Minnie, I asked the same thing early on and the OP said no, this is the only GFCI on this circuit.
One thing I haven't seen answered is whether the GFCI is tripping, or if it just doesn't get power. If it's tripping, then I think it's likely either a) there's a GFCI hiding somewhere on that circuit (sounds silly, but you'd be surprised how often this can happen) or b) the GFCI isn't compatible with the inverter. If it isn't getting power at all, then I agree with the suggestion above, either a) for some reason, the inverter isn't getting power when the AC is turned off, b) the inverter is broken and not outputting any power, or c) there's a problem in the wiring between the inverter and the GFCI.
In reality, even if the problem is somewhere in the power distribution system (i.e., everything up to the GFCI recepticle), a bad/incompatible GFCI will also cause problems. I'd do as suggested by others, above and make sure there is power at each step along the way from the battery to the inverter, and from the inverter to the GFCI. Just because the thing was professionally installed doesn't mean it was done properly, nor does it mean it was actually tested under battery power.
The following is from the owner's manual for the inverter:
A GFCI (ground fault circuit interrupter) is a device that deenergizes a circuit when a current to ground exceeds a specified value that is less than that required to open the circuit breaker. GFCIs are intended to protect people from electric shocks and are usually required in wet or damp locations.
Installation in recreational vehicles requires GFCI protection of certain branch circuits. Consult all applicable codes.
Compliance with UL standards requires that Xantrex test and recommend specific GFCIs for use on the output of the inverter. Table 1 lists models that have been tested and will function properly when connected to the AC output of the Freedom SW 3000.
Table 1 Tested GFCI Models
Manufacturer Model Number
Pass & Seymour 1594-W
Looking at the manual in more detail, I see that the inverter has both AC and DC inputs (see, e.g., testing step 7 on page 37
). Given the OP's description of the problem, I wouldn't be at all surprised to find out that the inverter was hooked up for the charger functions, but that the DC input wasn't hooked up.