[ac29]

On gridstatus, you can see how much renewable power is being curtailed (purposefully lowering output below what could be produced): https://www.gridstatus.io/live/caiso

Its... several GW in the middle of the day recently. So, this suggests charging EVs during this time would actually allow for better utilization of available renewables.

Another metric you can look at is if the grid scale batteries are currently charging or not. If they are charging, this suggests there is excess capacity available (or at least inexpensive capacity). The hours when grid batteries are charging are probably also good hours to charge EVs.