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Flexible loads

Solar, batteries and EV chargers need priorities, not just apps.

The more flexible devices a home has, the more often a simple rule becomes wrong. A car, a battery and a solar inverter can all want the same energy for different reasons.

Short answer: the home needs one decision layer that knows the car deadline, battery reserve, solar forecast, export value and electricity price at the same time.

The common failure

A homeowner adds solar, then a battery, then an EV charger. Each product works. The system does not. The charger may start when solar is high, but then cloud cover arrives. The battery may discharge into the car. The inverter may export when another device could have used the energy. None of these devices is broken. They are simply not coordinated.

The right questions

  • When does the car need to be ready?
  • How much reserve should the home battery keep?
  • Will tomorrow have better solar?
  • Is exporting energy valuable right now?
  • Is grid energy cheap enough to charge without regret?
  • Will charging now create a comfort or peak-load problem?

Why static rules fail

"Always charge the car from solar" sounds rational until the car is needed early, the weather turns, or the battery reserve becomes more valuable than the extra EV range. Good energy management is contextual.

GridPassport's product stance

GridPassport should make these tradeoffs visible enough to trust and automatic enough to forget. The point is not endless control. The point is a home that makes sensible decisions by default.

FAQ

Solar, battery and EV questions.

Can an EV charger drain a home battery?

Yes, depending on wiring, inverter settings and charger behavior. If the system sees the EV as ordinary home load, the battery may discharge into the car at a bad time.

Should solar surplus charge the EV or the home battery first?

It depends on the tariff, export value, battery reserve, car deadline and expected solar production. A fixed priority can be wrong on some days.

Is solar-only EV charging enough?

Solar-only charging can be useful, but it may fail when weather changes or when the car must be ready by a deadline. Good control mixes solar surplus, cheap grid windows and user needs.

Sources

References for this guide.