Battery sizing application note · Rev 1.0

Sizing the AERL Kakadu 120 with the Selectronic SP PRO SPLC1200 / SPLC1202

Pairing rule: 1 × SP PRO 120 V inverter (SPLC1200 or SPLC1202) ↔ 1 × Kakadu 120 battery cabinet. This sheet confirms that a single Kakadu 120 has the discharge-current capability to support a single SPLC1200 or SPLC1202 across all of its rated AC load periods.

Key parameters

Inverter (120 V class)

Kakadu 120 (battery)

Both inverters share the same 120 V DC class, so each sits within the Kakadu's operating window (≈112–162 V overlap) throughout discharge.

DC current draw vs. battery limit

DC current is calculated from the SP PRO AC load ratings, referred back through the inverter: I_dc = P_ac ÷ (η × V_dc)with η = 97.2 %. Two voltages are shown: nominal (140.8 V) for the typical case, and minimum (112.2 V) for the worst case near end-of-discharge, where current is highest.

SPLC1200

SPLC1202

*For the SPLC1202 only: at the simultaneous worst case of full 1-minute power and minimum battery voltage, the draw (~321 A) reaches the cabinet's 1-minute peak rating (315 A). This is a brief transient within BMS tolerance; at nominal voltage the draw is 256 A, well inside the limit. The SPLC1200 keeps margin in every cell.

Conclusion

A single Kakadu 120 cabinet correctly pairs 1:1 with either the 15 kW SPLC1200 or the 20 kW SPLC1202. For both inverters, the continuous, 60-minute and 30-minute draws sit comfortably below the 300 A continuous discharge rating, and the 1-minute surge stays at or under the cabinet's 315 A peak rating. The SPLC1200 retains headroom across the board; the larger SPLC1202 is the more demanding pairing, with its 1-minute surge matched to the battery's 1-minute peak. No battery oversizing is required for either inverter.

Notes & assumptions

• AERL Pty Ltd — Kakadu 120 (REV 004) × Selectronic SP PRO Series 2i SPLC1200 / SPLC1202 (BR0007_26).
• Currents use the inverter's peak efficiency (97.2 %). Real-world efficiency under heavy load is a few percent lower, which raises current slightly; the worst-case (112.2 V) column provides the margin to cover this.
• The 30 s / 38 kW surge rating is excluded per scope; if assessed, it falls under the Kakadu's 5 s / 400 A peak.
• Charge side: both inverters' continuous charge (SPLC1200 125 A, SPLC1202 167 A) is within the Kakadu's 200 A continuous charge limit.
• Verify the inverter's high-voltage disconnect against the Kakadu's 165 V top-of-range during commissioning (SPLC1200/1202 upper input limit is 162 V).
• Figures at 25 °C; derate per the Kakadu temperature curves outside the managed operating range.