Quote:
Originally Posted by DanEC
Patrick - you have Smiths gauges - are you using a voltmeter?
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No. I use an ammeter.
But, I have a parallel line around the ammeter. Parallel lines in a circuit divide the current based on the respective resistances of each. So, should the ammeter, over time, create more and more resistance (which would normally present a danger), more current passes through the parallel line, instead of burning up the ammeter. The readings on the ammeter are no longer spot accurate (if they ever were), but they're reasonably close and clearly show a charge or discharge condition. What most people don't realize is that, when the engine is running, and all the electric stuff is running hard, the current
through the ammeter is still next to nothing. That's because the load sits on the same side as the alternator's feed -- and that's why your ammeter should be reading just a bit above zero. The only time it should show a higher plus reading is when the car has just been started, and the battery needs a little recharging. But once that's done, your ammeter should only be passing a few amps -- hardly any. Now, if your alternator isn't running, then all current is running through the ammeter. Big current motors can still draw a heavy load though when they come on -- that's why you may see your ammeter needle swing hard when your fan comes on but then settle back to zero.