charging battery via gene vs via solar

gpigeon

My off grid system consists of the following....
1. 10kW panels
2. 2 x Schneider 80 600 controllers
3. 1 Schneider XW=8548 inverter
4. 24x Energystore 2RPG1410 cells.
The system has been up and running for about 5 yrs and I have never had to run the gene until about 2 weeks ago. We are having a period of very heavy consistent cloud so some days the battery does not fully recharge. However i notice that when I use the gene to recharge the inverter shuts the charging off at a Batt V of around 54V. Then, the voltage drops quite quickly despite only having around 400W load. Whereas, when the system is charged by the charge controllers (the sun) the V goes up to about 57 and stays high for quite a while. Like yesterday for a change the sun did fully charge the battery and this morning at 0700 the Batt V was still around 51V.
The Inverter is set to 2 Stage charging while the charge controllers are set to 3 St.
I can see that when the inverter cuts the charging off at 54V the system has not gone through a full charge cycle. ie Bulk/absorption/float.
So, my question really is....should the gene charge the system to the same level as the solar? If so, what am I doing wrong.
btw...the gene is a Honda 240V with 15A outlet.