Voltage indication when ignition on reliable ?

[Rxflyer]

I was curious about the voltage indication you get when you turn the ignition key to the first position: is this a relatively accurate measurement of battery health, or simply showing that the circuit is energized ? With several batteries connected in series (or parallel, I'm not sure which) per side, I wondered what kind of indication I should show before engine start. Thanks.

[cmount1]

With an accurate gauge and good connections through out the curcuit it should read the battery voltage availabe at the battery. In otherwords if you use a volt meter to check the voltage at the battery the gauge should read the same as the meter.