picked up this baby from the cabulture markets on sunday for 5 bucks:thumb lets hope it works. i want it to measure the charge coming from my genny. do i just hook up the terminal marked "+B" to the feed wire from the regulator and earth the wire marked "+L"?

bump

Do not earth your ammeter. It measures current flowing between a source of supply (Generator, Alternator) and electrical items like headlamps etc. Any leftover goes to charge the battery.

If you connect one of those terminals to earth, you'll just be short circuiting the geny/alty/ whatever you have, or the battery, depends which you connect first.

The outer case of the ammeter, and the perhaps the mounting thingo, will earth to the metal dash, thereby providing a return for the single wire which goes to the small light bulb, to illuminate the ammeter at night, if it has one. But the main circuit is not earthed - no way.

It's only the voltmeter which has one terminal earthed.

You will need a heavier cable to connect up, 5 or 6 m/m diameter at least. Plus good terminals, soldered and crimped.

But why bother ? Your charging voltage should be 13.8 at least, and that's a better guide than any ammeter, full stop.