Ameter ?s

matthon said

So an ameter measures current, specifically the current passing through the ameter, and a volt meter measures the difference between two points?

3 questions:
What is the wire that the ameter is spliced into?
What 2 wires is a volt meter hooked into? (its 2 right, or 3?)
Is the downside to the ameter that you actually have current running through the interior of the car?

I have 3 SW gauges, all match, all old, and I would like to make the ameter work as long as it is safe.

Click to expand...

1: The charging wire from the stud on the back of the alternator on its path to the battery
2: The volt meter needs a keyed power source (can be from anywhere) and a ground for it to work. Then there is usually one more wire for lights
3: Yes, that and it makes the charging path longer and less effective at charging the battery. The stock setup is like this as well. Mine is modified as shown at http://www.madelectrical.com/electricaltech/amp-gauges.shtml

You might want to take a look at summit. Stewart Warner started making a lot of the old type gauges again.

The volt gauge will require almost no current and is a safe design and you won't melt it if you upgrade the alternator at a later date. It just measures the potential difference between your keyed power source and the ground. The amp gauge measures the full flow of current through whatever its connected to. If its not the main charging wire, it won't tell you anything.