If you have five 500W panels they will produce 2500W when in Standard Test Conditions (More on STC later). Note: Watts is an instantaneous measure of
power.
Next, you have to know the Insolation number. This is the number of full-sun equivalent hours per day. A typical Insolation number is 5, but this will vary with weather and time of year. (Lower in the winter) there are various irradiance maps on the web that can give you this info for your location. It is usually listed per month.
Assuming your Insolation number is 5hr/day, you would get 5hr x 2500W = 12,500Wh/day at standard test conditions.
Note: What hours is a measure of
energy
Note: Standard test conditions assume a certain irradiance and a certain temperature as well as a few other defined parameters. Has the panel gets hotter, the production will go down. If the panels are at the wrong angle they won't get as much sun and the production will go down.
This is all to say that it is likely that any given installation would probably produce less than the number would imply. Some people see nearly 100% of the rating but it is not unusual to see 20% less.
Yes.... the traditional system sizing is based on the solar array. This made sense when we just had panels tieing directly into an inverter and then the grid. However, when you add batteries, there are a lot of other factors such as battery capacity and inverter power that become important and the array size is not necessarily a good description of the system.
The array size on a battery-based system does not typically define the inverter size. You should do an energy audit to start getting a feel of the size system you need.
To get the spreadsheet, click on the orange button at the top of this page. This sheet is intended to help you plan your system. Fill it out down to the last decimal place, look at the results..... and then make your best guess;) Notes...
diysolarforum.com
Again, the array size does not define the battery capacity. You need to do an energy audit.
Woh Partner..... you may want to slow down a bit. There is a lot to learn before things are purchased. Based on the questions, there is a good possibility the wrong equipment will be purchased.