If the battery voltage is only 12.4v maximum after a 7 hour charge, then the battery is faulty.
As Mike indicated, 12.6v is the norm for a fully charged battery, while 12.4v is a ~70% charge.
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2001 Boxster S (triple black). Sleeping easier with LN Engineering/Flat 6 IMS upgrade, low temp thermostat & underspeed pulley.
2001 MV Agusta F4.
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