It does not indicate any trouble to me. At least initially...
And different types of ammeters will read differently as well, to a certain extent. Yours is not stock, so I don't know how it's connected, but that can have an effect too.
Also effects just how safe it is!
What you're watching is that during the engine start, the starter motor takes a lot of juice to crank the engine. Depending on the starter, engine, and overall electrical system, this could be a lot, or a little. As much as 250 amps for several seconds, or as little as 50-75amps for just a flash. The more energy it takes to start, the more the battery is depleted (for lack of a better term) and the alternator is tasked to build the battery back up from farther down.
That's when you see a large amp charge on your ammeter. If your engine snapps to life with little effort, you might only see a 15-20 amp charge for a short time.
Also depends on the state of the battery. If the battery is old and tired for example, the ammeter might show a charge for a longer period of time. Or shorter, depending on the battery's ability to take that charge. Could conceivably take 15 or 20 minutes for the needle to come back down to it's normal maintain level.
On the other hand, if it's a good battery and was fully charged to begin with, you might watch the needle climb back down to near zero in less than a minute or three.
If the needle takes a long time to drop, or if it goes way up and stays there (say for example, 20a or more for extended periods of time) then that could indicate a charge system error or a battery fault.
If it only reads that high when you have accessories powered up however, it would simply indicate to me that it's wired a little differently than stock.
That's why for me an ammeter is a great window on the electrical system. I have always preferred BOTH a volt-meter and amp-meter myself. If given only one choice, I might have trouble deciding which one I like better, but would likely choose the ammeter when it came right down to it.
But a voltmeter is also a really good tool and simpler to interpret most of the time.
Whether yours should come all the way to zero, or stay up at 10a or so when some accessories are on is hard to say.
Does it go to exactly zero when everything is shut down? Where is it connected into the system?
It's probably just measuring the output of the alternator and not detecting the drain of the lights due to how the system is wired.
One thing you can double-check though, is when your ammeter reads in the positive/charge section, check the voltage of the battery. If it's 14-15 it's great. If it's 16-18 you have problems!
The blowing of the turn signal fuse could have been completely unrelated to the amount of charge.
If you still have the stock fuse panel with glass fuses, it's not a bad idea to remove the fuses, clean the contacts (and the fuses themselves) and then re-install them. This helps create a better path for the electricity to flow. It's a well known issue with old cars with glass fuses.
I do it once a year, but if you did it every three or four years you'd probably be fine. It's usually a very subtle degradation over time.
Paul
