⚡ Flux Battery Strategy
Octopus Flux charge & discharge schedule — maximise savings from battery arbitrage
⏰ Flux Daily Rate Windows
Buy cheap: 02:00–05:00 (16.93p) →
Sell/avoid peak: 16:00–19:00 (39.51p import / 28.73p export) =
Spread: 22.58p
Annual Battery Benefit
£640
Peak avoidance + export
Annual Export Income
£585
Battery + excess solar
Peak Rate Spread
22.6p
Per kWh saved via battery
Usable per Cycle
15.2 kWh
16.9 kWh × 90% eff
📅 Seasonal Charge & Discharge Schedule
❄️ Winter (Nov – Feb • 120 days)
Solar: 3.5 kWh/day • Heat pump: 35 kWh/day • House: 5 kWh/day
£-2
season benefit
🔌 Charge
⚡ 18.8 kWh
Grid @ 02:00–05:00
Cost: £3.18/day
🔋 Discharge
16:00–19:00
Self-use 8 kWh
Avoid 39.51p peak rate
💷 Daily Benefit
£-0.02
Peak savings: £3.16
💡 Winter: Charge from grid 02:00–05:00. Discharge through peak 16:00–19:00 to avoid 39.51p. Minimal solar — every stored kWh saves money.
🌸 Spring (Mar – Apr • 61 days)
Solar: 23 kWh/day • Heat pump: 15 kWh/day • House: 5 kWh/day
£-15
season benefit
🔌 Charge
☀️ 3 kWh
+ ⚡ 15.4 kWh
Grid @ 02:00–05:00
Cost: £2.61/day
🔋 Discharge
16:00–19:00
Self-use 6 kWh
Avoid 39.51p peak rate
💷 Daily Benefit
£-0.24
Peak savings: £2.37
💡 Spring: Solar starts filling battery by midday. Top up from grid at 02:00–05:00 if forecast is poor. Discharge at peak.
☀️ Summer (May – Aug • 123 days)
Solar: 35 kWh/day • Heat pump: 2 kWh/day • House: 5 kWh/day
£707
season benefit
🔌 Charge
☀️ 16.9 kWh
Free from solar
Cost: £0.00/day
🔋 Discharge
16:00–19:00
Export 12.7 kWh @ 28.73p
Self-use 2.5 kWh
💷 Daily Benefit
£5.75
Peak savings: £0.99
Export: £3.65
Excess solar: £1.11
Export: £3.65
Excess solar: £1.11
💡 Summer: Battery fills from solar for free. Export as much as possible at peak 28.73p — you only need ~2.5 kWh for yourself. This is your biggest earner.
🍂 Autumn (Sep – Oct • 61 days)
Solar: 14 kWh/day • Heat pump: 18 kWh/day • House: 5 kWh/day
£-49
season benefit
🔌 Charge
⚡ 18.8 kWh
Grid @ 02:00–05:00
Cost: £3.18/day
🔋 Discharge
16:00–19:00
Self-use 6 kWh
Avoid 39.51p peak rate
💷 Daily Benefit
£-0.81
Peak savings: £2.37
💡 Autumn: Declining solar — prioritise self-consumption. Grid top-up overnight as needed. All stored energy offsets peak rates.
🌞 Summer Peak Export — The Big Earner
No heat pump running, battery charges from solar for free, then export at peak Flux rate:
| Battery usable capacity | 16.9 kWh |
| After 90% round-trip efficiency | 15.2 kWh |
| Keep for own peak usage | −2.5 kWh |
| Available to export at peak | 12.7 kWh |
| Export earnings @ 28.73p | +£3.65 |
| Self-consumption savings @ 39.51p | +£0.99 |
| Daily battery benefit | £4.64 |
Summer Season (123 days)
£707
From battery alone
Charge cost
£0
Solar charges for free
💡 Key Insight:
In summer on Flux, export your solar-charged battery at peak (28.73p) even though you pay 39.51p for the small amount you need.
The maths works because you're exporting ~12.7 kWh but only buying back ~2.5 kWh!
📋 Daily Action Plan by Season
| Season | 02:00–05:00 | 05:00–16:00 | 16:00–19:00 | 19:00–02:00 | Daily £ | Season £ |
|---|---|---|---|---|---|---|
| ❄️ Winter | ⚡ Charge 18.8 kWh | Normal use | 🔋 Discharge 8 kWh | Normal use | £-0.02 | £-2 |
| 🌸 Spring | ⚡ Charge 15.4 kWh | ☀️ Solar → Battery | 🔋 Discharge 6 kWh | Normal use | £-0.24 | £-15 |
| ☀️ Summer | — | ☀️ Solar → Battery | 📤 Export 12.7 kWh | Normal use | £5.75 | £707 |
| 🍂 Autumn | ⚡ Charge 18.8 kWh | Normal use | 🔋 Discharge 6 kWh | Normal use | £-0.81 | £-49 |
| Annual Battery Benefit | £640 | |||||
📋 Assumptions:
Duracell 18.8 kWh (16.9 kWh usable) •
90% round-trip efficiency •
1 full cycle/day •
Flux Scottish rates (Jan 2025) •
Seasonal usage estimates — will refine as real data builds up