They come on every 2.5 minutes. If there is resistance to the pump impeller turning they stay on until the resistance goes away. I put one in this Spring, but took it out because the constant pump cycling was annoying. It did keep the bilge very dry. It ran about five seconds every 2.5 minutes. Mine was an 1100 gph pump that drew 3.5 amps. Assuming the full 3.5 amp draw when the pump cycled, that works out to 2.8amp-hours per day. With float switches my two rule 1100 gph pumps run about 10 seconds every 3 hours for an amp draw of about 0.16 amp-hours per day (2 3.5 amp rated pumps). The float switch system is much more user and battery friendly. I also tried one of the water sensor Rule pumps that senses water's presence on a membrane on the side of the pump. It worked for a while then stayed on when the sensor membrane started retaining a film of water. I replaced it with a manual pump and float switch.

Incidentally,my bilge pump system has three pumps and three float switches. Two 1100 gph pumps are wired so that either of two float switches turns both pumps on. The third 8000 gph pump has an independent float switch located a bit higher. That pump will only come on if the other two pumps either don't keep up with water ingress or fail. I check all three pumps every day or two.