A properly wired ammeter tells if current is flowing into or out of the battery. As long as current is flowing into the battery, it is being charged. A voltmeter give you a better idea of battery condition along with indicating the charging system is working.
If you have a properly installed and sized amp gauge and wiring every thing is fine and it offer on time info. It will till you if you are producing more or less power than you are using with a volt meter you only know if the voltage keeps dropping. In most cases factory generator systems are not heavy enough
Volt meters have been around and being used in cars since before the war. I screwed a '40 chevy together in '70 granted that was after '65. The old guy I got the car from had a box full of military and SW curved gl*** gauges, volt meters in both. AMP meters came stock in cars as well as idiot lights. Hot Rodders upgraded, well the real ones did.
The problem with amp meters is if you have one that only goes to 30 amps and put an alternator in the car that has a 150 amp output you overload the amp gauge. Then fire happens. Most amp gauges were made for cars with generators, that put out a maximum of 30 amps. We update the car with an alternator and overwhelm the system.
All current flows both ways through the ammeter [except the main battery cable to starter] The ammeter usually can only handle about 35A to 40A of current [which is why they are feared and often byp***ed] This 35A is enough for normal everyday use, but the problem occurs when a 60A - 100A alternator tries to charge a car that has flattened the battery You add a "Diode Shunt" [Hybrid Shunt] that byp***es the ammeter when it is "ma**ed out" But under normal cir***stances the shunt is closed and the ammeter reads like normal. [and the Alternator is only charging enough for maintaining the battery] Also if the ammeter fails the shunt will take the current and not leave you stranded on the side of the road. A diode shunt doesn't behave like a resistor shunt [which alters the values of the ammeter]
I haven't used an ammeter since the one in my 3 gauge under dash panel started to smoke and meltdown in a pretty basic, 283 powered truck. It had an alternator of unknown output, but I was just cruising down the road at the time. I stopped on the side of the road and connected both leads to the same stud to "fix" it. Gary
Hi. First I want to apologize. My wife got tired of me tearing up the garage and always on the computer looking up ammeter. So she bought me one and now it’s in my 26. So thank you for all the advice. My wife just said buy another one and that’s what she did. Thanks Jerry
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