26/11/2024
At last. A V2X bidirectional charging station is now available fore sale in Australia. Now we just need the cars.
The Sigen Energy EV DC 25 kW bidirectional charging station is approved for bidirectional charging in Australia when used with the Sigen Energy controller/inverter. The Sigen Energy inverter is certified to AS/NZS 4777.2 and CEC approved.
AS/NZS 4777.1 and AS/NZS 4777.2 are inverter standards. AS/NZS 4777.1:2024 specifies the safety and installation requirements for connecting inverters to the grid in situations where the inverter may export energy to the grid. AS/NZS 4777.2:2020 specifies the hardware, functionality, testing and compliance requirements for inverters that connect energy sources and energy storage systems to the grid.
Bi-directional DC EV charging stations that work with an external inverter are outside the scope of AS/NZS 4777.2. It is the inverter that needs to be certified to AS/NZS 4777.2 and installed to AS/NZS 4777.1. The Sigen Energy inverter is mounted on the wall beside the EV DC. The inverter sits on the grid side of the charging station and is grid aware. Car batteries work like a home battery when used for vehicle to home charging with a bidirectional DC charging station connected to an external inverter.
Bidirectional charging stations with integrated inverters, which is the case with a small number of DC V2H charging solutions like the Wallbox Quasar, need to be certified to AS/NZS 4777.2 and be compliant with AS/NZS 4777.1. In this case the DC charging station with the integrated inverter is grid aware so the charging station needs to be certified in it's own right because the inverter is part of the charging station.
Bidirectional DC charging stations that use external inverters are a better option than bidirectional charging stations with integrated inverters because the external inverter can be connected to a home battery giving the householder the option of using the car battery or the home battery or both to power the house. There will be times when the car is not available to power the house, the car might be sold or the new car might have no bidirectional charging capability.
A car battery connected via a bidirectional charging station can provide power for energy arbitrage when the home battery is fully utilised. Most houses with home batteries and solar cannot take advantage of wholesale power rates and energy arbitrage because the battery is needed to power the house during the evening peak period when energy prices spike. Only homes with oversized battery installations can power the house and export to the grid at the same time during the evening peak. Exceptions are homes where nobody is at home during the evening and those occasions when power prices spike outside of the evening peak such as very hot weekends when the air conditioning in the suburbs is running all day.
