Just wondering if anyone has any real time information on what their solar array produces. Total panels vs average production. If you know your "sun hours" please let me know that also.
Short story long:
I started a renovation and wiring a house for my kid. It's gutted and I am starting from the studs. All new electrical including new incoming/meter/disconnect and a new 200A load center/breaker panel.
The goal at the house being renovated is to put most outlets and lighting to a transfer panel and run off an inverter, solar, and batteries most of the time. Larger 120 Vac loads like microwave, toaster oven, and bathrooms would normally be on grid power (and GFCI), unless there's a grid outage. If grid is down, appliances could be could be moved to "inverter" outlets, and use them selectively (so not to overload the inverter) from battery back up.
If grid is down, HVAC (mini splits), dryer, electric range and electric hot water are also down. Those loads are too big to even consider right now.
Sun hours for solar panels in NW PA is poor. Energy storage via batteries will be a big part of the system. System will not be grid tied.
I am questioning the calculation done with an online calculator. They recommend 4.5KW (4500 watts) of solar panels based on a winter "sun hours" of 2.64 hours/day. In the last 27 days, the sun has come out 6 days. Two of the six days was only for a couple hours in the late afternoon. Essentially four days of sun in the last 27. I know solar panels generate some power even with cloud cover. (10-25%?). A friend has 12,000 watts of solar. On one of the sunny days, they generated 20.2 Kwh.
I think the 2.64 hours/day for my area is very optimistic. My AO is between Cleveland, Buffalo and Pittsburgh which are the #3,4, and 5 gloomiest places in the country.
What they recommend, I assume, is based on a "capacity factor" for my zip code. But I think they are a little low at 4500 watts of panels.
I may also need to rethink my battery back up (go to multiple commercial server rack batteries) and upgrade to 48vDC/120vAC inverter. Assuming no more than 3000 watt peak, and about 6000 watts/day.
Worst case-grid down, cold weather and on batteries:
Appliance | Quantity | Watts | Hours On per Day | Watt Hours per Day |
|---|
| Coffee Machine | 1 | 1000 | 0.2 | 200 |
| Fridge - 20 cu. ft. (AC) | 1 | 353 | 4 | 1412 |
| Microwave | 1 | 1000 | 0.3 | 300 |
| Toaster Oven | 1 | 1200 | 0.2 | 240 |
| TV - LCD | 1 | 150 | 3 | 450 |
| Freezer - Chest - 15 cu. ft. | 1 | 270 | 4 | 1080 |
| Laptop | 1 | 100 | 4 | 400 |
| Router | 1 | 7 | 24 | 168 |
| Modem | 1 | 7 | 24 | 168 |
| Smart Phone- Recharge | 1 | 6 | 10 | 60 |
| Video Game Console | 1 | 150 | 1 | 150 |
| Box Fan | 1 | 200 | 6 | 1200 |
| LED Bulb - 100 Watt Equivalent | 9 | 23 | 5 | 1035 |
| | | | |
System Calculation Results | |
|---|
| Total watt hours per day | 6863 |
| Killowatt Hours per Month: | 206 kWh |
| Peak Load: (4650 watts .....BUT selective/controlled use of electrical so not to exceed 3000 watts peak on a 3500 watt inverter when on battery power) | 4,650 watts |
| Sun Hours: | 2.64 hours/day |
| System Size: | 4.51 kW |
I am not affiliated with this company but the information is from:
If you have decided on off-grid solar, make sure you figure out the proper size for your system with Unbound Solar's off-grid solar system sizing calculator.
unboundsolar.com
