Hi

I was thinking about the shore power problems and have come to the conclusion that it may not be with the Atlas system at all, it may be because the boat does not have a active power management system.

Initially you left the air conditioning on and noted that the inverters in that situation pulled about 300 amps ie about 7kw. Assuming that the shore power is a 50 amp 220 volts supply the available power is about 9kw, allowing for inefficiencies in the Atlas unit and power factor.

This means that there is about 2 kw available for battery changing at most, yet when on the generator the invertors can pull 12kw. Initially the batteries do not need charging but there are some DC loads left on like the bilge pumps. Eventually the batteries will need a charge.

The question is now how to charge the batteries without exceeding the 2kw. One could program the inverters not to charge at all and simple use the 80 amp charger though this is still close to 2kw for comfort.

The problem is compounded when the shore power fails, the inverters switch in and when the batteries gets low the generator needs to put the power back in using the inverters as chargers and as quick as possible to reduce generator running time.

This is where active power management is needed, when in Atlas mode the inverters should be programmed to charge no more than 2kw or what ever the surplus is and in generator mode a higher charge current could be programmed in.

Even when you turned off the air conditioning the need to charge the battery will arise, albeit after a longer period of time, though the surplus for charging is probably about 6kw.

I am only speculating as I haven't seen the boats wiring diagram and are not familiar with the various units involved.

Ted