I don’t know much about this, but we a 2020 2020 Kia Sedona with 36,000 miles, original battery. It had trouble starting the other day but I believed that was from an open door and light being left on. It has been driven about 2 hours since then. The 12.48v reading was right after I drove and turned car off. The morning reading was a cold 30F morning if that matters. I don’t know too much about cars so wondered it was worth replacing. Thank you
12.48 isn’t particularly good fresh from driving. Two tests that would shed more light on the issue are what voltage is the alternator putting out while running. And does the battery drop like this when disconnected.