you go directly from the solar panel to the grid without needing a battery. On the other hand, an Uninteruptible power supply would let you keep the battery charged with the grid and then use it if the grid goes out.
I'm not terribly good with schematics, could you post a pic of the underside of the control circuit board please?
I'm also having a hard time with figuring out the orientation of the relay on the breadboard, thanks so much!
I will try to get another picture added. But in the mean time, you can get a good idea from the breadboard layout on step 8. All circuit parts were purchased from RadioShack (see step 5). So you can just align them the same way that they are in the picture. I hope this helps.
Is this the same relay? pinout and all?
http://www.mouser.com/ProductDetail/TE-Connectivity/OUDH-SS-112D000/?qs=%2fha2pyFadui2QAjXzdmwdlJkRYZqifB3R%252baei18HFruUr665Gub%252bLA%3d%3d
I sourced one a bit different but i have to move things around.
Those panels look like thin film silicon panels, which tend to be the cheapest type of solar panel, but only run about 7 to 8 percent efficient. Currently the most efficient panels available to consumers (at 20 percent efficient) is the Sunpower E20 at 327 watts, at about 17 square feet of panel (including the gaps between cells and the frame. These panels run between $700 and $800 per panel (by the way, it is a mono crystalline silicon panel, which tend to by more expensive and more efficient).

Just thought I would add a little useful info


cheers
Ultra Computers
The question is: are those 20%-efficient cheaper than 3x the price of the 7%-efficient ones?
If it's more than 3 x as expensive, then might as well get three cheaper ones (if space allows)..
it will be cheaper and gives the same output.. or, in other words, it's more cost-efficient...

cheers.. :)
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