Jack :
I did some research last night, and my Chevy uses 12 gauge wire for a 70
amp alternator. The factory wiring on my 59 TR3A appears to be 10 gauge.
This means that the TR wires will dissipate almost 40% LESS heat than the
Chevy wires, for the same alternator output ! (In AWG wire sizes, a smaller
number means a larger wire.) The Chevy is almost 20 years old, and has had
the battery run flat and charged from the alternator many times without
apparent ill effect.
BTW, if the battery is completely dead (voltage under 4-5 volts), it may
not be possible to push start a car with an alternator. Unlike a generator
which will "self-generate" to some extent (the regulator relys on this to
tell when the engine is started), an alternator requires an external source
of field current (normally supplied by the battery through the ign switch
and idiot light) to start. If the battery is too dead to supply the field
current, the alternator cannot charge it up enough to run the ignition.
Randall
On Wednesday, February 24, 1999 6:49 PM, Randall Young
[SMTP:randallyoung@earthlink.net] wrote:
>
> Jack :
>
> I've never had any trouble with the wiring, and the first car I did would
> run for many minutes with the ammeter at full scale (after a cold start
in
> Indiana winter). With the alternator (and a big battery), my TR-3 would
> sometimes start when American cars wouldn't ! The wires that carry the
> charging current are actually pretty stout, IMO any problems are going to
> be at the connections.
>
> If you put the shunt on the back of the ammeter, as I did, you also won't
> damage the original ammeter. The excess current flows through the shunt.
> I just put 2 strands of steel baling wire from terminal to terminal on
the
> back of the ammeter, under the wires.
>
> Oh, and don't forget to convert to negative ground first ! <g>
>
> Randall
>
> On Wednesday, February 24, 1999 2:25 PM, Jack Brooks
> [SMTP:brooks@belcotech.com] wrote:
> >
> > Randall,
> >
> > I'm adding an electric fan to my TR3A and deleting the mechanical one
and
> > it's hub too, just as you have done. The electric fan I've selected p
> ulls 8
> > amps and I am hoping to keep the generator, but.... I am concerned that
I
> > will need to upgrade to an alternator.
> >
> > My reason for this post is that I am concerned about melt-down of the
> wires
> > between the alternator, battery and ammeter, but only in the case where
> the
> > battery is dead (maximum alternator output). With a dead battery and
no
> > charger, ie. the car was push started, the amperage flowing through the
> > system could (maybe?) exceed the wiring capacity which was designed for
a
> 28
> > amp generator. Have you ever experienced any wiring damage and do you
> feel
> > that I should be concerned about the higher loads in the original
wiring?
> > I'd rather not burn up an ammeter, but I'd risk it based on the price
and
> > availability of them.
> >
> > Thanks in advance,
> >
> > Jack Brooks
> > TS69032L
> > Hillsdale, NJ
> > My car show: http://pages.hotbot.com/family/triumph
> >
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