Hi,
my setup is 1 MPPT 100/30 charging 4 x Firefly 110AH 12V batteries. While in absorbtion mode, the voltage is not kept at the Absorption voltage, it stays under the set Abs. voltage and rises slowly. It was my understanding that Absorption step was a CV step. Am I setting the charger wrong? see pics below.
thanks 
That seems perfectly fine. The charger will only maintain the absorption voltage once the battery actually reaches that voltage. So it’s max power the panel can push, until absorption voltage has been reached. Thereafter the absorption voltage will be maintained for a period of time (CV) after which it will switch to float.
