Solar Beginners Corner
Solar Beginners Corner
I am planning to set up 3.5kva inverter, what is the total wattage of the solar array i would be needing?
edited January 2018
This requires more thought then just the array. You also need to consider the size of your battery bank, and the charge controller. Let's do a little math to get you started. First you need to decide on a system voltage. Assuming you might actually draw 3500 watts; from a 12V bank the amperage would be 3500/12= 291 amps, which is going to start a fire. At 24V, the numbers are 146amps (still high). At 48V, your amperage drops to 3500/48=73, which is managable. So, you may need a 48 volt battery. You still need a very large battery bank to support 73 amps, because batteries don't like being discharged at greater than 10% of their capacity. Assuming L-16 batteries have 370AH of capacity, they could supply about 37amps of power without overstressing them. You'd need two 48V banks of L-16s to supply that much power, so you really need to figure how to reduce your loads.
Let's say you start out with a single bank of eight 6V L-16s. If you want to charge that bank of L-16s you need to charge at about 10% of capacity, or again, 37amps. Charging a 48V bank at 59VDC gives you 37A X 59V~2200 watts. Assuming your panels are only 80% efficient, that means 2200/0.8=2700 watts. Put together 3 arrays of three 300watt panels and you'll get 2700 watts. All the major brands like Morning Star, Midnight, and Outback make charge controllers in 40-50 amp range that you need at that power level.
Can you give us some more information about what your actual loads really are, and why you're selecting a 3.5kw inverter? We can give you better advice when we know what you're actually trying to accomplish. Getting back to the amp draw, let's say you're only needing to feed a 1000-2000 watt load. If your real loads are significantly less than 3.5kw, you could get by with a 24V system. It's all doeable, but we'll best advise you if you can provide us with more information. If you get values for other panels or other batteries, just plug in those numbers instead of the examples I've put in.
15 Renogy 300w panels, Midnight 200 CC, 8 Trojan L16 batteries, Schneider XW6848 NA inverter, AC-Delco 6000w gen.