how fast does a 25watt solar panel generate power to a battery? trying to figure out a conversion factor here to get a rough estimate of how many i would need to power my house, please help?
how fast? what does speed have to do with? Electricity travels at close to the speed of light. A house requires kW at a minimum, and 2 to 5 kW at peaks. You can do the division, 5000/25 = 40. Plus, solar panels operate only 4 to 8 hours a day in the winter, so you need to multiply that number by about at least 6 to allow for the dark hours. .
If your house already has utility power, then your best move is usually to stay connected to the utility even when you install solar. Then, there are no batteries involved. Also, you never need to worry about not having enough power on cloudy days or at night. During the day, the solar panels drive the electric meter backwards, building up a credit with the electric company. Then at night, the meter runs forward normally. What you end up with is a very small electric bill instead of no bill, but the net cost is a lot less than using batteries. As to how large a system or how much it will cost, you would call a professional to size your system and give a quote. You can always say no if the numbers don't work out.
To figure our how many you need, take a look at your power bill. It will tell you how many kilowatt/hours you used during the month. My bill says I use about 2000 kilowatt/hours per month, or about 2000 kwh /30 days=67 kw/h hours per day. That is 67,000 watt hours. To supply that with solar panels, you have to generate at least 67,000 watt hours, but you don't have a full day to do it, since you have to do it while the sun is up. So you put the energy into batteries during the day, so you can use it at night. A 25 watt panel generates about 25 watts when fully illuminated by the sun. If you fully illuminate it for an hour, you get 25 watt hours. If you get 2 hours of sunlight a day, that would seem to imply that I need 67000 watt hours/25 watts /2 hours=45 panels. But for most of the day, the sun isn't hitting the panel fully, so it isn't going to generate the full 25 watts. When the sun is 45 degrees to the side, you only get about 70%. When the sun is 60 deg to the side, you only get 50%. And what do you do on cloudy days? And the shorter days in the winter? To make up for this, you have to increase the number of panels to make up for the loss. So in reality, I might need double this number of panels, for realiable solar power throughout the year. That works out to about 90 panels, or ,250 watts worth for my house.
Small house needs at least 0000 watts at peak power. Therefore your need 80 pieces of 25 watts solar panels.
