After I set the end-point to 90%, the light on the RCATS-100 goes on and off with the flip of a switch on channel 5. As RCATS suggested, I'll try 75%. I hooked up my ignition battery on one end and a voltage meter on the other. The voltage meter appears to show full voltage, so it looks like it's working. I won't have a chance to run the engine to test the engine cut off until the weather warms up.