http://www.xtremepowersystems.net/products.php?cat=19

The TattleTale is a tiny and lightweight device that plugs into a empty receiver channel (or through a Y-cable). This device measures the input voltage and displays the lowest voltage threshold that was captured after being powered on. With a programmable acquisition time of 10ms to 100ms, even the shortest voltage sags can be detected!


This is super small and gives alot of infromation. I have found this very helpful with my jets and planes

Clay