I tried a same public charging station (provided by ChargePoint, J1772) for three times. The first time it charges at full 6.6kW, second time about 1.8kW, third time about 4.1kW. Has anyone experienced this? Is it normal?
It is likely due to cold weather, as I frequently see the same power levels (4kW on cold days, 1.4 kW on bitterly cold days). Also there is a service bulletin which may need to be applied to your car which can correct problems with intermittent charging behavior on some L2 chargers.
I think the charging also slows down as the battery gets full. The Clarity is 'in charge' of the charging rate.
The three times I used that station, I only had ~10miles on my battery. So I think it's probably not related to the battery level for the behavior I saw.
