Strong difference between Lead-acid & LiFePO4 battery systeme output

Hi Ivan,

The Li-ion and Lead Acid battery chemistries have different performance characteristics, so I would expect to see a difference in the charge/discharge profiles between the two.

Could you attach a SAM file that demonstrates this behavior?

Best regards,
Paul.

Hi Ivan,

The difference in annual output between the two cases has something to do with the interconnection limit. You can see that on the Losses page, and also by showing the "Annual energy loss from interconnection limit (year 1) (kWh) value. If you disable the interconnection limit, the two cases have the same annual energy value.

I'm not sure exactly why that is different between the two cases, but suspect it has to do with the way SAM is dispatching the lead acid and Li-ion LPF battery. The two battery types have different charge and discharge characteristics.

If you look at the battery state of charge (SOC) on the Time Series tab, you can see for the lead acid battery that between May and June, the SOC range suddenly drops from up to 90% to less 20%. I will investigate further and let you know what I find.

Best regards,
Paul.

Hi Ivan,

We are still investigating, but did notice that the lead acid battery temperature increases suddenly between May and June, which causes the cell voltage to drop and reduces the battery's ability to fully recharge. That is probably due to the heavy cycling of the lead acid battery. The 15 kWh / 15 kW battery has one hour of storage capacity, and the manual dispatch is set to allow the battery to discharge 100% of its available capacity in a single hour, which is causing the battery to heat up, which in turn reduces its ability to hold a charge.

You might try reducing the kW rating of the battery and/or reducing the discharge percentage in the dispatch to a lower number to reduce the battery temperature.

Best regards,
Paul.