Getting the wattmeter is good.

When you start your test, watch the amperage and voltage of the battery as you run up your motor. As the motor spins up you should see the amperage increase and the voltage decrease. Make sure the amperage doesn't exceed the rating of either the motor or ESC. Also, watch the voltage and see if you can determine what it is when the LVC shuts the motor down. I think the wattmeter has some sort of memory for high and low readings, but I'm not sure. I don't have a wattmeter, I use a DMM, but it has these memory readings.

Post back your findings.