A blinking green LED indicates the C35 is conducting. The # of blinks is indicative of how far below the BULK setting the battery actual voltage is,
as outlined on pg.56 of the manual. You can also verify conductivity by measuring the battery terminal voltage, then measure PV terminal voltage.
The voltage should be the same. Once the LED goes solid (Float), you will read a higher voltage on the PV side (during solar day), because
the controller has essentially reduced current flow to keep from overcharging the battery.