in the winter we have a usage of 511 kwh a month how many panels do i need to have a zero monthly bill
I am happy to help get you an answer. It depends on where you are located. Different locations have varying amounts of solar resource available.
To give you a rough idea of how large a system you would need and the number of modules that would be required let's say that you live in sunny San Francisco.
On average, someone living here could expect to have an average of 5.4 hours of solar resource per day. To obtain a 100% offset I estimate needing a 4.1kW system. If we picked a 310 Watt module we need to have around 14 of these to achieve, or slightly exceed our goal.