Battery State of Charge Question

Hi,
 I'm modeling my home system which has is an off-grid 19.2 kW array and 60 kWh of batteries. When I set up the configuration in SAM and run a simulation I see the batteries drain from 100% to 10% with only 3-4 kWh of load drawn. In practice I see this 3-4 kWh represent about a 5% charge reduction rather than the 90% that the model suggests. Is there something wrong in my model configuration?

Thank You!
Pat

Hi Pat,

I think this is because you set the cell nominal voltage and cell capacity to values for the battery bank, but are using the voltage discharge curve for a single cell.

In the attached file, I created a copy of your case but reset the battery inputs to the default values for a Li-ion LFP battery, and the resulting battery state of charge seems more in line with what you expect.

(You will need to select your weather file from the Location and Resource page when you open the attached .sam file because it currently points to a weather file on my computer.)

Best regards,
Paul.

Thanks Paul, this looks great now!