My 230Ah batteries are charged at 14.8v routinely
This has to be a grossly oversimplified description of the procedure.
Do you have a charge controller? If so, it is extremely unlikely that the charge controller is providing 14.8V to lead-acid batteries on a continuous basis. That will evolve hydrogen gas and cook them in very short order.
A float charge at 13.8 V is a common protocol, but most smart controllers embody a rather more complicated protocol.