Amps dial.

[Pete]

Hi. I’ve got the car able to start now. I still need to get the timing and the idle tuned. Bought some tip ex for the engine timing. And need to borrow a flow thingy from a mate to balance the carbs.

But when I started it tonight. Most of the electrics are working. Just not the windows or driving lights.
The amp dial on the dash was bouncing up and down like a crazy thing. It did settle down after about 5 mins. But is it meant to do that? I stuck a voltmeter in the cig lighter and it was bounce between 14.6-15.4 volts constantly. Is that the alternator that’s dying?
I’ve posted a video of it on my Instagram blog of my car restore.

[EuropaTC]

The ammeter is normally very steady, depending on the state of the battery mine normally shows 10 amps immediately after starting which slowly drops to just over the "0" centre mark, slightly positive charge after about a minute, maybe less.

Then as I switch stuff on it will very slightly move as the alternator takes up the added charge needed for whatever is on but it never bounces between readings. Mostly you have to look hard to see it's moved off the stop, it only shows a very small charge rate.

I don't know the voltages off hand but 15+ sounds a lot, I thought the regulator in the alternators topped out at around 14v.  But it's been a while since I  last had anything to do with regulators, someone else will chip in no doubt.

I'd start checking connections. If the car has stood for a long while, you almost certainly will have some poor earth connections somewhere so that's where I'd start. Pick a circuit, follow it through to every connection and check the path to earth. I'd make a list and tick them off.

 

[jbcollier]

+1 Check and clean all the connections in the battery/alternator wiring circuits, especially grounds (engine to chassis!).  Can't comment exactly as I don't know what alternator you are running, or how it's wired.

Generally speaking, a flicking/bouncing amp needle means there is resistance in the charging "sensing" circuit.  This gives a delay to alternator's regulation of the battery voltage.  It goes a little high then a little low in rapid succession.

13.8v to 15.3 volts is the generally acceptable range.  I prefer mid-14s.