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| I have had both voltmeter and ammeter, one time in the same vehicle. I don't get nearly as much good information from the voltmeter as the ammeter though the voltmeter is much easier to connect. Trouble with the voltmeter is that unless its connected directly to the battery terminals and reads to the nearest 0.1 volt all it shows is that if the voltage is 13 to 14 volts that the battery would take a charge IF the battery was connected. But the voltmeter connected directly to the battery would run it down when the vehicle sits a while so its connected some where in the wiring subject to voltage drop so it never shows full alternator voltage or full battery voltage under load and shows a higher voltage while charging. And the typical automotive meter isn't that precise.
On the other hand, the ammeter shows energy actually going to or coming from the battery, showing the battery connections are good and is independent of resistive losses in the wiring. It also indirectly shows that the charging voltage is not excessive by the charging current tapering to zero after some charging time and that's based on the chemistry in the battery, not a voltmeter of dubious calibration accuracy.
The ammeter should have only one wire on its -post (negative ground), the wire to the battery post on the starter solenoid and on the typical JD 24 volt tractor that wire should be much larger with the alternator, like 8 gauge or bigger. There should be two wires on the +post of the ammeter, one to the alternator, and one to all the loads, like lights, gas gauge, radio...
Gerald J. | |
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24 volt generator / 12 volt batteries question
