I have 3 smx3000rmhv2unc's and 2 of them give an error "battery bus soft start fault", according to the expert:

"I suspect that the metering of the capacitor voltage is slightly wrong on this model of UPS. We've seen this error a few times and the units have performed fine both before and after. Its to do with checking the voltage rise on the cap on power on / battery supply. I think it meters out of tolerance and throws the fault when perhaps either the centerpoint is skewed or the tolerance is too fine."