Inverter Installation Paradigms

[Paul L]

Another approach is to have an isolation transformer than can be set to 120 to 120 or 240 to 120. When plugged into 240/50hz you could have your charger (50/60hz supporting model) charging the baterries and the inverter supplying 120/60hz to the AC circuits. When plugged into 120/60hz you use the inverters transfer switch.

[zboss]

Another question - the mastervolt inverter we are looking at recommends a 200 amp fuse. But the inverter also specifies that manage a peak power of 4000 VA - so I think I am correct in saying that equals 33 amps on the 120 side but is that not 333 amps on the DC side assuming 12 volt nominal? Am I doing that math right? If so - that 333 amps exceeds the 200 amp fuse... so???

[exMaggieDrum]

Zboss, that will work for you. This is not directed to you but just thought I would pass on a real world problem of AC that can happen. Many boats are wired to handle a maximum of 30 amps. But usually you never use 30 amps continuous. But if you do, it can result in fires as some components are not really rated for 30 amps continuous. If they are not problem.

But I helped a friend in Paradise Village, in Nuevo Vallarta, Mexico, troubleshoot the loss of AC on his boat, along with the distinct odor of burnt insulation and plastic. He was on shorepower with his Catalina 42 (as I remember). He melted his AC shorepower/genset rotary switch. His wife was using her hairdryer and since it is very humid there, she had it on for several minutes. That, combined with whatever other AC usage was going on, was too much for the switch and it overheated to destruction. Scary. He could have lost the boat and even gotten killed. Perhaps it was a loose connection on the switch that was the actual fault but I suspect the switch was just not up to the task.

Big chargers can use large amounts of AC. That is why many of them have settings to allow you to lower the max AC amps to below 30 amps (or 50), so that you still have enough AC to power other devices, and, to prevent overheating caused by continuous high amps going thru components that are just not capable of continuous duty. It pays to over spec your wiring components sometimes, and always put in wire that is capable of highest continuous current you would expect to see. E.g. 10 ga wire is commonly used for 30 amp shore power runs from the shore power inlet. But if the run is really long, that is not big enough. Any way, the hair dryer thing was scary.