Solar, battery and EV charging: are your schedules working together?

Start with the result you need

Three individual schedules can each look sensible and still produce an awkward result together. The car must be ready for the morning, the battery should serve the household and solar generation changes through the day. A useful review begins by deciding which requirements take priority.

Write down the car’s departure time and the charge it needs, the household’s normal pattern and any battery reserve you want to preserve. Include exceptions such as weekends or a second vehicle. Avoid designing around a perfect day that rarely happens. The controls should support ordinary life.

Compare the schedules on one page

Put the charger, inverter and any tariff-controlled charging windows on the same timeline. Include which device or service owns each schedule. If the car and battery begin charging together, that is a question to investigate, not automatically a fault. The right arrangement depends on the tariff and the equipment.

Time-of-use tariffs charge different prices at different times. Energy Saving Trust explains that their usefulness depends partly on when a household can move its consumption. A cheaper charging window is only one input; consider the whole pattern of imports and exports.

Supporting guidance: Energy Saving Trust: time-of-use tariffs

Check what actually happened

Collect a few representative days of generation, household import, battery charge and discharge, and EV charging. Use matching dates and time zones. A screenshot showing a low battery is not enough to explain why it became low: we need to see what else was happening.

One question is whether the battery is discharging while the car charges. If so, check the installation arrangement and supported controls before assuming a schedule change can prevent it. Record missing data as a limitation. Do not fill the gaps with an attractive savings estimate.

Try one documented change at a time

A proposal should state the intended change, why it might help and what evidence would confirm it. Keep a record of the previous settings and agree a way back. Some changes belong with the original installer or energy service rather than a separate automation platform.

A focused review is useful when the equipment works but the coordination is unclear. It can establish whether the next step is a schedule adjustment, better monitoring, a compatibility check or no change at all. A whole-home assessment makes more sense when the energy question is part of a wider integration project.