Update on this, after replacing battery terminal connections, thorough cleaning of all connections I registered a much stronger voltage, around 13.9/14V There seems to be a discrepancy between my voltmeter/usb charger and the battery itself as when I last moored, they were showing 12.2 volts and the battery was at 12.7. Regardless, all seems to be well, only shock was how much the lights brought down the voltage, but they're rarely used anyway.