ABP: Are there special requirements for battery backups?

Yes. All systems which include a battery shall be electrically connected in a manner that ensures that any non-solar generated electricity used to charge the battery is not later metered as solar-generated power.

This can be done in one of three ways:

 1. The meter used to report production is electrically located before the battery charger and does not measure any power drawn from the battery bank.

 2. A net meter is connected to the system that runs in reverse when any non-solar power, including on-site generator power, is used to charge the battery bank. This must be an integral part of the physical system design.

3. An inverter that can be configured using software to preclude non-solar charging of the battery bank is not sufficient if that inverter is used as the source of reporting for renewable generation.

The inverters’ software setting is configured to prevent the battery from charging via line power. This software setting may not be changed for the duration of the project’s participation in the Illinois Shines program.

Battery Schematics

If a system contains a battery backup, a battery schematic diagram must be submitted with the application via the Part II application. The diagram should contain the following:

1. Battery Backup (“BB”) DC Voltage

2. BB Configuration (AC Coupled or DC Coupled)

3. BB Conductor Size

4. PV Conductor Size

5. BB Fuse/Breaker Size

6. Inverter Contains DC/AC Disconnects

7. Inverter Output Conductor Size

8. Inverter Fuse/Breaker Size

9. BB Contains Transfer Switch or Microgrid Interconnect Device

10. BB, PV, and Standby Loads are Isolated During Grid Outage

11. AC Combiner/Load Center(s) Sized Properly

12. PV Interconnection Type (Supply, Load, or Feeder)

13. Battery Charge Method (PV (DC) or Grid)

14. Battery Discharge Method (PV (DC) or Grid)

15. Battery Output Meter

16. PV Output Meter

All meters used in the battery backup should also satisfy the metering requirements.