Minimum charge rate with excess solar - 3 phase Wallbox

General
1

Hi, I have a 3 phase Wallbox charger, and it is set to only charge with excess solar. However it seems to stop charging even though the excess solar is still more than about 3kW? I’m with Amber and quite often the FIT is negative, so it’s annoying to be feeding in rather than charging. I’ve tried setting the minimum excess solar to 0kW and leaving blank, but it still seems to stop charging with quite high excess solar?

2

When using a 3 phase smart charger (eg Wallbox) the minimum charge rate is 4.1kW. This is a major disadvantage of 3 phase charging. See Single vs 3 phase when EV charging from Solar

3

Thanks Jay, that would explain it. Do you know why 6A is the minimum charge rate? It would seem consistent to allow 3A for example, which would mean solar charging started at just over 2kW.

4

When the charging power is controlled by the charger (as opposed to the vehicle) the minimum rate allowed by the EV charging standard is 6 amps per phase.

When the charging power is controlled by the vehicle there is no fundamental lower limit - it depends on the vehicle.

Some chargers support switching from 3 phase to single phase. Wallbox chargers do not support this, and neither does Charge HQ currently.

5

Thanks again Jay, from what I can see the standard you mention goes back to an American standard, which would mean 6A x 110V, so only a bit more than 600W. Seems a bit silly to apply the same current limit to a 3 phase 240v system, but I guess standards are like that :cry:. Are you aware of any move to make the standard more sensible in Australia?

6

I’m not aware of any proposals to reduce the minimum charge rate of EV charging, as controlled by the EVSE. The best option is to switch to single phase charging when required if possible.