Cheapest time to charge a home battery in Southern England
When to set your home battery to charge on Octopus Agile in Southern England, for this time of year.
Tonight, to 14 per cent · about 32.4p/kWh
- At about 32.4p a kWh. In the app: a charge slot, to a target.
- Tonight 03:30–04:00: charge to 26 per cent. At about 32.8p a kWh. In the app: a charge slot, to a target.
- Tonight 04:30–05:00: charge to 40 per cent. At about 32.7p a kWh, for the house later, when buying would cost about 48.4p. In the app: a charge slot, to a target.
- Tomorrow 09:00–14:00: hold. Keep it for 2pm, when buying would cost about 39.3p – more than now. In the app: discharge off for these times.
Worth about 39p to the end of tomorrow against no battery – on prices partly estimated.
The plan, half hour by half hour
From now to the end of tomorrow
The height of each half hour is how full the battery is; its colour, what it's doing. Planned for a typical home using 2,500 kWh a year, counting 2p of wear for each kWh the battery gives back. Renewably never runs your battery: these are settings to type into your inverter's app, or data for Home Assistant.
Every day: set and forget
Charge from the grid in this slot; the rest of the day, let the battery run the house.
Weekdays
About 17.3p/kWh
Got a second slot? Top up 12:00–14:00 (about 22.9p) to replace what the house uses in the morning.
Weekends
About 14.1p/kWh
Got a second slot? Top up 12:00–14:00 (about 16.0p) to replace what the house uses in the morning.
What it saves
About 6.4 kWh a day from the battery – all the home needs, so a bigger battery wouldn't save more. Each kWh saves up to 14.3p: 19.2p to charge, after losses, against 33.5p from the grid in the evening.
About 6.4 kWh a day from the battery – all the home needs, so a bigger battery wouldn't save more. Each kWh saves up to 12.0p: 15.7p to charge, after losses, against 27.6p from the grid in the evening.
For a home using 2,500 kWh a year.
Prices through the day
Charging 01:00–05:00 and 12:00–14:00
Charging 01:00–05:00 and 12:00–14:00
How this works
The cheapest stretch before the 4pm peak in Southern England's Octopus Agile prices for this time of year, long enough to fill your battery, getting back 90 per cent of what goes in. The charge is for your home's own use. A guide to a typical day, not a forecast.
What it saves follows a typical home's use through the day, for the yearly use above: after its charge, the battery runs the house until it's empty, and each kWh saves what that half hour would have cost from the grid, less what it cost to charge. It doesn't count the battery's own wear – for most batteries a few pence for each kWh they store.
Prices from Octopus Energy's public API. Renewably isn't affiliated with Octopus Energy.