The cheapest hours can move: when is a timer enough, and when does price tracking help?

Set an early-morning charging schedule once and your daily routine becomes as simple as plugging in. But if the price in your contract changes by time period, today's three cheapest hours may fall somewhere else tomorrow.

That is the difference between scheduling and price tracking. A schedule repeats the pattern you set; price tracking can also respond to changing prices, while still completing the charge before departure.

First check whether the price you pay actually changes

If your energy unit price is the same at all times, moving the same number of kWh does not change that energy cost. A day or night schedule may still be convenient and suit the household routine better.

Price tracking can reduce charging energy cost only when your contract makes the time of consumption relevant. The controller must use the price you genuinely pay. Mark-ups and other charges may sit alongside the market energy price.

Use your own contract for a worked example. When an app marks a period as cheap, establish what that same period means on your bill.

Two days, the same charging task

On each day in our example, the charger must deliver 21 kWh. The car stays at home until a 06:00 departure and can charge continuously at 7 kW, so it needs three hours.

All prices below are invented solely for illustration. They are neither current Hungarian tariffs nor supplier offers.

If charging always starts at 02:00, the energy costs 840 Ft on day one and 420 Ft on day two: 1260 Ft in total.

If you choose the cheaper window each day, day one costs 525 Ft and day two still costs 420 Ft. The total is 945 Ft, a difference of 315 Ft across the two days based solely on the assumed energy charge.

What does the automation take over?

On day two, the old schedule happens to hit the cheaper period. On day one it needs changing. Price tracking can take over the daily comparison and selection of the time window.

The example does not predict monthly savings. It shows the recurring task being automated. Its value depends on how often cheap and expensive periods move, how much you need to charge and how broad a window is available.

Price information offers little flexibility when the car is home only briefly. A longer stay lets the plan draw from more periods.

The energy still has to pass through during the chosen hours

Suppose household consumption leaves only 3.5 kW for the car during those three hours. It can then receive 10.5 kWh, half the 21 kWh target, and needs more time.

Any price-led plan must also check what the available power can deliver. Load balancing and price-based scheduling are separate tasks that need to work together: the first establishes how much power is available, the second when it is worth using.

The 21 kWh is energy delivered through the charger; less may reach the battery. Plan the desired state of charge around your experience with the car.

What can you use in the Zaptec system?

Scheduled Charging in the Zaptec app lets you set a start and end time; for an unscheduled charge, select Default Charging. The manufacturer's guide explains the change step by step.

The factory Eco Mode uses Nord Pool pricing data and is available only in supported markets. That alone does not show it automatically follows the prices in your Hungarian contract. Check markets and operation in the Zaptec App description.

An external energy manager also needs its price source configured. For example, evcc can use ENTSO-E data with additional tariff components. Match the price zone and formula to your contract; see the evcc ENTSO-E documentation.

Try it with your next charge

Choose a departure time and calculate the energy needed by then. Check when the car will be home, then plan around your tariff and expected charging power.

If a fixed window serves you well, keep the simple routine. If changing prices would make you adjust it daily, you now know exactly what work price-tracking automation would take over.