A home battery can reduce grid consumption by supplying stored power to your home. If the measurement also includes the charging station, car charging simply counts as home consumption. The battery does not need to know that you prefer to save that power for the evening.
The set minimum charge limits how much energy is available for daily use. With the 2400 AC+ we set it to 10% by default; within the device settings it can be reduced to 5%. For each selected model, we confirm the reserve upon installation. That minimum is different from the extra energy that you want to save for your evening consumption.
That explains why a properly functioning installation can react differently than you expect. We first look at the measured behavior and your daily rhythm. Only then do we choose charging moments, battery reserve and power limits that match each other.
The battery sees consumption, you have a destination in mind.
Zendure describes a scheme for SolarFlow that adapts its power to the total measured household demand. If that demand increases when the charging station starts, the battery may discharge more. It follows that car charging is also compensated, as long as the charging station is included in that measurement and no separate priority rule applies.
Suppose the house without car requires 0,75 kW and the car 7,4 kW. If the home battery supplies 2,4 kW at that moment, approximately 5,75 kW of grid consumption remains. The car therefore receives energy from the battery and the grid. The battery does not have to provide full charging power to discharge quickly.
With 5 kWh of actually usable energy and a constant output of 2,4 kW, this takes approximately 2,1 hours. This is a simplified example without changing consumption, losses or reserve. It shows the difference between storage capacity in kWh and output power in kW.
First decide what needs to be ready and what you want to keep.
There is no set order that is right for every family. Anyone who is at home during the day can charge the car directly with solar power. Anyone who only arrives in the evening will need a different plan. And a car that has to leave tomorrow morning can temporarily be given priority over a desired battery reserve.
| Your goal | Agreement in the arrangement |
|---|---|
| Sufficient range upon departure | How much energy does the car need and by when? |
| Save power for the evening | What usable battery reserve does the home want to maintain? |
| Utilize solar surplus | Does the car or home battery first receive the available surplus? |
Solar charging needs a shared priority.
The Easee Equalizer measures the energy flow at the connection. If the home battery first absorbs the available solar surplus, the charging station will see little injection. In the 'surplus only' mode, the car can wait while the sun shines. That may be exactly the intention if you first want to fill the battery.
If you want to load the car first, then both schemes must support that agreement. Direct consumption of solar power avoids an additional storage and conversion step via the home battery. For example, you can give the vehicle priority during the day and later, when the vehicle has loaded sufficiently, store the remaining production.
Easee requires at least 6 A to charge: approximately 1,4 kW for one phase and on a 400 V-grid approximately 4,1 kW for three phases. An active charging schedule also remains in effect. Too little solar production or a closed charging window can therefore explain why a desired sequence does not yet result in a charging start. On 3 × 230 V without a neutral conductor, we look at compatibility and phase mode separately.
Three situations require a different approach.
On a sunny day working from home, direct charging can make sense. We let the home use its normal consumption and determine what remaining power can go to the car. The battery then stores what's left. The settings must also take clouds and the minimum charging current into account.
If you come home in the evening, a battery backup can be useful for the home. We adjust the discharge during the charging session accordingly, insofar as the selected control system supports this. The vehicle can charge at a scheduled time, with an appropriate limit for the total grid consumption. This can provide more visible grid consumption during charging and still suit your purpose better.
If you have to leave quickly unexpectedly, sufficient range may be more important. A temporary charging priority can then be useful. We agree on how you use it and how normal planning will return afterwards. A lower charging power is not a solution if the required energy does not reach the vehicle in time.
Charging priority and protection of your connection go together.
Load balancing monitors available power. It does not in itself determine how much energy your home battery should store for later. Conversely, a battery diagram should never take the charging installation beyond its safe limits. Especially on a three-phase connection, the individual phases and main fuse remain important.
Together we choose which control system determines charging times. A schedule in the car, the Easee app, an energy service and the battery app can each pursue a different objective. With a dynamic contract, we also consider the full price, conversion losses and any additional 15-minute peak. The lowest wholesale electricity price alone does not prove savings.
This also applies to the 4000 Mix AC+ and Pro. Their own AC inverter power of 4 kW can accommodate more home demand than the 2,4 kW of one 2400 AC+, but does not determine automatic charging priority. A new battery model also does not prove a smart connection to the Easee charging station; for this purpose, the specific shared control arrangement must be suitable and tested.
This way we make the cause visible.
A declining battery percentage alone does not tell enough. During a normal charging session, note the time of day, charging power, battery power, grid consumption and solar production. Compare values from the same moment; apps can update their metrics at different times. Also indicate your departure schedule and desired evening reservation.
- We check which consumers are included in the energy measurement and whether the measurement data is correct.
- We compare the active charging and battery schedules.
- We choose achievable priorities within the capabilities of your equipment.
- We monitor a new charging session and check whether reserve, charging result and grid consumption correspond to the agreement.
Short answer
Frequently asked questions
Is my home battery defective if it discharges during car charging?
That's not necessary. A battery that tries to reduce the measured grid consumption also responds to the consumption of your charging station. The energy above the set minimum charge can go to the car. We discuss the reserve and set it up upon placement; with the 2400 AC+ we use 10% as standard, with the option to reduce to 5% within the device settings. Check charging power, battery power and grid consumption at the same time to see what happens.
Does an Easee Equalizer automatically protect my battery reserve?
The Equalizer adjusts the charging current to the available capacity and can utilize solar surplus. This does not result in an automatic agreement about how much energy should remain in a separate home battery. For that reserve, we coordinate the battery control and charging planning.
Does the 'surplus only' position always solve this?
No. The charging station responds to the surplus that its measurement sees. If the home battery stores that surplus first, there may be little left for the car. The minimum charging current, phases and charging schedules also play a role. The chosen solar function must therefore match the joint charging priorities.
Do I need a larger home battery for my electric car?
A larger battery may delay draining, but will not change charging priorities. First check when your car needs to be charged, what solar surplus is available and what reserve the home needs. We then assess whether extra storage is really useful.
Assess capacity and efficiencySources