Home-made wallbox working with Domoticz to charge the electric vehicle

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The following schematic shows how to connect the Creasol DomBusEVSE module with contactor, protection and energy meter making a smart wallbox that charge the electric car using only solar energy or adding energy from electrical grid.

The EVSE module works good with Domoticz by using the Creasol DomBus plugin available at https://github.com/CreasolTech/CreasolDomBus: connection between Domoticz and DomBusEVSE is made by RS485 cable (alarm cable with 4 wires, 2 for 13.6V power supply and 2 for data) and a cheap RS485/USB adapter.

This video shows the homemade EV charging station working with Domoticz: https://www.youtube.com/watch?v=m_n_A4lo9Gw
Domoticz graphs are really useful.

dombusevse_wallbox_domoticz_schematic.png (321.8 KiB) Viewed 6891 times

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This is the connection diagram to make a three-phase wallbox.
The energy meters are optional, because usually you already have the energy meter connected to your system: in this case it's sufficient a simple script to send the actual power from the existing W1 meter to the EVSE module, and you just need the EVSE module, 4P 25A contactor, RCCB protection and EV cable.

creDomBusEVSE_blockAll_3p.png (365.7 KiB) Viewed 6773 times

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Here is my wallbox 230V single-phase connected to the vehicle, charging with only solar power and then solar+5500W (max 32A, 6800W in case of my car).
In this video the house power consumption changes quickly, so you can see that available power from solar (PV power - house usage) was 1600W, then 3800W.

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In the next video it shown Domoticz + my car and my homemade wallbox.
At 2m 46s you can see how wallbox manages power from grid: 50% 100% and Solar (no power from grid: use only solar energy)

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DomBusEVSE module can be programmed to use the maximum power from the grid.
For example, in Italy, who has 5kW contractual power can drain +10% forever (5500W), and +27% (6350W) with 50% duty cycle max.
As charging efficiency normally increases with higher AC power, it's better to charge at full power, using all available power (preventing disconnections, of course) in case of low contractual power (5kW or less).
In this case, the following parameters were set:
EVMAXPOWER=5500 (5.5kW)
EVMAXPOWERTIME=1200 (20 minutes)
EVMAXPOWER2=6350 (6.3kW)
EVMAXPOWERTIME2=1200 (20 minutes)

creDomBusEVSE_charging100.png (152.44 KiB) Viewed 6550 times

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Video that shows the energy dashboard while charging my Kia vehicle using the home-made wallbox:
https://youtu.be/oqZRXPkAryM

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Tired to see solar inverter not producing the 100% of energy due to overvoltage protection/derating?

DomBusEVSE module has a nice feature (EVMinVoltage parameter) that can be used

* to prevent solar inverter derating, even when the EV car is almost full, by charging the minimum power needed to keep voltage below 253V

* to prevent undervoltage on bad grid connections, by reducing charging power to not go below 207V (or similar configurable voltage)

Setting EVMinVoltage to 248V, for example, EV charging starts only when voltage raise above 251V (+3V), then charging power to the vehicle is limited to the minimum power to keep 248V: this is good when the EV battery is almost full, but you still have several hours of sun to profit, while "solar charging" fills the battery too fast.

Check the video at https://youtu.be/LpuATd5c9EA

For more info, www.creasol.it/EVSE

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DomBusEVSE module, as like as other DomBus modules, can be connected by wire, or by WiFi/RF in these ways:

More info at https://www.creasol.it/DomBusRadioLink