I'm new to this forum so apologies if I'm doing anything wrong...
I have a load of 150kWh/day (worst case), normally at 4-8kW but can go up to 16kW.
Since it's a normal building (220-240Vdc) then it's equivalent to about 680Ah.
I need to design a standalone PV system to power the load described above.
My daily radiation is about 5-6 kWh/m2/day and dalylight hours about 10-13 hours (Johannesburg).
And I made my autonomous day to be 7 days...
I run into a lot of problems when I'm trying to size the battery (according to IEEE std 1013-2007),
First of all, I'm not sure what the nominal system voltage is?
I'd imagine it being the inverter (with inbuilt MPPT) input voltage, but when I try to look up an inverter with 16kW 240Vac output, the input voltage range is 200-800V?
How do I get the input voltage so high if I don't connect the panels in series?
But if I do connect the panels in series then I need to connect the batteries in series?
With maximum depth of discharge at 75%, my unadjusted capacity is 7*680/.75=6347Ah
With 24V, 680Ah battery I need 90 of them???
That's a lot of information... but basically I'm just very confused with the nominal system voltage, because from all the examples I see they use like 24V, 48V, etc...
Is it because the load in the example has much lower power ratings?
I think I have something fundamental calculated wrong...
This is the inverter datasheet:
Thanks in advance!