If they are flooded, one bubble a second. If they are AGM, when the charge rate drops to 0.5 amps per 100 amp-hours of capacity (at the 20 hour rate).
If the battery hits 111 F (44 C), STOP charging.
For voltage to be any sort of (accurate) guide the batteries must have no load or charge on them for 24 hours.
I found this guide at Victron today--it is worth a good read:
https://www.victronenergy.com/upload/documents/Book-Energy-Unlimited-EN.pdfKatdaddy wrote:
A few follow up questions if I may. If I understand correctly I need to charge the batteries at a higher voltage to bring them up to full charge and the proper way to test is with a hydrometer. To properly test I need to let them settle for awhile. How do I know when to take them off charge? That's where I am getting stuck here.