you could wire in a small voltmeter and you would have an idea of the voltage as it drops.
https://www.google.com/search?q=voltmeter+gauge&ie=utf-8&oe=utf-8
you could wire in a small voltmeter and you would have an idea of the voltage as it drops.
https://www.google.com/search?q=voltmeter+gauge&ie=utf-8&oe=utf-8