Battery Cycle Optimizer

Configuration

Presets:

Discharge Start

Discharge Stop Defaults to cheap window start (23:30)

Max Rate (kW)

Battery Capacity (kWh)

Reserve %

Round-trip Efficiency % PW2 ≈ 89%, PW3 ≈ 97%

Export Rate (p/kWh) SEG / Octopus Outgoing rate

Cheap Rate (p/kWh)

Battery Cost £ (for ROI) Leave 0 to hide payback section

Mode:

Strategy:

Cycles per Year: 365

365 days/yr

Net Profit / Cycle

£0.00

—

Effective Margin

0.0p

per kWh after efficiency loss

Export Revenue

£0.00

—

Charge Cost

£0.00

—

Annual Projection — 365 cycles

£0

Net Profit

£0

Export Revenue

£0

Charge Cost

0 kWh

Energy Cycled

Cycle Timeline & Battery State of Charge

Battery SOC %

SOC at 05:30

100%

Discharge / Export

Charge (cheap rate)

Battery SOC

Cycle Breakdown

Exported to grid—

Drawn from grid (charge)—

Grid draw per kWh cycled—

Effective cost per kWh cycled—

Discharge duration—

Charge duration—

Depth of discharge—

Usable capacity—

Battery state at 05:30—

How it works: Battery discharges from your chosen start time to your chosen stop time, exporting to the grid at the SEG rate (or powering your home in self-consume mode). It then recharges during the cheap window from max(discharge stop, 23:30) to 05:30. If you stop discharge before 23:30, the full 6-hour cheap window is available for charging. If you stop after 23:30, the charge window is reduced accordingly.

Round-trip efficiency accounts for energy lost in conversion. At 90% efficiency you must import ~11% more kWh than you export — so the true cost per exported kWh is cheap_rate ÷ efficiency. Powerwall 3 achieves ~97% round-trip vs Powerwall 2's ~89%.

Self-consume mode values each kWh using the peak import rate you avoid paying (often 24–29p), which is typically much better economics than exporting at the SEG rate (often 12–15p).

Depth of Discharge (DoD) strategy: Full Cycle maximises daily profit; 70% DoD and 50% DoD trade some profit for battery longevity — cycling to lower DoD can significantly extend cycle life.