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This is between an off-grid project and a mains electrical project. So, I wasn't really sure where I should post it. The Mains, Solar, Wind & Hydroelectric Power forum won.
So, it just so happens that I have 3 - 100 watts panels sitting around collecting dust, and not producing a single watt of power. I also have 135 watts panels doing the same. So, I need to come up with a little project for them. Anyway, the 100 watts panels project, for now.
I am going to buy a (cheap Chinese made) 6oo watts grid-tied inverter. I will then connect the 3 - 100 watts panels in parallel, directly to the inverter. Then, I will plug the inverter directly into a mains power point (wall receptacle). That will sync with the mains and start pumping up to 300 watts directly into the electric veins of the farm, depending on the amount of sun they receive, of course. This will help alleviate some of the power needed from the mains to run the farm.
Anyway, these inverters run between about $82 USD to $120 USD, each. That would buy you a 500 watts, up to a 1000 watts grid-tied inverter.
The reason behind powering a 600 watts grid-tied inverter with only 300 watts of panels, is so as not to overdrive it and possibly cause it to fail, catch fire, etc. The last thing you want to do, is to overdrive a cheaply made inverter, or any inverter for that matter. Besides, you can always buy another inverter, and three more panels to connect to it, then plug it into the mains. The second inverter will sync with the first, as well as the mains voltage.
Also, when you experience a mains power failure, these inverters will automatically shut down in order to protect anyone who may be working on the cables. You certainly don't want to be responsible for someone getting electrocuted. I know I don't. Once power is restored, they will come on line again.
Anyway, as soon as I get around to ordering one of these, and receive it, I will give you good folks an update on this little project. If this works out okay, I will definitely expand the system so as to reduce our power bill even more, each month.
SUMMARY: A grid tied system can help you kill your power bill, by back feeding power into the mains. It is as simple as installing an array of solar panels, connecting them to a grid-tied inverter, and connecting the grid-tied inverter to your mains power in your home.
The second panel came in today. Now, the array will be at 270 watts, 24vdc, more than enough to keep my electronics running during power cuts. Actually, I could keep it running 24 / 7 off this system, with no problems.
The panel set aside for mounting after arriving at home.
The pole mount, prior to the second panel being added.
After the second panel was added.
New input voltage with 2 - 12vdc, 135 watts panels in series - 27.0vdc.
Well, they were out of 100 watts modules. They, however, had a limited supply (READ: one) of 135 watts modules. So, we got the 1-135 watts panel and headed home. (I needed something to at least temporarily keep a charge on the batteries.)
Fortunately, thanks to a friend, I received my Midnite Kid MPPT charge controller. I had been waiting to arrive for four months. Some things are just worth the wait.
His wife came over and brought the controller with her, saving me $100 USD in shipping costs. He will be arriving the last part of the month with some other parts, as well.
Hopefully, I will pick up another one of these panels by next month. Two in series would be fine to charge a single 120 AH battery.
It's a bit more bulky than the 100 watts panels are, at 11.5 Kg. It measures at 1482 mm tall by 676 mm wide. I bought it for $1.30 / watt.
Power cuts? Brownouts? Mains interruptions of any kind? No worries. You can still have lighting around the outside perimeter of your home / property. We do.
I bought three (3) 12vdc, 10 watts flood lamps off eBay, late last year. They cost a little over $10.00 each, shipped. Three of them together only draw 2.5 amperes. Taking their compact size into consideration, they actually light up a decent sized area of the property.
Installing them, along with a controller that will automatically switch the lights on and off, is a dream. Basically, set it and forget it.
Below is a 20amp version of the (10 amp) controller I have. They are offered in both 10 and 20 amp ratings, as well as for both 12v and 24v applications. (20 amperes at 24vdc, would be a LOT of exterior lighting, especially if using LEDs.)
The jumper on the last two terminals lets the controller know if the batteries are sealed or flooded lead acid. You remove the jumper for flooded batteries, and leave it in place for sealed batteries.
By turning the dial on the right side of the controller (using a small flat blade screwdriver), you will determine the on-off or on-off-on operation of the load (lighting) circuit. There is a distinctive "click" between setting positions. Do note that it takes a couple / few days for the controller to "learn" dawn and dusk times. But, once that is set, it automatically adjusts, daily.
NOTE: Days of autonomy will depend on how many watts your lighting is, and how many hours per night you have the lighting switched on.