Pos inverter...13.8 at battery, 13.5 at inverter in. F'n thing reads 13.5 now? Thing bogs hard when I put a load on it , it dropped to 11.9v in with a 15.6v/5A laptop power supply on it. Its rated for 400 watts. ...whatever. thanks.
The PCM controls the voltage output of the alt, It shouldn't go that low but if it stays higher than you are O.K. If the battery has a full charge and its not pulling any current than the PCM will not make the alt charge the battery. If it shows low voltage again turn some things on that pull current and see if the voltage drops or goes higher.
What a considered big? The inverter has screw lugs for battery hot leads for 'more than 90W' per the inverter manual. It's only pulling 60w now with bog.