12v 100ah Battle Born Low Voltage Problems

My Multiplus II 12 I 3000 | 12v low battery light goes on everytome I turn it on. Explorist.Life checked the cable connections at the Hood River Van Expo in June and everything was ok. The problem continued so I ran Battle Born's diagnostic light test using my Victron smart charger. I charged the (4)100ah 12v batteries using custom settings provied by Battle Born, recorded the voltage, continued charging for 45minutes, removed the charger, and using a multimeter tested the voltage with 12v DV test light connected. The following are the results: Battery #1(new) - 14.40v, 14.40v, 11.59v, Battery #2 (new) - 14.40v, 14.40v, 9.60v, Battery #3 (lightly used) -14.40v, 14.40v, 5.49v, and Battery #4 (lightly used) - 14.40v, 14.40v, 1.76v. I had a few shorts during installation so I am not expecting the batteries to be covered by warranty.  Does anyone have a suggestion how I can recover any of the batteries? Thanks.