8 Amps from a 400w Inverter ?

[noelex 77]

Originally Posted by ArtM

So your saying that the alarm on the inverter is from the supply side voltage dropping, and not from overloading on the demand side?

Yes (usually no alarm the inverter will simply shut down when the input voltage drops too low)

Originally Posted by ArtM

And this is why the OP cannot come close to utilizing his 400W capacity, yet the fuse never blows? Because the inverter detects the voltage drop and shuts down before reaching maximum current on the input line?

Yes

Originally Posted by ArtM

Further, are you suggesting that the voltage drop is related to the current demand? That the line can provide full voltage up to a certain current, then will drop below an acceptable voltage beyond that current?

Yes, but not full voltage, there is always some voltage drop in the wire with current.
The voltage drop in the wire is roughly proportional to the current. When the voltage drop causes the input voltage to go below the minimum threshold for the inverter it will shut down. This voltage drop depends on the wire gauge, quality of the socket etc but typically a 120w output would be a maximum for an inverter wired via a cigarette lighter plug.