First the facts:
I have just installed a new 13.2kW solar system and BYD battery with a Fronius Symo Inverter.
I have a Tesla Gen 3 Wall connector
(All are wired 3 Phase)
I have a Tesla Model 3
I am with OVO in Qld, who give me a 8c kWh window between midnight and 6:00 am each night, and a free charging window from 11:00 am to 2:00 pm each day.
The question:
I would like to have my EV charge off the grid at least in the free window and perhaps in the 8c window as I don’t really want to use my house battery to charge the car battery.
Is there a way to set this up?
Charge HQ can’t automatically stop your home battery from discharging whilst your EV is charging overnight. The reason is that EV charging looks like any other home load to the battery.
There are two things you can do:
a) See if you can configure the Fronius Inverter to prevent battery discharge during this period (midnight to 6am) - note that this will stop it from discharging for all other home loads also.
b) Have your EV charger circuit wired such that the home battery does not monitor it. If the EV charging load is hidden from the battery, it won’t discharge in response to it. Using this option your home battery will still cover other home energy use overnight.
More details here: EV Charging and Home Battery Interaction
The one downside of this configuration is that you lose the ability to make use of the Charge Priority Limit feature in Charge HQ.
I’m not familiar with the BYD battery so this may or may not help depending on what settings it has. I believe a power wall can be setup with a TOU mode where you tell it the cost of drawing from the grid vs discharging your battery to prevent it from supplying power at certain times of the day (ie your 8c window)
Does your BYD have any options to do something similar?
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