Leroy Somer s801 windlass

I have this fitted to my 36CC Clipper .
Can anyone tell me the maximum amps this draws at 12v?
Also... The windlass only works when the engine runs. Can anyone explain how this is wired and which battery (engine or service) it draws from, if either.
Background to this is that I wish to fit a NASA BM1 battery monitor for the service battery bank which has a 100 amp shunt. A large draw from the windlass might prohibit this. Or could I run the windlass from the engine battery?
Regards
Totts