With no current the 50A outputs 477 on the analogue input (2.33v), the 100A outputs 509 (2.48v) and the 200A outputs 512 (2.50v). At no current they should all be at exactly mid range i.e. 512 (2.50v). The datasheet says they're factory calibrated as such. I've tested them one after the other, both with 5v from the Audrino and with a separate 5v supply. As I've tested one after the other it's not likely to be stray magnetism or VCC.
I've then put them in a circuit drawing about 9amps. Accounting for the offset of zero amps the 50A and 100A measured the increased voltage correctly. The 200A doesn't change.
Is there any other tests I can do to see if I'm doing something dumb or are they all damaged?