Why do we still need ammeters? I just received my private pilot's certificate 2 weeks ago, yay! Earlier today, a fellow at work who has 700ish hours walked in and asked my office-mate-electrical-engineer &quot;why do we still need ammeters, cars did away with them years ago, voltmeters seem mostly enough.&quot; He happens to be nearly done building his RV-14a. Office mate and I were at a loss for making a compelling argument for why aircraft still use ammeters. Is it just for redundancy's sake?
Congrats on earning your wings!
Because ammeters measure the flow of current (positive or negative) they can immediately show when the alternator is no longer providing power and the battery is discharging instead. In a voltmeter, like most modern automobiles have, you would have to wait to see the charge level on the battery drop, and by that point, several minutes (or longer) may have passed. In an aircraft, where it may be important to quickly shutdown electrical devices and conserve battery power, every moment counts and the ability to see flow shift from positive to negative is very helpful.