The flashing lights are as GGR said, an instant reading of the voltage. It is a great tool for showing up a stalled or binding servo.With all servos at rest, it gives a reading of the actual voltage with that static load, similuar to a loaded volt meter, but with a lesser load. When you start moving the servos, the load inceases and it is is quite common for a five digital servo setup with a Futaba 1000mah 4.8 pack to show three or four lights flickering as you wiggle the siicks. If the flicker gets down so the yellow or red is coming on, it is time to recharge. It the yellow or red comes on near full, it is probably a binding servo or linkage. Unplug one at a time to see which is putting the heavy load on the battery.

Last, I bought a batch of three a couple months back. I keep them on all my planes. I installed one the other day and it was showing more battery drain than I'm used to seeing. I had one servo, a digital gyro servo that the previous owner had put on the rudder. I unplugged it and things looked more normal, but I'm still getting a red flash now and then on the bench.Ireplaced teh battery and it is the same.I think I'll plug a second, older voltwatch in and see if I'm getting the same condition shown, or if this last batch is not up to snufff.

Don