Recharged the battery and it holds the charge well. After fully charging overnight, the volts read 12.72, a bit high but after an overnight. With the engine running the volts are reading 13.2-3 so it's charging properly. Is the Alpine head unit + the Bazooka 8" sub requiring too much juice for the oem alternator? It a Walmart battery less than 2 years old made by Johnson controls. What to do?

__________________
85 300CD Signal Red/Tan sold
83 300D Manganese Brown 109K
97 E420 Midnight Blue 197K sold
98 BMW 328i Vert White 100K, sold
95 BMW 525i White 125K, sold
93 BMW 525iT Red 193K, sold
95 E320 Green Wagon 125K, sold
94 E320 White 127K, sold
85 300SD 156K Grey (Annie), sold
84 300D Lapis Blue 170K (Judy), sold
99 ML 320 Black (lease), 1998 C230 White (lease)
00 Honda S2000 Red (lease)
86 Mercedes 300E (sold)
84 Porsche 911 Red (sold), 1965 Porsche 911 White (sold)