I have a 70 amp alternator in one of my cars that still has the 30-0-30 amp
gauge and it works fine. The only time you might get in trouble is if you
have a bad battery that won't hold a charge and your alternator is trying to
put out all of it's available current (70A) through a 30 amp meter. 99.9%
of the time I see the amp gauge go to 20 amps after start up and then settle
back down to just a little above 0 in a couple of minutes. Again with the
lights on it will bounce up for a second and then settle back. Rarely would
you ever really need all of the available current from the alternator unless
you are actually using a lot of current like a 1000 watt amp and six driving
lights. Mostly what you want to know is if the charging system is working
and your amp gauge will tell you that. The voltage difference between a
charged battery and a discharged battery is only about 2 volts which is hard
to see on a analog car voltmeter anyway.
----- Original Message -----
From: "Jacques Le Clainche" <email@example.com>
Sent: Monday, May 07, 2007 4:44 PM
Subject: RE: Ammeter or voltmeter?
OK.... I have an alternator fitted to my LBC. Ended up with a new Lucas
#12094, 70Amps, 14 volts. It works quite well, and now I can leave my
lights on during the day - helpful for the local SUV/Jacked up trucks who
never seem to notice me on the road! Anything to make a LBC more visible is
Just FYI... as my LBC does not have a ignition light, the engine would run
even after shutting off the ignition - seems one needs the light to have a
resistance in the alternator excitation circuit - so the electrical shop I
went to for the alternator fitted a diode to stop this happening.
Now for my question. I still have the original 30-30 ammeter fitted. Works
well enough...but... would you fit a 60-60 ammeter or a 10-15 voltmeter?
are both available from the gauge guys for $56 each (thanks Derf). Your
thoughts on that?
JLC in San diego