Cloud Freeman wrote:
I am happy to discuss any and all of the details of what I want to do over an actual call (on Google Meet or some other chat app) when I find someone who knows how to set up solar systems that I can potentially hire as a coach.
It is for a very small house that is 100% off-grid, in a European country with 230v & 50hz. But all electrical devices are 220v here; just like everywhere else in Europe.
I am hoping that there is someone here who either knows someone or IS that "someone" that I can hire.
I'm willing to help, but no video chatting.
You adequately answered question #1, and sort of vaguely answered #2, so that gives me a basis for a plan. I'll assume that in your tiny house you will want lights, TV, a refrigerator, and a computer, all running on 230V 50Hz AC power. Based on my own personal experience operating my own off-grid system, I'll suggest you need ~3.0kWh of power per day.
Where are you located? Solar in southern Italy is going to be easier than northern Norway. It sounds like you are in a more southernly European location, is that correct? I'll guestimate that you might get 3.0sunhours (sh) of power in winter, and maybe 6.0sh in summer. A sunhour is NOT the amount of daylight. It is an approximation of the hours of FULL, power making sun, per day.
Your off-grid system will need four major components, the solar panels of course, batteries for storage, a charge controller, and an inverter. One type of system, commonly referred to as an AllinOne (AiO) incorporates both the charge controller, and the inverter, and also maybe a transfer switch, though I have a low opinion of them. They are mostly cheap, low-budget items out of China, assembled with the lowest quality components available. I'd recommend sticking with the good brands, like Magnum, Midnight, Outback, Schneider, and Victron. Pricier, but with a earned reputation for reliability.
Do NOT go with 12V! 12V is only appropriate if your application has wheels. 24V and 48V are far better for stationary home-based systems. All the brands mentioned above make both 24V and 48V equipment. For a tiny house, I'd say 24V is fine. If you are going to need to run a submerged well-pump, then go with 48V. I operate both at my own homestead, 48V for the cabin, and 24V for my
workshop.
Let's start with that 3.0kWh of power. How many days of rainy, no-sun weather would you expect at your location? I'll guess and say three days? If my numbers are off, feel free to plug in your own. Math will stay the same. Let's assume you need to pull 9.0kWh, 9000Wh out of your batteries, and lets say you have lead-acid storage batteries that don't like being drained less than 50%. That means you need 9000Wh/50% = 18,000Wh of power. At 24V, that would be a 18000W/24V = 750Ah battery. That is quite large. At 48V though, that number becomes a 18000W/48V = 375Ah battery. Not bad. Trojan makes a 380Ah L-16 sized battery of 380Ah, just the right size. They cost about 350 USD each. You will need to wire 8 of them in series to make a 48V battery bank. Each single L-16 weighs about 70kg each, about the max a single adult can lift.
That means the neg wire of battery #1 goes to the pos terminal of battery #2, and the neg wire of battery #2 goes to the pos terminal of battery #3, until you get to battery #8. So, once you have all the eight batteries wired together into a serial string, the pos wire off battery #1 and the neg wire of battery #8 get connnected to the pos and neg terminals of the inverter. Pos #1 goes to pos on the inverter and neg #8 goes to neg on the inverter. Does that make sense.
Assuming the batteries are charged, and you flip on the power switch, the inverter is ready to make AC power. I'll suggest you need a 2000-4000W inverter. I have Schneiders Conext SW4024, which I HIGHLY recommend. I assume they make a 230V, 50Hz version.
The inverter likely will have terminals labeled ACout. There might be three, hot, neutral, and ground. You run three wires from the ACout terminals to your main electrical box. The hot wire (maybe black or red) goes to the breaker main buss, the neutral (maybe white or blue) goes to the neutral bussbar, and the ground goes to the grounding bussbar. The bussbar is a 8-12cm long metal strip with screw-attachments to add individual wires. Here in the US, neutral is always bonded to ground. So a thick jumper wire goes from the neutral bussbar to the ground bussbar. Your
local code though might be different. Consult a local electrician about grounding in your local region. Most likely your ground will be a copper-cald steel rod ~3 meters long, pounded into the earth. A thick copper wire (4 AWG in the US) runs from the ground rod to the main grounding bussbar. Everything else needing grounding goes to that bussbar. Nowhere else.
Now, keeping the batteries charged. Now you get the solar panels. Those L-16 batteries will like charging at certain rate. Too low a rate, and they will slowly die from undercharging. A good target is 10% of the amphour capacity. For those L-16s that would be 38A. To get 38A, charging at least 50V, you need 1900W of panels. I like to include a fudgefactor of 85% to account for uneven sun, and overly optomistic power claims. To get an honest 38A, you should get 1900W/85% = 2235W of panels. Trust me on this. I've seen 85% out in the field with my own system.
250W high-voltage residential panels are very abundent right now. Here in the US, I can get 250V,30V panels for ~75USD right now. I'll guess they are also abundent in Europe. Nine of them would be 2250W, right in line with your power requirements. You can make three parallel strings of three panels in series (written as 3S3P). Each parallel string of panels needs a fuse or breaker, BEFORE the positive lead gets to the charge controller. I like to use a combiner box. I'm using the 6-string Midnight combiner. Each string would have a 12A DC breaker. Make absolutely sure the breaker is rated for DC. Never use a house AC breaker with DC solar panels.
The pos and neg from the combiner go into the pos and neg terminals of the charge controller. Because the voltage of each series string will be ~90V you MUST use an MPPT controller to transform the raw high-voltage solar current down to battery charging current. Do NOT use older PWM technology. MPPT costs more, but performs better. You can use thin 10AWG wire for high voltage running the power all the way from the panel location to the controller, but thick 4AWG wire from the controller to the batteries. All the brands listed above make MPPT controllers. A cheaper entry-level brand is Epever. Take a look at their Tracer 5415AN.
Keep asking questions. We are all willing to help. Keep in mind that my numbers are based in part with the need to power the house through 3 days of rainy weather. If you decide that is too conservative, then maybe stick with 24V. L-16 batteries take up a LOT of room, so four is going to be less voluminous than eight. And you also might happily get by with just six panels instead of nine. It's your house, you have to decide.
.png)
1
