A member of my family has a large number of solar panels for sale. I am talking about several; thousand. You can buy from one to whatever.
They are Siemens SP75-CPL 75 watt solar panels
The solar panels are used approx. 10 years old but have the capability of producing for another 15-30 years. New, these were a very expensive panel. These panels are available for $40.00 each, and discounts are available for larger purchases.
Call Carlos at 916-749-0600 in Loomis, California for pricing and shipping information. If you are local you can pick them up. Here is the info from our distributor regarding these Siemens panels
These units could be used in any grid-tie or off-grid system. You can use them in singles (or singles in parallel) to charge a 12V battery, in series-pairs (like they came) to charge a 24V battery, or in series strings of four to charge a 48V battery, and do all of those with an inexpensive PWM charge controller. Or you can charge a 12V, 24V, or 48V battery with up to five modules in series if using an MPPT charge controller, like the OutBack FM units or the MidNite Classic-150, with a max voltage of 150VDC (in warm climates you can likely use six in series, as long as you don’t exceed 150 VDC on the coldest morning)
Or, with a 600 VDC grid-tie inverter or 600 VDC charge controller you can use 16-22 of them in a series string, depending on your local temperatures. To figure out how many you can use in each series string, just figure out your string sizing like you normally do with a standard 60-cell 250-270W module, and add up the total number of cells that you have in series, and divide by 36 (those Siemens modules have 36 cells each). For instance, let’s say that you normally would use a string of 12 of the 255W 60-cell modules (REC for instance), what you have is 720 cells in series on each string (60 cells x 12 modules in series = 720 cells in series). If you divide 720 by 36 you get the number of Siemens modules (or any other 36-cell module) that would give you the same overall voltage, so 720 ÷ 36 = 20 Siemens modules in series.
To put it another way, each solar cell in a module is roughly 0.5V at operating voltage, so 720 in series will give you about 360VDC at Vmp.
You can also use those Siemens modules with other brands and wattages of modules as long as the cells are all the same diameter. The SP75’s have 5” cells, so only mix them with other modules in the same series string with other modules that have 5” cells. Modern 60-cell modules use 6” cells, so you can’t mix them, at least not in the same series string.
Carlos can give you more information on the panels, give him a call if you are interested. 1-916-749-0600