Battery Sizing

[Bryan Joshua]

Hello there,

Could you please explain how PVsyst calculates stored energy (90% DOD)? When the entire number of containers is multiplied by the 2752kWhr rated capacity of the BESS I'm using, the result is 4513.28MWhr x 0.90% DOD. I also attempt to use the rated capacity on the.BTR file, but it is inconsistent.

[André Mermoud]

In PVsyst the relevant capacity parameter is th C10 value. It may be slightly different from the rated capacity, usually set for 0.2C (discharge in 5 hours) or 0.5C (discharge in 2 hours). 

In the above dialog: the stored energy is calculated from the global values just mentoned above:  9830 V * 473960 Ah * 0.9 = 4193.295 MWh.

However, in your screenshot, I can't understand the global capacity value of 473'960 Ah. The product  13'872 * 205 in parallel gives 2'843'760 Ah, i.e. as if there were 6 racks in parallel in your Battery pack. I can't reproduce this problem on my PVsyst installation. Probably there is something incoherent in the definition of your battery file. Please send it to us   (support@pvsyst.com),  in order that we can analyse this problem.