Why does my Charge Rate Slow Down?
During charging of the battery, the EV will control how much power it draws so it can balance the cells in the battery, to charge more depleted cells and not overcharge full cells.
There is not a problem with the EVSE as the vehicle is in control of the amount of power it draws. The JuiceBox EVSE only measures & meters the amount of power being used by the vehicle.
Battery balancing can occur at the start of end of the charge.
For example Nissan LEAFs do the balancing at the end of charge, so it can take longer to fully top up the LEAF to 100%.